Cavitary lung disease in AIDS: etiologies and correlation with immune status.

To investigate the etiology and differential features of cavitary lung disease in patients with acquired immune deficiency syndrome (AIDS), chest computed tomography (CT) records from a 2-year period were reviewed to identify all human immunodeficiency virus (HIV)-positive patients with cavitary lung disease. Medical records were reviewed for the documentation of specific causes of lung cavitation and the CD4 count at the time of imaging. Of 25 HIV-positive patients with cavitary lung disease, 20 had specific diagnoses. Infection was the etiology in all the cases. Polymicrobial infection was found in 17 patients (85%) and unimicrobial in 3 (15%). Seventeen patients (85%) had bacterial organisms, 10 of whom had other pathogens as well. Mycobacteria were isolated in 8 patients (40%), fungi in 3 (15%), cytomegalovirus (CMV) in 3 (15%), and Pneumocystis carinii pneumonia (PCP) in 1 (5%). Mediastinal or hilar lymphadenopathy and additional noncavitary ill-defined nodular opacities were found more frequently in patients with mycobacterial pathogens. Mean CD4 count in patients with cavitary disease because of bacterial pathogens alone was significantly higher than in patients with nonbacterial pathogens (alone or combined with bacterial pathogens) (203 vs. 42, p < 0.05). Four patients expired during the diagnostic hospital admission; 2 of them had pulmonary cavitary disease associated with Nocardia asteroides. Cavitary lung disease in patients with AIDS undergoing chest CT should be assumed infectious and is generally polymicrobial.