[Diagnostic imaging and therapeutic implications in lung infections in patients with HIV-1 infection].

We studied retrospectively 132 episodes of infectious pneumonias in 89 patients examined from 1990 to 1995. Pneumocystis carinii was found to be the most common cause of pneumonia (33 patients). The other causes were: Streptococcus pneumoniae (15), Mycobacterium tuberculosis (14), Pseudomonas aeruginosa (8), Staphylococcus aureus (5), Cytomegalovirus (4), Haemophilus influentiae (4), Mycobacterium avium intracellulare (2), Klebsiella pneumoniae (2), E. coli (2), Serratia marcescens (1). No etiologic agent was found in 40 cases. We stress the need of a more frequent use of invasive diagnostic procedures in the study of focal lung consolidations because this radiologic sign is highly aspecific and may be caused by too many different pathogenic agents, needing different therapies-i.e., Streptococcus pneumoniae (15 cases), Pseudomonas aeruginosa (8), Staphylococcus aureus (5), Klebsiella pneumoniae (2), Escherichia coli (2), Pneumocystis carinii, Serratia marcescens and Haemophilus influentiae (1). Since there is an increase in mortality among patients treated with empiric antibiotic therapy, we stress the need of the routinary use of bronchoalveolar lavage in HIV+ patients with lung consolidation to perform specific therapy. Moreover, Pneumocystis carinii is by far the most frequent cause of diffuse interstitial infiltrates, and PCP has very suggestive clinical (dyspnea), radiologic (diffuse perihilar interstitial infiltrates; ground glass opacities; pneumatoceles) and laboratory (CD3+CD4 < 200/mcl; LDH > 600 UI/dl; PO2 < 70 mmHg) patterns, always related to the discovery of Pneumocystis carinii in escreatum. Thus, we decided to treat 15 patients with specific therapy for Pneumocystis carinii pneumonia with the above diagnostic algorithm, obtaining in all of them complete clinical and radiologic recovery. To conclude, in critical patients, invasive procedures should be performed only in the cases in which PCP is clinically improbable.