Inflammatory Bowel Disease

Inflammatory Bowel Disease is a topic covered in the 5-Minute Emergency Consult.

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  • Idiopathic, chronic inflammatory diseases of intestines, which can involve extraintestinal sites as well.
  • Differentiation between ulcerative colitis (UC) and Crohn's is not always clear; intermediate forms of inflammatory bowel disease (IBD) exist.
  • May present as initial onset of disease or exacerbation of existing disease.
  • Maintain high index of suspicion owing to frequent, subtle presentation of Crohn's disease.
  • Pediatric considerations:
    • Can occur in 1st few years of life.
    • Extraintestinal manifestations may predominate.
  • Differences between Crohn's and UC:
    • Rectum almost always involved in UC with continuous inflammation proximally.
    • Small intestine is not involved in UC.
    • Crohn's can occur anywhere from mouth to anus, often with normal GI tract segments between affected areas.
    • Crohn's involves transmural inflammation, whereas UC is confined to submucosa.
  • Similarities between Crohn's and UC:
    • Higher rate of colon cancer with disease >10 yr.
    • Bimodal age distribution, with early peak between teens and early 30s and 2nd peak about age 60 yr.
  • Crohn's disease clinical pattern:
    • Ileocecal: ∼40%
    • Small bowel: ∼30%
    • Colon: ∼25%
    • Other: ∼5%
  • UC clinical pattern on presentation:
    • Pancolitis: 30%:
      • Most severe clinical course
  • Proctitis or proctosigmoiditis: 30%:
    • Relatively mild clinical course
  • Left-sided colitis (up to splenic flexure): 40%:
    • Moderate clinical course


  • Unknown
  • Crohn's disease and UC are separate entities with common genetic predisposition.
  • A positive family history is very common.
  • Multifactorial origin involving interplay among the following factors:
    • Genetic
    • Environmental
    • Immune
  • Pathogenesis:
    • Gut wall becomes unable to downregulate its immune responses, ultimately resulting in chronic inflammation.
  • There is no definitive evidence for the etiologic role of infectious agents.
  • Psychogenic factors may play a role in some symptomatic exacerbations.

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