The etiology of acquired immunodeficiency syndrome (AIDS) enteropathy is unknown. This condition has been associated with malabsorption and villous atrophy. Other disorders with similar findings, including celiac disease, are characterized by altered intestinal permeability. Our objective was to confirm (or reject) our hypothesis that processes that cause increased permeability may occur in patients with AIDS, and thus be a cause of idiopathic diarrhea.
A lactulose-mannitol differential intestinal permeability test was performed in healthy controls, asymptomatic human immunodeficiency virus (HIV)-positive patients, and AIDS patients with and without diarrhea.
Asymptomatic HIV-positive patients lactulose and mannitol recoveries were no different than healthy control patients. AIDS patients without diarrhea had lactulose recovery similar to healthy controls and decreased mannitol recoveries; their mean lactulose:mannitol ratio was no different from that of controls, and less than that of AIDS patients with diarrhea. AIDS patients with diarrhea had increased lactulose recovery and decreased mannitol recovery; their mean lactulose:mannitol ratio was significantly greater than the ratios in all the other groups.
Patients with AIDS and diarrhea have altered intestinal permeability. The decreased absorption of mannitol suggests that the functional absorptive surface of the intestine decreases as HIV disease progresses.