No abstract

Unyielding rigidity of one thoracic limb due to continuous involuntary muscle spasm was seen as the presenting complaint in two cats and a dog. A distal forelimb injury on the affected limb preceded the development of clinical signs in two animals. No abnormalities were detected in a detailed histological examination of the first case. The continuous localised muscular spasm subsided completely over a prolonged period in the remaining two cases. These findings strongly suggest a diagnosis of local tetanus. The diagnosis and treatment of this rare condition are discussed.

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Canine fucosidosis was studied as an animal model for the treatment of neurovisceral lysosomal storage disease. Following successful bone marrow engraftment, dogs with fucosidosis had increased levels of alpha-L-fucosidase enzyme activity in leukocytes, plasma, and neural and visceral tissues. This widespread increase in enzyme activity was accompanied by a rapid improvement in the peripheral nerve and visceral lesions of fucosidosis and a more gradual improvement in the central nervous system pathology. Long-term engraftment from an early age reduced the severity and slowed the progression of clinical neurological disease. Transplantation after the onset of clinical signs was not effective. These findings suggest that the neurological damage caused by some inherited metabolic disorders, such as fucosidosis, may be preventable but emphasise the need for early diagnosis and treatment.

Two young Doberman Pinschers with painless, firm enlargement of the mandibles were investigated. Craniomandibular osteopathy was diagnosed in each case on the basis of characteristic radiographic and gross and microscopic lesions.

Equine motor neuron disease (EMND), a newly described neurodegenerative disease, bears a striking resemblance to progressive muscular atrophy (PMA) in humans. We present a comparison of the equine and human diseases and the results of a case-control study conducted to identify intrinsic factors associated with EMND. Cases included all horses with a confirmed diagnosis of EMND diagnosed in the United States since 1985 (32 cases). Controls included horses diagnosed with either cervical stenotic myelopathy, equine degenerative myeloencephalopathy, or protozoan myelitis at the Veterinary Teaching Hospital at the College of Veterinary Medicine, Cornell University (153 controls). Logistic regression analysis identified factors associated with the risk of EMND. Risk factors considered were age, sex, and breed of the horse. Most cases of EMND (30 of 32) have been sporadic. There was a breed association with the risk of EMND. Quarter horses were at a high risk for developing EMND (odds ratio [OR] = 12.7; 95% confidence interval, 3.3 to 49.6); thoroughbred horses were at increased risk (OR = 2.9, 0.8 to 10.4). There was also an age association with the risk of EMND. The risk increased with age, peaked at 16 years, and then declined, a pattern similar to that for amyotrophic lateral sclerosis in humans. There was no sex association with the disease. Despite the breed association, equine lymphocyte antigen studies have not revealed a systematic pattern, suggesting that genetic factors influencing susceptibility to EMND may be outside the major histocompatibility complex.

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Four related Chow Chow puppies which were presented because of stiffness in their movements were shown to have myotonia similar to myotonia congenita of man. Electromyography revealed characteristic myotonic discharges. Repetitive nerve stimulation studies showed a marked fade in the compound muscle action potential (CMAP) which was most apparent at stimulation rates of 10 per sec or higher. If stimulation was continued at a rate of 10 per sec the CMAP returned to normal or sometimes greater than normal following several seconds of the reduced response. The decremental response could be exaggerated by cooling the muscle prior to repetitive nerve stimulation. A therapeutic trial to assess the efficacy of the commonly used membrane stabilizing agents, quinidine, procainamide and phenytoin, indicated that all three drugs were beneficial in the treatment of myotonia but procainamide produced the best response. Hypocholesterolaemia was documented in one case. The possibility of a multisystem membrane defect in hereditary myotonia associated with low serum cholesterol was considered.