Septic Arthritis of the Knee with Toxoplasma gondii in a Patient with Rheumatoid Arthritis.

Toxoplasmosis is a parasitic infection that may affect several viscera. The locomotor system is rarely involved, and no case has been published of a septic arthritis in which Toxoplasma gondii was identified in the cultures of the joint fluid and of the synovial specimen.We describe a patient with septic arthritis of the knee in which Toxoplasma gondii was found by culture in a patient with seropositive rheumatoid arthritis treated with corticosteroids and gold salts who developed multi-visceral toxoplasmosis.