Evaluation of AIDS-related diarrhea.

A 31-year-old man was hospitalized for evaluation of chronic diarrhea accompanied by profound dehydration, abdominal pain, nausea, vomiting, and low-grade fever. He had been identified as hepatitis B surface antigen-positive in 1983 and HIV antibody-positive two years later. In 1987, after a diagnosis of Pneumocystis carinii pneumonia, he had been placed on zidovudine and prophylactic pentamidine. Subsequently, thrush developed, which was treated with nystatin. The patient's gastrointestinal symptoms were of about six months' duration and originally had responded fairly well to diphenoxylate. More recently, however, he had been losing weight steadily and had required emergency room rehydration on two occasions. A search for stool ova and parasites and routine enteric pathogens, conducted by the outpatient department, had revealed Cryptosporidium cysts.