Culture-negative septic arthritis and bacterial endocarditis. Diagnosis by synovial biopsy.

The capacity of bacterial endocarditis to mimic other systemic illnesses is well known. This report describes a patient with blood culture-negative bacterial endocarditis who presented with features suggestive of rheumatoid arthritis. Despite sterile synovial fluid, synovial biopsy culture resulted in identification of the causative organism and led to specific antibiotic therapy and cure. This is the first report of such a case.