title: Idiopathic localized eosinophilic synovitis in a cat.
abstract: A 4-year-old male castrated Seal Point Himalayan cat was presented for evaluation of right thoracic limb lameness of 6 weeks duration. Synovial fluid analysis of the swollen right carpal joint revealed a mixed cell synovitis, with a total nucleated cell count of 13,200/microliter and 34% eosinophils. A diagnosis of idiopathic localized eosinophilic arthritis was made. Additional clinical and diagnostic findings included mild lymphadenopathy with lymphoid hyperplasia and an antinuclear antibody titer of 1:320. Lack of multisystem involvement made systemic lupus erythematosis unlikely. Immunosuppressive therapy with oral prednisone alleviated the lameness. Eosinophilic synovitis has not previously been reported in cats. An immune-mediated mechanism was likely in this case; however, the exact etiology remains unknown.
authors.affiliation: Veterinary Medical Teaching Hospital, University of California, Davis, CA 95616, USA. dcsilverstein@ucdavis.edu
authors.forename: Deborah C.
authors.initials: DC
authors.lastname: Silverstein
authors.forename: Frederick S.
authors.initials: FS
authors.lastname: Almy
authors.forename: Joseph G.
authors.initials: JG
authors.lastname: Zinkl
authors.forename: Mary M.
authors.initials: MM
authors.lastname: Christopher