The estimated incidence of gastrointestinal (GI) complaints among patients infected with HIV varies
between 30% and 90%. All structures from the mouth to the anus may be affected by HIV; oral and
esophageal lesions, hepatobiliary disorders, and diarrhea are most common, and can result in malabsorption, maldigestion, or decreased intake of nutrients, thus adding to the wasting and malnutrition
characteristic of AIDS. In the course of a diagnostic evaluation, unusual opportunistic organisms are
frequently identified, and common pathogens may be found in unusual anatomic locations. Because
multiple pathogens may be found as well, clinicians should keep an open mind to the wide variety of
potential causes of GI diseases in patients with HIV infection. Patients often take as many as 20 different drugs; the potential adverse effects of the therapeutic drugs themselves should therefore be considered in patients with GI complaints. Further complicating the patient evaluation, extraintestinal
processes such as pneumonia may cause diarrhea, and meningitis and CNS mass lesions may cause
vomiting. Gastrointestinal complaints must not be routinely dismissed in the pregnant HIV-infected
woman. These symptoms should be carefully considered and possibly investigated further. Finally,
HIV-infected patients will occasionally develop non-HIV-related diseases appropriate to their age, sex,
and social habits.