Pulmonary disease in the immunocompromised host (2).

In this second segment of our article on pulmonary disease in the immunocompromised host (ICH), we review the infections associated with pulmonary infiltrates in the ICH and the diagnostic approaches for both infectious and noninfectious conditions. Although certain immunologic defects may predispose patients to specific infectious agents, virtually any infectious agent can cause pulmonary disease in any ICH. Physical findings and laboratory observations may give the clinician clues about probable causes of infection. Nevertheless, invasive diagnostic procedures-in particular, open-lung biopsy-are often necessary to diagnose pulmonary disease in the ICH. The relatively new technique of bronchoalveolar lavage is useful in diagnosing pulmonary disease in the patients with acquired immunodeficiency syndrome (AIDS). Further studies are necessary to confirm the reliability of this procedure as a diagnostic method in the ICH who does not have AIDS.