Noninfectious colitis

Pseudomembranous colitis

Topic Completed: 1 May 2013

Minor changes: 26 August 2021

Copyright: 2003-2021,, Inc.

PubMed Search: antibiotic associated colitis

Hanni Gulwani, M.B.B.S.
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Cite this page: Gulwani H. Pseudomembranous colitis. website. Accessed October 25th, 2021.
Definition / general
  • Also called pseudomembranous colitis
  • Acute colitis with adherent inflammatory exudate (pseudomembrane) overlying sites of mucosal injury, usually after broad spectrum antibiotics (clindamycin, lincomycin, others), which favor the overgrowth of Clostridium difficile over other gut bacteria (Merck manual, eMedicine #1, #2)
  • Also after surgery or chronic debilitating illness without antibiotics
  • Clinical disease is due to toxins (Clin Microbiol Rev 2005;18:247, Indian J Med Res 2010;131:487)
Clinical features
  • Detect Clostridium difficile toxin (toxin A-enterotoxin or less commonly toxin B-cytotoxin) in stool (Am J Med 2006;119:356.e7, J Clin Microbiol 2006;44:1145)
  • Must interpret results within context of patient history and clinical features (Am J Clin Pathol 2012;137:10)
  • Suggested to accept only loose or liquid stool specimens for analysis; monitor / regulate test-ordering practices such as repeated requests after negative results, testing for cure, testing of infants and children
Case reports
Gross description
  • Yellow-white mucosal plaques or pseudomembranes; may resemble polyps or aphthoid ulcers of Crohn's disease
Gross images

Images hosted on other servers:

Hyperemic mucosa and green-yellow exudate

Pseudomembranous colitis

Microscopic (histologic) description
  • Denuded epithelium
  • Mucopurulent exudate erupts out of crypts to form a mushroom-like cloud with a linear configuration of karyorrhectic debris and neutrophils that adheres to surface
  • Superficial crypts show patchy necrosis and dilation
  • Later in disease, entire crypt becomes necrotic and disease resembles ischemic colitis
  • Adjacent mucosa is normal, but may be covered by pseudomembrane
  • Superficial lamina propria contains dense neutrophils and some capillary fibrin thrombi
  • Rarely signet ring cell change (Am J Surg Pathol 2004;28:1111)
Microscopic (histologic) images

Images hosted on other servers:

Pseudomembrane with intact mucosa

Eruption of exudate resembling mushroom cloud

Superficial ulcer /

Various images

Pseudomembranous colitis

Pseudomembrane contains abundant neutrophils

Positive stains
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