Myotonic dystrophy-like disease in a dog.
A mature female Rhodesian Ridgeback was determined to have a progressive, degenerative myopathy associated with myotonia, dysphagia, and marked muscle wasting. Clinical findings revealed a diffuse muscular disease with percussion dimpling, dysphagia, and creatine kinase elevation. A paroxysmal atrial tachycardia was found. Electromyography revealed a diffuse myopathy with high-frequency bizarre waves, myotonic discharges especially in the masticatory, laryngeal, and pharyngeal muscles. A few positive sharp waves were found in some of the appendicular muscles. Histopathologic and histochemical stains on skeletal muscle biopsy specimens demonstrated moderate fiber-size variation, myofiber architectural changes, muscle-fiber splitting, focal necrosis and phagocytosis, high percentage of internal nuclei, and atrophy of type-2 muscle fibers. A review of myotonic myopathies in the dog is presented. The clinical, electrophysiologic, and histochemical findings are similar to those for myotonic muscular dystrophy in man.
D000818:Animals; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D004576:Electromyography; D005260:Female; D009132:Muscles / Q000473:pathology; D009135:Muscular Diseases / Q000473:pathology / Q000662:veterinary*; D009222:Myotonia / Q000662:veterinary*