In the United States, almost all people with AIDS develop diarrhea at some time in the course of their disease. Severe or prolonged diarrhea can lead to weight loss and malnutrition. Symptoms Diarrhea, which means two or more loose or unformed stools per day, can last for a few days or can be chronic, lasting for weeks or months. Many people with AIDS have diarrhea that persists for more than a month or is so severe they expel several gallons of fluid a day. The diarrhea may be accompanied by abdominal cramps, nausea, vomiting, fever, blood in the stool or weakness.
Diarrhea also can have non-infectious causes.
For example, most people with AIDS are lactose intolerant, which means they cannot digest lactose, a milk sugar. When they eat dairy products such as milk, cheese or ice cream they may develop diarrhea, cramping and gas. It is important to determine the cause of diarrhea so that the best treatment can be offered. Doctors examine stool samples to determine whether diarrhea-causing organisms are present. Doctors also may need to take small samples of tissue from the stomach or intestines to detect diarrhea-causing organisms or determine if cancer is present.