Small intestine & ampulla

Inflammatory disorders

Ulcerative colitis



Topic Completed: 1 August 2012

Minor changes: 19 November 2020

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PubMed Search: Ulcerative colitis[TI] small bowel[TIAB]

Hanni Gulwani, M.B.B.S.
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Cite this page: Gulwani H. Ulcerative colitis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/smallbowelUC.html. Accessed December 6th, 2021.
Definition / general
  • Severe UC is associated with contiguous backwash ileitis and appendix involvement
  • UC also associated with postcolectomy pouchitis
  • Rarely diffuse duodenitis is associated with ulcerative colitis but it does not behave as Crohn's disease (Am J Surg Pathol 2000;24:1407)
  • Diffuse chronic duodenitis in ulcerative colitis patients who have colectomy is a strong predictor of pouchitis (Am J Surg Pathol 2010;34:1672)
Backwash ileitis
  • Recommended to restrict use of term to active enteritis involving ileum contiguously from cecum that has a similar or greater degree of active inflammation; mild cases predominantly involves the superficial mucosa in a contiguous pattern
  • Focal isolated ileal erosions, mucous gland metaplasia or patchy edema with mild active inflammation are features of Crohn's disease (Am J Clin Pathol 2006;126:365)
Microscopic (histologic) images

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Mild backwash ileitis in moderately active cecal chronic ulcerative colitis resection specimen; mucosa
of distal ileum is edematous and villi are slightly wider and flatter than normal; most of the active colitis
stops abruptly at transition point between the two mucosae; the two most distal villi have the greatest
degree of injury, including blunting, edema and neutrophils in the lamina propria and surface epithelium


Moderate backwash ileitis

Severe backwash ileitis

Terminal ileum inflammation: (A) grade
1, cryptitis; (B) grade 2, scattered
crypt abscesses; (C) grade 3, numerous
crypt abscesses; (D) grade 4, ulcer

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