Mycobacterium kansasii diffuse pulmonary infection in a patient with acquired immune deficiency syndrome. Successful therapy with an antituberculous regimen.

Mycobacterium kansasii is a rare cause of disseminated mycobacterial infection in patients with the acquired immune deficiency syndrome (AIDS). It occurs as the index AIDS diagnosis in only 0.2% of AIDS cases. Previously reported cases of AIDS-associated M. kansasii infection have manifested as diffuse interstitial pneumonitis and diffuse small bowel inflammation and have been refractory to antimycobacterial therapy. The authors now report success in treating a hypoxemic patient with AIDS-associated M. kansasii diffuse granulomatous interstitial pneumonitis that was diagnosed by open lung biopsy. The patient has no evidence of mycobacterial disease after 12 months of therapy with isoniazid, rifampin, and ethambutol.