Giardiasis: A Histologic Analysis of 567 Cases

Abstract

Background: The histopathology of the upper and lower gastrointestinal tract of patients with giardiasis as shown by endoscopy with biopsy is ill-defined. We therefore report on 567 cases observed in our institution. Methods: A retrospective analysis of all cases with giardiasis observed between 1988 and 1994 was performed. Results: On histologic slides trophozoites were found in duodena] (82.5%) and jejunal (2.1%) mucosa and also in gastric antral (8.7%) and ileal mucosa (12.1%) but rarely in the colon (0.4%). An entirely normal light-microscopic appearance of the duodenal mucosa was found in 462 cases (96.3%). Mild villous shortening and mild inflammation of the lamina propria were observed in duodenal mucosa in 18 subjects (3.7%). In jejunal, ileal, gastric, and colonic mucosa, no Giardia-specific histologic changes were identified. There was a clear male predominance with 347 (61.2%) males and 220 (38.8%) females. Mean age, which was comparable in males and females, was 49.5 ± 17 years (range, 3–95 years). In 252 Giardia-positive cases gastric biopsy specimens were available, and showed Helicobacter pylori-associated gastritis in 57.8%, reactive gastritis in 10.3%, normal mucosa in 12.9%, chronic atrophic gastritis of the body in 2.9%, and other forms of gastritis in 16.1%. Conclusions: This study shows that the histology of the small-bowel mucosa is inconspicuous in most subjects with giardiasis. A search for the parasite must therefore be made in all biopsy samples obtained from this area. Furthermore, giardiasis was not associated with a particular gastric disease, such as chronic atrophic gastritis of the body.