Infections in the Immunocompromised Host

The population of immunocompromised patients has multiplied greatly in recent years due to an expansion of indications for immunosuppressive therapies combined with improved survival following organ and bone marrow transplantation, cancer chemotherapy, and other chronic diseases requiring immunosuppressive therapy. Despite advances in prophylactic strategies and antimicrobial therapies, infectious complications remain a leading complication of immunosuppressive therapy. Familiarity with the clinical presentation, differential diagnosis, and management of infectious complications in immunocompromised patients is essential for the practice of critical care medicine. An understanding of the nature of the patient’s underlying immune deficits—neutropenia and humoralor cell-mediated immune deficit—and their epidemiologic exposure—intensity and virulence of offending pathogens—will often define the most likely pathogens responsible for an infectious syndrome. The following points should be considered when evaluating any immunocompromised patient presenting with a suspected infection.