Gastric Giardiasis

Author: Elliot Weisenberg, M.D. (see Authors page)

Revised: 1 December 2016, last major update August 2012

Copyright: (c) 2003-2016,, Inc.

PubMed Search: Gastric Giardiasis
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Cite this page: Gastric Giardiasis. website. Accessed January 23rd, 2019.
Definition / general
  • Caused by Giardia lamblia
  • Often associated with H. pylori infection (J Clin Pathol 1992;45:964)
  • Very rarely reported in the stomach, overwhelming majority detected in small intestine (see Small Bowel topic)
Clinical features
  • Severe diarrhea, vomiting, abdominal cramps, fever
  • Also anorexia, malaise, fatigue
  • Associated with chronic atrophic gastritis (J Egypt Soc Parasitol 1996;26:481)
  • Recommended to search carefully for giardia in patients with chronic atrophic gastritis, as it may cause persistent upper GI symptoms even after H. pylori eradication (Indian J Pathol Microbiol 2006;49:519)
Case reports
  • Metronidazole or other antibiotics (eMedicine)
Microscopic (histologic) description
  • Trophozoites are sickle or teardrop shaped and can be found along the surface of the foveolar epithelial cells
Microscopic (histologic) images

Images hosted on PathOut server:

Giardial trophozoites along the surface of foveolar epithelial cells

Sickle-shaped trophozoites

Images hosted on other servers:

Small intestinal giardia

Pear-shaped trophozoites from stool

Positive stains

"Falling leaf" motion of trophozoite, contributed by Dr. Shrinivasan Chamarajan
Differential diagnosis
  • H. pylori associated follicular gastritis