Objective: to identify risk factors for, clinical and radiological findings of, treatment and outcome of pneumothorax PTX) associated with HIV infection. Design: a retrospective logistic regression analysis, conducted between Jan 1987 and Dec 1994, considering 2,954 hospital admissions relative to 2,094 HIV-infected patients. Results: in the study period, 30 episodes of PTX were identified in 26 patients. The rate of PTX was 8.2 in patients with AIDS and Pneumocystis carinii pneumonia (PCP), and 5% in those with AIDS and mycobacterial pulmonary infections. Sixty-one percent of the patients with PTX suffered from current or previous PCP and 46% from mycobacterial pulmonary infections. Three patients had been under aerosolized pentamidine as prophylaxis for PCP. Univariate analysis identified five risk factors significantly associated with PTX: 1) current PCP; 2) previous PCP; 3) mycobacterial pulmonary infections; 4) low number (less than 100 x mm3) of circulating TCD4+ cells; 5) presence of radiological alterations of the lung i.e. cysts, pneumatoceles or bullae. As regards to mycobacterial infections, pulmonary tuberculosis is, in our patients, a predisposing factor for PTX while NT-Mycobacteria pulmonary infections are not statistically associated with PTX. On multivariate analysis, the only factor significantly correlated to PTX is current PCP. Varying previous reports, PCP prophylaxis with aerosolized pentamidine is not a risk factor for PTX. Conclusions: this study confirms the relevant importance of PCP for PTX development in HIV-infected patients and it also suggests a possible etiologic role of pulmonary tuberculosis.

*Acquired Immunodeficiency Syndrome/COMPLICATIONS *HIV Infections/COMPLICATIONS *Mycobacterium Infections/COMPLICATIONS *Pneumonia, Pneumocystis carinii/COMPLICATIONS *Pneumothorax/ETIOLOGY *Tuberculosis, Pulmonary/ETIOLOGY

www.aegis.org