Intestinal microsporidiosis in a patient with acquired immunodeficiency syndrome (AIDS)

A 25-year-old promiscuous heterosexual man with AIDS diagnosed in 1989 and with a history of several episodes of pulmonary pneumocystosis developed chronic diarrhea and severe epigastric pain in August 1990 when he was hospitalized for these symptoms that had been present for one month. Up to August 1990 he had experienced 10 episodes of Pneumocystis carinii pneumonia which was treated with sulfatrimethoprim until it was suspended because of intense neutropenia. He also received zidovudine. The patient developed anorexia and lost about 10 kg of weight. The diagnosis was AIDS in the 4th stage with chronic diarrheal and epigastric syndrome probably due to peptic ulcer. Endoscopy revealed granular intestinal mucosa. There was also atrophy of villi and Giemsa Ziehl-Nielsen and Gram staining identified 1.5-2 micromillimeter spores in the cytoplasm of intestinal cells. Transmission electron microscopy of the spores revealed a thick wall a sporoplasm with a nucleus ribosomes a posterior vacuole and polar filament with multiple coils; no mitochondria were seen. Thus the patient had intestinal microsporidiosis caused by Enterocytozoon bieneusi. This is a rare pathogen recently identified in man. Enterocytozoon bieneusi was described in 1985 and about 31 cases have been documented with intestinal infection but only in patients with AIDS all of whom had chronic diarrhea and pronounced weight loss.