OBJECTIVES:Immune-mediated polyneuropathy (IMPN) manifests with generalized lower motor neuron (LMN) weakness and a remittent or relapsing clinical course. Evidence-based treatment recommendations for severely or chronically affected cats are limited. The objective of this study was to evaluate the clinical course and outcome of cats with IMPN following treatment with human intravenous immunoglobulins (hIVIg). METHODS:Medical records from two veterinary referral hospitals were reviewed (2018-2025) for cats with IMPN treated with hIVIg. Cats were treated with 1-2 g/kg hIVIg divided over 2-4 days (0.5 g/kg/day).Clinical information, diagnostic findings, treatment details and short- and long-term follow-up were evaluated retrospectively. Follow-up information was obtained from medical records and owner communication. Minimum follow-up duration was 8 months (8-51 months; median 17 months).Clinical course (partial and complete recovery, relapses) was compared between cats with acute/recent onset (4 cats) or chronic presentation (5 cats). RESULTS:Eight of nine cats exhibited clinical improvement following hIVIg administration, achieving ambulatory status (walking >5 steps) within a median of 4 days (2-8 days). One cat failed to respond to hIVIg but improved after subsequent prednisolone therapy. For the overall cohort, the median time to complete recovery was 20 days, while the median time to partial recovery was 14 days. Relapses occurred in four cats, but weakness was less severe, and all cats recovered again. The remaining five cats remained relapse-free. CONCLUSIONS AND RELEVANCE:Human IVIg was well tolerated in this small cohort, and rapid clinical improvement was observed in most treated cats. These findings suggest that hIVIg may be considered as a treatment option in selected cats with IMPN, including those with acute and chronic presentations. Larger prospective studies, including comparison with no treatment or corticosteroids, are warranted to further assess its efficacy.

Choroid plexus tumors are commonly described as intraventricular mass lesions and account for 7–10% of intracranial, primary tumors in dogs. A 3-year-old Shetland sheepdog was presented with a history of slowly progressive lethargy, vision impairment and cognitive deficits. On magnetic resonance imaging, a subdural fluid accumulation (SFA) overlying and compressing the left parietotemporal lobe as well as multifocal changes consisting of cyst-like lesions, supposed intra-axial brain lesions and mild, multifocal meningeal thickening and generalized contrast enhancement were identified. Cerebrospinal fluid (CSF) analysis showed a mononuclear pleocytosis with negative results for infectious agents. The dog was treated with prednisolone followed by burr hole craniotomy with puncture of the SFA, which macroscopically appeared to be CSF-like fluid. After initial improvement, the dog deteriorated despite continuation of prednisolone and cytarabine therapy and was euthanized four weeks after surgery. Histopathology was consistent with a disseminated, neuroinvasive choroid plexus carcinoma (CPC) that involved the entire neuroaxis including the meninges of the brain and spinal cord. Immunohistochemical examination showed a strong Kir7.1 and a heterogenous cytokeratin-immunoreactivity in neoplastic cells. In conclusion, a CPC should be considered as a possible cause of a SFA even in the absence of an intraventricular mass lesion.

Case summary A 15-week-old male British Shorthair cat was presented for peracute paralysis immediately after microchip implantation. Neurological examination revealed a non-ambulatory tetraparesis and left thoracic limb plegia localised to C1–C5 spinal cord segments. CT of the cervical spine showed a diagonally orientated metallic foreign body (microchip transponder, 10 mm in length) within the vertebral canal at the level of C1–C2, resulting in a penetrating spinal cord injury. Based on concerns about further iatrogenic spinal cord injury through surgery, medical management was chosen. Despite the severe clinical signs, the kitten returned to ambulation within 6 days of the injury, with controlled urination and defecation. Continuous neurological improvement was seen for up to 6 weeks after the injury at which point a mild-to-moderate ambulatory tetraparesis and ataxia remained, with an overall good quality of life. Follow-up CT at the age of 13 months revealed a relative cranial displacement and rotation of the microchip towards the foramen magnum, while the cat’s neurological status was unchanged. Relevance and novel information This case demonstrated a cervical penetrating spinal cord injury in a growing cat caused by a microchip, which was successfully managed with medical treatment, suggesting that this might be an option for patients at risk of severe surgery-related complications or where owners reject surgery.

