Synovial fluid eosinophilia: a case report in a dog and review of the literature

The first known report of synovial fluid eosinophilia in a dog is described here. The occurrence of eosinophils in joint fluid is rare. Sporadic cases have been recorded in humans and most can be related to immunemediated reactions, both parasitic and non- parasitic. The dog in this case report had 20-52% eosinophils in multiple joints, as well as hemarthrosis and marked mononuclear cell reactivity. An intense peripheral eosinophilia was demonstrated one week later. The associated lameness resolved with non-steroidal anti-inflammatory therapy. Lack of remarkable history or other clinical symptoms led to a diagnosis of idiopathic, eosinophilic, polyarthritis, likely immune-mediated.