Internal Medicine
Arthrocentesis is the sampling of joint fluid. This is typically done in dogs and cats with lameness secondary to joint disease. Most causes of joint effusion (excessive fluid in joints) are immune-mediated polyarthritis (IMPA), joint infection, and tick borne diseases. The diagnosis of IMPA is based on the sampling of multiple joints. Findings include inflammation without evidence of bacterial infection on culture. Rarely fungal disease (e.g. blastomycosis) and cancer may be found in the joint. Treatment of septic arthritis (infected joint) is based on chronic aggressive antibiotic therapy. While treatment of IMPA is based on chronic immuneosuppressants to help prevent that body from continuing to attack the joints.