Abstract
Mycobacterium avium complex (MAC) is an uncommon cause of soft tissue infection. There are no standard guidelines for management of localized MAC infections especially when it is refractory to therapy. We describe a 29 year old white male with right wrist tenosynovitis. He was initially treated with local injection of steroids with no improvement. MRI of the hand showed no evidence of osteomyelitis. Tissue obtained at surgical débridement grew MAC. The infection did not show any significant resolution after 4 months of treatment with ethambutol and clarithromycin. Rifabutin and sparfloxacin were added to the regimen and repeat surgical débridement was done. MAC was grown again. Based on in vitro susceptibility results, sparfloxacin was changed to clofazimine with no significant improvement. Repeat surgical débridement showed acid-fast bacilli on staining but no growth on culture. GM-CSF 500 μg SQ three times a week was started. The wrist wound showed complete closure after a week. GM-CSF was stopped at 2 months due to side effects and antimycobacterial drugs were stopped at 18 months. After 6 months, the patient presented with swelling of right 5th MCP joint. Biopsy showed acid-fast bacilli on staining with no growth on culture. Patient was started on ethambutol, rifabutin, clarithromycin and clofazimine again along with IFN gamma 50 μg SQ three times a week. A repeat surgical débridement showed acid-fast bacilli in tenosynovium, necrotizing granulomatous inflammation and caseating granulomas. No organisms were grown. T helper cell count was normal. IFN-gamma was stopped at 3 months. Patient is nearing completion of an 18-onth course of antimycobacterial regimen and is doing well. To our knowledge, this is the first report of successful treatment of recurrent localized MAC infection using IFN-gamma in a patient with no detectable evidence of immunodeficiency.