IMAGING DIAGNOSIS-MAGNETIC RESONANCE IMAGING OF DIFFUSE LEPTOMENINGEAL OLIGODENDROGLIOMATOSIS IN A DOG WITH "DURAL TAIL SIGN".

A case of diffuse leptomeningeal oligodendrogliomatosis affecting the brain and spinal cord of a dog is presented. A 7.5-year old, male neutered Staffordshire bull terrier presented for evaluation of a chronic history of tetraparesis and seizures, with a multifocal neuroanatomical localization was determined. Extra-axial intradural lesions with an atypical presentation of a dural tail sign were seen on MRI. Histologically, the lesions were consistent with leptomeningeal oligodendrogliomatosis. To the authors' knowledge, a dural tail sign has not previously been reported as an MRI characteristic of diffuse leptomeningeal oligodendrogliomatosis in dogs.

Evaluation of cytospin precision in low cellularity canine cerebrospinal fluid.

The cell count and differential of cerebrospinal fluid (CSF) cytologic examination classify CSF as inflammatory or not. The cytospin cell yield is related to cell count, but to our knowledge a relationship has not been characterized and cytospin precision is undocumented in any species. The objective of our study was to calculate intra-assay precision of cellular yield and differential on cytocentrifuged canine CSF, determine the factors that may affect precision, and predict the number of cytospins necessary to confirm mild neutrophilic pleocytosis. Ten concurrent replicate cytospins were created from nonhemorrhagic CSF, obtained from 60 dogs in other terminal studies, with either a manual or calibrated pipetting technique. Up to 500 cells per cytospin were counted and classified on each slide. Coefficient of variation (CV), multiple regression, and probabilities were calculated for relationships between cell yield and independent factors including technique, total nucleated cell count, cell differential, and total protein. Manual and calibrated pipetting had similar CVs (average 31%) for total cell yield, but the calibrated technique had fewer foamy macrophages. CV for neutrophil percentage among low cellularity samples with any neutrophils was 146%. Probability based on linear regression showed that 1 cytospin is sufficient to identify samples with >3% neutrophils. Occasional neutrophils, eosinophils, mitotic figures, phagocytic cells, and ependymal cells were seen in many low cellularity canine CSF samples. Canine CSF cytospin cell yield and differential evaluations are imprecise. Calibrated rather than manual pipetting is recommended.

Denervation of the Tensor Veli Palatini Muscle and Effusion in the Tympanic Cavity.

An English springer spaniel was presented for right-sided atrophy of the muscles of mastication, analgesia and paralysis of the face, and vestibular dysfunction. Neurological signs were consistent with a lesion involving the pons and rostral medulla resulting in deficits in the function of the trigeminal, facial, and vestibular nerves. MRI disclosed a right-sided extraparenchymal mass consistent with a trigeminal nerve sheath neoplasm that was compressing and invading the pons and medulla. Atrophy of the muscles of mastication, innervated by the trigeminal nerve, was also observed on MRI. Additionally, effusion was present in the ipsilateral tympanic cavity. Gross and microscopic evaluation of the right tensor veli palatini muscle (TVPM) was consistent with neurogenic atrophy. Effusion in the tympanic cavity was likely the result of an inability to open the auditory tube as a consequence of paralysis of the TVPM. Without the ability to open the auditory tube, gases present within the auditory tube and tympanic cavity may be absorbed, creating a negative pressure environment that leads to fluid transudation and effusion build up. To the authors' knowledge, this is the first report to document neurogenic atrophy of the TVPM with concurrent effusion in the ipsilateral tympanic cavity.

Pharmacokinetic evaluation of immediate- and extended-release formulations of levetiracetam in dogs.

