Histologic detection of trophozoites of Giardia lamblia in the terminal ileum.

Abstract

The occurrence of trophozoites of Giardia lamblia in mucosal biopsy specimens obtained from the terminal ileum and associated histologic changes are reported. In this retrospective histologic analysis an average of 3.2 (range, 1-7) Giardia-positive biopsy specimens obtained from the terminal ileum of 32 subjects was examined. Colonization was defined as sparse (1-10 trophozoites per specimen), intermediate (10-30 trophozoites per specimen), or heavy (more than 30 trophozoites). The number of intraepithelial lymphocytes (IEL) was assessed and the results expressed as the number of IEL/100 epithelial cells. Grade of villous flattening was determined semiquantitatively. The number of lymphoid follicles per biopsy specimen was counted, and the degree of mucosal inflammation determined semiquantitatively. Ileal mucosa biopsy specimens from 32 Giardia-free cases, classified histologically as normal, served as control. Twelve of the patients were female, and twenty male. The mean age was 46 years (range, 20-68 years). Light colonization with G. lamblia was observed in 13 (40.6%) patients, intermediate in 6 (18.8%), and heavy colonization in 13 (40.6%; range, 2-215 trophozoites/case). Normal villous architecture was seen in all cases. The numbers of lymphocytes and granulocytes in the lamina propria were considered to be within the normal range in all patients with giardiasis and in all controls. The occurrence of lymphoid follicles and the content in IEL did not differ significantly in Giardia-positive and -negative cases. G. lamblia can colonize the terminal ileum and may therefore be detected in biopsy specimens obtained from this area. Owing to the absence of associated histologic changes a search for the parasites themselves has to be made in the specimen.