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Myotonia congenita (MC) is a skeletal muscle channelopathy characterized by inability of the muscle to relax following voluntary contraction. Worldwide population prevalence in humans is 1:100,000. Studies in mice, dogs, humans and goats confirmed myotonia associated with functional defects in chloride channels and mutations in a skeletal muscle chloride channel (CLCN1). CLCN1 encodes for the most abundant chloride channel in the skeletal muscle cell membrane. Five random bred cats from Winnipeg, Canada with MC were examined. All cats had a protruding tongue, limited range of jaw motion and drooling with prominent neck and proximal limb musculature. All cats had blepharospasm upon palpebral reflex testing and a short-strided gait. Electromyograms demonstrated myotonic discharges at a mean frequency of 300 Hz resembling the sound of a 'swarm of bees'. Muscle histopathology showed hypertrophy of all fiber types. Direct sequencing of CLCN1 revealed a mutation disrupting a donor splice site downstream of exon 16 in only the affected cats. In vitro translation of the mutated protein predicted a premature truncation and partial lack of the highly conserved CBS1 (cystathionine β-synthase) domain critical for ion transport activity and one dimerization domain pivotal in channel formation. Genetic screening of the Winnipeg random bred population of the cats' origin identified carriers of the mutation. A genetic test for population screening is now available and carrier cats from the feral population can be identified.

Background: Increased D-lactate concentrations cause neurological signs in humans with gastrointestinal disease., Hypothesis/objectives: To determine if serum D-lactate concentrations are increased in cats with gastrointestinal disease compared to healthy controls, and if concentrations correlate with specific neurological or gastrointestinal abnormalities., Animals: Systematically selected serum samples submitted to the Gastrointestinal Laboratory at Texas A&M University from 100 cats with clinical signs of gastrointestinal disease and abnormal gastrointestinal function tests, and 30 healthy cats., Methods: Case-control study in which serum D- and L-lactate concentrations and retrospective data on clinical signs were compared between 30 healthy cats and 100 cats with gastrointestinal disease. Association of D-lactate concentration with tests of GI dysfunction and neurological signs was evaluated by multivariate linear and logistic regression analyses, respectively., Results: All 100 cats had a history of abnormal gastrointestinal signs and abnormal gastrointestinal function test results. Thirty-one cats had definitive or subjective neurological abnormalities. D-lactate concentrations of cats with gastrointestinal disease (median 0.36, range 0.04-8.33 mmol/L) were significantly higher than those in healthy controls (median 0.22, range 0.04-0.87 mmol/L; P = .022). L-lactate concentrations were not significantly different between the 2 groups of cats with gastrointestinal disease and healthy controls. D-lactate concentrations were not significantly associated with fPLI, fTLI, cobalamin, folate, or neurological abnormalities (P > .05)., Conclusions and Clinical Importance: D-lactate concentrations can be increased in cats with gastrointestinal disease. These findings warrant additional investigations into the role of intestinal microbiota derangements in cats with gastrointestinal disease, and the association of D-lactate and neurological abnormalities., (Copyright © 2012 by the American College of Veterinary Internal Medicine.)

Dysautonomia of domestic animals is pathologically characterized by chromatolytic degeneration of the neurons in the autonomic nervous ganglia that results in clinical signs related to dysfunction or failure of the sympathetic and parasympathetic nervous systems. The exact cause is unknown. It has a poor prognosis among all species reported and no definitive treatment is available currently. To date, most reported feline cases have occurred in the United Kingdom and Scandinavia. The cases reported here highlight the clinical signs, physical examination findings, and results of autonomic nervous system function testing in nine cats with dysautonomia in the US. Feline dysautonomia is uncommon in the US, but may have a regional prevalence, as is seen in dogs with most cases reported in Missouri and Kansas.

