Professor Clare Rusbridge

Professor in Veterinary Neurology
+44 (0)1483 682322
01 VSM 02
Thursday and Friday

Academic and research departments

School of Veterinary Medicine.


Areas of specialism

Veterinary Neurology and Neurosurgery ; Cerebrospinal fluid disorders; Maladaptive pain; Inherited neurological disorders ; Epilepsy

Affiliations and memberships

The Dog Breeding Reform Group (DBRG)
The DBRG promote humane behaviour towards animals by providing and supporting initiatives to improve dog welfare related to: a) genetic and breed related health, breeding, rearing and selling practices; and b) to inform the general public about irresponsible dog breeding in order to make them aware of the potential impact on their dogs' health and welfare. DBRG was the CEVA Charity team of the Year 2018.
The Advisory Council for Welfare Breeding Pedigree Dogs
The role of the Council was to encourage and facilitate significant improvements in the welfare issues associated with dog breeding by providing independent, expert advice to governments and other stakeholders. Clare was appointed to this panel in 2010, from its inception until it retired in 2014.
Scrutineer British Veterinary Association/Kennel Club CMSM MRI screening scheme
Clare played a pivotal role in establishing this scheme and has been a scrutineer since its inception.
International Veterinary Epilepsy Task Force
Clare is part of a multicentre task force, firstly to suggest consensus statements and provide definitions for canine and feline epilepsy, and secondly to advance the field by doing collaborative research and exchanging ideas.
British Syringomyelia Group
Clare is a member of a group of neurosurgeons involved in the treatment of syringomyelia and has been awarded Honorary Friendship of the Ann Conroy Trust.
Phyllis Croft Foundation for Canine Epilepsy
Clare is the veterinary advisory for this charity.


In the media

 BBC TV series – 24/7 Pet Hospital (10 part series) Expect drama, emotion and plenty of heart-warming moments as the TV cameras follow the work of our close knit team who devote their lives to saving animals 24 hours a day, seven days a week. With behind the scenes access to our operating theatres, prep rooms and wards, where access for owners isn’t normally possible, you’ll witness specialists at work as they tackle whatever comes their way in this new 10-part series. Viewers will get to know the team here at Wear Referrals which, by day, is a specialist care unit treating animals with complex needs and conditions and by night transforms into an A&E unit responding to emergency cases from across the area. The job always throws up surprises and our team deal with anything from performing hip replacement surgery on tiny Shih Tzus and extracting corn on the cobs from Boxer dogs to treating suspected kidney tumours on much-loved Labradors, wild owls injured by cars – and everything in between. The series also follows the devoted pet owners who travel from far and wide with their beloved animals to get them specialist treatment and expert care. 24/7 Pet Hospital has been produced for BBC One by Twenty Six 03, the Gateshead-based production company behind BBC Three series Angels of the North. Commissioned by BBC Daytime and BBC England. To watch the show on iPlayer follow this link:
Veterinary Neurologist
24/7 Pet Hospital


Research interests

Research projects

Start date: September 2021

End date: September 2023

Scientific journals

Clare is a regular reviewer of scientific articles for BMC Veterinary,  Veterinary Comparative Orthopedics and Traumatology, Journal of Small Animal Practice, Veterinary Record, Veterinary Radiology and Ultrasound, American Journal of Veterinary Research, Journal of Veterinary Internal Medicine and occasionally other journals including Plos One and Nature.


Postgraduate research supervision

Postgraduate research supervision


Sarah Butterfield, Danielle Whittaker, Joana Tabanez, Jordina Caldero Carrete, Clare Pitchford, Charles R. J. Mattias, Abbe Crawford, Clare Rusbridge (2023)Bacterial meningitis secondary to otogenic infection in 10 French bulldogs: A retrospective case series, In: Veterinary record open10(1)e263 Wiley

BackgroundThere is limited published information to guide the clinical management of bacterial meningitis/encephalitis in dogs. MethodsThis was a retrospective case series comprising 10 French bulldogs from two referral centres. The cases were diagnosed with bacterial meningitis/encephalitis suspected secondary to otogenic infection based on detection of abnormal fluid/soft tissue opacity within the middle/inner ear, associated meningeal/intracranial involvement through MRI, the findings of cerebro-spinal fluid (CSF) analysis suggestive of sepsis and/or clinical improvement following antibiosis. ResultsTen dogs were included (three female and seven male), with a median age of 60 months. Dogs presented with acute onset (median 2 days), progressive history of vestibular signs and/or intra-oral or cervical pain. Five dogs had gross signs of concurrent otitis externa. Common MRI findings included material within the tympanic bulla with adjacent meningeal enhancement. Analysis of CSF documented pleocytosis in all eight dogs, intracellular bacteria seen in three with positive bacteriological culture in two dogs. One dog was euthanised following diagnosis. Nine remaining dogs received antimicrobial therapy and six underwent surgical management. Three dogs treated surgically were neurologically normal within 2 weeks and the remaining three improved. Two dogs treated medically improved and one had complete resolution reported within a 4-week follow-up period. Study limitations include its retrospective nature and small sample size with minimal longer term follow-up. ConclusionsBacterial meningitis/encephalitis in French bulldogs can require both medical and surgical treatment to achieve a favourable outcome.

Sergio A Gomes, Laurent S Garosi, Sebastien Behr, Cristina Toni, Joana Tabanez, Clare Rusbridge, Mike Targett, Mark Lowrie (2021)Clinical features, treatment and outcome of discospondylitis in cats, In: Journal of Feline Medicine and Surgery SAGE Publications

Objectives There is a paucity of information on feline discospondylitis. This study aimed to describe the signalment, clinical and laboratory findings, aetiological agents, treatment and outcome in cats affected by discospondylitis. Methods This was a retrospective review of the medical records of cats diagnosed with discospondylitis at four referral institutions. Results A total of 17 cats were identified. Most were domestic shorthair cats (76.5%) and male (58.8%), with a median age of 9 years (range 0.9–14) and a median duration of clinical signs of 3 weeks (range 0.3–16). All cats presented with spinal hyperaesthesia; 3/17 had pyrexia. Neurological dysfunction was found in 64.7% of cats, which was indicative of a T3–L3 or L4–S2 spinal segment, associated nerve root or associated nerve neurolocalisation. Haematology, serum biochemistry and urinalysis revealed occasional inconsistent non-specific changes. All cats underwent urine culture; 9/17 cats also had a distinct tissue cultured. Positive bacterial cultures were obtained in two cats (11.8%) for Staphylococcus species (urine, blood and intradiscal fine-needle aspirate) and Escherichia coli (urine); both presented with multifocal discospondylitis. Treatment was non-surgical in all cats, with sustained antibiotic therapy for a median of 3 months (range 1–9). Analgesia provided included non-steroidal anti-inflammatory drugs, alone or in combination with gabapentin. Restricted exercise was advised for a minimum of 4 weeks. Outcome information available in 12 cats was excellent in terms of pain control and neurological function in 10 cats (83.3%) at the time of stopping antibiotics. Recurrence occurred in one case, which had received a single antibiotic for 6 weeks, and relapsed 4 months after presentation. One other case failed to improve and was euthanased during the course of hospitalisation. Conclusions and relevance Feline discospondylitis is uncommon and no obvious signalment predisposition was found in this study. Spinal hyperaesthesia was universally present, with neurological dysfunction also highly prevalent. Bacterial culture was unrewarding in most cases. Amoxicillin–clavulanic acid or cephalosporins are reasonable choices for first-line antibiotics. Prognosis was favourable, with no long-term evidence of recurrence in cats on sustained antibiotic therapy, for a mean duration of 3 months.

Jordina Caldero Carrete, Joana Tabanez, Alexander Civello, Clare Rusbridge (2023)Vertebral giant cell tumour of bone in a domestic shorthair cat, In: JOURNAL OF FELINE MEDICINE AND SURGERY OPEN REPORTS9(1) Sage

Case summary A 10-year-old male neutered domestic shorthair cat was presented with a 5-month history of progressive non-ambulatory paraparesis. Initial vertebral column radiographs revealed an L2-L3 expansile osteolytic lesion. Spinal MRI showed a well-demarcated, compressive expansile extradural mass lesion affecting the caudal lamina, caudal articular processes and right pedicle of the second lumbar vertebra. The mass was hypointense/isointense on T2-weighted images, isointense on T1-weighted images and had mild homogeneous contrast enhancement after gadolinium administration. MRI of the remaining neuroaxis and CT of the neck, thorax and abdomen with ioversol contrast revealed no additional neoplastic foci. The lesion was removed by en bloc resection via a dorsal L2-L3 laminectomy, including the articular process joints and pedicles. Vertebral stabilisation was performed with titanium screws placed within L1, L2, L3 and L4 pedicles with polymethylmethacrylate cement embedding. Histopathology revealed an osteoproductive neoplasm composed of spindle and multinucleated giant cells without detectable cellular atypia or mitotic activity. On immunohistochemical evaluation, osterix, ionised calcium-binding adaptor molecule 1 and vimentin labelling were observed. Based on the clinical and histological features, a giant cell tumour of bone was considered most likely. Follow-up at 3 and 24 weeks postoperatively demonstrated significant neurological improvement. Postoperative full-body CT at 6 months showed instability of the stabilisation construct but absence of local recurrence or metastasis.Relevance and novel information This is the first reported case of a giant cell tumour of bone in the vertebra of a cat. We present the imaging findings, surgical treatment, histopathology, immunohistochemistry and outcome of this rare neoplasm.

Emma Foster, Natalie West, Sarah Butterfield, Clare Rusbridge, Abbe Crawford (2023)Respiratory compromise in French bulldogs presented with intervertebral disc extrusion, In: Veterinary recordpp. e3603-e3603

Abstract Background French bulldogs hospitalised for the management of intervertebral disc extrusion (IVDE) are frequently affected by respiratory compromise, typically brachycephalic‐associated upper respiratory obstruction and/or aspiration events. We evaluated the occurrence of such respiratory compromise events in French bulldogs presented to two referral hospitals. Methods Clinical data for French bulldogs diagnosed with IVDE were retrospectively collated, including severity of neurological deficits, neuroanatomical localisation, diagnosis, details of respiratory compromise, treatment and outcome. Results A total of 306 dogs diagnosed with IVDE were included. Sixty dogs (19.6%) experienced respiratory compromise, of which 31 dogs (10.1%) progressed to cyanosis, collapse or respiratory arrest. Limitations The study was limited by its retrospective nature. Furthermore, the duration of hospitalisation was not evaluated and the decision for euthanasia was often multifactorial. Conclusion One in five French bulldogs presented with IVDE experienced respiratory compromise. The detrimental welfare effects of this warrant further discussion.

Lord Trees, Marisa Heath, Vanessa Barnes, Helena Howe, Dan O'Neill, Rowena Packer, Mike Radford, Paula Sparks, Natalie Harney, Clare Rusbridge, Stephanie Young, Sean Wensley, Fiona Cooke, Michael Webb, Emma Milne, Hannah Molloy, Marc Abrahams (2023)Strengthening legislation around dog breeding, In: Veterinary record193(3)pp. 116-117
Carina Rotter, Clare Rusbridge, Noel Fitzpatrick (2021)Occipitoatlantoaxial Malformation in a Dog Treated with a Custom-Made Implant, In: VCOT Open3(2)pp. e170-e176 Georg Thieme Verlag KG

Background Occipitoatlantoaxial malformation (OAAM) is reported rarely in dogs and few treatment options are described. The congenital condition is thought to be associated with a proatlas re-segmentation failure resulting in malformation and malalignment of the craniovertebral junction which can result in C1 to 5 myelopathic signs. Methods Customized three-dimensional printed locking plate with trajectory screw implantation points for the stabilization of the atlantoaxial joint in a dog with OAAM. The dog was evaluated at time points 0, 2, 6 and 9 months to determine clinical outcome, degree of fusion, implant positioning and subsidence. Results New bone formation was noted 9 months after surgery, but complete fusion remained absent, although no implant failure occurred. Clinically, the dog made a good recovery and was able to exercise normally 9 months after surgery. The only residual deficit was a subtle left-sided cervical torticollis. Clinical Significance This report illustrates a management option and outcome of a dog treated with OAAM. Collaboration between clinicians and engineers provides a new dimension of care for patients with vertebral malformations.

Fraje Watson, A Augusto Coppi, Holger A Volk, Rowena M A Packer, Anna Tauro, Clare Rusbridge (2021)Comparison of volume of the forebrain, subarachnoid space and lateral ventricles between dogs with idiopathic epilepsy and controls using a stereological approach: Cavalieri's principle, In: Canine medicine and genetics8(3) BMC

Canine idiopathic epilepsy (IE) is the most common chronic neurological brain disease in dogs, yet it can only be diagnosed by exclusion of all other potential causes. In people, epilepsy has been associated with a reduction in brain volume. The objective was to estimate the volume of the forebrain (FB), subarachnoid space (SAS) and lateral ventricles (LV) in dogs with IE compared to controls using Cavalieri's principle. MRI scans of case and control dogs were identified from two neurology referral hospital databases. Eight breeds with increased odds of having IE were included: Golden Retriever, Labrador Retriever, Cocker Spaniel, Border terrier, German Shepherd dog, Parson Jack Russell terrier, Boxer, and Border Collie. Five dogs of each breed with IE and up to five controls were systematically and uniformly randomly sampled (SURS). The volume of the FB, SAS and LV were estimated from MRI scans by one blinded observer using Cavalieri's principle. One hundred-two dogs were identified; 56 were diagnosed with IE and 46 were controls. There was no statistically significant difference in FB, SAS and LV volume between dogs with IE and controls. Dogs with a history of status epilepticus had significantly larger FB than those without (p = 0.05). There was a border-line trend for LV volume to increase with increasing length of seizure history in the IE group (p = 0.055). The volumes of the FB, SAS and LV are not different between dogs with IE and controls, so IE remains a diagnosis of exclusion with no specific neuroanatomical biomarkers identified. This is the first time FB and SAS volume has been compared in dogs with IE. Unfortunately, we have shown that the results reporting significantly larger FBs in dogs with status epilepticus and LV volume increase with length of seizure history were likely confounded by breed and should be interpreted cautiously. Whilst these associations are interesting and clinically relevant, further investigation with breed-specific or larger, breed-diverse populations are required to permit strong conclusions. The Cavalieri principle provided an effective estimation of FB, SAS and LV volumes on MRI, but may be too time-intensive for use in clinical practice.

C Rusbridge (2014)Veterinary Aspects, In: G Flint, C Rusbridge (eds.), Syringomyelia: A Disorder of CSF Circulation(14)pp. 209-230 Springer-Verlag Berlin Heidelberg

Syringomyelia is an increasingly common diagnosis in veterinary medicine, especially in toy breed dogs where selections for small size and brachycephalic head shape are contributing factors. The most common cause is a condition analogous to Chiari I malformation in humans. This chapter details the pathophysiology, clinical signs, medical and surgical management, progression and prognosis of the canine condition. As a naturally occurring model of both syringomyelia and central neuropathic pain, observations that may have relevance to understanding of the pathophysiology of Chiari malformation and syringomyelia in humans are discussed. Finally, current knowledge of genetic factors and breeding advice is reviewed.

JK Hesselink, C Rusbridge (2014)Pain Management, In: G Flint, C Rusbridge (eds.), Syringomyelia: A Disorder of CSF Circulation(16)pp. 237-259 Springer-Verlag Berlin Heidelberg

In this chapter, our current understanding of the mechanisms causing neuropathic pain and the nonsurgical therapy of syringomyelia are reviewed. Traditional pharmacological therapies such as tricyclic antidepressants, serotonin antagonist and reuptake inhibitors, antiepileptic drugs, opioids and NMDA receptor antagonists are detained, together with novel drug therapies such as cannabis, endocannabinoids and naltrexone. Management strategies for central neuropathic pain are suggested, including combination therapy, topical analgesics and intrathecal infusions. Limitations of therapy are discussed, together with likely future directions for treatment. Non-pharmacological treatments, such as acupuncture, complementary medicine, cognitive therapy and neurostimulation, are also considered.

SP Knowler, AK McFadyen, C Freeman, M Kent, SR Platt, Z Kibar, Clare Rusbridge (2014)Quantitative Analysis of Chiari-Like Malformation and Syringomyelia in the Griffon Bruxellois Dog, In: PLoS ONE9(2)e88120 Public Library of Science

This study aimed to develop a system of quantitative analysis of canine Chiari-like malformation and syringomyelia on variable quality MRI. We made a series of measurements from magnetic resonance DICOM images from Griffon Bruxellois dogs with and without Chiari-like malformation and syringomyelia and identified several significant variables. We found that in the Griffon Bruxellois dog, Chiari-like malformation is characterized by an apparent shortening of the entire cranial base and possibly by increased proximity of the atlas to the occiput. As a compensatory change, there appears to be an increased height of the rostral cranial cavity with lengthening of the dorsal cranial vault and considerable reorganization of the brain parenchyma including ventral deviation of the olfactory bulbs and rostral invagination of the cerebellum under the occipital lobes.

Clare Rusbridge (2021)Neurobehavioral Disorders: The Corticolimbic System in Health and Disease, In: Veterinary Clinics of North America: Small Animal Practice50(5)pp. 1157-1181 Elsevier

The corticolimbic system (Fig. 1) integrates emotion with cognition and produces a behavioral output that must be flexible based on the environmental circumstances.1 The corticolimbic system circuitry of the prefrontal cortex, amygdala, and hippocampus is connected to the hypopituitary-pituitary axis, and environmental circumstances such as stress and anxiety input decision making, emotion regulation, and memory.1 The corticolimbic system is also the modulator for acute pain, a mediator for chronic pain, and critical for the chronification of pain.2 There is a high comorbidity of negative affective disorders with chronic pain and vice versa, hypothesized because of similar changes in neuroplasticity and overlapping neurobiological mechanisms.3 This article discusses 3 feline disorders that affect or are affected by the corticolimbic systems: the maladaptive pain disorder feline orofacial pain syndrome (FOPS) in which disease expression is influenced by environmental stress; feline hyperesthesia syndrome (FHS) in which there is still debate as to whether this is a primary neurobehavioral disorder or a behavioral response to a negative affective state; and limbic encephalitis, an autoimmune encephalitis that results in neurobehavioral signs and seizures. There is a focus on diagnosis and management, which is challenging in all 3 diseases.

TJ Mitchell, SP Knowler, H van den Berg, J Sykes, Clare Rusbridge (2014)Syringomyelia: determining risk and protective factors in the conformation of the Cavalier King Charles Spaniel dog., In: Canine Genet Epidemiol1 BioMed Central

BACKGROUND: Syringomyelia (SM) is a painful neurological condition, prevalent in brachycephalic toy breeds including the Cavalier King Charles Spaniel (CKCS). In these breeds, SM is typically secondary to Chiari-like Malformation (CM). There has been much debate in the scientific and veterinary communities to what extent head shape is indicative of either pathology, especially as certain craniosynostosis syndromes in humans (highly associated with CM) have characteristic facial and cranial morphologies. Elucidating a risk morphology would allow for selection away from these traits and proffer further breeding guidelines for the condition. Dogs were measured in multiple countries by means of a standardised bony landmark measuring protocol and photo analysis by blinded, trained researchers. RESULTS: The results found two significant risk factors in the conformation of the CKCS: extent of brachycephaly and distribution of cranium. The study identified a greater amount of cranium distributed caudally (relative to the amount distributed rostrally) to be significantly protective against syrinx development at the levels of three years of age, five years of age and when comparing a sample of SM clear individuals over the age of five to those affected younger than three years of age. A decreased cephalic index (decreasing brachycephaly) was significantly protective at the latter level. Cephalic index and caudal cranium distribution exhibited a negative, linear relationship. Cephalic index demonstrated a positive linear relationship with the amount of doming of the head. CONCLUSIONS: This study proposes a risk phenotype of brachycephaly with resulting rostrocaudal doming that is more rostrally distributed and hence sloping caudally. The results of this study may allow for selection against risk aspects of conformation in the CKCS in combination with the British Veterinary Association/Kennel Club CM/SM scheme to enable reduction in CM/SM incidence. Further research comparing this external risk phenotype to the internal presentation upon MRI would determine how these features are indicative of syrinx development. Utilising breeds in which CM free individuals are more available may allow for validation of this risk phenotype for CM or determine alternatives.

