Introduction Mycobacterium avium complex (MAC) infection in patients with AIDS classically presents as a disseminated infection involving liver, bone marrow, and lymph nodes. However, we have noted that the increasing use of azithromycin for treatment of pneumonia and the presence of immune reconstitution syndrome in patients with AIDS beginning antiretroviral therapy can greatly complicate the diagnosis. We report here a patient with AIDS who presented with waxing and waning mediastinal adenopathy, endobronchial masses, and pulmonary infiltrates. We believe these findings represent an atypical presentation of MAC infection that may become increasingly common in the current era of antibiotic choices and antiretroviral treatment.
Case Report A 32 year old male with AIDS, CD4 cell count of 36/mm3, on no antiretroviral therapy, presented with a nonproductive cough, pleuritic chest pain, fever, and pancytopenia. He had 4 cm mediastinal and hilar lymph nodes and a right middle lobe infiltrate. Blood, bone marrow, and bronchoscopy cultures were negative. The patient improved on empiric treatment for pneumonia with ceftriaxone and azithromycin with resolution of fevers and chest CT findings. Two months after initiating antiretroviral therapy he was readmitted for fever and cough with CD4 cell count of 140/mm3. Chest CT showed a left lower lobe infiltrate and a recurrence of hilar and mediastinal lymphadenopathy. Bronchoscopy was remarkable for an nearly occlusive nodular endobronchial lesion. Biopsy demonstrated +AFB in poorly formed granulomas. Sputum cultures were positive for MAC. The patient was diagnosed with MAC and immune reconstitution syndrome. His symptoms and CT abnormalities resolved with treatment for MAC and continued antiretroviral therapy.
Conclusions Disseminated MAC in AIDS patients was previously a well described syndrome with a straightforward diagnostic approach. However, the increased use of empiric antibiotics to cover atypical pneumonia has made diagnosis by culture increasingly difficult. Furthermore, partial resolution of MAC infection from azithromycin for empiric treatment of pneumonia may also confuse the clinical picture. In addition, immune reconstitution syndrome leads to atypical presentations with localized findings (endobronchial nodules in this case) not usually seen with MAC in AIDS. We believe that a heightened awareness of the changing presentation of disseminated MAC in AIDS is important to prevent delay in diagnosing this opportunistic infection.