DIAGNOSIS OF CANINE RHEUMATOID ARTHRITIS

Abstract

Canine rheumatoid arthritis is a chronic inflammatory disease that affects the joints of dogs. The inflammation can cause damage to cartilage and bones and early diagnosis is the main factor determining treatment success. This report describes an unusual case of rheumatoid arthritis in a dog, highlighting the relevance of radiographic examination in association with histopathology in the definitive diagnosis. An 8year old, male German Spitz dog, weighing 5kg was admitted with a history of cruciate ligament rupture and grade IV patella dislocation. Previously, surgery had been performed to correct the cranial cruciate ligament rupture, without success. On physical examination, the dog showed a palmigrade stance, severe pelvic limb lameness, and pain on palpation of all joints. Blood count and biochemical analysis were within normal ranges. Orthogonal radiographs of the joints of the pelvic and thoracic limbs were performed. The lesions were bilaterally symmetrical. Samples were taken from the patellofemoral joints for cytology, microbiology, and histopathologic analysis. Rheumatoid factor antibody assay was negative. In conclusion, the combination of more than one clinical sign and diagnostic tests, such as radiographs suggestive of rheumatoid arthritis, histopathologic analysis of the joints, and rheumatoid factor testing is required to reach a definitive diagnosis of rheumatoid arthritis.