A Lujan Feliu-Pascual, GD Shelton, MP Targett, SN Long, EJ Comerford, C McMillan, D Davies, C Rusbridge, D Mellor, KC Chang, TJ Anderson (2006)Erratum: Inherited myopathy of great Danes (Journal of Small Animal Practice (2006) 47, (249-254)), In: Journal of Small Animal Practice47(6)pp. 355-?
Fraje Watson, Rowena Mary Anne Packer, Clare Rusbridge, Holger Andreas Volk (2019)Behavioural changes in dogs with idiopathic epilepsy, In: Veterinary Record186(3)pp. 93-93 BMJ Publishing Group

Background: Breed-specific and broader cohort studies have shown behavioural changes in dogs following the onset of idiopathic epilepsy (IE). Methods: A cross-sectional, case–control questionnaire study was carried out to strengthen this body of evidence. Owners of eight breeds of dog completed an online questionnaire about their dogs’ behaviour; once for control dogs and twice for dogs with IE, for both pre-IE and post-IE onset behaviour. Results: Ninety-six (24.74 per cent) dogs with IE and 292 (75.26 per cent) age and breed-matched control dogs met the inclusion criteria. Control dogs had significantly higher ‘Trainability’ scores than dogs with IE (P=0.04). After IE, dogs had significantly higher ‘Dog-Directed Fear or Aggression’ (P=0.02), ‘Non-Social Fear’ (P=0.01), ‘Attachment/Attention-Seeking Behaviour’ (P=0.04), ‘Attention-Deficit’ (P=0.02) and significantly lower ‘Trainability’ (P=0.02) than prior to the onset of IE. Medication status did not significantly affect any behavioural factor, but drug-resistant dogs had significantly less ‘Trainability’ than drug-responsive (P=0.04) and partially drug-responsive dogs (P=0.03). Conclusion: Behavioural differences related to cognitive function are seen between dogs with IE and controls. Behavioural changes related to anxiety, attention and cognition are seen in dogs following the onset of IE. The ability to clinically define and diagnose behavioural comorbidities in dogs is much needed from both a clinical and research perspective.

Matthew Green, Mark Lowrie, Clare Rusbridge (2022)Myoclonus in Cavalier King Charles spaniels, In: Veterinary record191(6)pp. 260-260 Wiley
C Rusbridge, H Carruthers, MP Dubé, M Holmes, ND Jeffery (2007)Syringomyelia in cavalier King Charles spaniels: the relationship between syrinx dimensions and pain., In: J Small Anim Pract48(8)pp. 432-436

OBJECTIVES: This study was designed to test the hypothesis that pain associated with syringomyelia in dogs is dependent upon size and involvement of the dorsal part of the spinal cord. METHODS: Masked observers determined syrinx dimensions and precise location within the spinal cord on magnetic resonance images of 55 cavalier King Charles spaniels with syringomyelia. After removal of masking, syrinx size and location were compared between the cohorts of dogs that exhibited pain with those that did not. RESULTS: Maximum syrinx width was the strongest predictor of pain, scratching behaviour and scoliosis in dogs with syringomyelia. Both pain and syrinx size were positively correlated with syrinxes located in the dorsal half of the spinal cord. CLINICAL SIGNIFICANCE: Large syrinxes associated with damage to the dorsal part of the spinal cord are associated with persistent pain suggesting that the pain behaviour expressed by this group of patients is likely to be "neuropathic pain," resulting from disordered neural processing in the damaged dorsal horn. As such it is likely that conventional analgesic medication may be ineffective.

Many epileptic patients will have satisfactory seizure control using the first-line anticonvulsants phenobarbital and/or bromide, as discussed in the first article of this series (In Practice, March 2013, vol 35, pp 106-113). However, some patients will continue to have an unacceptable number or severity of seizures despite adequate drug serum concentrations. Some patients have a compromised quality of life because of the adverse effects of their medication. In this article, the anticonvulsant drugs used for second-line therapy are discussed, together with other anticonvulsants and alternative therapies.

A Tauro, D Addicott, RD Foale, C Bowman, C Hahn, S Long, J Massey, AC Haley, Susan Knowler, MJ Day, LJ Kennedy, Clare Rusbridge (2015)Clinical features of idiopathic inflammatory polymyopathy in the Hungarian Vizsla, In: BMC Veterinary Research11(97) BioMed Central

Background A retrospective study of the clinicopathological features of presumed and confirmed cases of idiopathic inflammatory polymyopathy in the Hungarian Vizsla dog and guidelines for breeding. Results 369 medical records were reviewed (1992–2013) and 77 Hungarian Vizslas were identified with a case history consistent with idiopathic inflammatory polymyopathy. Inclusion criteria were: group 1 (confirmed diagnosis); histopathology and clinical findings compatible with an inflammatory polymyopathy and group 2 (probable diagnosis); clinical findings compatible with a polymyopathy including dysphagia, sialorrhea, temporal muscle atrophy, elevated serum creatine kinase (CK) activity, and sufficient clinical history to suggest that other neuromuscular disorders could be ruled out. Some group 2 dogs had muscle biopsy, which suggested muscle disease but did not reveal an inflammatory process. The mean age of onset was 2.4 years; male dogs were slightly overrepresented. Common presenting signs were dysphagia, sialorrhea, masticatory muscle atrophy, and regurgitation. Common muscle histopathological findings included degenerative and regenerative changes, with multifocal mononuclear cell infiltration with lymphoplasmacytic myositis of variable severity. A positive response to immunosuppressive treatment supported an immune-mediated aetiology. The mean age at death and survival time were 6.4 and 3.9 years, respectively. Recurrence of clinical signs and aspiration pneumonia were common reasons for euthanasia. Conclusions Diagnosis of Vizsla idiopathic inflammatory polymyopathy can be challenging due to lack of specific tests, however the presence of dysphagia, regurgitation and masticatory muscle atrophy in this breed with negative serological tests for masticatory muscle myositis and myasthenia gravis, along with muscle biopsies suggesting an inflammatory process, support the diagnosis. However, there is an urgent need for a more specific diagnostic test. The average of inbreeding coefficient (CoI) of 16.3% suggests an increased expression of a Dog Leukocyte Antigen Class II haplotype, leading to an increased disease risk. The prognosis remains guarded, as treatment can only manage the disease. Recurrence of clinical signs and perceived poor quality of life are the most common reasons for humane euthanasia.

RMA Packer, M Berendt, S Bhatti, M Charalambous, S Cizinauskas, L De Risio, R Farquhar, R Hampel, M Hill, PJJ Mandigers, A Pakozdy, SM Preston, Clare Rusbridge, VM Stein, F Taylor-Brown, A Tipold, HA Volk (2015)Inter-observer agreement of canine and feline paroxysmal event semiology and classification by veterinary neurology specialists and non-specialists, In: BMC Veterinary Research11(39) BioMed Central

Background: Advances in mobile technology mean vets are now commonly presented with videos of paroxysmal events by clients, but the consistency of the interpretation of these videos has not been investigated. The objective of this study was to investigate the level of agreement between vets (both neurology specialists and non-specialists) on the description and classification of videos depicting paroxysmal events, without knowing any results of diagnostic workup. An online questionnaire study was conducted, where participants watched 100 videos of dogs and cats exhibiting paroxysmal events and answered questions regarding: epileptic seizure presence (yes/no), seizure type, consciousness status, and the presence of motor, autonomic and neurobehavioural signs. Agreement statistics (percentage agreement and kappa) calculated for each variable, with prevalence indices calculated to aid their interpretation. Results: Only a fair level of agreement (κ = 0.40) was found for epileptic seizure presence. Overall agreement of seizure type was moderate (κ = 0.44), with primary generalised seizures showing the highest level of agreement (κ = 0.60), and focal the lowest (κ =0.31). Fair agreement was found for consciousness status and the presence of autonomic signs (κ = 0.21–0.40), but poor agreement for neurobehavioral signs (κ = 0.16). Agreement for motor signs ranged from poor (κ = ≤ 0.20) to moderate (κ = 0.41–0.60). Differences between specialists and non-specialists were identified. Conclusions: The relatively low levels of agreement described here highlight the need for further discussions between neurology experts regarding classifying and describing epileptic seizures, and additional training of non-specialists to facilitate accurate diagnosis. There is a need for diagnostic tools (e.g. electroencephalogram) able to differentiate between epileptic and non-epileptic paroxysms.

C Rusbridge (2013)Choosing the right drug 1. Anticonvulsants used for first-line therapy, In: In Practice35(3)pp. 106-113

This article aims to give the general practitioner a step by step approach to first-line medical management of epilepsy in both cats and dogs. The licensed drugs, bromide and phenobarbital, are discussed in detail with particular reference to the common problems that might be observed. A second article in this two-part series, to be published in a subsequent issue of In Practice, will discuss second-line medical management of epilepsy.

Zoe R. Nalborczyk, Angus K. McFadyen, Jelena Jovanovik, Anna Tauro, Colin J. Driver, Noel Fitzpatrick, Susan P. Knower, Clare Rusbridge (2017)MRI characteristics for “phantom” scratching in canine syringomyelia, In: BMC Veterinary Research13(1) BioMed Central

Background A classic sign of canine syringomyelia (SM) is scratching towards one shoulder. Using magnetic resonance imaging (MRI) we investigate the spinal cord lesion relating to this phenomenon which has characteristics similar to fictive scratch secondary to spinal cord transection. Medical records were searched for Cavalier King Charles spaniels with a clinical and MRI diagnosis of symptomatic SM associated with Chiari-like malformation (CM). The cohort was divided into SM with phantom scratching (19 dogs) and SM but no phantom scratching (18 dogs). MRI files were anonymised, randomised and viewed in EFILM ™. For each transverse image, the maximum perpendicular dimensions of the syrinx in the dorsal spinal cord quadrants were determined. Visual assessment was made as to whether the syrinx extended to the superficial dorsal horn (SDH). Results We showed that phantom scratching appears associated with a large dorsolateral syrinx that extends to the SDH in the C3-C6 spinal cord segments (corresponding to C2-C5 vertebrae). Estimated dorsal quadrant syrinx sizes based on the perpendicular diameters were between 2.5 and 9.5 times larger in dogs with phantom scratching, with the largest mean difference p-value being 0.009. Conclusion SM associated phantom scratching appears associated with MRI findings of a large syrinx extending into the mid cervical SDH. We hypothesise that damage in this region might influence the lumbosacral scratching central pattern generator (CPG). If a scratching SM affected dog does not have a large dorsolateral cervical syrinx with SDH involvement then alternative explanations for scratching should be investigated.

GB Cherubini, C Rusbridge, BP Singh, S Schoeniger, P Mahoney (2007)Rostral cerebellar arterial infarct in two cats., In: J Feline Med Surg9(3)pp. 246-253

A 10-year-old female neutered domestic shorthair (DSH) cat and a 6-year-old female neutered Siamese cat were presented following a peracute onset of decerebellate rigidity and a cerebellar vestibular syndrome, respectively. In both cats, physical examination and routine blood tests were unremarkable, as was routine analysis of cerebrospinal fluid obtained from the DSH cat. Based on the magnetic resonance imaging (MRI) features - focal wedge-shaped lesion in the cerebellum characterised by hyperintensity in T2-weighted, T2( *)-gradient echo and fluid attenuated inversion recovery (FLAIR) images - a presumptive diagnosis of cerebellar infarct was made in both cases. In the DSH cat, the post-mortem examination confirmed the diagnosis of cerebellar infarct and additionally found acute renal infarcts and a pulmonary neoplasia. In the Siamese cat, ultrasonographic evaluation of the heart revealed a probable low-grade chronic valvular endocarditis which was thought to be a potential source of thromboembolism. This paper describes the first two cases - one confirmed and the other suspected - of cerebellar infarct in the cat. The in vivo potential diagnostic value of the MRI study is highlighted. Cerebellar infarcts should be included in the differential diagnosis of cat with a peracute onset of cerebellar signs regardless of the severity of neurological deficits.

Anna Tauro, Clare Rusbridge (2020)Syringopleural shunt placement in a pug with a cervical spinal diverticulum and associated syringomyelia, In: Clinical Case Reports8(7)pp. 1142-1148 Wiley

We report persistence of associated syringomyelia and formation of newly caudal spinal arachnoid diverticulum, following marsupialization surgery. We describe syringopleural shunt placement as a novel approach to treat both conditions in a Pug dog.

K Matiasek, M Pumarola i Batlle, M Rosati, F Fernandez-Flores, A Fischer, E Wagner, M Berendt, SFM Bhatti, L De Risio, RG Farquhar, S Long, K Munana, EE Patterson, A Pakozdy, J Penderis, S Platt, M Podell, H Potschka, C Rusbridge, VM Stein, A Tipold, HA Volk (2015)International veterinary epilepsy task force recommendations for systematic sampling and processing of brains from epileptic dogs and cats, In: BMC VETERINARY RESEARCH11ARTN 216 BIOMED CENTRAL LTD
SP Knowler, H V/D Berg, A McFadyen, RM La Ragione, Clare Rusbridge (2016)Inheritance of Chiari-Like Malformation: Can a Mixed Breeding Reduce the Risk of Syringomyelia?, In: PLoS One11(3) Public Library of Science (PLoS)

Canine Chiari-like malformation (CM) is a complex abnormality of the skull and craniocervical junction associated with miniaturization and brachycephaly which can result in the spinal cord disease syringomyelia (SM). This study investigated the inheritance of CM in a Griffon Bruxellois (GB) family and feasibility of crossbreeding a brachycephalic CM affected GB with a mesaticephalic normal Australian terrier and then backcrossing to produce individuals free of the malformation and regain GB breed characteristics. The study family cohort (n = 27) included five founder dogs from a previous baseline study of 155 GB which defined CM as a global malformation of the cranium and craniocervical junction with a shortened skull base and increased proximity of the cervical vertebrae to the skull. T1-weighted sagittal DICOM images of the brain and craniocervical junction were analysed for five significant traits (two angles, three lines) identified from the previous study and subsequent Qualitative Trait Loci analysis. Mean measurements for mixed breed, pure-breed and baseline study groups were compared. Results indicated that mixed breed traits posed less risk for CM and SM and were useful to distinguish the phenotype. Moreover on the MR images, the filial relationships displayed by the traits exhibited segregation and those presenting the greatest risk for CM appeared additive towards the severity of the condition. The external phenotypes revealed that by outcrossing breed types and with careful selection of appropriate conformation characteristics in the first generation, it is possible to regain the GB breed standard and reduce the degree of CM. The four GB affected with SM in the study all exhibited reduced caudal skull development compared to their relatives. The craniocervical traits may be useful for quantifying CM and assessing the possibility of SM thus assisting breeders with mate selection. However, such a system requires validation to ensure appropriateness for all breeds at risk.

V-I Huelsmeyer, A Fischer, PJJ Mandigers, L DeRisio, M Berendt, C Rusbridge, SFM Bhatti, A Pakozdy, EE Patterson, S Platt, RMA Packer, HA Volk (2015)International Veterinary Epilepsy Task Force's current understanding of idiopathic epilepsy of genetic or suspected genetic origin in purebred dogs, In: BMC VETERINARY RESEARCH11ARTN 175 BIOMED CENTRAL LTD
H Potschka, A Fischer, W Loescher, N Patterson, S Bhatti, M Berendt, L De Risio, R Farquhar, S Long, P Mandigers, K Matiasek, K Munana, A Pakozdy, J Penderis, S Platt, M Podell, C Rusbridge, V Stein, A Tipold, HA Volk (2015)International veterinary epilepsy task force consensus proposal: outcome of therapeutic interventions in canine and feline epilepsy, In: BMC VETERINARY RESEARCH11ARTN 177 BIOMED CENTRAL LTD

Background: Feline idiopathic ulcerative dermatosis is a rare, poorly understood condition characterized by self-trauma. The lesion presents as a nonhealing, crusted ulcer, which occurs most commonly on the dorsal midline of the neck or between the scapulae. Animal: A 2-year-old female neutered domestic short hair cat was presented with an ulcerative dermatosis affecting the dorsal midline. Previous investigations had failed to identify the cause, and the lesion was resistant to treatment. Methods and results: Diagnosis was based on clinical findings and confirmed by histopathology showing epidermal ulceration and superficial necrosis with a mild dermal infiltrate together with subepidermal fibrosis. The cat had been fed a commercial hypoallergenic diet for 6 months, which had successfully managed its chronic diarrhoea. Deep skin scrapings, cytology and fungal culture failed to demonstrate pathogens. Conclusions and clinical importance: Remission was obtained within 4 weeks and has been maintained over a 30 month period with topiramate (5 mg/kg orally twice daily), an anti-epileptic drug used in human medicine. Attempts to withdraw this therapy led to relapse within 24 h on two occasions. To the best of the authors' knowledge, this is the first case report of the use of this drug for feline idiopathic ulcerative dermatosis. © 2014 ESVD and ACVD.

C Rusbridge, S Long, J Jovanovik, M Milne, M Berendt, SFM Bhatti, L De Risio, RG Farqhuar, A Fischer, K Matiasek, K Munana, EE Patterson, A Pakozdy, J Penderis, S Platt, M Podell, H Potschka, VM Stein, A Tipold, HA Volk (2015)International Veterinary Epilepsy Task Force recommendations for a veterinary epilepsy-specific MRI protocol, In: BMC VETERINARY RESEARCH11ARTN 194 BIOMED CENTRAL LTD
S Loderstedt, L Benigni, K Chandler, JM Cardwell, C Rusbridge, CR Lamb, HA Volk (2011)Distribution of syringomyelia along the entire spinal cord in clinically affected Cavalier King Charles Spaniels., In: Vet J190(3)pp. 359-363

Chiari-like malformation (CM) and syringomyelia (SM) is an important disease complex in the Cavalier King Charles Spaniel (CKCS) but data about the anatomical distribution of SM along the spinal cord are lacking in veterinary medicine. The objective of this study was to define the anatomic distribution of SM in CKCS clinically affected by CM/SM. Magnetic resonance imaging (MRI) of the brain and the entire spinal cord of 49 dogs was performed and different morphological parameters compared. Syrinx formation was present in the C1-C4 region and in other parts of the spinal cord. The maximal dorsoventral syrinx size can occur in any region of the spinal cord and the total syrinx size was positively correlated with age. Seventy-six per cent of CKCS with a cranial cervical syrinx also have a syrinx affecting more caudal spinal cord regions. MRI restricted to the cervical region may underestimate the extent of SM and the severity of the disease process in the majority of dogs.

C Costanzo, LS Garosi, EN Glass, C Rusbridge, CE Stalin, HA Volk (2011)Brain abscess in seven cats due to a bite wound: MRI findings, surgical management and outcome., In: J Feline Med Surg13(9)pp. 672-680

UNLABELLED: PRESENTATION AND LESION LOCALISATION: Seven adult domestic shorthair cats were presented with a 1- to 6-day history of progressive neurological signs. A focal skin puncture and subcutaneous swelling over the dorsal part of the head were detected on physical examination. Neurological examination indicated lesion(s) in the right forebrain in four cats, multifocal forebrain in one cat, left forebrain in one cat, and multifocal forebrain and brainstem in the remaining cat. In all cats, magnetic resonance imaging revealed a space-occupying forebrain lesion causing a severe mass effect on adjacent brain parenchyma. CLINICAL APPROACH AND OUTCOME: All cats were managed with a combination of medical and surgical treatment. At surgery a small penetrating calvarial fracture was detected in all cats, and a tooth fragment was found within the content of the abscess in two cats. The combination of surgical intervention, intensive care and intravenous antimicrobials led to a return to normal neurological function in five cats. PRACTICAL RELEVANCE: As this series of cases indicates, successful resolution of a brain abscess due to a bite injury depends on early recognition and combined used of antimicrobials and surgical intervention. A particular aim of surgery is to remove any skull and foreign body (tooth) fragments that may represent a continuing focus of infection.

HZ Hu, C Rusbridge, F Constantino-Casas, N Jeffery (2012)Histopathological investigation of syringomyelia in the Cavalier King Charles spaniel., In: J Comp Pathol146(2-3)pp. 192-201

Syringomyelia (SM) in Cavalier King Charles spaniels (CKCSs) is identified commonly on magnetic resonance images and is sometimes associated with clinical signs of pain and cervical hyperaesthesia. However, the mechanism by which SM develops in this breed has not been fully elucidated and the associated effects on spinal cord structure have not been reported previously. The aims of this study were to describe changes found in the spinal cord of CKCSs, to compare findings between symptomatic and asymptomatic dogs and to determine whether syrinx formation was associated with tissue destruction. Anomalies of the central canal were found in all specimens and many dogs had grossly visible fluid-filled cavities within the spinal cord. Prominent microscopical findings were spongy degenerative changes associated with neuronal necrosis and Wallerian degeneration. The ependyma was discontinuous in many specimens, notably in symptomatic individuals, and there was evidence of angiogenesis and fibrous tissue proliferation around blood vessels adjacent to syrinx cavities. Compared with two different samples of the normal dog population, dogs with syrinxes had significantly less grey matter, although this decrease was associated with generalized loss of spinal cord area. Therefore, SM is associated with degenerative changes in the spinal cord and may develop through primary disruption of ependymal integrity followed by vascular hypertrophy and proliferation. Glial and fibrous proliferation appears to be associated with expression of clinical signs.

