Mechanism of malabsorption in giardiasis: a study of bacterial flora and bile salt deconjugation in upper jejunum.

Sixty-three unselected cases of giardiasis, with no evidence of other systemic disease, were screened for evidence of steatorrhoea. No patient had any evidence of protein-energy malnutrition. Seventeen (27%) of the cases had steatorrhoea; three (17-8%) of the 17 patients having steatorrhoea also had D-xylose malabsorption. Vitamin B12 absorption was normal in all. Bacterial culture and qualitative analysis of bile salt in jejunal fluid was carried out in all the 17 cases having steatorrhoea as well as 13 cases with normal absorptive parameters (eight cases of irritable bowel syndrome and five cases of giardia infection) who served as controls. All the patients showing bacterial overgrowth had free bile acids in their duodenal aspirate. Free bile acids could also be detected in jejunal aspirates of five of the seven patients having no bacterial overgrowth. Two control cases of giardia infection with normal small bowel function and sterile duodenal aspirate showed evidence of bile salt deconjugation. The significance of these findings is discussed in relation to the pathogenesis of steatorrhoea in patients with giardiasis. The possible role of giardia in bile salt deconjugation is suggested.