Clinical neurology of ferrets

Surgical Resection of a Parietal Osteoma in a Domestic Ferret Using Advanced Neurosurgical Techniques

A 3.5 yr old male neutered ferret presented with progressive enlargement of a right dorsocaudal skull mass that had occurred over 18 mo. Computed tomography imaging revealed a large (2.4 × 2.7 cm), well-defined, pedunculated osseous mass arising from the right parietal bone. Cytology was inconclusive, and surgical biopsy was consistent with an osteoma. Further enlargement of the mass occurred over the next 3 mo, at which time surgical intervention was pursued. The patient recovered well, despite the persistence of a bony defect at the former mass site, and no mass regrowth occurred in the 14 mo following the surgical resection. This is one of only two reports in the literature to document the surgical removal of an osteoma in a ferret, and this is the sole case in which a custom apparatus was fabricated for head stabilization, a multiaxis adjustable surgical table was used to improve access to the surgical site, and an ultrasonic scalpel was used for the mass resection.

Paraplegia in a Domestic Ferret (Mustela Putorius Furo) Secondary to Metastatic Adrenocortical Carcinoma with Myxoid Differentiation

Neurologic disease is a common presentation of domestic ferrets (Mustela putorius furo) with infectious, neoplastic, and traumatic etiologies documented. Adrenocortical neoplasia is also well documented in domestic ferrets, with metastatic lesions rarely described. This case report describes an abnormal presentation of adrenocortical adenocarcinoma with myxoid differentiation and subsequent metastasis to the spinal cord and vertebral bodies, resulting in hind limb paraplegia in an adult spayed female ferret.

Invasive histiocytic sarcoma of the lumbar spine in a ferret (Mustela putorius furo)

This report describes the history, clinical examination and histopathology of a histiocytic sarcoma in a domestic ferret. Clinical signs were acute paraplegia and dysuria. Physical examination revealed a firm, smooth, touch-sensitive mass in and around the lumbar vertebral column. Neurologic examination was consistent with a lesion between spinal cord segments T3 and L3. Magnetic resonance images revealed bone lesions of L2 and L3 combined with compression of the spinal cord due to a homogenous, isointense mass that was diagnosed as a malignant round cell tumour and the ferret was euthanased. Histopathology confirmed the diagnosis of an infiltrative histiocytic sarcoma.

Epidemiology and clinical presentation of canine distemper disease in dogs and ferrets in Australia, 2006-2014

OBJECTIVE

To determine the status and distribution of distemper in Australian dogs and ferrets.

DESIGN

Retrospective case series.

METHODS

Cases were identified via a national voluntary disease reporting system, veterinarian groups and a national laboratory database. The geographic distribution, seasonal distribution, signalment and clinical presentation of cases were described using maps and frequency distributions.

RESULTS

A total of 48 individually affected dogs and ferrets in 27 case groups were identified, including eight confirmed case groups (> one individual). Confirmed cases were more common in summer and on the central coast of New South Wales and southern Victoria, and occurred exclusively in young, unvaccinated dogs. For dogs there was no obvious sex predilection. A mortality rate of 100% in ferrets and up to 77% in dogs was estimated. Neurological, gastrointestinal and respiratory were the most commonly reported systems affected in dogs and ferrets. There was no evidence that any large, unreported outbreaks occurred during the study period.

CONCLUSIONS

Continuation of vaccination against canine distemper virus is justified within Australia, particularly for younger dogs. Veterinarians should continue to consider distemper in their differential diagnosis of cases with neurological, gastrointestinal and respiratory presentation.

Unusual presentation of systemic coronavirosis in a ferret

A young ferret was presented for a posterior paresis, urinary and fecal incontinence, weight loss, anorexia and lethargy. Biochemichemistry and hematology revealed hyperproteinemia with hyperglobulinemia and anemia. Abdominal ultrasonography showed splenomegaly, adenomegaly and nephromegaly with abdnomal echogenicity of the abdominal organs, compatible with a diagnosis of systemic coronavirosis. The ferret was humanely euthanized. On histopathology, a severe pyogranulomatous inflammation with neutrophilic vasculitis was seen in several organs (kidney, liver, lung, spleen and lymph node). Immunochemistry with FIPV3-70 antibody revealed the presence of coronaviral antigen within the lesions, confirming the diagnosis of Feline Infectious Peritonitis-like disease. A slight mononuclear radiculoneuritis was also present in the sciatic nerve, possibly explaining the peripheral neuropathy observed in this ferret. Whereas posterior paresis is common and non-specific in ferrets, fecal and urinary incontinence are rarely described. Radiculoneuritis caused by systemic coronavirus should be considered in young patients presenting these symptoms.

