ABSTRACT
This chapter presents an algorithm for the investigation of severely immunocompromised patients with suspected lung infection and the clinical, radiological, microbiological, and pathological features of infection with cytomegalovirus (CMV), Pneumocystis carinii, Aspergillus spp., and Candida spp. with recommendations on possible treatment regimens. CMV infection is very common, but severe clinical manifestations usually occur only in immunocompromised individuals. Infection with the more unusual organisms such as P carinii, CMV, and invasive fungal infections are, however, usually seen in the more severely immunosuppressed patient such as those receiving chemotherapy or immunosuppressive agents, or with HIV infection. In active infection patients who would normally be expected to show radiological changes, CMV would be detected by polymerase chain reaction from blood and/or bronchoalveolar lavage and there would be typical histological features of CMV pneumonitis. The introduction of antiretrovirals in HIV patients has significantly reduced the incidence of P. carinii pneumonia infection in the patients.