C Rusbridge, N Nicholas, D Addicott (2011)Polymyositis and DNA collection in the Hungarian vizsla dog., In: Vet Rec168(3)pp. 85-86
JE Parker, SP Knowler, C Rusbridge, E Noorman, ND Jeffery (2011)Prevalence of asymptomatic syringomyelia in Cavalier King Charles spaniels., In: Vet Rec168(25)pp. 667-?

The prevalence of syringomyelia was investigated in a sample population of 555 Cavalier King Charles spaniels. All dogs, which were declared by their owners to be showing no clinical signs of syringomyelia, underwent MRI to determine the presence or absence of the condition. Data were analysed by logistic regression to determine the effects of sex and age on the prevalence of syringomyelia. Only increased age was found to have a significant effect. The prevalence of syringomyelia was 25 per cent in dogs aged 12 months, increasing to a peak of 70 per cent in dogs aged 72 months or more.

SF Bhatti, AE Vanhaesebrouck, I Van Soens, VA Martlé, IE Polis, C Rusbridge, LM Van Ham (2011)Myokymia and neuromyotonia in 37 Jack Russell terriers., In: Vet J189(3)pp. 284-288

The clinical and clinicopathological characteristics, treatment and outcome of vermicular muscle contractions (myokymia) and generalized muscle stiffness (neuromyotonia) in 37 Jack Russell terriers were evaluated retrospectively. Thirty dogs were affected by both disorders, whereas seven were presented with myokymia and never developed neuromyotonia. Clinical signs started at the mean age of 8 months. Except for signs of myokymia and neuromyotonia, clinical and neurological examination was normal in all dogs. Thirty dogs demonstrated typical signs of hereditary ataxia. Changes in serum chemistry included increased creatine kinase, aspartate aminotransferase and alanine aminotransferase concentrations. Electromyographic abnormalities, especially in muscles showing macroscopically visible myokymia, consisted of semirhythmic bursts of doublet, triplet, or multiplet discharges of a single motor unit. The amplitudes varied between 80 μV and 1 mV and occurred with an interburst frequency between 10 and 40 Hz and an intraburst frequency between 150 and 280 Hz. Most dogs were treated with a sodium channel blocker with variable results. Seven dogs died (most likely because of hyperthermia) or were euthanased during a neuromyotonic attack; 15 dogs were euthanased due to worsening of clinical signs, or lack of or no long-lasting effect of medication, and three were euthanased for unknown or unrelated reasons. Nine dogs were lost to follow-up and three were still alive 5-10.5 years after the start of clinical signs. In conclusion, young Jack Russell terriers with myokymia and neuromyotonia should undergo a complete blood and electrophysiological examination. Long-term prognosis is not favourable.

L Rutherford, A Wessmann, C Rusbridge, IM McGonnell, S Abeyesinghe, C Burn, HA Volk (2012)Questionnaire-based behaviour analysis of Cavalier King Charles spaniels with neuropathic pain due to Chiari-like malformation and syringomyelia., In: Vet J194(3)pp. 294-298

Chiari-like malformation (CM)/syringomyelia (SM) is a disease complex recognised in Cavalier King Charles spaniels (CKCSs) that can lead to neuropathic pain (NeP). In humans, NeP is associated with anxiety, depression and reduced quality of life (QoL). In this study, databases of three specialist veterinary centres were searched and CKCS breed societies and health forums were contacted to identify CKCS with an imaging diagnosis of CM/SM. Owners completed questionnaires on behaviour, signalment, general health status, NeP and QoL. Data were analysed from 122 dogs out of 564 questionnaires completed, after incomplete questionnaires and data from dogs that had other potentially debilitating disease processes were excluded. NeP severity score was significantly and positively correlated with 'stranger-directed' fear (r(S)=0.28), non-social fear (r(S)=0.34), 'separation-related' behaviour (r(S)=0.38), attachment behaviour (r(S)=0.24), excitability (r(S)=0.21) and proxy for pain sensation (r(S)=0.29). Increased NeP was also significantly associated with decreased QoL (r(S)=0.47), ability to settle (r(S)=0.26) and willingness to exercise (r(S)=0.50). Severity of NeP was positively associated with certain fear-associated behaviour and with decreased owner-perceived QoL. Thus, neurobehavioural changes should be considered in the management of NeP in CKCS with CM/SM.

CJ Driver, C Rusbridge, HR Cross, I McGonnell, HA Volk (2010)Relationship of brain parenchyma within the caudal cranial fossa and ventricle size to syringomyelia in cavalier King Charles spaniels., In: J Small Anim Pract51(7)pp. 382-386

OBJECTIVES: To assess if the volumes of the caudal cranial fossa (CCF), parenchyma within the caudal cranial fossa (CCFP) or ventricles (V) are associated with syringomyelia (SM) in cavalier King Charles spaniels (CKCS) with Chiari-like malformation (CM). To evaluate if volumes are associated with transverse syrinx width. METHODS: Magnetic resonance images of 59 CKCS with CM were retrospectively reviewed and grouped with or without SM. Three-dimensional images were created and volumes of the fossae, brain parenchyma and ventricular system were calculated from which percentages of CCF, CCFP and V were created. If present, syrinx size was measured from its maximal transverse width. The percentages were statistically compared between groups, and correlation between percentages and syrinx dimensions was made. RESULTS: CKCS with SM had significantly higher CCFP (P=0.0001) and V (P=0.0002) to those without but no significant difference in CCF (P=0.925). There was a positive correlation between CCFP and syrinx width (Pearson r=0.437) and ventricle size to syrinx width (Spearman r=0.627). CLINICAL SIGNIFICANCE: A more marked overcrowding of the CCF is associated with SM, which may explain the high incidence of SM in CKCS with CM. The association between ventricle and syrinx dimensions supports the theory that SM development is the result of altered cerebrospinal fluid dynamics.

L De Risio, S Bhatti, K Munana, J Penderis, V Stein, A Tipold, M Berendt, R Farqhuar, A Fischer, S Long, PJJ Mandigers, K Matiasek, RMA Packer, A Pakozdy, N Patterson, S Platt, M Podell, H Potschka, M Pumarola Batlle, C Rusbridge, HA Volk (2015)International veterinary epilepsy task force consensus proposal: diagnostic approach to epilepsy in dogs, In: BMC VETERINARY RESEARCH11ARTN 148 BIOMED CENTRAL LTD
SP Knowler, AK McFadyen, C Rusbridge (2011)Effectiveness of breeding guidelines for reducing the prevalence of syringomyelia., In: Vet Rec169(26)pp. 681-?

Several toy breed dogs are predisposed to syringomyelia (SM), a spinal cord disorder, characterised by fluid-filled cavitation. SM is a complex trait with a moderately high heritability. Selective breeding against SM is confounded by its complex inheritance, its late onset nature and high prevalence in some breeds. This study investigated the early outcome of existing SM breeding guidelines. Six hundred and forty-three dogs, 550 Cavalier King Charles spaniels (CKCS) and 93 Griffon Bruxellois (GB), were identified as having either one (454 dogs) or both parents (189 dogs) with MRI-determined SM status. Offspring without SM were more common when the parents were both clear of SM (SM-free; CKCS 70 per cent, GB 73 per cent). Conversely, offspring with SM were more likely when both parents had SM (SM-affected; CKCS 92 per cent, GB 100 per cent). A mating of one SM-free parent with an SM-affected parent was risky for SM affectedness with 77 per cent of CKCS and 46 per cent of GB offspring being SM-affected. It is recommended that all breeding dogs from breeds susceptible to SM be MRI screened; that the SM status at five years old is established; and all results submitted to a central database that can be used by dog breeders to better enable mate selection based on estimated breeding values.

The causes of clinical signs associated with syringomyelia in the Cavalier King Charles Spaniel (CKCS) are incompletely understood. In this study we compared expression of two pain-related neuropeptides: substance P (SP) and calcitonin gene related peptide (CGRP), in the spinal cord dorsal horn of normal dogs with that in CKCS with and without clinical signs of syringomyelia. There was a decrease in expression of both peptides in CKCS with 'symptomatic' syringomyelia that was also associated with significant asymmetry in SP-I and similar, though non-significant, asymmetry in CGRP-I compared with other groups. The asymmetric distribution of these pain-related peptides may be a consequence of syrinx-associated damage to grey matter but may also play a role in generation of pain.

K Lazzerini, R Gutierrez-Quintana, R Jose-Lopez, F McConnell, R Goncalves, J McMurrough, S De Decker, C Muir, SL Priestnall, L Mari, F Stabile, L De Risio, C Loeffler, A Tauro, Clare Rusbridge, S Rodenas, S Anor, C de la Fuente, A Fischer, A Bruehschwein, J Penderis, J Guevar (2017)Clinical Features, Imaging Characteristics, and Long-term Outcome of Dogs with Cranial Meningocele or Meningoencephalocele., In: Journal of Veterinary Internal Medicine31pp. 505-512 Wiley

Background: The term meningoencephalocele (MEC) describes a herniation of cerebral tissue and meninges through a defect in the cranium, whereas a meningocele (MC) is a herniation of the meninges alone. Hypothesis/Objectives: To describe the clinical features, magnetic resonance imaging (MRI) characteristics, and outcomes of dogs with cranial MC and MEC. Animals: Twenty-two client-owned dogs diagnosed with cranial MC or MEC. Methods: Multicentric retrospective descriptive study. Clinical records of 13 institutions were reviewed. Signalment, clinical history, neurologic findings and MRI characteristics as well as treatment and outcome were recorded and evaluated. Results: Most affected dogs were presented at a young age (median, 6.5 months; range, 1 month – 8 years). The most common presenting complaints were seizures and behavioral abnormalities. Intranasal MEC was more common than parietal MC. Magnetic resonance imaging identified meningeal enhancement of the protruded tissue in 77% of the cases. Porencephaly was seen in all cases with parietal MC. Cerebrospinal fluid (CSF) analysis identified mild abnormalities in 4 of 11 cases. Surgery was not performed in any affected dog. Seventeen patients were treated medically, and seizures were adequately controlled with anti-epileptic drugs in 10 dogs. Dogs with intranasal MEC and mild neurologic signs had a fair prognosis with medical treatment. Conclusion and clinical importance: Although uncommon, MC and MEC should be considered as a differential diagnosis in young dogs presenting with seizures or alterations in behavior. Medical treatment is a valid option with a fair prognosis when the neurologic signs are mild.

P Batle, Clare Rusbridge, T Nuttall, S Heath, K Marioni-Henry (2018)Feline hyperaesthesia syndrome with self-trauma to the tail: retrospective study of seven cases and proposal for integrated multidisciplinary diagnostic approach, In: Journal of Feline Medicine and Surgery SAGE Publications

This was a retrospective study on the clinical features and response to treatment in seven cats with feline hyperaesthesia syndrome (FHS) and tail mutilation. FHS is a poorly understood disorder characterised by skin rippling over the dorsal lumbar area, episodes of jumping and running, excessive vocalisation, and tail chasing and self-trauma. The majority of the cats were young, with a median age of 1 year at the onset of clinical signs, male (n = 6) and with access to the outdoors (n = 5). Multiple daily episodes of tail chasing and self-trauma were reported in five cats, with tail mutilation in four cats. Vocalisation during the episodes (n = 5) and rippling of lumbar skin (n = 5) were also reported. Haematology, serum biochemistry, Toxoplasma gondii and feline immunodeficiency virus/feline leukaemia virus serology, MRI scans of brain, spinal cord and cauda equina, cerebrospinal fluid analysis and electrodiagnostic tests did not reveal any clinically significant abnormalities. A definitive final diagnosis was not reached in any of the cats, but hypersensitivity dermatitis was suspected in two cases. A variety of medications was used alone or in combination, including gabapentin (n = 6), meloxicam (n = 4) antibiotics (n = 4), phenobarbital (n = 2), prednisolone (n = 2) and topiramate (n = 2); ciclosporin, clomipramine, fluoxetine, amitriptyline and tramadol were used in one cat each. Clinical improvement was achieved in six cases; in five cats complete remission of clinical signs was achieved with gabapentin alone (n = 2), a combination of gabapentin/ciclosporin/amitriptyline (n = 1), gabapentin/prednisolone/phenobarbital (n = 1) or gabapentin/topiramate/meloxicam (n = 1).

TS Jokinen, C Rusbridge, F Steffen, R Viitmaa, P Syrjä, A De Lahunta, M Snellman, S Cizinauskas (2007)Cerebellar cortical abiotrophy in Lagotto Romagnolo dogs., In: J Small Anim Pract48(8)pp. 470-473

This case report documents two pathological variations of potentially inherited, cerebellar cortical abiotrophy in two unrelated Lagotto Romagnolo breed dogs. The first dog had an atypical lesion in the cerebellar cortex with depletion of cerebellar granular cell layer and sparing of the Purkinje cell layer. The second case had degenerative changes in both Purkinje and granular cell layers. The clinical picture was similar in both cases presented, although the severity of the signs of cerebellar dysfunction varied.

L Swain, G Key, A Tauro, S Ahonen, P Wang, C Ackerley, BA Minassian, Clare Rusbridge (2017)Lafora disease in miniature Wirehaired Dachshunds., In: PLoS ONE12(8)e0182024. Public Library of Science

Lafora disease (LD) is an autosomal recessive late onset, progressive myoclonic epilepsy with a high prevalence in the miniature Wirehaired Dachshund. The disease is due to a mutation in the Epm2b gene which results in intracellular accumulation of abnormal glycogen (Lafora bodies). Recent breed-wide testing suggests that the carrier plus affected rate may be as high as 20%. A characteristic feature of the disease is spontaneous and reflex myoclonus; however clinical signs and disease progression are not well described. A survey was submitted to owners of MWHD which were homozygous for Epm2b mutation (breed club testing program) or had late onset reflex myoclonus and clinical diagnosis of LD. There were 27 dogs (11 male; 16 female) for analysis after young mutation-positive dogs that had yet to develop disease were excluded. Average age of onset of clinical signs was 6.94 years (3.5–12). The most common initial presenting sign was reflex and spontaneous myoclonus (77.8%). Other presenting signs included hypnic myoclonus (51.9%) and generalized seizures (40.7%). Less common presenting signs include focal seizures, “jaw smacking”, “fly catching”, “panic attacks”, impaired vision, aggression and urinary incontinence. All these clinical signs may appear, and then increase in frequency and intensity over time. The myoclonus in particular becomes more severe and more refractory to treatment. Signs that developed later in the disease include dementia (51.9%), blindness (48.1%), aggression to people (25.9%) and dogs (33.3%), deafness (29.6%) and fecal (29.6%) and urinary (37.0%) incontinence as a result of loss of house training (disinhibited type behavior). Further prospective study is needed to further characterize the canine disease and to allow more specific therapeutic strategies and to tailor therapy as the disease progresses.

Clare Rusbridge, Angus K. McFadyen, Susan P. Knower (2019)Behavioral and clinical signs of Chiari‐like malformation‐associated pain and syringomyelia in Cavalier King Charles spaniels, In: Journal of Veterinary Internal Medicine33(5)pp. 2138-2150 BMJ Publishing Group

Background: Diagnosis of Chiari-like malformation-associated pain (CM-P) or clinicallyrelevant syringomyelia (SM) is challenging. We sought to determine common signs.Animals:One hundred thirty client-owned Cavalier King Charles spaniels with neuroaxismagnetic resonance imaging (MRI) and diagnosis of CM-P/SM. Dogs with comorbiditiescausing similar signs were excluded with exception of otitis media with effusion (OME). Methods: Retrospective study of medical records relating signalment, signs, and MRIfindings. Dogs were grouped by SM maximum transverse diameter (1 = no SM;2 = 0.5-1.99 mm; 3 = 2-3.9 mm: 4 =≥4 mm). Differences between all groups—groups1 versus 2-4 and groups 1-3 versus 4—were investigated. Continuous variables wereanalyzed using 2-samplet-tests and analysis of variance. Associations between categori-cal variables were analyzed using Fisher's exact or chi-square tests. Results:Common signs were vocalization (65.4%), spinal pain (54.6%), reduced activ-ity (37.7%), reduced stairs/jumping ability (35.4%), touch aversion (30.0%), alteredemotional state (28.5%), and sleep disturbance (22%). Head scratching/rubbing(28.5%) was inversely associated with syrinx size (P= .005), less common in group4(P= .003), and not associated with OME (P= .977). Phantom scratching, scoliosis,weakness, and postural deficits were only seen in group 4 (SM≥4 mm;P= .004). Conclusions and Clinical Importance: Signs of pain are common in CM/SM but arenot SM-dependent, suggesting (not proving) CM-P causality. Wide (≥4 mm) SM isassociated with signs of myelopathy and, if the dorsal horn is involved, phantomscratching (ipsilateral) and torticollis (shoulder deviated ipsilateral; head tiltcontralateral).

Barbara Gandolfi, Hasan Alhaddad, Mona Abdi, Leslie H. Bach, Erica K. Creighton, Brian W. Davis, Jared E. Decker, Nicholas H. Dodman, Jennifer C. Grahn, Robert A. Grahn, Bianca Haase, Jens Haggstrom, Michael J. Hamilton, Christopher R. Helps, Jennifer D. Kurushima, Hannes Lohi, Maria Longeri, Richard Malik, Kathryn M. Meurs, Michael J. Montague, James C. Mullikin, William J. Murphy, Sara M. Nilson, Niels C. Pedersen, Carlyn B. Peterson, Clare Rusbridge, Rashid Saif, Diane G. Shelton, Wesley C. Warren, Muhammad Wasim, Leslie A. Lyons (2018)Applications and efficiencies of the first cat 63K DNA array, In: Scientific Reports8(1)7024pp. 1-15 Nature Publishing Group

The development of high throughput SNP genotyping technologies has improved the genetic dissection of simple and complex traits in many species including cats. The properties of feline 62,897 SNPs Illumina Infnium iSelect DNA array are described using a dataset of over 2,000 feline samples, the most extensive to date, representing 41 cat breeds, a random bred population, and four wild felid species. Accuracy and efciency of the array’s genotypes and its utility in performing population-based analyses were evaluated. Average marker distance across the array was 37,741 Kb, and across the dataset, only 1% (625) of the markers exhibited poor genotyping and only 0.35% (221) showed Mendelian errors. Marker polymorphism varied across cat breeds and the average minor allele frequency (MAF) of all markers across domestic cats was 0.21. Population structure analysis confrmed a Western to Eastern structural continuum of cat breeds. Genome-wide linkage disequilibrium ranged from 50–1,500 Kb for domestic cats and 750 Kb for European wildcats (Felis silvestris silvestris). Array use in trait association mapping was investigated under diferent modes of inheritance, selection and population sizes. The efcient array design and cat genotype dataset continues to advance the understanding of cat breeds and will support monogenic health studies across feline breeds and populations.

M Berendt, RG Farquhar, PJJ Mandigers, A Pakozdy, SFM Bhatti, L De Risio, A Fischer, S Long, K Matiasek, K Munana, EE Patterson, J Penderis, S Platt, M Podell, H Potschka, MB Pumarola, C Rusbridge, VM Stein, A Tipold, HA Volk (2015)International veterinary epilepsy task force consensus report on epilepsy definition, classification and terminology in companion animals, In: BMC VETERINARY RESEARCH11ARTN 182 BIOMED CENTRAL LTD
IN Plessas, C Rusbridge, CJ Driver, KE Chandler, A Craig, IM McGonnell, DC Brodbelt, HA Volk (2012)Long-term outcome of Cavalier King Charles spaniel dogs with clinical signs associated with Chiari-like malformation and syringomyelia., In: Vet Rec171(20)pp. 501-?