Successful medical management of lumbar intervertebral disc prolapse in a ferret

Thoracolumbar disc herniation was diagnosed in a two-year-old ferret using a myelogram followed by a computed tomography scan. The ferret was paraplegic with no control over urination and defecation. Conservative treatment that included cage rest and passive range of motion exercises for three weeks followed by extensive physiotherapy and hydrotherapy resulted in full recovery two months after the onset of treatment. Although intervertebral disc disease has been reported previously in four ferrets, this is the first report in which a postmyelogram computed tomography was used to demonstrate the herniated disc, and physiotherapy was used as principal treatment modality.

Autoimmune myasthenia gravis in a ferret

CASE DESCRIPTION

A 7-month-old neutered male ferret was evaluated for episodic pelvic limb weakness of 2 weeks' duration.

CLINICAL FINDINGS

Neurologic examination revealed flaccid tetraparesis with decreased spinal reflexes suggestive of a neuromuscular disease. Results of hematologic and CSF analyses, thoracic radiography, and abdominal ultrasonography were unremarkable. Electrodiagnostic testing revealed subtle spontaneous activity localized to pelvic limb interosseous muscles, unremarkable motor nerve conduction velocities, and lower than typical compound muscle action potential (CMAP) amplitude for tibial nerve stimulation only. A severe decremental response of the CMAP was detected with repetitive nerve stimulation (45.5% at the third ulnar nerve). An esophagogram revealed mild megaesophagus. Intravenous neostigmine methylsulfate administration resulted in immediate resolution of muscle weakness. Cross-reacting anti-acetylcholine receptor (AChR) antibodies were detected in serum (0.35 nmol/L) by use of a canine- and feline-specific muscle extract. Clinical signs and ancillary test results were diagnostic of acquired myasthenia gravis.

TREATMENT AND OUTCOME

Pyridostigmine bromide was administered (1 mg/kg [0.45 mg/lb], PO, q 8 h), resulting in complete remission of clinical signs. However, 1 month after the diagnosis, the ferret was euthanized because of recurrence of weakness despite anticholinesterase treatment.

CLINICAL RELEVANCE

To the authors' knowledge, this is the first report of acquired myasthenia gravis in a ferret and the first identification of anti-AChR antibodies in this species. Autoimmune myasthenia gravis should be considered in ferrets when weakness and flaccid paresis suggest a neuromuscular disease. Electrodiagnostic testing, anticholinesterase challenge, and AChR antibody titer determination were helpful for diagnosis of this condition.

Electrodiagnostic Examination of the Tibial Nerve in Clinically Normal Ferrets

Tibial nerves of 10 normal domestic ferrets (Mustela putorius furo) were evaluated by means of electrodiagnostic tests: motor nerve conduction studies (MNCSs), supramaximal repetitive nerve stimulation (SRNS), F waves, and cord dorsum potentials (CDPs). Values of conduction velocity, proximal and distal compound muscular action potentials, and amplitudes of MNCS were, respectively, 63.25 ± 7.56 m/sec, 10.79 ± 2.75 mV, and 13.02 ± 3.41 mV. Mean decrements in amplitude and area of compound muscular action potentials of wave 9 with low frequency SRNS were 0.3 ± 3.83% and 0.1 ± 3.51%. The minimum latency of the F waves and the F ratio were, respectively, 8.49 ± 0.65 ms and 1.92 ± 0.17. Onset latency of CDP was 1.99 ± 0.03 ms. These tests may help in diagnosing neuromuscular disorders and in better characterizing the hindlimb paresis reported in many ferrets with systemic illnesses.