Table of Contents
Definition / general | Terminology | Diagrams / tables | Diagnosis | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Videos | Additional referencesCite 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])
Diagnosis
- Detect cysts, trophozoites or antigens in stool
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
Positive stains
- Trichrome with iron hematoxylin counterstain, Giemsa stain
- KIT / CD117 may be useful for diagnosis (Hum Pathol 2009;40:323)
Videos
"Falling leaf" motion of trophozoite