The disease complex Chiari-like malformation (CM) and syringomyelia (SM) has been associated with the development of neuropathic pain (NeP), and commonly affects Cavalier King Charles spaniels (CKCS). This prospective cohort study followed 48 CKCSs with CM and/or SM and clinical signs suggestive of NeP for a period of 39 (±14.3) months from diagnosis. At the end of the study, 36 dogs were still alive; five dogs died of an unrelated or unknown cause, and seven were euthanased due to severe clinical signs suggestive of NeP. During the follow-up period, the clinical signs of scratching, facial rubbing behaviour, vocalisation and exercise ability were evaluated. Nine out of 48 dogs stopped scratching (P

Susan P. Knowler, Eleonore Dumas, Michaela Spiteri, Angus K. McFadyen, Felicity Stringer, Kevin Wells, Clare Rusbridge (2019)Facial changes related to brachycephaly in Cavalier King Charles Spaniels with Chiari‐like malformation associated pain and secondary syringomyelia, In: Journal of Veterinary Internal Medicine34(1)pp. 237-246 Wiley Open Access

Background: Recent studies including an innovative machine learning technique indicated Chiari-like malformation (CM) is influenced by brachycephalic features. Objectives: Morphometric analysis of facial anatomy and dysmorphia in CM-associated pain (CM-P) and syringomyelia (SM) in the Cavalier King Charles Spaniel (CKCS). Animals:Sixty-six client-owned CKCS. Methods:Retrospective study of anonymized T2W sagittal magnetic resonance imaging of 3 clinical groups: (1) 11 without central canal dilation (ccd) or SM (CM-N),(2) 15 with CM-P with no SM or

Srdjan Cirovic, R Lloyd, J Jovanovik, H Volk, Clare Rusbridge (2018)Computer simulation of syringomyelia in dogs, In: BMC Veterinary Research14(82) BioMed Central

Background: Syringomyelia is a pathological condition in which fluid-filled cavities (syringes) form and expand in the spinal cord. Syringomyelia is often linked with obstruction of the craniocervical junction and a Chiari malformation,which is similar in both humans and animals. Some brachycephalic toy breed dogs such as Cavalier King Charles Spaniels (CKCS) are particularly predisposed. The exact mechanism of the formation of syringomyelia is undetermined and consequently with the lack of clinical explanation, engineers and mathematicians have resorted to computer models to identify possible physical mechanisms that can lead to syringes. We developed a computer model of the spinal cavity of a CKCS suffering from a large syrinx. The model was excited at the cranial end to simulate the movement of the cerebrospinal fluid (CSF) and the spinal cord due to the shift of blood volume in the cranium related to the cardiac cycle. To simulate the normal condition,the movement was prescribed to the CSF. To simulate the pathological condition, the movement of CSF was blocked. Results: For normal conditions the pressure in the SAS was approximately 400 Pa and the same applied to all stress components in the spinal cord. The stress was uniformly distributed along the length of the spinal cord.When the blockage between the cranial and spinal CSF spaces forced the cord to move with the cardiac cycle,shear and axial normal stresses in the cord increased significantly. The sites where the elevated stress was most pronounced coincided with the axial locations where the syringes typically form, but they were at the perimeter rather than in the central portion of the cord. This elevated stress originated from the bending of the cord at the locations where its curvature was high. Conclusions: The results suggest that it is possible that repetitive stressing of the spinal cord caused by its exaggerated movement could be a cause for the formation of initial syringes. Further consideration of factors such as cord tethering and the difference in mechanical properties of white and grey matter is needed to fully explore this possibility.

Clare Rusbridge, K Marioni‐Henry, HA Volk (2016)Clinical Features in Border Terrier Dogs with Paroxysmal Involuntary Movements, In: Movement Disorders Clinical Practice3(1)pp. 73-79 Wiley

Abstract Background There have been anecdotal reports of episodic involuntary movements in the Border Terrier dog breed for over a decade. Recently, it has been hypothesized that this condition may be a form of paroxysmal dystonic choreoathetosis. The aim of this study was to characterize the phenomenology and clinical course of this condition and compare it to known human movement disorders. Methods Data were collected retrospectively from clinical cases treated by veterinary neurologists and additional information was collected prospectively with an ad-hoc online survey directed to owners of affected dogs. Results The episodes are characterized by generalized dystonia, tremors, titubation, and, in some cases, autonomic signs, such as salivation and vomiting. The median age at onset of the episodes was 3 years and the interval between clusters of episodes could last several months. Most of the episodes occurred from rest, and 67% of the owners reported that the episodes were associated with a trigger, most often excitement. Some owners reported an improvement after changing their dog's diet. We hypothesize that the Border Terrier attacks represent a form of paroxysmal nonkinesigenic dyskinesia. Conclusions The finding of a dystonia phenotype within an inbred population suggests a genetic predisposition, and elucidating the genetic cause could facilitate improved understanding of dystonia. This genetic predisposition and the effect of treatment with anticonvulsant drugs and dietary changes on the severity of the paroxysms warrant further investigation on this condition.

SJ McGuinness, EJ Friend, SP Knowler, ND Jeffery, C Rusbridge (2013)Progression of otitis media with effusion in the Cavalier King Charles spaniel., In: Vet Rec172(12)pp. 315-?
H Gredal, BB Thomsen, A Boza-Serrano, L Garosi, Clare Rusbridge, D Anthony, A Møller, B Finsen, T Deierborg, KL Lambertsen, M Berendt (2017)Interleukin-6 is increased in plasma and cerebrospinal fluid of community-dwelling domestic dogs with acute ischaemic stroke, In: Neuroreport28(3)pp. 134-140 Lippincott, Williams & Wilkins

Inflammatory cytokines are potential modulators of infarct progression in acute ischaemic stroke, and are therefore possible targets for future treatment strategies. Cytokine studies in animal models of surgically induced stroke may, however, be influenced by the fact that the surgical intervention itself contributes towards the cytokine response. Community-dwelling domestic dogs suffer from spontaneous ischaemic stroke, and therefore, offer the opportunity to study the cytokine response in a noninvasive set-up. The aims of this study were to investigate cytokine concentrations in plasma and cerebrospinal fluid (CSF) in dogs with acute ischaemic stroke and to search for correlations between infarct volume and cytokine concentrations. Blood and CSF were collected from dogs less than 72 h after a spontaneous ischaemic stroke. Infarct volumes were estimated on MRIs. Interleukin (IL)-2, IL-6, IL- 8, IL-10 and tumour necrosis factor in the plasma, CSF and brain homogenates were measured using a canine-specific multiplex immunoassay. IL-6 was significantly increased in plasma (P=0.04) and CSF (P=0.04) in stroke dogs compared with healthy controls. The concentrations of other cytokines, such as tumour necrosis factor and IL-2, were unchanged. Plasma IL-8 levels correlated significantly with infarct volume (Spearman’s r=0.8, P=0.013). The findings showed increased concentrations of IL-6 in the plasma and CSF of dogs with acute ischaemic stroke comparable to humans. We believe that dogs with spontaneous stroke offer a unique, noninvasive means of studying the inflammatory processes that accompany stroke while reducing confounds that are unavoidable in experimental models.

TA Shaw, IM McGonnell, CJ Driver, C Rusbridge, HA Volk (2013)Caudal cranial fossa partitioning in Cavalier King Charles spaniels., In: Vet Rec172(13)pp. 341-?

OBJECTIVE: To evaluate long-term success of cranial cervical decompression for management of canine Chiari-like malformation with syringomyelia (CM/SM). STUDY DESIGN: Retrospective clinical study. ANIMALS: Cavalier King Charles spaniels (n=15). METHODS: After diagnosis by magnetic resonance imaging (MRI) dogs had cranial cervical decompression with durotomy. Seven dogs had the durotomy patched with biocompatible collagen matrix. Clinical outcome was monitored for >12 months. RESULTS: All dogs either improved (80%) or were unchanged (20%) postoperatively. Postoperative MRI in 6 dogs revealed persistence of syringomyelia. Seven dogs (47%) subsequently deteriorated, 0.2-2.3 years after surgery (mean, 1.3 years) and 2 dogs were eventually euthanatized as a consequence. Twelve dogs were still alive, 1-6.5 years after surgery (mean, 2.5 years). CONCLUSION: Cranial cervical decompression surgery is associated with low mortality and morbidity, and results in clinical improvement in most dogs. The procedure seemingly does not result in syrinx collapse and resolution. Clinical improvement may not be sustained and some dogs can be expected to deteriorate. CLINICAL RELEVANCE: Cranial cervical decompression surgery may have a role in management of CM/SM. In dogs with severe pain, it can improve quality of life for several years; however, it does not appear to adequately address the primary cause of syringomyelia. Further prospective study is needed to better understand the pathogenesis and treatment of this disorder. Because this condition causes neuropathic pain but does not necessarily result in euthanasia more information is needed on appropriate pain management for these patients.

F Watson, Clare Rusbridge, RMA Packer, RA Casey, S Heath, HA Volk (2018)A review of treatment options for behavioural manifestations of clinical anxiety as a comorbidity in dogs with idiopathic epilepsy, In: The Veterinary Journal238pp. 1-9 Elsevier

Psychiatric comorbidities affect a large percentage of people with epilepsy and have a detrimental impact on their quality of life. Recently, behavioural comorbidities, with similar characteristics to human psychiatric diseases, have been identified in dogs with idiopathic epilepsy. In particular, behaviours motivated by the fear–anxiety emotional system have been found to be associated with the occurrence of idiopathic epilepsy in both dogs receiving anti-epileptic drugs, and drug-naïve dogs. There has been little research into the relationship between epilepsy and behavioural signs, and even less into potential treatment protocols. The following article will review available literature from human medicine to describe the current state of knowledge about the bi-directional relationship between anxiety and epilepsy, draw parallels from reported anxiogenic and anxiolytic properties of anti-epileptic drugs and attempt to provide pharmaceutical and behavioural guidance for veterinary patients with epilepsy and comorbid anxiety.

B Thomsen, L Garosi, G Skerritt, Clare Rusbridge, T Sparrow, M Berendt, H Gredal (2016)Neurological signs in 23 dogs with suspected rostral cerebellar ischaemic stroke, In: Acta Veterinaria Scandinavica58(40) BioMed Central

Background: In dogs with ischaemic stroke, a very common site of infarction is the cerebellum. The aim of this study was to characterise neurological signs in relation to infarct topography in dogs with suspected cerebellar ischaemic stroke and to report short-term outcome confined to the hospitalisation period. A retrospective multicentre study of dogs with suspected cerebellar ischaemic stroke examined from 2010–2015 at five veterinary referral hospitals was performed. Findings from clinical, neurological, and paraclinical investigations including magnetic resonance imaging were assessed. Results: Twenty-three dogs, 13 females and 10 males with a median age of 8 years and 8 months, were included in the study. The Cavalier King Charles Spaniel (n = 9) was a commonly represented breed. All ischaemic strokes were located to the vascular territory of the rostral cerebellar artery including four extensive and 19 limited occlusions. The most prominent neurological deficits were gait abnormalities (ataxia with hypermetria n = 11, ataxia without hypermetria n = 4, non-ambulatory n = 6), head tilt (n = 13), nystagmus (n = 8), decreased menace response (n = 7), postural reaction deficits (n = 7), and proprioceptive deficits (n = 5). Neurological signs appeared irrespective of the infarct being classified as extensive or limited. All dogs survived and were discharged within 1–10 days of hospitalisation. Conclusions: Dogs affected by rostral cerebellar ischaemic stroke typically present with a collection of neurological deficits characterised by ataxia, head tilt, and nystagmus irrespective of the specific cerebellar infarct topography. In dogs with peracute to acute onset of these neurological deficits, cerebellar ischaemic stroke should be considered an important differential diagnosis, and neuroimaging investigations are indicated. Although dogs are often severely compromised at presentation, short-term prognosis is excellent and rapid clinical improvement may be observed within the first week following the ischaemic stroke.

Clare Rusbridge (2020)New considerations about Chiari-like malformation, syringomyelia and their management, In: In Practice42(5)pp. 252-267 Wiley

Background: Chiari-like malformation (CM) is a developmental condition, characterised by a conformational change and overcrowding of the brain and cranial cervical spinal cord. CM-associated pain (CM-P) and syringomyelia are increasingly being diagnosed, due to the rising popularity of predisposed brachycephalic breeds and the availability of MRI in veterinary practices.

C Rusbridge, SP Knowler, L Pieterse, AK McFadyen (2009)Chiari-like malformation in the Griffon Bruxellois., In: J Small Anim Pract50(8)pp. 386-393

OBJECTIVES: This study describes Chiari-like malformation and syringomyelia in the Griffon Bruxellois and establishes if skull radiographs are useful for disease prediction. METHODS: Magnetic resonance imaging from 56 Griffon Bruxellois dogs was assessed for Chiari-like malformation and cerebrospinal fluid pathway abnormalities. Skull radiographs were obtained in 33 dogs. Two rostrocaudal and two ventrodorsal measurements were made, and ratios of one length to another were compared. RESULTS: In this selected sample, 60.7 per cent had Chiari-like malformation. Syringomyelia occurred with and without Chiari-like malformation (37.5 and 8.9 per cent study population, respectively). The radiographic study demonstrated that one measurement ratio could be used to predict Chiari-like malformation (sensitivity of 87 per cent and specificity of 78 per cent) and that there were significant interaction factors between sex and syringomyelia for two measurement ratios. CLINICAL SIGNIFICANCE: The study suggests that Chiari-like malformation is characterised by a shortening of the basicranium and supra-occipital bone with a compensatory lengthening of the cranial vault, especially the parietal bone. We described a simple radiographic technique, which may be useful as a screening test until a more definite genetic test for Chiari-like malformation is available.

K Chandler, H Volk, C Rusbridge, N Jeffery (2008)Syringomyelia in cavalier King Charles spaniels., In: Vet Rec162(10)pp. 324-?
Colin J. Driver, Jeremy Rose, Anna Tauro, Ricardo Fernandes, Clare Rusbridge (2019)Magnetic resonance image findings in pug dogs with thoracolumbar myelopathy and concurrent caudal articular process dysplasia, In: BMC Veterinary Research15(1)

Background: A retrospective case series study was undertaken to describe the magnetic resonance imaging (MRI)findings in Pug dogs with thoracolumbar myelopathy and concurrent caudal articular process (CAP) dysplasia. Electronic clinical records were searched for Pug dogs who underwent MRI for the investigation of a T3-L3 spinalcord segment disease with subsequent confirmation of CAP dysplasia with computed tomography between January 2013 and June 2017. Clinical parameters age, gender, neuter status, body weight, urinary or faecal incontinence, severity and duration of clinical signs were recorded. MRI abnormalities were described. Univariablenon-parametric tests investigated the association between the clinical parameters and evidence of extra- or intra-dural spinal cord compression on MRI. Results: 18 Pug dogs were included. The median age was 106 months with median duration of clinical signs 5months. All presented with variable severity of spastic paraparesis and ataxia; 50% suffered urinary/faecalincontinence. In all cases, MRI revealed a focal increase in T2-weighted signal intensity within the spinal cord at anintervertebral level where bilateral CAP dysplasia was present; this was bilateral aplasia in all but one case, whichhad one aplastic and one severely hypoplastic CAP. MRI lesions were associated with spinal cord compression in allbut one case; intervertebral disc protrusion resulted in extra-dural compression in 10 (56%) cases; intra-duralcompression was associated with a suspected arachnoid diverticulum in 4 (22%) cases and suspected pia-arachnoidfibrosis in 3 cases (17%). There was no association between clinical parameters and a diagnosis of intra-dural vsextra-dural compression. CAP dysplasia occurred at multiple levels in the T10–13 region with bilateral aplasia atT11–12 most often associated with corresponding spinal cord lesions on MRI. Conclusions: All Pugs dogs in this study were presented for chronic progressive ambulatory paraparesis;incontinence was commonly reported. Although intervertebral disc disease was the most common radiologic diagnosis, intra-dural compression associated with arachnoid diverticulae/fibrosis was also common. Bilateral CAPaplasia was present in all but one Pug dog at the level of MRI detectable spinal cord lesions. A causal relationship between CAP dysplasia and causes of thoracolumbar myelopathy is speculated but is not confirmed by this study.

OBJECTIVES: To ascertain whether cavalier King Charles spaniels (CKCSs) have a proportionately smaller caudal fossa compared with other small dogs and with Labradors. To evaluate if cerebellar herniation in CKCS correlates with caudal fossa volume. METHODS: In this retrospective study, three-dimensional images were created from magnetic resonance imaging brain series of 117 dogs (split into three groups: CKCS, Labradors and small breeds) from which the volumes of the fossae and brain parenchyma were calculated. These volumes were transformed into percentages of total cranial cavity and parenchyma volumes, respectively. The percentages were statistically compared among the groups. The percentage of herniated cerebellum in the CKCS was compared using linear regression with the caudal fossa and parenchyma percentages. RESULTS: Cavalier King Charles spaniels had a proportionately smaller caudal fossa compared with Labradors (P=0.002) but not to small breeds (P=0.103). Their caudal fossa parenchyma was proportionately the same volume as Labradors (P=0.976) but greater than small breeds (P=0.005). No relationship was found for the per cent of cerebellum herniated. CLINICAL SIGNIFICANCE: The results support mesoderm insufficiency or craniosynostosis as the pathogenesis of Chiari-like malformation (CM) in CKCS. It presents evidence for overcrowding of the caudal fossa due to a mismatch of brain parenchyma and fossa volumes as to why CKCS and not other small dogs are affected.

OBJECTIVE: To compare radiographic morphology of the atlantoaxial region between Cavalier King Charles Spaniels (CKCSs) and dogs of other breeds and determine whether there was an association between radiographic morphology of the atlantoaxial region and syringomyelia in CKCSs. ANIMALS: 65 CKCSs and 72 dogs of other breeds. PROCEDURES: The amount that the spinous process of the axis overlapped the dorsal arch of the atlas, the relative size of the spinous process of the axis, and the amount of widening of the atlantoaxial joint that occurred when the neck was moved from a neutral to a flexed position were measured on lateral radiographic projections of the atlantoaxial region. Magnetic resonance images were reviewed to identify CKCSs with syringomyelia. RESULTS: The amount of overlap of the atlas and axis and the relative size of the spinous process of the axis were significantly smaller in CKCSs than in dogs of other breeds. However, the amount of widening of the atlantoaxial joint that occurred when the neck was moved from a neutral to a flexed position was not significantly different between groups, and no association was detected between syringomyelia and excessive atlantoaxial joint space widening or between syringomyelia and an excessively small axial spinous process. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that radiographic morphology of the atlantoaxial region in CKCSs differs from morphology of that region in dogs of other breeds, but that these differences do not account for why some CKCSs develop syringomyelia and others do not.

C Rusbridge, S Heath, DA Gunn-Moore, SP Knowler, N Johnston, AK McFadyen (2010)Feline orofacial pain syndrome (FOPS): a retrospective study of 113 cases., In: J Feline Med Surg12(6)pp. 498-508

Feline orofacial pain syndrome (FOPS) is a pain disorder of cats with behavioural signs of oral discomfort and tongue mutilation. This report describes the findings from a case series of 113 cats including 100 Burmese. FOPS is suspected to be a neuropathic pain disorder and the predominance within the Burmese cat breed suggests an inherited disorder, possibly involving central and/or ganglion processing of sensory trigeminal information. The disease is characterised by an episodic, typically unilateral, discomfort with pain-free intervals. The discomfort is triggered, in many cases, by mouth movements. The disease is often recurrent and with time may become unremitting - 12% of cases in this series were euthanased as a consequence of the condition. Sensitisation of trigeminal nerve endings as a consequence of oral disease or tooth eruption appears to be an important factor in the aetiology - 63% of cases had a history of oral lesions and at least 16% experienced their first sign of discomfort during eruption of permanent teeth. External factors can also influence the disease as FOPS events could be directly linked to a situation causing anxiety in 20% of cats. FOPS can be resistant to traditional analgesics and in some cases successful management required anti-convulsants with an analgesic effect.

A-M Kiviranta, Clare Rusbridge, O Laitinen-Vapaavuori, A Hielm-Bjorkman, AK Lappalainen, Susan Knowler, TS Jokinen (2017)Syringomyelia and Craniocervical Junction Abnormalities in Chihuahuas, In: J Vet Intern Med31(6)pp. 1771-1781 Wiley

Background: Chiari-like malformation (CM) and syringomyelia (SM) are widely reported in Cavalier King Charles Spaniels and Griffon Bruxellois dogs. Increasing evidence indicates that CM and SM also occur in other small and toy breed dogs, such as Chihuahuas. Objectives: To describe the presence of SM and craniocervical junction (CCJ) abnormalities in Chihuahuas and to evaluate the possible association of CCJ abnormalities with SM. To describe CM/SM-related clinical signs and neurologic deficits and to investigate the association of CM/SM-related clinical signs with signalment, SM, or CCJ abnormalities. Animals: Fifty-three client-owned Chihuahuas. Methods: Prospective study. Questionnaire analyses and physical and neurologic examinations were obtained before magnetic resonance and computed tomography imaging. Images were evaluated for the presence of SM, CM, and atlantooccipital overlapping. Additionally, medullary kinking, dorsal spinal cord compression, and their sum indices were calculated. Results: Scratching was the most common CM/SM-related clinical sign and decreased postural reaction the most common neurologic deficit in 73 and 87% of dogs, respectively. Chiari-like malformation and SM were present in 100 and 38% of dogs, respectively. Syringomyelia was associated with the presence of CM/SM-related clinical signs (P = 0.034), and medullary kinking and sum indices were higher in dogs with clinical signs (P = 0.016 and P = 0.007, respectively). Conclusions and Clinical Importance: Syringomyelia and CCJ abnormalities are prevalent in Chihuahuas. Syringomyelia was an important factor for the presence of CM/SM-related clinical signs, but many dogs suffered from similar clinical signs without being affected by SM, highlighting the clinical importance of CCJ abnormalities in Chihuahuas.