Cross-sectional area (CSA) decreases and fat infiltration increases in epaxial muscles of Dachshunds with intervertebral disc disease (IVDD), but less is known about large breed dogs with IVDD. The aim here was to investigate thoracolumbar epaxial muscle CSA and fat infiltration in large breed dogs with compressive IVDD and acute non-compressive nucleus pulposus extrusion (ANNPE) or fibrocartilaginous embolism (FCE). This retrospective study included large breed dogs with MRI-confirmed IVDD (n = 17) and ANNPE or FCE (n = 13). The CSA and fat infiltration of the thoracolumbar M. longissimus and Mm. multifidi were assessed from T1-weighted transverse MR images using Osirix. The CSA was significantly smaller in dogs with compressive IVDD than in dogs with non-compressive ANNPE or FCE for Mm. multifidi (p = 0.015), M. longissimus (p = 0.070), and these two muscles combined (p = 0.016). Fat infiltration in all muscle measurements was significantly higher in dogs with compressive IVDD than in dogs with non-compressive ANNPE or FCE (all P < 0.050). A significant positive correlation existed between age, duration of clinical signs, and fat infiltration, suggesting more fat infiltration in older dogs with more chronic signs. These signs of muscle atrophy are likely caused by denervation and secondary disuse due to chronic spinal cord compression and prolonged duration of clinical signs.

Abstract Objective Steroid-responsive meningitis arteritis (SRMA) is one of the most common inflammatory diseases of the central nervous system in dogs. The present study examined breed and sex predisposition factors based on the population of dogs in Germany as well as epidemiological and clinical factors regarding the relapse rate of SRMA. Material and methods Data of 153 dogs with SRMA (SRMA) were analysed retrospectively in this multicentre study. It was investigated whether some dog breeds that suffer from SRMA were disproportionately more often (n ≥ 5) represented when compared to the total population of dogs in Germany. Furthermore it was examined which sex is affected more often. Data provided by “Verband für das deutsche Hundewesen“ (VDH) and „Tasso e. V.“ was used as reference data of the total population. The following factors were investigated with regard to the occurrence of one or more relapses: signalment; body weight; age at first presentation; time period between last vaccination and onset of clinical signs; clinical signs and timepoint of the first SRMA manifestation; results of cerebrospinal fluid (CSF) analysis at first presentation (nucleated cell count and differentiation, protein concentration); immunglobulin A and C-reactive protein (CRP) concentrations in serum and CSF; immunosuppressive medication; follow-up data including response to therapy, occurrence of relapses and mortality including reasons, i. e. due to the disease, therapy or euthanasia. Results The breed had a statistically significant influence on the development of SRMA (p < 0.05). Beagles and Boxers were affected more often by SRMA than other breeds in relation to the total population in Germany. Relapses occurred in 29.4 % of the 153 dogs of this study. In contrast to the development of SRMA, in which male dogs have a significantly increased risk of developing SRMA (p < 0.05), female dogs are more likely to relapse (p = 0.02). Patients on prednisolone monotherapy had fewer relapses than those with prednisolone and azathioprine in combination (p < 0.05). Younger age (p = 0.071) und lower CRP concentrations (p = 0.081) at first presentation were tentatively associated with a higher incidence of relapses. Conclusion The determined breed and sex predispositions support the diagnosis of SRMA arteritis and confirm previous observations. This study allows a more accurate explanation to owners about the risk of relapse.

