Non-tuberculous mycobacterial tenosynovitis

Mycobacterial synovitis caused by slow-growing nonchromogenic species: eighteen cases and a review of the literature

CONTEXT

Slow-growing nonchromogenic mycobacterial species are an infrequent cause of soft tissue infection. Because these organisms are rare, they are not often initially considered in the differential diagnosis of synovitis.

OBJECTIVE

To evaluate the clinical and pathologic characteristics of patients with synovitis resulting from slow-growing nonchromogenic mycobacterial species.

DESIGN

A 20-year retrospective review of records from The Methodist Hospital Microbiology Laboratory identified 18 culture-positive cases of synovitis that resulted from slow-growing nonchromogenic mycobacteria, including 14 caused by Mycobacterium avium complex, 1 caused by Mycobacterium malmoense, 1 caused by Mycobacterium haemophilum, and 2 caused by Mycobacterium nonchromogenicum isolates. In addition, a comprehensive literature search revealed an additional 48 cases of synovitis caused by slow-growing nonchromogenic mycobacteria.

RESULTS

The historic literature described the majority of the 48 patients as previously healthy, elderly individuals with a several-month history of monoarticular pain and swelling in the small joints of the upper extremity. In contrast, the current series demonstrated the probable role of multiple chronic coexisting medical conditions in promoting disease susceptibility. These patients were also unique in their significantly younger age distribution and diversity of infection sites. Histologic examination and direct acid-fast bacteria stains generally did not aid the diagnosis. Amputation was performed in 2 patients because of delayed identification of disease.

CONCLUSIONS

The current series demonstrates that difficult identification and infrequent occurrence cause these organisms to be overlooked by physicians and laboratory personnel. A heightened clinical suspicion for slow-growing nonchromogenic mycobacterial species is necessary when routine culture and histopathologic findings do not readily isolate an organism, or when the patient does not respond to antibiotic and anti-inflammatory treatment.

Tenosynovitis caused by Mycobacterium kansasii associated with a dog bite

A 68-year-old man with adult-onset diabetes mellitus suffered an accidental puncture wound to the palm of his hand while playing with his pet dog. He received cephalosporin prophylaxis for 1 week. No inflammation occurred. Six months later, a mass developed near his elbow. It was removed. Histopathology revealed granulomas containing acid-fast bacilli (AFB). No culture was done. Swelling and decreased motion of the wrist and fingers developed. Magnetic resonance imaging revealed inflammation of the flexor compartment of the hand, wrist, and forearm. Surgical incision and drainage yielded purulent material, granulomatous inflammation, with AFB. Cultures yielded Mycobacterium kansasii. Several surgical procedures were required; M kansasii was recovered. He received isoniazid and rifampin for 1 year and prolonged rehabilitation. After 4 years, he was relatively asymptomatic, with good function of wrist and fingers. We believe this to be the first report of tenosynovitis caused by M kansasii in association with a dog bite.

Non-tuberculous mycobacterial tenosynovitis: a review

The clinical characteristics, outcome and treatment of non-tuberculous mycobacterial tenosynovitis are reviewed. From lesions localized in the hand, 10 different species of non-tuberculous mycobacteria have been reported. The most common are Mycobacterium marinum and Mycobacterium kansasii. Other less frequent organisms are Mycobacterium avium complex, Mycobacterium szulgai, Mycobacterium terrae, Mycobacterium fortuitum, Mycobacterium chelonae, Mycobacterium abscessus, Mycobacterium malmoense and Mycobacterium xenopi. The infections appear to be the result of previous trauma, surgical procedure, corticosteroid injection or non-apparent inoculation (water contamination). Immunosuppression is sometimes associated with the infections and can be considered as a risk factor. Surgical debridement and appropriate mycobacterial cultures are critical to enable diagnosis and appropriate management. Specimens should be inoculated on a range of media and incubated at a range of temperatures in order to isolate mycobacteria with different growth characteristics (with prolonged incubation). The optimal treatment of these infections is discussed.

Granulomatous tenosynovitis: a rare musculoskeletal manifestation of tuberculosis

A patient with tenosynovial tuberculosis affecting the extensor tendons of the wrist and hand is presented. This case highlights the clinical and magnetic resonance features of tuberculous tenosynovitis, and seeks to increase awareness of what may represent a resurgent musculoskeletal entity.