Diskospondylitis is uncommon in cats. We describe a cat with diskospondylitis of the L7-S1 intervertebral disk, and a concurrent sublumbar abscess. Radiographic, computed tomographic and ultrasonographic findings are presented. Aerobic and anaerobic cultures of blood and spinal fluid yielded no growth. Aerobic and anaerobic urine cultures resulted in growth of an Enterococcus sp. and Clostridium perfringens, respectively. The cat was successfully treated with enrofloxacin and amoxicillin/clavulanic acid. Clinical signs resolved completely, and based on follow-up ultrasonography there was no remaining evidence of the sublumbar abscess. Etiologic agents and outcome from other cats with diskospondylitis are reviewed.

The autonomic nervous system can be affected as part of a more diffuse peripheral nerve disease such as inflammatory polyneuropathy or diabetes, or as a primary disease, such as dysautonomia. Dysautonomia is being diagnosed with increasing frequency in dogs and other species in the Midwest. Affected animals present with absence of parasympathetic and autonomic ganglia and brainstem nuclei degenerate with minimal inflammation. The cause is unknown and treatment symptomatic.

We report laminin alpha 2 (merosin) deficiency associated with muscular dystrophy and demyelinating neuropathy in two cats. The cats developed progressive muscle weakness, and atrophy. Either hypotonia or contractures resulted in recumbency, necessitating euthanasia. Muscle biopsies showed dystrophic changes including marked endomysial fibrosis, myofiber necrosis, variability of fiber size, and perimysial lipid accumulation. Immunohistochemistry showed that laminin alpha 2 chain was absent or reduced, while dystrophin and all the components of the dystrophin-associated glycoprotein complex were present and normal. One cat was examined in detail. Motor nerve conduction velocity (MNCV) was decreased, and ultrastructurally the peripheral nerves showed Schwann cell degeneration and demyelination. Brain imaging was not performed, but white matter changes were not apparent in the brain at necropsy. The disease in these cats is similar to primary or secondary merosin (laminin alpha 2)-deficient congenital muscular dystrophy (CMD) in humans and to dystrophia muscularis in mice.

A 2.5-year-old domestic shorthair cat was evaluated because of dysphagia and weight loss of 4 weeks' duration. MIld blepharospasm and conjunctival hyperemia were evident in both eyes, oral mucous membranes were tacky on palpation, and salivary glands were enlarged. Results of a Schirmer tear test were 0 mm/min for both eyes. Administration of atropine did not cause salivation or caused secretion fo thick rope-like saliva. Examination of biopsy specimens of salivary glands revealed a plasmacytic infiltrate. Sjögren's syndrome (SS) was diagnosed. Oral administration of prednisone was instituted but was discontinued after a minimal positive response was evident 6 weeks after initiation of treatment. Palliative treatment with a 6% solution of pilocarpine 4 to 5 times/d, cyclosporine, hylan A, and neomycin-polymyxin-bacitracin ophthalmic ointment resulted in clinical improvement in the cat. Although reported rarely in animals, SS may be more common than currently is recognized. Most treatment regimens for SS are aimed at alleviating clinical signs.

A 6-year-old cat that was laterally recumbent and panting was evaluated because of a 10-day history of progressive neurologic abnormalities. Despite aggressive treatment, the cat died on the day of admission. At necropsy, a 1.5-cm-diameter, fluid-filled cyst was found in the white matter of the left cerebrum. The cyst was identified as a coenurus of Taenia serialis, on the basis of the cyst wall, distribution of scolices, and the shape and dimensions of rostellar hooks. Scolices were found in varying stages of ontogeny, ranging from undifferentiated to nearly mature. Taenia serialis has a canid-lagomorph life cycle, with cats being accidental intermediate hosts. However, the potential exists for rare zoonotic transmission and subsequent serious disease in human beings and other accidental intermediate hosts.

Clinical signs of dysautonomia, including dilated pupils, dry mucous membranes, and megaesophagus, were observed in a cat. The diagnosis was confirmed by use of autonomic nervous system function testing including 0.1% pilocarpine and physostigmine ocular response tests, plasma catecholamine assays, and cardiovascular responses to various perturbations intended to elicit autonomic responses. The cause of the autonomic dysfunction was not ascertained, and the cat was euthanatized after 5 weeks of unsuccessful treatment with pilocarpine, metoclopramide, prochlorperazine, and parenteral nutrition.