Four MRI variables have recently been suggested to be independently associated with a diagnosis of thoracolumbar intervertebral disk extrusion or protrusion. Midline intervertebral disk herniation, and partial intervertebral disk degeneration were associated with intervertebral disk protrusion, while presence of a single intervertebral disk herniation and disk material dispersed beyond the boundaries of the intervertebral disk space were associated with intervertebral disk extrusion. The aim of this retrospective, cross-sectional study was to determine whether using these MRI variables improves differentiation between thoracolumbar intervertebral disk extrusions and protrusions. Eighty large breed dogs with surgically confirmed thoracolumbar intervertebral disk extrusions or protrusions were included. Randomized MRI studies were presented on two occasions to six blinded observers, which were divided into three experience categories. During the first assessment, observers made a presumptive diagnosis of thoracolumbar intervertebral disk extrusion or protrusion without guidelines. During the second assessment they were asked to make a presumptive diagnosis with the aid of guidelines. Agreement was evaluated by Kappa-statistics. Diagnostic accuracy significantly improved from 70.8 to 79.6% and interobserver agreement for making a diagnosis of intervertebral disk extrusion or intervertebral disk protrusion improved from fair (κ = 0.27) to moderate (κ = 0.41) after using the proposed guidelines. Diagnostic accuracy was significantly influenced by degree of observer experience. Intraobserver agreement for the assessed variables ranged from fair to excellent and interobserver agreement ranged from fair to moderate. The results of this study suggest that the proposed imaging guidelines can aid in differentiating thoracolumbar intervertebral disk extrusions from protrusions.

A 3-year, 11-month male neutered Rhodesian ridgeback presented for evaluation of cervical hyperaesthesia, generalised ataxia and right thoracic limb lameness. Neurological examination was suggestive of a lesion affecting the C1–C5 spinal cord segments. MRI of the neck identified an irregularly shaped and shortened vertebral body of C6, a mild subluxation between C5 and C6, multiple hypertrophic and abnormally shaped articular processes, and multiple dorsal lamina abnormalities. CT confirmed these findings and revealed additionally multiple visible fracture lines and identified the axial and appendicular skeleton to be characterised by abnormally hypoattenuating cancellous bone and a thin cortex. The dog was euthanased and a postmortem examination confirmed generalised osteoporosis, vertebral malformations and identified distended and swollen neurons in the cerebrum, hippocampus, cerebellum and brainstem, containing intracytoplasmic, granular, PAS-positive inclusions. These findings were considered consistent with a lysosomal storage disease, with a presumptive diagnosis of mucopolysacharidosis being most likely.

This is the peer reviewed version of the following article: De Decker, S., Gomes, S. A., Packer, R. M., Kenny, P. J., Beltran, E., Parzefall, B., Fenn, J., Nair, D., Nye, G. and Volk, H. A. (2016), EVALUATION OF MAGNETIC RESONANCE IMAGING GUIDELINES FOR DIFFERENTIATION BETWEEN THORACOLUMBAR INTERVERTEBRAL DISK EXTRUSIONS AND INTERVERTEBRAL DISK PROTRUSIONS IN DOGS. Veterinary Radiology & Ultrasound. doi: 10.1111/vru.12394 which has been published in final form at http://dx.doi.org/10.1111/vru.12394. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. The full details of the published version of the article are as follows:

Neosporosis is a polysystemic disease that can affect dogs of any age and can cause inflammation of the central nervous system. Antemortem diagnosis can be challenging, as clinical and conventional laboratory test findings are often nonspecific. A previous report described cerebellar lesions in brain MRI studies of seven dogs and proposed that these may be characteristic for central nervous system Neosporosis. The purpose of this retrospective study was to describe MRI characteristics in another group of dogs with confirmed central nervous system neosporosis and compare them with the previous report. The hospital's database was searched for dogs with confirmed central nervous system neosporosis and four observers recorded findings from each dog's MRI studies. A total of four dogs met inclusion criteria. Neurologic examination was indicative of a forebrain and cerebellar lesion in dog 2 and multifocal central nervous system disease in dogs 1, 3, and 4. Magnetic resonance imaging showed mild bilateral and symmetrical cerebellar atrophy in three of four dogs (dogs 2, 3, 4), intramedullary spinal cord changes in two dogs (dogs 3, 4) and a mesencephalic and metencephalic lesion in one dog (dog 2). Multifocal brain lesions were recognized in two dogs (dogs 1, 4) and were present in the thalamus, lentiform nucleus, centrum semiovale, internal capsule, brainstem and cortical gray matter of the frontal, parietal or temporal lobe. Findings indicated that central nervous system neosporosis may be characterized by multifocal MRI lesions as well as cerebellar involvement in dogs.