H Carruthers, C Rusbridge, MP Dubé, M Holmes, N Jeffery (2009)Association between cervical and intracranial dimensions and syringomyelia in the cavalier King Charles spaniel., In: J Small Anim Pract50(8)pp. 394-398

OBJECTIVES: To investigate the possible association between caudal fossa area and cervical vertebral dimensions and the presence of syringomyelia in cavalier King Charles spaniels. METHODS: From magnetic resonance imaging scans of 78 cavalier King Charles spaniels, measurements were made of the widest vertical spinal width at C1/C2, C2, C2/C3 and C3; angulation of the C2/C3 spine; and estimated caudal fossa area. A correlation between these measurements and syringomyelia was sought. RESULTS: A total of 59 dogs with and 19 without syringomyelia were compared. Older dogs had a significantly higher incidence of syringomyelia. No difference in incidence was noted between genders. There was no significant difference in vertebral canal width at C1/C2 and C2, or angulation of C2/C3 between syringomyelia and non-syringomyelia groups. The width of the canal at C2/C3 and C3 was significantly increased in syringomyelia dogs. There was no significant difference in the caudal fossa area between groups. CLINICAL SIGNIFICANCE: Although syringomyelia was shown to be more prevalent in older dogs, the age beyond which dogs were considered at greater risk was not deducible from the dataset. The association identified between wider spinal canal at C3, and C2/C3 and syringomyelia presence is of questionable clinical significance, as the difference between syringomyelia and non-syringomyelia groups is too small to be measured in a clinical setting.

R Cappello, C Rusbridge, Chiari-Like Malformation and Syringomyelia Working Group (2007)Report from the Chiari-Like Malformation and Syringomyelia Working Group round table., In: Vet Surg36(5)pp. 509-512
ACC Kent, F Constantino-Casas, C Rusbridge, BM Corcoran, M Carter, T Ledger, PJ Watson (2016)Prevalence of pancreatic, hepatic andrenal microscopic lesions in post-mortem samples from cavalier King Charles spaniels, In: JOURNAL OF SMALL ANIMAL PRACTICE57(4)pp. 188-193 WILEY-BLACKWELL
I Hajek, F Kettner, V Simerdova, Clare Rusbridge, P Wang, BA Minassian, V Palus (2016)NHLRC1 repeat expansion in two beagles with Lafora disease, In: Journal of Small Animal Practice57(11)pp. 650-652 Wiley

Lafora disease is a fatal genetic disorder characterised by neurotoxic deposits of malformed insoluble glycogen. In humans it is caused by mutation in the EPM2A or NHLRC1 genes. There is a known mutation in miniature wirehaired dachshunds which has not been documented in other dog breeds, including beagles, in which the disease is relatively commonly reported. This case report describes the causative defect in two affected beagles, namely the same massive expansion as in miniature wirehaired dachshunds of a 12-nucleotide repeat sequence that is unique to the canine NHLRC1 gene. This is the first mutation described in beagles with Lafora disease, and so far the only Lafora disease genetic variant in dogs.

SFM Bhatti, L De Risio, K Munana, J Penderis, VM Stein, A Tipold, M Berendt, RG Farquhar, A Fischer, S Long, W Loescher, PJJ Mandigers, K Matiasek, A Pakozdy, EE Patterson, S Platt, M Podell, H Potschka, C Rusbridge, HA Volk (2015)International Veterinary Epilepsy Task Force consensus proposal: medical treatment of canine epilepsy in Europe, In: BMC VETERINARY RESEARCH11ARTN 176 BIOMED CENTRAL LTD
A Cockburn, M Smith, Clare Rusbridge, C Fowler, E Paul, J Murrell, E Blackwell, R Casey, H Whay, M Mendl (2017)Evidence of negative affective state in Cavalier King Charles Spaniels with syringomyelia, In: Applied Animal Behaviour Science201pp. 77-84 Elsevier

Syringomyelia is a common and chronic neurological disorder affecting Cavalier King Charles Spaniels. The condition is putatively painful, but evaluating the affective component of chronic pain in non-human animals is challenging. Here we employed two methods designed to assess animal affect – the judgement bias and reward loss sensitivity tests – to investigate whether Cavalier King Charles Spaniels with syringomyelia (exhibiting a fluid filled cavity (syrinx) in the spinal cord of ≥2mm diameter) were in a more negative affective state than those without the condition. Dogs with syringomyelia did not differ in age from those without the condition, but owners reported that they scratched more (P

C Rusbridge (2014)Canine idiopathic epilepsy, In: IN PRACTICE36(Supp 1)pp. 17-23 BRITISH VETERINARY ASSOC

Canine idiopathic epilepsy has an estimated prevalence of 0.62 per cent in primary veterinary practice (Kearsley-Fleet and others 2013) and as such is one of the most common chronic neurological diseases. Descriptions of ‘epilepsy of unknown origin . . . where no symptom characteristic of any other condition has as yet presented’ can be found in early veterinary textbooks (Kirk 1922) and although our knowledge is now considerably greater, and we are no longer treating it with arsenic, we are still a long way from preventing or curing this enigmatic disease. This article describes the diagnosis, management and considerations to take when dealing with this condition.

Clare Rusbridge, Francisco Salguero Bodes, Monique A. David, Kiterie Faller, Jose T. Bras, Rita Guerreiro, Angela C. Richard-Loendt, Duncan Grainger, Elizabeth Head, Sebastian G. Brandner, Brian Summers, John Hardy, Mourad Tayebi (2018)An aged canid with behavioural deficits exhibits blood and cerebrospinal fluid amyloid beta oligomers, In: Nibaldo C. Inestrosa (eds.), Frontiers in Aging Neuroscience107pp. 1-8 Frontiers Media

Many of the molecular and pathological features associated with human Alzheimer disease (AD) are mirrored in the naturally occurring age-associated neuropathology in the canine species. In aged dogs with declining learned behaviour and memory the severity of cognitive dysfunction parallels the progressive build up and location of Aβ in the brain. The main aim of this work was to study the biological behaviour of soluble oligomers isolated from an aged dog with cognitive dysfunction through investigating their interaction with a human cell line and synthetic Aβ peptides. We report that soluble oligomers were specifically detected in the dog’s blood and cerebrospinal fluid via anti-oligomer- and anti-Aβ specific binders. Importantly, our results reveal the potent neurotoxic effects of the dog’s cerebrospinal fluid on cell viability and the seeding efficiency of the cerebrospinal fluid-borne soluble oligomers on the thermodynamic activity and the aggregation kinetics of synthetic human Aβ. The value of further characterising the naturally occurring Alzheimer-like neuropathology in dogs using genetic and molecular tools is discussed.

Susan Knowler, C Cross, S Griffiths, AK McFadyen, J Jovanovik, A Tauro, Z Kibar, KJ Driver, Roberto La Ragione, Clare Rusbridge (2017)Use of Morphometric Mapping to Characterise Symptomatic Chiari-Like Malformation, Secondary Syringomyelia and Associated Brachycephaly in the Cavalier King Charles Spaniel, In: PLoS One12(1)e0170315 Public Library of Science (PLoS)

Objectives To characterise the symptomatic phenotype of Chiari-like malformation (CM), secondary syringomyelia (SM) and brachycephaly in the Cavalier King Charles Spaniel using morphometric measurements on mid-sagittal Magnetic Resonance images (MRI) of the brain and craniocervical junction. Methods This retrospective study, based on a previous quantitative analysis in the Griffon Bruxellois (GB), used 24 measurements taken on 130 T1-weighted MRI of hindbrain and cervical region. Associated brachycephaly was estimated using 26 measurements, including rostral forebrain flattening and olfactory lobe rotation, on 72 T2-weighted MRI of the whole brain. Both study cohorts were divided into three groups; Control, CM pain and SM and their morphometries compared with each other. Results Fourteen significant traits were identified in the hindbrain study and nine traits in the whole brain study, six of which were similar to the GB and suggest a common aetiology. The Control cohort had the most elliptical brain (p = 0.010), least olfactory bulb rotation (p = 0.003) and a protective angle (p = 0.004) compared to the other groups. The CM pain cohort had the greatest rostral forebrain flattening (p = 0.007), shortest basioccipital (p = 0.019), but a greater distance between the atlas and basioccipital (p = 0.002) which was protective for SM. The SM cohort had two conformation anomalies depending on the severity of craniocervical junction incongruities; i) the proximity of the dens (p

Susan Knowler, A-M Kiviranta, AK McFadyen, TS Jokinen, Roberto La Ragione, Clare Rusbridge (2017)Craniometric Analysis of the Hindbrain and Craniocervical Junction of Chihuahua, Affenpinscher and Cavalier King Charles Spaniel Dogs With and Without Syringomyelia Secondary to Chiari-Like Malformation, In: PLoS One12(1)e0169898 Public Library of Science (PLoS)

Objectives:To characterize and compare the phenotypic variables of the hindbrain and craniocervical junction associated with syringomyelia (SM) in the Chihuahua, Affenpinscher and Cavalier King Charles Spaniel (CKCS). Method Analysis of 273 T1-weighted mid-sagittal DICOM sequences of the hindbrain and craniocervical junction from 99 Chihuahuas, 42 Affenpinschers and 132 CKCSs. The study compared 22 morphometric features (11 lines, eight angles and three ratios) of dogs with and without SM using refined techniques based on previous studies of the Griffon Bruxellois (GB) using Discriminant Function Analysis and ANOVA with post-hoc corrections. Results The analysis identified 14/22 significant traits for SM in the three dog breeds, five of which were identical to those reported for the GB and suggest inclusion of a common aetiology. One ratio, caudal fossa height to the length of the skull base extended to an imaginary point of alignment between the atlas and supraoccipital bones, was common to all three breeds (p values 0.029 to

AC Freeman, SR Platt, M Kent, E Huguet, C Rusbridge, S Holmes (2014)Chiari-Like Malformation and Syringomyelia in American Brussels Griffon Dogs, In: JOURNAL OF VETERINARY INTERNAL MEDICINE28(5)pp. 1551-1559 WILEY-BLACKWELL
J Brocal, S De Decker, R Jose-Lopez, EG Manzanilla, J Penderis, C Stalin, S Bertram, JJ Schoenebeck, Clare Rusbridge, Noel Fitzpatrick, R Gutierrez‐Quintana (2018)C7 vertebra homeotic transformation in domestic dogs - are Pug dogs breaking mammalian evolutionary constraints?, In: Journal of Anatomy233(2)pp. 255-265 Wiley

The number of cervical vertebrae in mammals is almost constant at seven, regardless of their neck length, implying that there is selection against variation in this number. Homebox (Hox) genes are involved in this evolutionary mammalian conservation, and homeotic transformation of cervical into thoracic vertebrae (cervical ribs) is a common phenotypic abnormality when Hox gene expression is altered. This relatively benign phenotypic change can be associated with fatal traits in humans. Mutations in genes upstream of Hox, inbreeding and stressors during organogenesis can also cause cervical ribs. The aim of this study was to describe the prevalence of cervical ribs in a large group of domestic dogs of different breeds, and explore a possible relation with other congenital vertebral malformations (CVMs) in the breed with the highest prevalence of cervical ribs. By phenotyping we hoped to give clues as to the underlying genetic causes. Twenty computed tomography studies from at least two breeds belonging to each of the nine groups recognized by the Federation Cynologique Internationale, including all the brachycephalic ‘screw‐tailed’ breeds that are known to be overrepresented for CVMs, were reviewed. The Pug dog was more affected by cervical ribs than any other breed (46%; P 

P Lemay, Susan Knowler, S Bouasker, Y Nédélec, S Platt, C Freeman, G Child, LB Barreiro, GA Rouleau, Clare Rusbridge, Z Kibar (2014)Quantitative Trait Loci (QTL) Study Identifies Novel Genomic Regions Associated to Chiari-Like Malformation in Griffon Bruxellois Dogs, In: PLoS ONE9(4)e89816 Public Library of Science

Chiari-like malformation (CM) is a developmental abnormality of the craniocervical junction that is common in the Griffon Bruxellois (GB) breed with an estimated prevalence of 65%. This disease is characterized by overcrowding of the neural parenchyma at the craniocervical junction and disturbance of cerebrospinal fluid (CSF) flow. The most common clinical sign is pain either as a direct consequence of CM or neuropathic pain as a consequence of secondary syringomyelia. The etiology of CM remains unknown but genetic factors play an important role. To investigate the genetic complexity of the disease, a quantitative trait locus (QTL) approach was adopted. A total of 14 quantitative skull and atlas measurements were taken and were tested for association to CM. Six traits were found to be associated to CM and were subjected to a whole-genome association study using the Illumina canine high density bead chip in 74 GB dogs (50 affected and 24 controls). Linear and mixed regression analyses identified associated single nucleotide polymorphisms (SNPs) on 5 Canis Familiaris Autosomes (CFAs): CFA2, CFA9, CFA12, CFA14 and CFA24. A reconstructed haplotype of 0.53 Mb on CFA2 strongly associated to the height of the cranial fossa (diameter F) and an haplotype of 2.5 Mb on CFA14 associated to both the height of the rostral part of the caudal cranial fossa (AE) and the height of the brain (FG) were significantly associated to CM after 10 000 permutations strengthening their candidacy for this disease (P = 0.0421, P = 0.0094 respectively). The CFA2 QTL harbours the Sall-1 gene which is an excellent candidate since its orthologue in humans is mutated in Townes-Brocks syndrome which has previously been associated to Chiari malformation I. Our study demonstrates the implication of multiple traits in the etiology of CM and has successfully identified two new QTL associated to CM and a potential candidate gene.

Background: Chiari-like malformation (CM) is a complex malformation of the skull and cranial cervical vertebrae potentially resulting in pain and secondary syringomyelia (SM). CM associated pain can be challenging to diagnose [35]. We propose a machine learning approach to characterize morphological changes in dogs that may/may not be apparent to human observers. This data driven approach can remove potential bias (or blindness) that may be produced by a hypothesis driven expert observer approach. Hypothesis/Objectives: Using a novel machine learning approach to understand neuromorphological change and to identify image-based biomarkers in dogs with CM associated pain (CM-P) and symptomatic SM (SM-S), with the aim of deepening the understanding on these disorders. Animals: 32 client owned Cavalier King Charles Spaniels (CKCS) (11 controls, 10 CM-P, 11 SM-S) Methods: Retrospective study using T2W midsagittal DICOM anonymized images which were mapped to a images of a average clinically normal CKCS reference using Demons image registration. Key deformation features were automatically selected from the resulting deformation maps. A kernelized Support Vector Machine was used for classifying characteristic localized changes in morphology. Results: Candidate biomarkers were identified with receiver operating characteristic (ROC) curves with area under the curve (AUC) of 0.78 (sensitivity = 82%; specificity = 69%) for the CM-P biomarkers collectively, and an AUC of 0.82 (sensitivity = 93%; specificity = 67%) for the SM biomarkers collectively. Conclusions and clinical importance: Machine learning techniques can assist CM/SM diagnosis and understand abnormal morphology location with the potential to be applied to a variety of breeds and conformational diseases.

Ricardo Fernandes, Colin Driver, J H Rose, Clare Rusbridge (2019)MRI findings in two West Highland White Terrier dogs with hepatic encephalopathy secondary to portosystemic shunt, In: Veterinary Record Case Reports7(3) BMJ Publishing Group

A portosystemic shunt is an abnormal communication between the portal vascular system and the systemic circulation. A significant number of clinical signs associated with portosystemic shunting result from hepatic encephalopathy (HE); a syndrome encompassing neurological signs such as including changes in behaviour, ataxia, unresponsiveness, pacing, circling, blindness, seizures, coma and death. We present two West Highland White Terrier dogs diagnosed with HE based on clinical signs, bile acid stimulation test and imaging of the abnormal vessel communicating the portal and the systemic circulation. Magnetic resonance sequences of the brain revealed a poorly marginated and diffuse, bilateral and symmetric hyperintense lesions on T2-weighted, fluid attenuation inversion recovery and diffusion-weighted sequences relative to the brain parenchyma including the medial longitudinal fasciculus and reticular formation in the brainstem. No abnormalities were detected on T1-weighted sequences.

Sarah Butterfield, Beatriz Garcia-Gonzalez, Colin J Driver, Clare Rusbridge (2020)Limited dorsal myeloschisis in three cats: a distinctive form of neural tube defect, In: Journal of Feline Medicine and Surgery Open Reports6(1) SAGE Publications

Case series summary The aim of this case series was to describe the clinical presentation, imaging findings and histopathology of three cats with limited dorsal myeloschisis (LDM). The history, examination and MRI sequences were reviewed in three cases presented to a single referral hospital. The surgery report and histopathology were described in two cases. All cats were young (10 weeks old, 5 months old, 4 years old), presenting with varying degrees of progressive paraparesis. All had a midline skin defect overlying the spinal column that was either sunken or saccular, containing fluid thought to be cerebrospinal fluid. MRI sequences demonstrated tissue extending from the dura through an overlying bifid spinous process and attached to the dermis, with associated spinal cord tethering, atrophy and syringomyelia. Lesions were located at L2–L3, T8–T9 and L4. Histopathology described a fibroneural stalk with a glio-ependymal lining, surrounded by glial nests and nerve fibres. The youngest and most severely affected was euthanased, while the other two underwent surgery. Both regained independent ambulation with persistent paraparesis; however, one required ongoing management of urinary incontinence. Relevance and novel information LDM is a primary neural tube defect that may result in neurological deficits, including bladder dysfunction, and is characterised by a fibroneural stalk between the dermis and the spinal cord. Distinct MRI features, such as a visible intrathecal tract, dorsally tethered cord and syringomyelia, help distinguish this condition from the clinically similar dermoid sinus. The presence of progressive neurological signs, with a palpable midline defect overlying the affected spinal cord segment, may raise suspicion for this clinical entity in veterinary patients.

Pablo Amengual-Batle, Clare Rusbridge, Roberto Jose-Lopez, Lorenzo Golini, G. Diane Shelton, Cathryn S. Mellersh, Rodrigo Gutierrez-Quintana (2018)Two Mixed Breed Dogs With Sensory Neuropathy Are Homozygous for an Inversion Disrupting FAM134B Previously Identified in Border Collies, In: Journal of Veterinary Internal Medicine32(6)pp. 2082-2087 Journal of Veterinary Internal Medicine

Two unrelated 8-month-old male mixed breed dogs were presented for evaluation of progressive ataxia, knuckling, and lack of pain perception in the distal limbs. Because of the similarity in age of onset, progression, and clinical findings with previously described sensory neuropathy in Border Collies, the affected dogs were screened for an FAM134B mutation and were determined to be homozygous for the mutation. Despite few phenotypic similarities with other breeds, genetic testing for specific diseases should be considered in mixed breed dogs with compatible clinical signs, especially if ancestry is unknown.

Susan Penelope Knowler, Lena Gillstedt, Thomas J Mitchell, Jelena Jovanovik, Holger Andreas Volk, Clare Rusbridge (2018)Pilot study of head conformation changes over time in the Cavalier King Charles spaniel breed, In: Veterinary Record184(4)pp. 122-122 BMJ Publishing Group

Modern interpretation of head conformation in the Cavalier King Charles spaniel (CKCS) has favoured a smaller, more exaggerated, brachycephalic type than originally described in the 1929 breed standard. Recent research studies identified brachycephaly and reduced hind cranium as two conformational (dysmorphic) features that increase risk for symptomatic Chiari-like malformation and secondary syringomyelia (SM). A prospective pilot study investigated the hypothesis that dysmorphic head features could be assessed visually and correlated with risk of SM. Thirteen CKCS, selected from anonymised photographic evidence, were physically appraised by authorised Kennel Club judges using a head shape checklist. These subjective evaluations were then matched with objective measurements of the cranium (cephalic index and rostrocaudal doming) and their subsequent MRI. A positive correlation (P=0.039) between the judges’ checklist score and rostrocaudal doming (hindskull ratio) and a positive correlation between the cephalic index and hindskull ratio (P=0.042) were identified. Five CKCS had no SM and their status tallied with 62 per cent of the judges’ evaluation. Although the ability of adjudicators to identify differences in head conformation varied, there was sufficient association between the dysmorphic parameters and the risk of SM to cause concern and propose a larger study in CKCS breed.

