NEUROMUSCULAR CASE OF THE MONTH - AUGUST 2006

Movement disorder in Border Terriers
Contributed by Dr. Diane Shelton
Department of Pathology
University of California, San Diego
La Jolla , CA

          A paroxysmal cramping or hypertonicity syndrome in Border Terriers has been described on the Internet (Go to video clip).  Unfortunately, there are no published scientific studies on this disorder, and information provided only by breeders and owners on the Internet is often misleading.  From the available information, a seizure disorder is unlikely, because dogs are not unconscious during an episode and are responsive to owners. Age of onset is usually 2 to 6 years. Muscle hypertonicity may be evident by mounding of muscle over the back and limb rigidity, resulting in the dog falling over and being unable to rise for a period lasting from seconds to minutes. The frequency of episodes varies from daily to monthly. As far as can be determined from the reports, there is no association with exercise and excitement. There are reports that the cramping activity can be stopped with diazepam, suggesting that it may be similar to hypertonicity disorders in other breeds.

          Reports also suggest that affected dogs respond to dietary changes, including feeding Science K/D diet (Hills Pet Nutrition, Topeka, KS), Eukanuba Early Stage Kidney Diet (The Iams Company, Dayton, OH), and lamb and rice, suggesting a metabolic component. Other abnormalities that may be associated with this syndrome include elevation of bile acids and possibly hepatic microvascular dysplasia.  Muscle biopsies from affected dogs have been normal making a primary muscle disease unlikely. Urinary organic acid excretion was also evaluated in several affected dogs, with variable and inconsistent elevations of lactate, pyruvate, and citrate. Clinical evaluations by specialists in Veterinary Neurology and Internal Medicine are encouraged. Only through these evaluations will it be possible to determine the precise clinical phenotype, relevant laboratory abnormalities, and identify candidate genes for development of a DNA based test for detection of affected and carrier animals.

DNA samples are currently being banked on affected and related Border Terrier dogs at the University of Missouri.

For information on sample submission go to the following website:
www.canine-epilepsy.net

Acknowledgement: The author would like to thank Dr. Charlotte Davies, Veterinary Referral and Critical Care, Manakin-Sabot, VA for  providing the video clip of an affected dog.

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