Tenosynovitis caused by Mycobacterium malmoense in two kidney transplant recipients and review of the literature

A refractory tenosynovitis of the wrist: a case report

Background

Mycobacterium malmoense is a species of slow-growing nontuberculous mycobacteria. It causes mostly pulmonary infections or lymphadenitis in children, but is increasingly encountered in isolated tenosynovitis in adults. Diagnosis is often delayed because of the rarity of the condition and the difficulty of culturing the bacteria.

Case presentation

We report on a rare association of seronegative polyarthritis with infectious nontuberculous mycobacteria tenosynovitis. A 65-year-old Caucasian female was referred to our clinic because of persisting tenosynovitis of the finger flexor tendons of her right hand, despite two previous synovectomies. She also reported bilateral shoulder and left wrist pain. Paraclinical investigations showed slightly elevated inflammatory parameters. Ultrasound showed synovitis of metacarpophalangeal joints of the right hand and right knee, and a bilateral subacromial bursitis. Hand magnetic resonance imaging also revealed an erosive carpal synovitis. Bacteriological analysis of the second tenosynovectomy specimen showed no growths in aerobic and anaerobic cultures. An additional synovial fluid analysis of the wrist joint was negative for mycobacteria and crystals. Seronegative polyarthritis was suspected, but the initiated immunosuppressive treatment with prednisolone and methotrexate resulted in no clinical improvement of the tenosynovitis. Yet the other joints responded well, and the inflammatory parameters normalized. The immunosuppression was later stopped because of side effects. Due to massive worsening of the tenosynovitis, a third synovectomy was performed. Mycobacterium malmoense was identified on biopsy, leading to the diagnosis of infectious tenosynovitis. At this point, we started an antituberculous therapy, with incomplete response. A combination of antimicrobial and immunosuppressive treatment finally led to the desired clinical improvement.

Conclusion

The treatment of nontuberculous mycobacteria tenosynovitis is not well established, but combining antibiotics with surgical debridement is probably the most adequate approach. Our case highlights the importance of having a high clinical suspicion of an atypical infection in patients with inflammatory tenosynovitis not responding to usual care.

Extensor Tenosynovitis due to Mycobacterium marseillense Infection in a Renal Transplant Recipient

Renal transplant recipients are at an increased risk of atypical nontuberculous mycobacterial (NTM) infections. Infections caused by NTM are uncommon in the general population, rarely occurring in immunocompetent individuals. NTM infections are an uncommon cause of tenosynovitis. Mycobacterium marseillense is a rare, atypical mycobacteria that has been reported to cause pulmonary and cutaneous infections; however, no previous reports of this pathogen causing tenosynovitis exist. This case reports a 73-year-old male renal transplant recipient who presented with chronic extensor tenosynovitis of the right hand caused by M marseillense. The patient was treated with radical extensor tenosynovectomy and 6 months of antibiotic treatment. A review of literature on tenosynovitis caused by atypical mycobacteria was performed. The patient successfully responded to treatment with no complications or recurrence of infection at the 18-month follow-up. Tenosynovitis of the hand caused by atypical mycobacteria is rare. A high index of suspicion is required to prevent a delay in diagnosis, particularly in immunocompromised individuals.