A Lujan Feliu-Pascual, GD Shelton, MP Targett, SN Long, EJ Comerford, C McMillan, D Davies, C Rusbridge, D Mellor, KC Chang, TJ Anderson (2006)Inherited myopathy of great Danes., In: J Small Anim Pract47(5)pp. 249-254

A hereditary, non-inflammatory myopathy occurring in young great Danes with distinctive histological features in muscle biopsy specimens is reviewed. Onset of clinical signs is usually before one year of age and both sexes are affected. Clinical signs are characterised by exercise intolerance, muscle wasting, and an exercise-induced tremor. Although most affected dogs have a severe form of the disease, occasional dogs may have a less pronounced form and survive into adulthood with an acceptable quality of life. Litters containing affected puppies are born to clinically unaffected parents, and an autosomal recessive pattern of inheritance is likely. All recorded cases have had fawn or brindle coat coloration. Elevated serum creatinine kinase concentrations and spontaneous electrical activity in skeletal muscles are frequently found. While originally reported (Targett and others 1994) as a central core myopathy in this breed, the histochemical characteristics of the distinct cytoarchitectural structures differ from those of the well-characterised central core myopathy in human beings. In fact, these structures differ from any known myopathy in human beings and likely represents a unique non-inflammatory myopathy affecting dogs. Until this myopathy is characterised further, the name inherited myopathy in great Danes is suggested.

Jagmeet S. Grewal, Tyler Gloe, Joseph Hegedus, Kathleen Bitterman, Brendon K. Billings, Samson Chengetanai, Sarah Bentil, Victoria X. Wang, Johnny C. Ng, Cheuk Y. Tang, Simon Geletta, Bridget Wicinski, Mads Bertelson, Benjamin C. Tendler, Rogier B. Mars, Geoffrey K. Aguirre, Clare Rusbridge, Patrick R. Hof, Chet C. Sherwood, Paul R. Manger, Muhammad A. Spocter (2020)Brain gyrification in wild and domestic canids: Has domestication changed the gyrification index in domestic dogs?, In: Journal of Comparative Neurology528(18)pp. 3209-3228 Wiley

Over the last 15 years, research on canid cognition has revealed that domestic dogs possess a surprising array of complex socio‐cognitive skills pointing to the possibility that the domestication process might have uniquely altered their brains; however, we know very little about how evolutionary processes (natural or artificial) might have modified underlying neural structure to support species‐specific behaviors. Evaluating the degree of cortical folding (i.e., gyrification) within canids may prove useful, as this parameter is linked to functional variation of the cerebral cortex. Using quantitative magnetic resonance imaging to investigate the impact of domestication on the canine cortical surface, we compared the gyrification index (GI) in 19 carnivore species, including six wild canid and 13 domestic dog individuals. We also explored correlations between global and local GI with brain mass, cortical thickness, white and grey matter volume and surface area. Our results indicated that GI values for domestic dogs are largely consistent with what would be expected for a canid of their given brain mass, although more variable than that observed in wild canids. We also found that GI in canids is positively correlated with cortical surface area, cortical thickness and total cortical grey matter volumes. While we found no evidence of global differences in GI between domestic and wild canids, certain regional differences in gyrification were observed.

LJ Kennedy, S Quarmby, GM Happ, A Barnes, IK Ramsey, RM Dixon, B Catchpole, C Rusbridge, PA Graham, NS Hillbertz, C Roethel, WJ Dodds, NG Carmichael, WE Ollier (2006)Association of canine hypothyroidism with a common major histocompatibility complex DLA class II allele., In: Tissue Antigens68(1)pp. 82-86

Dogs exhibit a range of immune-mediated conditions including a lymphocytic thyroiditis which has many similarities to Hashimoto's thyroiditis in man. We have recently reported an association in Doberman Pinschers between canine hypothyroidism and a rare DLA class II haplotype that contains the DLA-DQA1*00101 allele. We now report a further series of 173 hypothyroid dogs in a range of breeds where a significant association with DLA-DQA1*00101 is shown.

Ricardo Fernandes, Noel Fitzpatrick, Clare Rusbridge, Jeremy Rose, Colin J. Driver (2019)Cervical vertebral malformations in 9 dogs: radiological findings, treatment options and outcomes, In: Irish Veterinary Journal72(1) Wiley Open Access

Two unrelated 8-month-old male mixed breed dogs were presented for evaluation of progressive ataxia, knuckling, and lack of pain perception in the distal limbs. Because of the similarity in age of onset, progression, and clinical findings with previously described sensory neuropathy in Border Collies, the affected dogs were screened for an FAM134B mutation and were determined to be homozygous for the mutation. Despite few phenotypic similarities with other breeds, genetic testing for specific diseases should be considered in mixed breed dogs with compatible clinical signs, especially if ancestry is unknown.

A Tauro, E Beltran, GB Cherubini, AT Coelho, A Wessmann, CJ Driver, CJ Rusbridge (2018)Metronidazole-induced neurotoxicity in 26 dogs, In: Australian Veterinary Journal96(12)pp. 495-501 Wiley

Background: Metronidazole is an antibacterial, antiprotozoal and anthelmintic medication commonly used in veterinary medicine. We describe cases of neurotoxicity associated with the drug’s administration. Methods: Medical records between 2004 and 2017 from four veterinary referral hospitals were reviewed. Inclusion criteria were the presence of neurological signs compatible with metronidazole toxicity, clinical history supporting recent metronidazole therapy and resolution of clinical signs upon discontinuation of metronidazole administration. Results: A total of 26 dogs were identified with clinical signs supporting a diagnosis of metronidazole toxicity. Median age at presentation was 7.2 years (range, 0.1–12 years); median duration of treatment was 35 days (range, 5–180 days); median treatment dosage was 21 mg/kg BID (range, 13–56 mg/kg every 12 h); median resolution of the clinical signs upon discontinuation of metronidazole was 3 days (range, 1–26 days). Magnetic resonance imaging (MRI) of the brain was performed in 19 cases and only one dog had brain lesions affecting the dentate nuclei, which resembled the MRI appearance of this disease in humans. Conclusions: We found evidence of neurotoxicity in dogs at much lower doses than previously reported and we suggest caution when administering metronidazole at doses > 40 mg/kg every 24 h, regardless of the duration of the treatment.

Susan P Knowler, Gabriel L Galea, Clare Rusbridge (2018)Morphogenesis of canine Chiari malformation and secondary syringomyelia: Disorders of cerebrospinal fluid circulation, In: Frontiers in Veterinary Science5171 Frontiers Media

Chiari-like Malformation (CM) and secondary syringomyelia (SM), as well as their analogous human conditions, is a complex developmental condition associated with pain and accompanying welfare concerns. CM/SM is diagnosed ever more frequently, thanks in part to the increased availability of magnetic resonance imaging in veterinary medicine. Research over the last two decades has focused primarily on its pathophysiology relating to overcrowding of the cranial caudal fossa. More recent characterizations of CM/SM include brachycephaly with osseous reduction and neural parenchymal displacement involving the entire brain and craniocervical junction to include rostral flattening, olfactory bulb rotation, increased height of the cranium, reduced cranial base with spheno-occipital synchondrosis angulation, reduced supraoccipital and interparietal crest and rostral displacement of the axis and atlas with increased odontoid angulation. The most shared manifestation of CM is the development of fluid-filled pockets (syrinx, syringes) in the spinal cord that can be readily quantified. Dogs with symptomatic CM without SM have a reduced basioccipital bone, compensatory increased cranial fossa height with displaced parenchyma whereby the cerebellum is invaginated beneath the occipital lobes but without compromising cerebrospinal fluid channels enough to cause SM. Thus, broadly defined, CM might be described as any distortion of the skull and craniocervical junction which compromises the neural parenchyma and cerebrospinal fluid circulation causing pain and/or SM. The etiology of CM is multifactorial, potentially including genetically-influenced, breed-specific abnormalities in both skeletal and neural components. Since causation between specific morphologic changes and SM or clinical signs is unproven, CM might be more appropriately considered as a brachycephalic obstructive CSF channel syndrome (BOCCS) rather than a single malformation. Understanding the normal development of the brain, skull and craniocervical junction is fundamental to identifying deviations which predispose to CM/SM. Here we review its anatomical, embryological, bio-mechanical, and genetic underpinnings to update the profession’s understanding of this condition and meaningfully inform future research to diminish its welfare impact.

CJ Driver, HA Volk, C Rusbridge, LM Van Ham (2013)An update on the pathogenesis of syringomyelia secondary to Chiari-like malformations in dogs., In: Vet J198(3)pp. 551-559

Syringomyelia (SM) is a spinal cord disease that can cause neuropathic pain in dogs. The pathogenesis of SM secondary to Chiari-like malformation (CM) has been the focus of intense research in recent years. The gulf in our understanding of CM/SM in dogs relative to the analogous human condition has progressively narrowed. CM is primarily a disease of abnormal geometric morphometry affecting the caudal cranial fossa and the brain parenchyma contained within it. This review describes how advanced imaging techniques have revealed a series of morphometric abnormalities associated with CM/SM. The series is presented in a logical order to help describe the pathogenesis of CM and the subsequent formation of syringes, with particular reference to the concepts of craniospinal compliance and cerebrospinal fluid pulse pressure timing.

IN Plessas, HA Volk, C Rusbridge, AE Vanhaesebrouck, ND Jeffery (2015)Comparison of gabapentin versus topiramate on clinically affected dogs with Chiari-like malformation and syringomyelia, In: VETERINARY RECORD177(11)pp. 288-+ BMJ PUBLISHING GROUP
F Ancot, P Lemay, Penny Knowler, K Kennedy, S Griffiths, G Cherubini, J Sykes, P Mandigers, G Rouleau, Clare Rusbridge, Z Kibar (2018)A genome-wide association study identifies candidate loci associated to syringomyelia secondary to Chiari-like malformation in Cavalier King Charles Spaniels, In: BMC Genetics19(16) BioMed Central

Background: Syringomyelia (SM) is a common condition affecting brachycephalic toy breed dogs and is characterized by the development of fluid-filled cavities within the spinal cord. It is often concurrent with a complex developmental malformation of the skull and craniocervical vertebrae called Chiari-like malformation (CM) characterized by a conformational change and overcrowding of the brain and cervical spinal cord particularly at the craniocervical junction. CM and SM have a polygenic mode of inheritance with variable penetrance. Results: We identified six cranial T1-weighted sagittal MRI measurements that were associated to maximum transverse diameter of the syrinx cavity. Increased syrinx transverse diameter has been correlated previously with increased likelihood of behavioral signs of pain. We next conducted a whole genome association study of these traits in 65 Cavalier King Charles Spaniel (CKCS) dogs (33 controls, 32 with extreme phenotypes). Two loci on CFA22 and CFA26 were found to be significantly associated to two traits associated with a reduced volume and altered orientation of the caudal cranial fossa. Their reconstructed haplotypes defined two associated regions that harbor only two genes: PCDH17 on CFA22 and ZWINT on CFA26. PCDH17 codes for a cell adhesion molecule expressed specifically in the brain and spinal cord. ZWINT plays a role in chromosome segregation and its expression is increased with the onset of neuropathic pain. Targeted genomic sequencing of these regions identified respectively 37 and 339 SNPs with significantly associated P values. Genotyping of tagSNPs selected from these 2 candidate loci in an extended cohort of 461 CKCS (187 unaffected, 274 SM affected) identified 2 SNPs on CFA22 that were significantly associated to SM strengthening the candidacy of this locus in SM development. Conclusions: We identified 2 loci on CFA22 and CFA26 that contained only 2 genes, PCDH17 and ZWINT, significantly associated to two traits associated with syrinx transverse diameter. The locus on CFA22 was significantly associated to SM secondary to CM in the CKCS dog breed strengthening its candidacy for this disease. This study will provide an entry point for identification of the genetic factors predisposing to this condition and its underlying pathogenic mechanisms.

Clare Rusbridge, Felicity Stringer, Susan P. Knowler (2018)Clinical Application of Diagnostic Imaging of Chiari-Like Malformation and Syringomyelia, In: Frontiers in Veterinary Science5(280) Frontiers Media

Chiari-like malformation (CM) and syringomyelia (SM) is a frequent diagnosis in predisposed brachycephalic toy breeds since increased availability of MRI. However, the relevance of that MRI diagnosis has been questioned as CM, defined as identification of a cerebellar herniation, is ubiquitous in some breeds and SM can be asymptomatic. This article reviews the current knowledge of neuroanatomical changes in symptomatic CM and SM and diagnostic imaging modalities used for the clinical diagnosis of CM-pain or myelopathy related to SM. Although often compared to Chiari type I malformation in humans, canine CM-pain and SM is more comparable to complex craniosynostosis syndromes (i.e., premature fusion of multiple skull sutures) characterized by a short skull (cranial) base, rostrotentorial crowding with rostral forebrain flattening, small, and ventrally orientated olfactory bulbs, displacement of the neural tissue to give increased height of the cranium and further reduction of the functional caudotentorial space with hindbrain herniation. MRI may further reveal changes suggesting raised intracranial pressure such as loss of sulci definition in conjunction with ventriculomegaly. In addition to these brachycephalic changes, dogs with SM are more likely to have craniocervical junction abnormalities including rostral displacement of the axis and atlas with increased odontoid angulation causing craniospinal junction deformation and medulla oblongata elevation. Symptomatic SM is diagnosed on the basis of signs of myelopathy and presence of a large syrinx that is consistent with the neuro-localization. The imaging protocol should establish the longitudinal and transverse extent of the spinal cord involvement by the syrinx. Phantom scratching and cervicotorticollis are associated with large mid-cervical syringes that extend to the superficial dorsal horn. If the cause of CSF channel disruption and syringomyelia is not revealed by anatomical MRI then other imaging modalities may be appropriate with radiography or CT for any associated vertebral abnormalities.

Muhammad A Spocter, Ashraf Uddin, Johnny C Ng, Edmund Wong, Victoria X Wang, Cheuk Tang, Bridget Wicinski, Jordan Haas, Kathleen Bitterman, Mary Ann Raghanti, Rachel Dunn, Patrick R Hof, Chet C Sherwood, Jelena Jovanovik, Clare Rusbridge, Paul R Manger (2018)Scaling of the corpus callosum in wild and domestic canids: Insights into the domesticated brain., In: JOURNAL OF COMPARATIVE NEUROLOGY526(15)pp. 2341-2359 WILEY-LISS

All domesticated mammals exhibit marked reductions in overall brain size, however, it is unknown whether the corpus callosum, an integral white matter fiber pathway for interhemispheric cortical communication, is affected by domestication differentially or strictly in coordination with changes in brain size. To answer this question, we used quantitative magnetic resonance imaging to compare the mid‐sagittal cross‐sectional areas of the corpus callosum in 35 carnivore species, including eight wild canids and 13 domestic dogs. We segmented rostro‐caudal regions of interest for the corpus callosum and evaluated correlations with brain mass. The results of this study indicate that under the influence of domestication in canids, the corpus callosum scales to brain size in an allometric relationship that is similar to that of wild canids and other carnivores, with relatively high correlation coefficients observed for all regions, except the rostrum. These results indicate that architectural and energetic considerations are likely to tightly constrain variation in caudal components of the corpus callosum relative to overall brain size, however fibers passing through the rostrum, putatively connecting prefrontal cortex, are less constrained and therefore may contribute more towards species‐specific differences in connectivity. Given the species diversity of the Canidae and the resurgence of interest in the brain of the domestic dog, further studies aimed at characterizing the neural architecture in domesticated species is likely to provide new insights into the effects of domestication, or artificial selection, on the brain.

C Rusbridge, ND Jeffery (2008)Pathophysiology and treatment of neuropathic pain associated with syringomyelia., In: Vet J175(2)pp. 164-172

The pain behaviour expressed by dogs with syringomyelia suggests that they experience neuropathic pain, probably due to disordered neural processing in the damaged dorsal horn. As such it is likely that conventional analgesic medication will be ineffective. In this review, physiological and pathological pain processing through the dorsal horn is summarised and mechanisms by which syringomyelia could result in a persistent pain state are discussed. Finally, current knowledge regarding treatment of Chiari malformation and syringomyelia is reviewed and possible drugs which may give improved pain relief in affected dogs are discussed.

Natalie West, Sarah Butterfield, Clare Rusbridge, Ana Fernandez, Joana Tabanez, Nichola Jane Rudolf, Simon Archer, Danielle Whittaker (2023)Non‐traumatic hemorrhagic myelopathy in dogs, In: Journal of veterinary internal medicine37(3)pp. 1129-1138 John Wiley & Sons, Inc

Background Non‐traumatic spinal cord hemorrhage (NTSH) is an uncommon cause of myelopathy in dogs. Objectives Describe the clinical characteristics, concurrent medical conditions and underlying causes, magnetic resonance imaging (MRI) findings and outcome in dogs with NTSH. Animals Dogs diagnosed with NTSH using gradient echo T2‐weighted (GRE) sequences with or without histopathological confirmation of hemorrhage were included. Dogs with a traumatic cause were excluded, including those with compressive intervertebral disc extrusion. Methods Retrospective descriptive study; the databases of 2 referral hospitals were searched between 2013 and 2021. Results Twenty‐three dogs met inclusion criteria. The onset of signs was acute and progressive in 70% of cases; spinal hyperesthesia was variable (48%). Hemorrhage was identified in the thoracolumbar spinal segments in 65% of dogs. An underlying cause was identified in 65% of cases. Angiostrongylus vasorum represented 18% of the total cohort, followed by steroid‐responsive meningitis arteritis (SRMA; 13%). Overall, 64% of dogs had a good or excellent outcome, regardless of cause; which was increased to 100% for SRMA, 75% for A. vasorum and 75% for idiopathic NTSH. Outcome was not associated with neurological severity. Recovery rate was 67% and 50% for nociception‐intact and nociception‐negative dogs, respectively. Conclusions Larger prospective studies would be required to define prognostic factors for dogs with NTSH, but outcome appeared to be most influenced by the underlying cause, as opposed to neurological severity at presentation.

Susan K Halstead, Mark Jackson, Ezio Bianchi, Stefan Rupp, Nicolas Granger, Marika Menchetti, Greta Galli, Paul Freeman, Adriana Kaczmarska, Sofie F M Bhatti, Josep Brocal, Roberto José-López, Andrea Tipold, Rodrigo Gutierrez Quintana, Edward J Ives, Theofanis Liatis, Jasmin Nessler, Clare Rusbridge, Hugh J Willison, Angie Rupp (2023)Serum anti-GM2 and anti-GalNAc-GD1a ganglioside IgG antibodies are biomarkers for immune-mediated polyneuropathies in cats, In: Journal of the peripheral nervous system28(1)pp. 32-40 Wiley

Recent work identified anti-GM2 and anti-GalNAc-GD1a IgG ganglioside antibodies as biomarkers in dogs clinically diagnosed with acute canine polyradiculoneuritis, in turn considered a canine equivalent of Guillain-Barré syndrome. This study aims to investigate the serum prevalence of similar antibodies in cats clinically diagnosed with immune-mediated polyneuropathies. The sera from 41 cats clinically diagnosed with immune-mediated polyneuropathies (IPN), 9 cats with other neurological or neuromuscular disorders (ONM) and 46 neurologically normal cats (CTRL) were examined for the presence of IgG antibodies against glycolipids GM1, GM2, GD1a, GD1b, GalNAc-GD1a, GA1, SGPG, LM1, galactocerebroside and sulphatide. A total of 29/41 IPN-cats had either anti-GM2 or anti-GalNAc-GD1a IgG antibodies, with 24/29 cats having both. Direct comparison of anti-GM2 (sensitivity: 70.7%; specificity: 78.2%) and anti-GalNAc-GD1a (sensitivity: 70.7%; specificity: 70.9%) antibodies narrowly showed anti-GM2 IgG antibodies to be the better marker for identifying IPN-cats when compared to the combined ONM and CTRL groups (P = .049). Anti-GA1 and/or anti-sulphatide IgG antibodies were ubiquitously present across all sample groups, whereas antibodies against GM1, GD1a, GD1b, SGPG, LM1 and galactocerebroside were overall only rarely observed. Anti-GM2 and anti-GalNAc-GD1a IgG antibodies may serve as serum biomarkers for immune-mediated polyneuropathies in cats, as previously observed in dogs and humans.

