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Small intestine & ampulla

Infectious disorders

Giardia lamblia

Author: Hanni Gulwani, M.B.B.S.

Last author update: 1 August 2012

Last staff update: 10 November 2022 (update in progress)

Copyright: 2003-2023, PathologyOutlines.com, Inc.

PubMed Search: Giardia lamblia[TI] small bowel[mh]

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Table of Contents

Cite this page: Gulwani H. Giardia lamblia. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/smallbowelgiardiasis.html. Accessed February 3rd, 2023.

Definition / general

Protozoan infection associated with malabsorption, chronic diarrhea
Spreads by fecally contaminated water, common in underdeveloped countries
Affects 1/3 of homosexual men in urban communities
Attaches to mucosa but does not invade
May cause endoscopic duodenal nodularity (Indian J Pathol Microbiol 2011;54:312)
Causes epithelial barrier dysfunction by down regulating claudin1 and increasing epithelial apoptoses (Gut 2007;56:328)

Terminology

Giardia duodenalis, also known as G. lamblia, G. intestinalis (Pritt: Creepy Dreadful Wonderful Parasites Blog - Answer to Case 508 [Accessed 17 October 2018])

Diagrams / tables

Images hosted on other servers:

Life cycle

Diagnosis

Detect cysts, trophozoites or antigens in stool

Gross images

Contributed by Centers for Disease Control and Prevention

Giardia

Microscopic (histologic) description

Variable villous blunting, increased inflammatory cells, organisms are teardrop (pear) shaped with paired nuclei in lumen between villi
Size of organism is similar to enterocyte nuclei

Microscopic (histologic) images

Contributed by Bobbi Pritt, M.D., Emily Fernholz and Case #157