Mycobacterium avium/Mycobacterium intracellulare[cf1] complex (MAC) is a rare cause of
tenosynovitis. We describe a case in which a previously healthy patient developed bilaterally symmetric
synovitis and was treated with disease modifying
anti rheumatic drugs (DMARDs); the
synovitis progressed into a bilaterally symmetric chronic granulomatous
tenosynovitis that was uncontrollable despite a
synovectomy and
DMARD therapy. Three years after developing symptoms, and 2 1/2 years after her diagnosis of
rheumatoid arthritis, MAC was cultured from synovial fluid. All DMARDS were stopped, and the patient received a total of 24 months of triple
antibiotic therapy. All swelling and stiffness resolved after 7 months of
therapy. The patient remains asymptomatic two months after completion of
antibiotic therapy. Rheumatologists and other
arthritis specialists need to include MAC in their differential diagnosis of seronegative symmetrical inflammatory
arthritis.