Natalie West, Kaspar Matiasek, Clare Rusbridge (2021)Olivopontocerebellar degeneration associated with 3-hydroxy-3-methylglutaric aciduria in a domestic shorthair cat, In: JOURNAL OF FELINE MEDICINE AND SURGERY OPEN REPORTS7(2) Sage

Case summary A rescue charity-owned 6-month-old neutered female domestic shorthair cat was presented with progressive tetraparesis, increased extensor muscle tone and signs of spinocerebellar ataxia, including hypermetria. The cat's male sibling, with similar progressive neurological signs, had been euthanased 2 months previously. An inherited metabolic disorder was suspected. Urine for determination of organic acid concentration was obtained and the cat was prescribed carnitine and taurine supplementation. The cat was euthanased 3 months later following progressive neurological signs, including ataxia, tetraparesis, tendency to fall, bilateral absent menace response and intention tremor. A selective post-mortem examination was obtained, taking samples from the brain, cervical spinal cord, tibial branch of the sciatic nerve, muscle, liver and kidneys. Organic acid analysis results received after euthanasia revealed a marked elevation of 3-hydroxy-3-methylglutaric acid (45 mmol/mol creatine [normal range 0-2]) and isovalerylglycine (27 mmol/mol creatinine [normal range 0-2]). 3-Hydroxy-3-methylglutaric acid was deemed clinically relevant as it is a metabolite of 3-hydroxy-3-methylglutaryl-CoA lyase, the enzyme involved in the final step of leucine degradation. Post-mortem examination revealed diffuse, chronic-active, severe olivoponto-(spino)-cerebellar degeneration. Relevance and novel information This is the first report of 3-hydroxy-3-methylglutaric aciduria in the veterinary literature and the first description of the neuropathology of this disorder in any species. 3-Hydroxy-3-methylglutaric aciduria in humans occurs rarely and is due to a deficiency in 3-hydroxy-3-methylglutaryl-coenzyme A lyase.

Francesca Genova, Simona Nonnis, Elisa Maffioli, Gabriella Tedeschi, Maria Giuseppina Strillacci, Michela Carisetti, Giuseppe Sironi, Francesca Anna Cupaioli, Noemi Di Nanni, Alessandra Mezzelani, Ettore Mosca, Christopher R. Helps, Peter A. J. Leegwater, Laetitia Dorso, Maria Longeri, Reuben M. Buckley, Danielle Aberdein, Paulo C. Alves, Asa Ohlsson Andersson, Gregory S. Barsh, Rebecca R. Bellone, Tomas F. Bergstrom, Adam R. Boyko, Jeffrey A. Brockman, Margret L. Casal, Marta G. Castelhano, Ottmar Distl, Nicholas H. Dodman, N. Matthew Ellinwood, Jonathan E. Fogle, Oliver P. Forman, Dorian J. Garrick, Edward Ginns, Bianca Haase, Jens Haggstrom, Robert J. Harvey, Daisuke Hasegawa, Isabel Hernandez, Marjo K. Hytonen, Maria Kaukonen, Christopher B. Kaelin, Tomoki Kosho, Emilie Leclerc, Teri L. Lear, Tosso Leeb, Ronald H. L. Li, Hannes Lohi, Mark A. Magnuson, Richard Malik, Shrinivasrao P. Mane, John S. Munday, William J. Murphy, Niels C. Pedersen, Simon M. Peterson-Jones, Max F. Rothschild, Clare Rusbridge, Beth Shapiro, Joshua A. Stern, William F. Swanson, Karen A. Terio, Rory J. Todhunter, Wesley C. Warren, Elizabeth A. Wilcox, Julia H. Wildschutte, Yoshihiko Yu, Leslie A. Lyons (2021)Multi-omic analyses in Abyssinian cats with primary renal amyloid deposits, In: Scientific reports11(1)8339 NATURE PORTFOLIO

The amyloidoses constitute a group of diseases occurring in humans and animals that are characterized by abnormal deposits of aggregated proteins in organs, affecting their structure and function. In the Abyssinian cat breed, a familial form of renal amyloidosis has been described. In this study, multi-omics analyses were applied and integrated to explore some aspects of the unknown pathogenetic processes in cats. Whole-genome sequences of two affected Abyssinians and 195 controls of other breeds (part of the 99 Lives initiative) were screened to prioritize potential disease-associated variants. Proteome and miRNAome from formalin-fixed paraffin-embedded kidney specimens of fully necropsied Abyssinian cats, three affected and three non-amyloidosis-affected were characterized. While the trigger of the disorder remains unclear, overall, (i) 35,960 genomic variants were detected; (ii) 215 and 56 proteins were identified as exclusive or overexpressed in the affected and control kidneys, respectively; (iii) 60 miRNAs were differentially expressed, 20 of which are newly described. With omics data integration, the general conclusions are: (i) the familial amyloid renal form in Abyssinians is not a simple monogenic trait; (ii) amyloid deposition is not triggered by mutated amyloidogenic proteins but is a mix of proteins codified by wild-type genes; (iii) the form is biochemically classifiable as AA amyloidosis.

Matthias Christen, Rodrigo Gutierrez-Quintana, Matthew Green, Kiterie M. E. Faller, Mark Lowrie, Clare Rusbridge, Kenny Bossens, Cathryn Mellersh, Louise Pettitt, Tiina Heinonen, Hannes Lohi, Vidhya Jagannathan, Tosso Leeb (2023)A TNR Frameshift Variant in Weimaraner Dogs with an Exercise-Induced Paroxysmal Movement Disorder, In: Movement disorders38(6)pp. 1094-1099 Wiley

BackgroundSome paroxysmal movement disorders remain without an identified genetic cause. ObjectivesThe aim was to identify the causal genetic variant for a paroxysmal dystonia-ataxia syndrome in Weimaraner dogs. MethodsClinical and diagnostic investigations were performed. Whole genome sequencing of one affected dog was used to identify private homozygous variants against 921 control genomes. ResultsFour Weimaraners were presented for episodes of abnormal gait. Results of examinations and diagnostic investigations were unremarkable. Whole genome sequencing revealed a private frameshift variant in the TNR (tenascin-R) gene in an affected dog, XM_038542431.1:c.831dupC, which is predicted to truncate more than 75% of the open read frame. Genotypes in a cohort of 4 affected and 70 unaffected Weimaraners showed perfect association with the disease phenotype. ConclusionsWe report the association of a TNR variant with a paroxysmal dystonia-ataxia syndrome in Weimaraners. It might be relevant to include sequencing of this gene in diagnosing humans with unexplained paroxysmal movement disorders. (c) 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Lea Hemmeter, Christian G. Bien, Corinna I. Bien, Andrea Tipold, Jasmin Nessler, Andrea Bathen-Noethen, Kaspar Matiasek, Maik Dahlhoff, Clare Rusbridge, Carina Rotter Black, Kai Rentmeister, Holger A. Volk, Andrea Fischer (2023)Investigation of the presence of specific neural antibodies in dogs with epilepsy or dyskinesia using murine and human assays, In: Journal of veterinary internal medicine37(4)pp. 1409-1417 Wiley

Background: Autoimmune mechanisms represent a novel category for causes of seizures and epilepsies in humans, and LGI1-antibody associated limbic encephalitis occurs in cats. Hypothesis/Objectives: To investigate the presence of neural antibodies in dogs with epilepsy or dyskinesia of unknown cause using human and murine assays modified for use in dogs. Animals: Fifty-eight dogs with epilepsy of unknown cause or suspected dyskinesia and 57 control dogs. Methods: Serum and CSF samples were collected prospectively as part of the diagnostic work-up. Clinical data including onset and seizure/episode type were retrieved from the medical records. Screening for neural antibodies was done with cell-based assays transfected with human genes for typical autoimmune encephalitis antigens and tissue-based immunofluorescence assays on mouse hippocampus slices in serum and CSF samples from affected dogs and controls. The commercial human und murine assays were modified with canine-specific secondary antibody. Positive controls were from human samples. Results: The commercial assays used in this study did not provide unequivocal evidence for presence of neural antibodies in dogs including one dog with histopathologically proven limbic encephalitis. Low titer IgLON5 antibodies were present in serum from one dog from the epilepsy/dyskinesia group and in one dog from the control group. Conclusion and Clinical Importance: Specific neural antibodies were not detected using mouse and human target antigens in dogs with epilepsy and dyskinesia of unknown origin. These findings emphasize the need for canine-specific assays and the importance of control groups.

Benjamin Cogné, Xenia Latypova, Lokuliyanage Dona Samudita Senaratne, Ludovic Martin, Daniel C Koboldt, Georgios Kellaris, Lorraine Fievet, Guylène Le Meur, Dominique Caldari, Dominique Debray, Mathilde Nizon, Eirik Frengen, Sara J Bowne, Elizabeth L Cadena, Stephen P Daiger, Kinga M Bujakowska, Eric A Pierce, Michael Gorin, Nicholas Katsanis, Stéphane Bézieau, Simon M Petersen-Jones, Laurence M Occelli, Leslie A Lyons, Laurence Legeai-Mallet, Lori S Sullivan, Erica E Davis, Bertrand Isidor, Clare Rusbridge (2020)Mutations in the Kinesin-2 Motor KIF3B Cause an Autosomal-Dominant Ciliopathy, In: American journal of human genetics106(6)pp. 893-904

Kinesin-2 enables ciliary assembly and maintenance as an anterograde intraflagellar transport (IFT) motor. Molecular motor activity is driven by a heterotrimeric complex comprised of KIF3A and KIF3B or KIF3C plus one non-motor subunit, KIFAP3. Using exome sequencing, we identified heterozygous KIF3B variants in two unrelated families with hallmark ciliopathy phenotypes. In the first family, the proband presents with hepatic fibrosis, retinitis pigmentosa, and postaxial polydactyly; he harbors a de novo c.748G>C (p.Glu250Gln) variant affecting the kinesin motor domain encoded by KIF3B. The second family is a six-generation pedigree affected predominantly by retinitis pigmentosa. Affected individuals carry a heterozygous c.1568T>C (p.Leu523Pro) KIF3B variant segregating in an autosomal-dominant pattern. We observed a significant increase in primary cilia length in vitro in the context of either of the two mutations while variant KIF3B proteins retained stability indistinguishable from wild type. Furthermore, we tested the effects of KIF3B mutant mRNA expression in the developing zebrafish retina. In the presence of either missense variant, rhodopsin was sequestered to the photoreceptor rod inner segment layer with a concomitant increase in photoreceptor cilia length. Notably, impaired rhodopsin trafficking is also characteristic of recessive KIF3B models as exemplified by an early-onset, autosomal-recessive, progressive retinal degeneration in Bengal cats; we identified a c.1000G>A (p.Ala334Thr) KIF3B variant by genome-wide association study and whole-genome sequencing. Together, our genetic, cell-based, and in vivo modeling data delineate an autosomal-dominant syndromic retinal ciliopathy in humans and suggest that multiple KIF3B pathomechanisms can impair kinesin-driven ciliary transport in the photoreceptor.

Joana Tabanez, Samuel Beck, Colin Driver, Clare Rusbridge (2021)Spinal ectopic choroid plexus papilloma in a cat, In: JOURNAL OF FELINE MEDICINE AND SURGERY OPEN REPORTS7(2) Sage

Case summary A 10-year-old male neutered Russian Blue cat was presented with a 2-month history of progressive non-ambulatory paraparesis. Spinal MRI revealed a well-demarcated, compressive intradural extramedullary mass at the level of T1 vertebra. The mass had subtle hyperintensity on T2-weighted images, was isointense on T1-weighted images and had diffuse, marked enhancement following gadolinium administration. Neuroaxis MRI, including limited brain sequences, excluded other visible lesions. Thoracic and abdominal radiographs were unremarkable. The mass was resected via a dorsal C7-T2 laminectomy and durotomy. Histopathology revealed a neoplasm composed of columnar-to-polygonal cells forming bilayered palisading patterns with a few apical cilia. Three mitoses were noted in 10 high-power fields. This was consistent with an epithelial neoplasm and initially a metastatic adenocarcinoma was considered most likely. Full-body CT with contrast and including the brain found rhinitis but did not identify any additional neoplastic foci. Biopsies of the nasal cavity and fine-needle aspiration of the spleen and liver were unremarkable. On immunohistochemical evaluation, pan-cytokeratin and E-cadherin immunolabelling was observed; however, synaptophysin, thyroglobulin, chromogranin A and glial fibrillary acidic protein was not detected. This, along with the histological morphology and absence of a primary tumour, was compatible with an ectopic choroid plexus neoplasm. Follow-up performed at 3, 14 and 24 months postoperatively revealed neurological improvement without recurrence. Relevance and novel information We describe the presentation, histopathological and immunohistochemical features and outcome of a case of a rare ectopic choroid plexus neoplasm in the spinal cord of a cat.

Yoshihiko Yu, Erica K. Creighton, Reuben M. Buckley, Leslie A. Lyons, Clare Rusbridge (2020)A Deletion in GDF7 is Associated with a Heritable Forebrain Commissural Malformation Concurrent with Ventriculomegaly and Interhemispheric Cysts in Cats, In: Genes11(6)672 MDPI

An inherited neurologic syndrome in a family of mixed-breed Oriental cats has been characterized as forebrain commissural malformation, concurrent with ventriculomegaly and interhemispheric cysts. However, the genetic basis for this autosomal recessive syndrome in cats is unknown. Forty-three cats were genotyped on the Illumina Infinium Feline 63K iSelect DNA Array and used for analyses. Genome-wide association studies, including a sib-transmission disequilibrium test and a case-control association analysis, and homozygosity mapping, identified a critical region on cat chromosome A3. Short-read whole genome sequencing was completed for a cat trio segregating with the syndrome. A homozygous 7 bp deletion in growth differentiation factor 7 ( GDF7 ) (c.221_227delGCCGCGC [p.Arg74Profs]) was identified in affected cats, by comparison to the 99 Lives Cat variant dataset, validated using Sanger sequencing and genotyped by fragment analyses. This variant was not identified in 192 unaffected cats in the 99 Lives dataset. The variant segregated concordantly in an extended pedigree. In mice, GDF7 mRNA is expressed within the roof plate when commissural axons initiate ventrally-directed growth. This finding emphasized the importance of GDF7 in the neurodevelopmental process in the mammalian brain. A genetic test can be developed for use by cat breeders to eradicate this variant.

Srdjan Cirovic, Clare Rusbridge (2021)Slosh Simulation in a Computer Model of Canine Syringomyelia, In: Life (Basel, Switzerland)11(10)1083 Mdpi

The exact pathogenesis of syringomyelia is unknown. Epidural venous distention during raised intrathoracic pressure (Valsalva) may cause impulsive movement of fluid ( "slosh ") within the syrinx. Such a slosh mechanism is a proposed cause of syrinx dissection into spinal cord parenchyma resulting in craniocaudal propagation of the cavity. We sought to test the "slosh " hypothesis by epidural excitation of CSF pulse in a computer model of canine syringomyelia. Our previously developed canine syringomyelia computer model was modified to include an epidural pressure pulse. Simulations were run for: cord free of cavities; cord with small syringes at different locations; and cord with a syrinx that was progressively expanding caudally. If small syringes are present, there are peaks of stress at those locations. This effect is most pronounced at the locations at which syringes initially form. When a syrinx is expanding caudally, the peak stress is typically at the caudal end of the syrinx. However, when the syrinx reaches the lumbar region; the stress becomes moderate. The findings support the "slosh " hypothesis, suggesting that small cervical syringes may propagate caudally. However, when the syrinx is large, there is less focal stress, which may explain why a syrinx can rapidly expand but then remain unchanged in shape over years.

Reuben M. Buckley, Barbara Gandolfi, Erica K. Creighton, Connor A. Pyne, Delia M. Bouhan, Michelle L. LeRoy, David A. Senter, Johnny R. Gobble, Marie Abitbol, Leslie A. Lyons, Clare Rusbridge (2020)Werewolf, There Wolf: Variants in Hairless Associated with Hypotrichia and Roaning in the Lykoi Cat Breed, In: Genes11(6)pp. 1-15 Mdpi

A variety of cat breeds have been developed via novelty selection on aesthetic, dermatological traits, such as coat colors and fur types. A recently developed breed, the lykoi (a.k.a. werewolf cat), was bred from cats with a sparse hair coat with roaning, implying full color and all white hairs. The lykoi phenotype is a form of hypotrichia, presenting as a significant reduction in the average numbers of follicles per hair follicle group as compared to domestic shorthair cats, a mild to severe perifollicular to mural lymphocytic infiltration in 77% of observed hair follicle groups, and the follicles are often miniaturized, dilated, and dysplastic. Whole genome sequencing was conducted on a single lykoi cat that was a cross between two independently ascertained lineages. Comparison to the 99 Lives dataset of 194 non-lykoi cats suggested two variants in the cat homolog forHairless(HR) (HRlysine demethylase and nuclear receptor corepressor) as candidate causal gene variants. The lykoi cat was a compound heterozygote for two loss of function variants inHR, an exon 3 c.1255_1256dupGT (chrB1:36040783), which should produce a stop codon at amino acid 420 (p.Gln420Serfs*100) and, an exon 18 c.3389insGACA (chrB1:36051555), which should produce a stop codon at amino acid position 1130 (p.Ser1130Argfs*29). Ascertainment of 14 additional cats from founder lineages from Canada, France and different areas of the USA identified four additional loss of functionHRvariants likely causing the highly similar phenotypic hair coat across the diverse cats. The novel variants inHRfor cat hypotrichia can now be established between minor differences in the phenotypic presentations.

Theofanis Liatis, Rodrigo Gutierrez-Quintana, Lorenzo Mari, Michał Czopowicz, Dakir Polidoro, Sofie F M Bhatti, Francesca Cozzi, Federica Tirrito, Josep Brocal, Roberto José-López, Adriana Kaczmarska, Rodolfo Cappello, Georgina Harris, Lisa Alves, Clare Rusbridge, John H Rossmeisl (2022)Primary orthostatic tremor and orthostatic tremor-plus in dogs: 60 cases (2003-2020), In: Journal of veterinary internal medicine36(1)pp. 179-189 Wiley

Orthostatic tremor (OT) is a rare movement disorder characterized by high-frequency (>12 Hz) involuntary, rhythmic, sinusoidal movements affecting predominantly the limbs while standing. To describe the signalment, presenting complaints, phenotype, diagnostic findings, treatment, and outcome of a large sample of dogs with OT. Sixty dogs diagnosed with OT based on conscious electromyography. Multicenter retrospective case series study. Dogs were included if they had a conscious electromyography consistent with muscle discharge frequency >12 Hz while standing. Fifty-three cases were diagnosed with primary OT (POT). Giant breed dogs represented most cases (83%; 44/53). Most dogs (79%; 42/53) were younger than 2 years of age at onset of signs, except for Retrievers which were all older than 3.5 years of age. The most common presenting complaints were pelvic limb tremors while standing (85%; 45/53) and difficulty when rising or sitting down (45%; 24/53). Improvement of clinical signs occurred in most dogs (85%; 45/53) treated medically with phenobarbital, primidone, gabapentin, pregabalin or clonazepam, but it was mostly partial rather than complete. Orthostatic tremor-plus was seen in 7 dogs that had concurrent neurological diseases. Primary OT is a progressive disease of young, purebred, giant/large-breed dogs, which appears to begin later in life in Retrievers. Primary OT apparently responds partially to medications. Orthostatic tremor-plus exists in dogs and can be concomitant or associated with other neurological diseases.

Carina Rotter, Danielle Whittaker, Clare Rusbridge (2022)Myoclonus in older Cavalier King Charles Spaniels, In: Journal of veterinary internal medicine36(3)pp. 1032-1038 Wiley

Background Myoclonus is observed in older Cavalier King Charles Spaniels (CKCS) but a full description is lacking. Objectives The presence, age of onset, characteristics and treatment of myoclonic episodes were retrospectively evaluated in a cohort of CKCS which presented to 1 board-certified neurologist. Clinical data, imaging studies, presence of seizures and their management, as well as other comorbidities were noted. Animals Thirty-nine CKCS that were presented to 2 institutions between 2001 and 2018 with signs consistent with myoclonus. Clinical examination, blood sampling, advanced diagnostic imaging, cerebrospinal fluid analysis, and record keeping of other comorbidities was performed. Methods This is a retrospective case series, describing the presence of myoclonus in CKCS. Results Clinical signs reported were spontaneous in onset, lasted a few seconds and consisted of rapid blinking with head nodding and variable extension down the thoracic limbs. Myoclonus occasionally led to stumbling of the thoracic limbs or collapse. Mean age of onset was 8.38 years (SD +/- 1.96). Thirteen of 39 dogs with myoclonus had paroxysmal events, such as generalized seizures (9/13). Conclusions and Clinical Importance Myoclonus occurs in middle-aged to older CKCS and seems to be another epiphenomena of this breed. A link to epilepsy might be present.

