Gastrointestinal tract in the immunocompromised host: opportunistic infections and other complications.

In the decade since the early 1980s, the increasing use of immunosuppressive therapy for cancer and autoimmune disease, as well as for organ transplantation, has combined with the acquired immunodeficiency syndrome epidemic to increase greatly the incidence of opportunistic infections and other complications of the gastrointestinal tract. Consequently, barium fluoroscopic and cross-sectional imaging studies tailored to address these problems are no longer uncommon. Although overlap exists, there are radiographic patterns that can direct the diagnosis to an opportunistic infection and sometimes to a specific pathogen. This article describes and illustrates the radiographic findings of gastrointestinal superinfection with Candida albicans, cytomegalovirus, Cryptosporidium spp, herpes simplex virus, Mycobacterium tuberculosis, M avium-intracellulare, and human immunodeficiency virus. Other gastrointestinal tract complications of immunosuppression are discussed, including graft-versus-host disease following bone marrow transplantation, typhlitis, and pseudomembranous colitis.