OBJECTIVE: To compare the pharmacokinetics of various formulations of levetiracetam after oral administration of a single dose to healthy dogs. ANIMALS: 6 neurologically normal mixed-breed dogs. PROCEDURES: A crossover study design was used. Blood samples for serum harvest were collected from each dog before and at various points after oral administration of one 500-mg tablet of each of 2 generic extended-release (ER) formulations, 1 brand-name ER formulation, or 1 brand-name immediate-release (IR) formulation of levetiracetam. Serum samples were analyzed to determine pharmacokinetic properties of each formulation by means of ultra-high-performance liquid chromatography with tandem mass spectrometry. RESULTS: No dogs had clinically important adverse effects for any formulation of levetiracetam. All ER formulations had a significantly lower maximum serum drug concentration and longer time to achieve that concentration than did the IR formulation. Half-lives and elimination rate constants did not differ significantly among formulations. Values for area under the drug concentration-versus-time curve did not differ significantly between ER formulations and the IR formulation; however, 1 generic ER formulation had a significantly lower area under the curve than did other ER formulations. CONCLUSIONS AND CLINICAL RELEVANCE: All ER formulations of levetiracetam had similar pharmacokinetic properties in healthy dogs, with some exceptions. Studies will be needed to evaluate the clinical efficacy of the various formulations; however, findings suggested that twice-daily administration of ER formulations may be efficacious in the treatment of seizures in dogs.

Clinical features of idiopathic inflammatory polymyopathy in the Hungarian Vizsla.

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.

Ischemic stroke in Greyhounds: 21 cases (2007-2013).

OBJECTIVE: To determine the prevalence of ischemic stroke in Greyhounds and determine whether affected dogs had coagulation abnormalities and hypertension. DESIGN: Multi-institutional, retrospective study. ANIMALS: 21 dogs. PROCEDURES: Medical records (including diagnostic testing results) and MRI images of the brain were reviewed for Greyhounds with ischemic stroke that had been evaluated at 4 institutions. The proportion of Greyhounds with ischemic stroke was compared with the proportion of non-Greyhound dogs with ischemic stroke. Demographic information for dogs evaluated at each institution was obtained to determine the proportion of Greyhounds in the hospital populations. RESULTS: 21 Greyhounds with ischemic stroke were identified. Abnormalities in coagulation were not identified in the 14 Greyhounds that underwent such testing. Systemic hypertension was identified in 6 of 14 Greyhounds that underwent such testing. No other abnormalities were identified by means of other routine diagnostic tests for Greyhounds. For all institutions combined, the prevalence of ischemic stroke in Greyhounds was 0.66% (21/3,161 Greyhounds). Greyhounds were significantly more likely to be evaluated because of ischemic stroke, compared with all other dog breeds combined (OR, 6.6; 95% confidence interval, 4.2 to 10.2). CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study suggested that Greyhounds were predisposed to ischemic stroke, compared with all other breeds combined. Coagulation abnormalities did not seem to contribute to ischemic stroke. Hypertension may have contributed to the development of ischemic stroke. Greyhounds with ischemic stroke should undergo measurement of systolic arterial blood pressure. Antihypertensive treatments may be warranted for such dogs.

Traumatic pneumocephalus in a dog.

CASE DESCRIPTION: A 17-month-old dog was evaluated because of progressive tetraparesis. The dog had a history of craniofacial trauma at 2 months of age. CLINICAL FINDINGS: Results of a neurologic examination were suggestive of a lesion localized to the medulla. Computed tomography revealed extensive pneumocephalus extending throughout the ventricular system and into the cranial cervical subarachnoid space. TREATMENT AND OUTCOME: Because of the deterioration in the dog's clinical condition, an emergency bilateral transfrontal craniectomy was performed. A large amount of pyogranulomatous material was found intraoperatively. Neurologic and computed tomographic abnormalities were no longer evident during a recheck examination 8 weeks after surgery. CLINICAL RELEVANCE: Findings suggested that pneumocephalus should be considered in the differential diagnosis for dogs with neurologic signs of an intracranial abnormality, particularly if the dog has a history of craniofacial trauma.