S K Halstead, D S Gourlay, J Penderis, E Bianchi, M Dondi, A Wessmann, M Musteata, M Le Chevoir, L Martinez-Anton, S F M Bhatti, H Volk, I Mateo, A Tipold, E Ives, A Pakozdy, R Gutierrez-Quintana, J Brocal, Z Whitehead, N Granger, P Pazzi, T Harcourt-Brown, R José-López, S Rupp, H C Schenk, P Smith, G Gandini, M Menchetti, V Mortera-Balsa, C Rusbridge, A Tauro, F Cozzi, M Deutschland, F Tirrito, P Freeman, M Lowrie, M R Jackson, H J Willison, A Rupp (2022)Serum anti-GM2 and anti-GalNAc-GD1a IgG antibodies are biomarkers for acute canine polyradiculoneuritis, In: Journal of small animal practice63(2)pp. 104-112 Wiley

A previous single-country pilot study indicated serum anti-GM2 and anti-GA1 anti-glycolipid antibodies as potential biomarkers for acute canine polyradiculoneuritis. This study aims to validate these findings in a large geographically heterogenous cohort. Sera from 175 dogs clinically diagnosed with acute canine polyradiculoneuritis, 112 dogs with other peripheral nerve, cranial nerve or neuromuscular disorders and 226 neurologically normal dogs were screened for anti-glycolipid antibodies against 11 common glycolipid targets to determine the immunoglobulin G anti-glycolipid antibodies with the highest combined sensitivity and specificity for acute canine polyradiculoneuritis. Anti-GM2 anti-glycolipid antibodies reached the highest combined sensitivity and specificity (sensitivity: 65.1%, 95% confidence interval 57.6 to 72.2%; specificity: 90.2%, 95% confidence interval 83.1 to 95.0%), followed by anti-GalNAc-GD1a anti-glycolipid antibodies (sensitivity: 61.7%, 95% confidence interval 54.1 to 68.9%; specificity: 89.3%, 95% confidence interval 82.0 to 94.3%) and these anti-glycolipid antibodies were frequently present concomitantly. Anti-GA1 anti-glycolipid antibodies were detected in both acute canine polyradiculoneuritis and control animals. Both for anti-GM2 and anti-GalNAc-GD1a anti-glycolipid antibodies, sex was found a significantly associated factor with a female to male odds ratio of 2.55 (1.27 to 5.31) and 3.00 (1.22 to 7.89), respectively. Anti-GalNAc-GD1a anti-glycolipid antibodies were more commonly observed in dogs unable to walk (OR 4.56, 1.56 to 14.87). Anti-GM2 and anti-GalNAc-GD1a immunoglobulin G anti-glycolipid antibodies represent serum biomarkers for acute canine polyradiculoneuritis.

Thilo von Klopmann, Saija Ahonen, Irene Espadas-Santiuste, Kaspar Matiasek, Daniel Sanchez-Masian, Stefan Rupp, Helene Vandenberghe, Jeremy Rose, Travis Wang, Peixiang Wang, Berge Arakel Minassian, Clare Rusbridge (2021)Canine Lafora Disease: An Unstable Repeat Expansion Disorder, In: Life (Basel, Switzerland)11(7)689 MDPI

Canine Lafora disease is a recessively inherited, rapidly progressing neurodegenerative disease caused by the accumulation of abnormally constructed insoluble glycogen Lafora bodies in the brain and other tissues due to the loss of NHL repeat containing E3 ubiquitin protein ligase 1 (NHLRC1). Dogs have a dodecamer repeat sequence within the NHLRC1 gene, which is prone to unstable (dynamic) expansion and loss of function. Progressive signs of Lafora disease include hypnic jerks, reflex and spontaneous myoclonus, seizures, vision loss, ataxia and decreased cognitive function. We studied five dogs (one Chihuahua, two French Bulldogs, one Griffon Bruxellois, one mixed breed) with clinical signs associated with canine Lafora disease. Identification of polyglucosan bodies (Lafora bodies) in myocytes supported diagnosis in the French Bulldogs; muscle areas close to the myotendinous junction and the myofascial union segment had the highest yield of inclusions. Postmortem examination of one of the French Bulldogs revealed brain Lafora bodies. Genetic testing for the known canine NHLRC1 mutation confirmed the presence of a homozygous mutation associated with canine Lafora disease. Our results show that Lafora disease extends beyond previous known breeds to the French Bulldog, Griffon Bruxellois and even mixed-breed dogs, emphasizing the likely species-wide nature of this genetic problem. It also establishes these breeds as animal models for the devastating human disease. Genetic testing should be used when designing breeding strategies to determine the frequency of the NHLRC1 mutation in affected breeds. Lafora diseases should be suspected in any older dog presenting with myoclonus, hypnic jerks or photoconvulsions.

Anna‐Mariam Kiviranta, Clare Rusbridge, Anu K Lappalainen, Jouni J. T Junnila, Tarja S Jokinen (2021)Persistent fontanelles in Chihuahuas. Part I. Distribution and clinical relevance, In: Journal of veterinary internal medicine35(4)pp. 1834-1847 Wiley

Background The Chihuahua dog breed is known for frequent occurrence of a bregmatic fontanelle on the dorsal skull. A common conception is that this skull defect is a clinically irrelevant finding. No studies, however, describe its prevalence or whether it is accompanied by other persistent fontanelles (PFs). Although Chihuahuas are predisposed to Chiari-like malformation (CM) and syringomyelia (SM), it is unknown whether PFs occur more commonly in dogs with clinical signs that are caused by CM or SM. Hypothesis/Objectives To describe the number and location of PFs at cranial sutures (CSs) and to compare the occurrence of these PFs in dogs with and without CM/SM-related clinical signs. We hypothesized that PFs also occur commonly at lateral and caudal cranial surfaces, affect a higher number of CSs, and are larger in dogs with CM/SM-related clinical signs. Animals Fifty client-owned Chihuahuas with or without CM/SM-related clinical signs. Results Of the 50 dogs evaluated, 46 (92%) had either 1 or several PFs. The mean ± SD number of PFs was 2.8 ± 3.0 (range, 0-13). A total of 138 PFs occupied 118 CSs with 57 (48%) located dorsally, 44 (37%) caudally, and 17 (14%) laterally. The number of CSs affected by PFs was significantly higher (P ≤ .001) and total PF area was significantly larger (P = .003) in dogs with CM/SM-related clinical signs. Conclusions and Clinical Importance Persistent fontanelles are very common in this group of Chihuahuas and appear at dorsal, lateral, and caudal cranial surfaces. They are more numerous and larger in Chihuahuas with CM/SM-related clinical signs.

L. A Lyons, Clare Rusbridge, R. M Buckley, R. J Harvey, Marie Abitbol, Danielle Aberdein, Paulo C Alves, Asa Ohlsson Andersson, Rebecca R Bellone, Tomas F Bergström, Nuket Bilgen, Adam R Boyko, Jeffrey A Brockman, Margret L Casal, Marta G Castelhano, Brian W Davis, Lucy Davison, Ottmar Distl, Nicholas H Dodman, N. Matthew Ellinwood, Jonathan E Fogle, Oliver P Forman, Dorian J Garrick, Edward I Ginns, Jens Häggström, Daisuke Hasegawa, Bianca Haase, Vidhya Jagannathan, Philippa Lait, Isabel Hernandez, Marjo K Hytönen, Maria Kaukonen, Tomoki Kosho, Emilie Leclerc, Teri L Lear, Tosso Leeb, Ronald H.L Li, Hannes Lohi, Maria Longeri, Mark A Magnuson, Richard Malik, Shrinivasrao P Mane, Rondo Middleton, John S Munday, William J Murphy, Alexandra N Myers, Niels C Pedersen, Simon M Peterson‐Jones, Max F Rothschild, Jeffrey J Schoenebeck, Beth Shapiro, Joshua A Stern, William F Swanson, Karen A Terio, Rory J Todhunter, Wesley C Warren, Elizabeth A Wilcox, Julia H Wildschutte, Yoshihiko Yu (2021)Mining the 99 Lives Cat Genome Sequencing Consortium database implicates genes and variants for the Ticked locus in domestic cats (Felis catus), In: Animal Genetics52(3)pp. 321-332

Tabby patterns of fur coats are defining characteristics in wild and domestic felids. Historically, three autosomal alleles at one locus (Tabby): Abyssinian (Ta; a.k.a. ticked), mackerel (Tm; a.k.a. striped) and blotched (tb; a.k.a. classic, blotched) were thought to control these patterns in domestic cats and their breeds. Currently, at least three loci influence cat tabby markings, two of which are designated Tabby and Ticked. The Tabby locus is laeverin (LVRN) and affects the mackerel and blotched patterns. The unidentified gene for the Ticked locus on cat chromosome B1 was suggested to control the presence or absence of the ticked pattern (Tabby – Abyssinian (Ta; a.k.a. ticked). The cat reference genome (Cinnamon, the Abyssinian) has the ticked phenotype and the variant dataset and coat phenotypes from the 99 Lives Cat Genome Consortium (195 cats) were used to identify candidate genes and variants associated with the Ticked locus. Two strategies were used to find the Ticked allele(s), one considered Cinnamon with the reference allele or heterozygous (Strategy A) and the other considered Cinnamon as having the variant allele or heterozygous (Strategy B). For Strategy A, two variants in Dickkopf Wnt Signaling Pathway Inhibitor 4 (DKK4), a p.Cys63Tyr (B1:41621481, c.188G>A) and a less common p.Ala18Val (B1:42620835, c.53C>T) variant are suggested as two alleles influencing the Ticked phenotype. Bioinformatic and molecular modeling analysis suggests that these changes disrupt a key disulfide bond in the Dkk4 cysteine‐rich domain 1 or Dkk4 signal peptide cleavage respectively. All coding variants were excluded as Ticked alleles using Strategy B.

Clare Rusbridge, Penny Knowler (2021)The Need for Head Space: Brachycephaly and Cerebrospinal Fluid Disorders, In: Life11(2)139 MDPI

Brachycephalic dogs remain popular, despite the knowledge that this head conformation is associated with health problems, including airway compromise, ocular disorders, neurological disease, and other co-morbidities. There is increasing evidence that brachycephaly disrupts cerebrospinal fluid movement and absorption, predisposing ventriculomegaly, hydrocephalus, quadrigeminal cistern expansion, Chiari-like malformation, and syringomyelia. In this review, we focus on cerebrospinal fluid physiology and how this is impacted by brachycephaly, airorhynchy, and associated craniosynostosis.

Natalie West, Clare Rusbridge (2021)Ethanol toxicity in a dog due to gin‐soaked sloe berry (Prunus spinosa) ingestion, In: Vet Record Case Reports9(1)e12 Wiley

A 10‐month‐old male Labrador retriever was presented for acute onset altered mentation and inability to walk. The dog was presented with a modified glasgow coma scale (MGCS) of 12 with tachycardia (148 bpm) and hypothermia (37°C). The dog had been normal the previous night then found semi‐comatose at the following morning. Investigations included haematology, biochemistry, C‐reactive protein, magnetic resonance imaging, urine toxicology and cerebrospinal fluid analysis. Ten hours after being found the dog passed faeces containing a significant volume of berries. The owner later determined that 750 g of sloe berries soaked in gin were missing from the garden compost heap. Serum ethanol concentrations measured approximately 20 hours after the suspected consumption were 310 mgD/L. The dog was treated with intralipid, intravenous fluid therapy and paracetamol. He was neurologically normal (MGCS = 0) 24 hours later, following diagnosis and treatment. Differential diagnosis and management of the comatose dog and management of ethanol toxicity are discussed.

Anna‐Mariam Kiviranta, Clare Rusbridge, Anu K Lappalainen, Jouni J. T Junnila, Tarja S Jokinen (2021)Persistent fontanelles in Chihuahuas. Part II: Association with craniocervical junction abnormalities, syringomyelia, and ventricular volume, In: Journal of veterinary internal medicine35(4)pp. 1848-1856 Wiley

Background Persistent fontanelles (PFs) are, in Chihuahuas, almost ubiquitous. Furthermore, Chihuahuas are predisposed to other craniomorphological abnormalities, including syringomyelia (SM), ventriculomegaly, and craniocervical junction (CCJ) overcrowding resulting in neural tissue deviation. It is, however, undetermined if PFs are more common in dogs with these structural abnormalities, and their etiology is unknown. Hypothesis/Objectives Persistent fontanelles are more numerous and larger in Chihuahuas with low body weight, older age, SM, dilated fourth ventricle, ventriculomegaly, and CCJ overcrowding. Animals Fifty client-owned Chihuahuas. Methods Cross-sectional study evaluating the association of both the number of cranial sutures affected by PFs (NAS) and total fontanelle area (TFA), based on computed tomography with SM, fourth ventricle dilatation, lateral ventricle volume, and extent of neural tissue compression at the CCJ based on magnetic resonance images. Results The NASs was higher and TFA larger in dogs with low body weight (NAS: P = .007; 95% confidence interval [CI] = 0.384-0.861; TFA: P = .002; 95% CI = −1.91 to −0.478), larger lateral ventricles (NAS: P ≤ .001; 95% CI = 1.04-1.15; TFA: P ≤ .001; 95% CI = 0.099-0.363), and more severe neural tissue compression at the CCJ (NAS: P ≤ .001; 95% CI = 1.26-2.06; TFA: P = .03; 95% CI = 0.066-1.13). Similarly, dogs with SM (NAS: P = .004; 95% CI = 1.26-3.32; TFA: mean ± SD, 130 ± 217 mm2; P = .05) had higher NAS and larger TFA than did dogs without SM (43.7 ± 61.0 mm2). Age was not associated with NAS (P = .81; 95% CI = 0.989-1.01) or TFA (P = .33; 95% CI = −0.269 to 0.092). Conclusions and Clinical Importance Persistent fontanelles are associated with small size, SM, ventriculomegaly, and CCJ overcrowding.

G Flint, Clare Rusbridge (2014)Historical Vignettes, In: G Flint, Clare Rusbridge (eds.), Syringomyelia: A Disorder of CSF Circulationpp. 329-335 Springer

A patient once remarked about how a certain individual, by the name of Arnold Chiari, had affected her and her family’s life. This serves to remind us that it might sometimes be helpful if doctors could find time to explain to their patients not only the meaning of the term Arnold-Chiari malformation but also its origins.

C Rusbridge, CW Dewey (2008)Treatment of Chiari-like malformation and Syringomyelia, In: JD Bonagura, D Twedt (eds.), Kirk's Current Veterinary Therapy XIV(240)pp. 1102-1107 Saunders
P Mandigers, C Rusbridge (2009)[Chiari-like malformation--syringomyelia in the Cavalier King Charles Spaniel]., In: Tijdschr Diergeneeskd134(18)pp. 746-750

This article, which is based on the PhD thesis of Clare Rusbridge, is a review of chiari-like malformation and syringomyelia in the Cavalier King Charles Spaniel. The abnormality is becoming more common among dwarf breeds and brachychepalic breeds. The nature, prevalence, and treatment of the disease are described, as is current knowledge on its heritability in the Cavalier King Charles Spaniel.

Clare Rusbridge, S Heath (2015)Feline Orofacial Pain Syndrome in Feline Behavioral Health and Welfare Elsevier Health Sciences

Ilona Rodan, Sarah Heath. 10. 11. 12. 13. 14. 15. 16. 6. 7. 8. 9. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. PART The Cat in the Veterinary Practice Physiologic and Diagnostic. (MEMO) in the management of cats with idiopathic cystitis.

GB Cherubini, SR Platt, TJ Anderson, C Rusbridge, V Lorenzo, P Mantis, R Cappello (2006)Characteristics of magnetic resonance images of granulomatous meningoencephalomyelitis in 11 dogs., In: Vet Rec159(4)pp. 110-115

The characteristics of magnetic resonance imaging (mri) of the brains and spinal cords of 11 dogs with histologically confirmed granulomatous meningoencephalomyelitis (gme) were determined. The lesions were in the brain of eight of the dogs, in the brain and spinal cord of two, and in the spinal cord alone in one dog. A single lesion was present in four of the dogs and multiple lesions were found in six. In one dog with intracranial signs, no visible lesions could be detected on mri. No meningeal enhancement was detected in T1-weighted images post-contrast, or in fluid attenuation inversion recovery (flair) images, but there were histological lesions in the meninges in nine of the dogs. The T2-weighted images and flair sequences were characterised in all cases by hyperintensity, whereas the signal intensity of the lesions on T1-weighted images was variable. After the administration of paramagnetic contrast, some of the lesions showed no enhancement, but others showed marked patterns of enhancement. The lesions in 10 of the dogs were easily identifiable by mri and the images had several unifying characteristics, but they could not be considered disease-specific.

C Rusbridge, D Greitz, BJ Iskandar (2006)Syringomyelia: current concepts in pathogenesis, diagnosis, and treatment., In: J Vet Intern Med20(3)pp. 469-479

Syringomyelia is a condition that results in fluid-containing cavities within the parenchyma of the spinal cord as a consequence of altered cerebrospinal fluid dynamics. This review discusses the history and the classification of the disorder, the current theories of pathogenesis, and the advanced imaging modalities used in the diagnosis. The intramedullary pulse pressure theory (a new pathophysiologic concept of syringomyelia) also is presented. In addition, the current understanding of the painful nature of this condition is discussed and the current trends in medical and surgical management are reviewed.

C Rusbridge (2015)Syringomyelia and Chiari malformation, In: LP Tilley, FWKJ Smith (eds.), Blackwell's Five-Minute Veterinary Consult: Canine and Felinepp. 1289-1290 Wiley-Blackwell
C Rusbridge (2016)Tremors, In: SJ Ettinger, EC Feldman, E Cote (eds.), Textbook of Veterinary Internal Medicine(32)pp. 130-133 Saunders
C Rusbridge, S Heath (2015)Feline Orofacial Pain Syndrome, In: I Rodan, S Heath (eds.), Feline Behavioral Health and Welfare(16)pp. 213-227 Saunders
P Mandigers, C Rusbridge (2009)Op Chiari lijkende malformatieSyringomyelie bij de Cavalier King Charles Spaniel, In: Tijdschrift voor Diergeneeskunde134(18)pp. 746-750

This article, which is based on the PhD thesis of Clare Rusbridge, is a review of chiari-like malformation and syringomyelia in the Cavalier King Charles Spaniel. The abnormality is becoming more common among dwarf breeds and brachychepalic breeds. The nature, prevalence, and treatment of the disease are described, as is current knowledge on its heritability in the Cavalier King Charles Spaniel.

Clare Rusbridge (2014)Chiari–like malformation and syringomyelia, In: European Journal Companion Animal Practice23(3)pp. 70-89 Federation of European Companion Animal Veterinary Associations

Syringomyelia is a condition characterised by fluid filled cavities (syrinxes or syringes) within the central spinal cord and the resulting damage produces clinical signs of pain and neurological deficits. Since the increase in availability of magnetic resonance imaging (MRI), syringomyelia is an increasingly common diagnosis in veterinary medicine [1, 2] The most common cause of syringomyelia in the dog is Chiari-like malformation (Fig 1), a condition analogous to Chiari Type I and 0 malformation in humans [3, 4].

C. Trace, C. Rusbridge (2018)Combination of a Xerte Bootstrap and Survey to teach Neurological Examination, In: Proceedings of the VSC Veterinary Education Symposium (VetEd) 2018 Veterinary Schools Council (VSC)

A resource was created for a third-year Neurology module using the Xerte Bootstrap template. Students were given 3 hours to work through cases and log answers in an online survey, then 1 hour for a wrap-up session where group answers were discussed then answers revealed. This format proved overwhelmingly positive for students.

G Flint, C Rusbridge (2014)Syringomyelia: A Disorder of CSF Circulation Springer-Verlag Berlin Heidelberg

Syringomelia is a relatively rare clinical entity in which fluid-filled cavities develop within the spinal cord. Although modern imaging technologies usually permit an accurate diagnosis at an early stage, syringomyelia remains an enigmatic condition. This reference monograph provides an up-to-date account of the present state of understanding of syringomyelia and related disorders. The editors aim to document the best clinical practice in diagnosis and treatment and to provide clear guidance on how to reduce the incidence of severe outcomes. New challenges are addressed, including the appropriate management of the increasing number of apparently idiopathic syrinx cavities that are detected. In addition, controversies in current practice and directions for future research are fully discussed. Syringomelia will be an invaluable source of information for experts in the field, specialists in various related disciplines and other interested health care professionals.

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