SUMMARYA 48-yr-old female on immunosuppressive therapy for ®brosing alveolitis and polymyositis developed a septic arthritis of the left middle ®nger proximal interphalangeal joint, tenosynovitis of the left palm and osteomyelitis of the right hindfoot due to infection with Mycobacterium marinum. Such widespread and severe bone and joint involvement has not been described previously with this organism.
CASE REPORTIn March 1994, a 48-yr-old woman presented with erythema and full-thickness ulceration over the left middle ®nger proximal interphalangeal joint (PIPJ) and a red nodule on the¯exor aspect of the right forearm. Biopsy of the nodule showed a pallisaded granuloma consistent with a rheumatoid nodule. She was known to have the Jo-1 syndrome with mild polymyositis, biopsy-proven severe ®bros-ing alveolitis and the presence of the Jo-1 antibody. Immunosuppressive treatment with oral cyclophosphamide (150 mg/day) and prednisolone had been commenced in September 1993. Following a deterioration in lung function, the dose of prednisolone was increased to 60 mg/day in December 1994. One month later, she presented with a 2 week history of pain and swelling about the right ankle and midfoot, and a swelling in the left palm.On examination in January 1995, she was cushingoid. There was purple macular discolouration over the metacarpophalangeal joints (MCPJ) of both hands. The PIPJ of the left middle ®nger was swollen, red and tender (Fig. 1). The left palm was swollen. There was a nodular erythematous rash over the¯exor aspect of the right forearm near the elbow. The right ankle and midfoot were swollen and painful to move.Investigations revealed a white cell count of 12.6 Â 10 9 /l (compared with a previous count of 9.3 Â 10 9 /l) with 11.4 Â 10 9 /l neutrophils, 0.5 Â 10 9 /l lymphocytes and an erythrocyte sedimentation rate of 50 mm in the ®rst hour. Radiographs of the left hand revealed joint space narrowing at the third PIPJ. X-ray of the right foot showed narrowing of the joint space between the navicular and medial cuneiform bones. Green turbid¯uid was aspirated from the right midfoot and bloodstained¯uid from the PIPJ of the left middle ®n-ger. Culture of the¯uid was sterile. The right ankle was injected with intra-articular steroids with temporary relief. Further aspiration gave frank pus containing acid-fast bacilli (AFB), eventually identi®ed as Mycobacterium marinum. The tendon sheaths of the left palm were incised and drained surgically. Mycobacterium marinum was again isolated.The patient kept tropical ®sh and cleaned the tank twice a year.Standard anti-tuberculous chemotherapy (rifampicin, isoniazid and pyrazinamide) caused intolerable nausea. Doxycycline, 100 mg b.d., was prescribed instead.Radiographs of the left hand 6 weeks later showed an erosion of the PIPJ of the middle ®nger. Computed tomography of the right foot showed joint space narrowing and erosions involving the navicular, cuboid and all three cuneiform bones consistent with septic arthritis and osteomyelitis of the entire midfoot (Fig. 2)...