Imaging of Mycobacterium avium-intracellulare infection in AIDS patients on highly active antiretroviral therapy: reversal syndrome.

OBJECTIVE: We recently encountered six patients with AIDS and an unusual complication of disseminated infection with Mycobacterium avium-intracellulare, which developed after the initiation of highly active antiretroviral therapy, including protease inhibitors and two new nucleoside analogues. Each patient had a febrile illness after the initiation of therapy and then developed mass lesions containing mycobacterial organisms in various organ systems, including bone, skin, and mesenteric and mediastinal nodes. All these patients suddenly experienced improvement in immunologic status as evidenced by decreasing viral loads and increasing CD4 cell counts. We chose to call this reaction "M. avium-intracellulare reversal syndrome." We describe the radiologic appearance of this unusual manifestation of infection with M. avium-intracellulare in patients with AIDS.
CONCLUSION: New or enlarging lymphadenopathy or unusual musculoskeletal and cutaneous infections in patients with AIDS who are receiving highly active antiretroviral therapy may represent a response of the recovering immune system to a new or previously subclinical infection with M. avium-intracellulare.