Rounded, sessile, hyperattenuating structures detected in computed tomography (CT) studies of canine tympanic bullae have been termed "otoliths." These have been proposed to represent dystrophic mineralizations or heterotopic bone formations in the middle ear that are potentially related to chronic otitis media. Aims of the current study were to describe the prevalence, macroscopic, and histological features of structures consistent with "otoliths" in the canine tympanic cavity. Tympanic bullae from 50 routinely necropsied dogs and 139 retrospectively retrieved CT scans of canine clinical cases were examined. Small tympanic bone spicules with pointed or clubbed tips essentially arising from the free margin of the septum bullae were bilaterally present in the tympanic cavities of all 50 of the necropsied dogs. In 48% of the dogs, "otolith"-like CT-detectable bone spicules carrying drumstick-like hyperostoses that were 1-6 mm in diameter were also present. In the retrospective survey of bulla CT scans of 139 cases, the prevalence of hyperostotic tympanic bone spicules (HTBS) was 20%. Findings from the current study indicated that the presence of small tympanic bone spicules in adult dogs is most likely due to physiological bone growth in the septum bullae and that HTBS represent osseous proliferations of small tympanic bone spicules. However, the factors inducing formation of hyperostotic spicules from small tympanic bone spicules remain unknown. The high prevalence of HTBS displaying a similar appearance in bulla CT scans in dogs suggests that these spicules should be included in a differential diagnosis list for "otoliths."

In humans, herpes simplex virus type-1 has recently been detected in the vestibular ganglion (VG) and labyrinth (VL) and may be associated with vestibular signs. Feline herpesvirus-1 (FHV-1) is widespread amongst cat populations and affects many different tissues. The aim of this pilot study was to investigate the presence of FHV-1 DNA in the VG and VL of randomly selected domestic cats using PCR. FHV-1 DNA was detected in the VG of 14% of the cats. There was no detectable FHV-1 DNA in the VL of any cat. None of the infected cats had vestibular signs related to the VG infection.

Although the involvement of herpesviruses in vestibular disease of humans has been recognised for many years, knowledge of such a link in companion animal species is restricted to cats. This study was conducted to assess the prevalence of canine herpesvirus-1 (CaHV-1) infection of the vestibular labyrinth (VL) and vestibular ganglion (VG) of dogs by PCR. 'Field' herpesvirus was detected in the VL of 17% and in the VG of 19% of 52 dogs, respectively. None of the 11 dogs with infected VG and/or VL exhibited signs of vestibular disease, whereas clinical signs in the remaining three animals were attributable to intra-cranial neoplasia. As reported for other species, the putative role of herpesvirus infection in canine vestibular disease requires further elucidation.

The vestibular labyrinth is the organ for sensation of equilibrium. It is part of the inner ear and located in the caudodorsal aspect of the temporal bone which makes it very difficult to access. This study evaluated a preparation technique in cats and dogs for morphological and DNA analysis. The study included 44 temporal bones of 14 cats and 11 dogs collected within 48h after death. Preparation was performed after peri-/endolymphatic injection of Fast-Green-FCF through the fenestra vestibuli to visualize the membranous labyrinth. The vestibular nerve, including its ganglion, and the vestibular labyrinth were exposed by drilling and cracking of the petrous temporal bone along the meatus acusticus internus. The posterior ampulla was collected for histology and transmission electron microscopy whereas the vestibular nerve, the utriculus, sacculus, and the lateral and anterior ampullae were harvested for subsequent DNA analysis. Histology and electron microscopy showed well-preserved cells. A total DNA amount of 4753+/-1502ng in cats and 5865+/-2911ng in dogs was retrieved from the ganglion, and 2390+/-561ng in cats and 2544+/-1277ng in dogs, respectively, from membranous vestibular organs. Polymerase chain reaction of a 229 base pair product of the Gapdh-gene proved for presence of amplifiable DNA. Taken together, mechanical bone removal after Fast-Green-FCF injection allows for reliable gross, microscopic and ultrastructural examination of the feline and canine vestibular labyrinth, and it does not interfere with DNA analysis via PCR. This technique is feasible for multimodal investigation of the vestibular labyrinth retrieved from individual necropsy cases.