title: Canine inflammatory myopathies: a clinicopathologic review of 200 cases.
abstract: A retrospective study was performed on 200 randomly selected cases of inflammatory myopathy in dogs from diagnostic muscle biopsies received at the Comparative Neuromuscular Laboratory, University of California, San Diego. The most common clinical signs in dogs diagnosed with an inflammatory myopathy were generalized weakness, stilted gait, dysphagia, masticatory or generalized muscle atrophy, inability to open the jaw, megaesophagus, and dysphonia. Myalgia was rarely described. Age of onset ranged from 0.25 to 14 years. Genders were equally represented. Breed distribution approximated the 2002 American Kennel Club registration statistics (r = .85) with the notable exception of Boxers and Newfoundlands. From the results of muscle biopsies, clinical signs, and presence or absence of antibodies against type 2M fibers, dogs were classified as a generalized inflammatory myopathy (gIM)--including immune-mediated polymyositis; infectious and preneoplastic myositis; and, rarely, dermatomyositislike or overlap syndromes or unclassified myositis-or a focal inflammatory myopathy (flM)--including masticatory muscle and extraocular myositis. Average creatine kinase (CK) and aspartate aminotransferase (AST) concentrations in gIMs were significantly higher than those with fIMs (P < .05). Neoplasia developed in 12 of 200 dogs within 12 months of diagnosis of polymyositis, with lymphoma diagnosed in 6 of 32 Boxers. Inflammatory myopathy was associated with antibody titers against infectious diseases in 38 dogs. Neospora caninum and Hepatozoon americanum cysts were found in tissues of 2 dogs not serologically tested. Antibodies against an unidentified sarcolemmal antigen were found in 9 of 19 Newfoundlands with polymyositis. The spectrum of canine inflammatory myopathies can be broad, with infectious etiologies relatively common, and can include preneoplastic and uncharacterized syndromes.
authors.affiliation: Veterinary Neurological Center, Las Vegas, NV 89108, USA. DrJasonDVM@aol.com
authors.forename: Jason
authors.initials: J
authors.lastname: Evans
authors.forename: Donald
authors.initials: D
authors.lastname: Levesque
authors.forename: G Diane
authors.initials: GD
authors.lastname: Shelton
mesh_terms: D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D003402:Creatine Kinase / Q000097:blood; D003882:Dermatomyositis / Q000473:pathology / Q000662:veterinary; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D005260:Female; D008297:Male; D008410:Masticatory Muscles / Q000473:pathology; D018656:Muscle Fibers, Fast-Twitch / Q000276:immunology; D009220:Myositis / Q000473:pathology / Q000662:veterinary*; D017285:Polymyositis / Q000473:pathology / Q000662:veterinary; D012189:Retrospective Studies; D012698:Serologic Tests / Q000662:veterinary
chemical_list: D001219:Aspartate Aminotransferases; D003402:Creatine Kinase