Prevalence of clinical abnormalities in cats found to have nonneoplastic middle ear disease at necropsy: 59 cases (1991-2007).

To determine the prevalence of nonneoplastic middle ear disease among cats undergoing necropsy and the prevalence of clinical abnormalities in cats in which nonneoplastic middle ear disease was identified. Retrospective case series. 59 cats that underwent necropsy between January 1991 and August 2007. Medical records were searched to identify cats in which nonneoplastic middle ear disease was identified at necropsy. For cats included in the study, data that were recorded included signalment, initial complaint, whether the cat had any clinical signs of middle or external ear disease, whether the cat had upper respiratory tract disease, necropsy diagnosis, gross appearance of the bullae, and reason for euthanasia. Signs of middle ear disease that were considered included unilateral peripheral vestibular disease without motor deficits, Horner syndrome, and facial nerve paralysis. Of the 3,442 cats that underwent necropsy during the study period, 59 (1.7%) had nonneoplastic middle ear disease. Six of the 59 (10%) cats, including 1 cat that was affected bilaterally, had clinical signs of middle ear disease. Of these, 5 had signs of unilateral peripheral vestibular disease, and 1 had Horner syndrome. Results suggested that most cats with nonneoplastic middle ear disease did not have associated clinical signs. Findings may be of clinical relevance for cats in which middle ear disease is identified as an incidental finding during computed tomography or magnetic resonance imaging for unrelated diseases.