Abstract

Thirty of 81 consecutive HIV antibody positive patients referred with non-cryptosporidial diarrhoea had no potential infectious cause; most had AIDS related complex rather than the full blown syndrome. Opportunistic infections with cytomegalovirus (CMV), mycobacterium avium-intracellulare (MAI), and herpes simplex virus (HSV), which allowed a diagnosis of AIDS to be made, were found in 19 patients and were the presenting features of AIDS in five. Other potential pathogenic species included entamoeba, giardia, campylobacter, and salmonella (without septicaemia). Cytomegalovirus infection was often accompanied by abdominal pain. Severe weight loss (greater than 10 kg) at presentation was found in patients with CMV infection and MAI. Bloody diarrhoea was confined to the group with HSV procitis. Malignant causes of diarrhoea were rare. Two patients developed a squamous carcinoma of the anorectal margin and one a non-Hodgkin's lymphoma. In only two of 12 patients who had Kaposi's sarcoma was this considered as a cause of diarrhoea. Rigid sigmoidoscopy showed macroscopic abnormalities in over a third (32) of the 81 patients with non-cryptosporidial diarrhoea. Most commonly this was severe inflammation (17) or discrete ulceration (four) [three of whom had CMV colitis]. Kaposi's sarcoma was identified in 11 patients. Non-specific inflammation was seen histologically in 40 of the 60 patients with no sigmoidoscopic inflammatory changes. Barium enema only revealed an abnormality in a minority of the patients and a colonoscopy only revealed information additional to rigid sigmoidoscopy in two patients--one with CMV ulcers in the transverse colon and the other with evidence of Kaposi's sarcoma not seen in the rectum. Ten patients had a rectal biopsy examined by electron microscopy as no infective cause of diarrhoea was uncovered. In four of these microtubular structures which are commonly seen in viral infections were found and two had prelymphomatous changes and in one of these frank lymphoma has developed. We recommend multiple stool analysis, sigmoidoscopy and rectal biopsy as the initial investigations in these patients reserving tests of malabsorption, colonoscopy, and barium enema for the small number of more difficult cases.