Crohn’s Disease


Summary 1) First Aid for the Basic Sciences: Organ Systems by Tao Le

Crohn’s disease, also known as Crohn syndrome and regional enteritis, is a type of inflammatory bowel disease (IBD) that may affect any part of the gastrointestinal tract from mouth to anus.

Pathophysiology 2) Wikipedia

Crohn’s disease

Certain characteristic features of the pathology seen point toward Crohn’s disease; it shows a transmural pattern of inflammation, meaning the inflammation may span the entire depth of the intestinal wall. Ulceration is an outcome seen in highly active disease. There is usually an abrupt transition between unaffected tissue and the ulcer – a characteristic sign known as skip lesions. Under a microscope, biopsies of the affected colon may show mucosal inflammation, characterized by focal infiltration of neutrophils, a type of inflammatory cell, into the epithelium. This typically occurs in the area overlying lymphoid aggregates. These neutrophils, along with mononuclear cells, may infiltrate the crypts, leading to inflammation (crypititis) or abscess (crypt abscess). Granulomas, aggregates of macrophage derivatives known as giant cells, are found in 50% of cases and are most specific for Crohn’s disease. The granulomas of Crohn’s disease do not show “caseation”, a cheese-like appearance on microscopic examination characteristic of granulomas associated with infections, such as tuberculosis. Biopsies may also show chronic mucosal damage, as evidenced by blunting of the intestinal villi, atypical branching of the crypts, and a change in the tissue type (metaplasia). One example of such metaplasia, Paneth cell metaplasia, involves development of Paneth cells (typically found in the small intestine and a key regulator of intestinal microbiota) in other parts of the gastrointestinal system.

Causes 3) Wikipedia

  • Genetics
  • Impaired innate immunity 
  • Microbes – Mycobacterium avium subspecies paratuberculosis (MAP), Escherechia coli

Symptoms 4) Wikipedia

  • Gastrointestinal  loose bowel movements, bleeding, intestinal stenosis, abdominal pain, vomiting, dysphagia and flatulence
  • Systemic – growth failure, fever and weight loss, usually related to decreased food intake
  • Extraintestinal – uveitis, blurred vision and eye pain, especially when exposed to light (photophobia) and episcleritis

Severe Crohns disease in the sigmoid colon

Diagnosis 5)First Aid for the Basic Sciences: Organ Systems by Tao Le6)Rapid Review Pathology by Edward Goljan

  • Endoscopy  – transmural involvement of the bowel wall, noncaseating granulomas, and fistula formation, “string” sign in terminal ileum from luminal narrowing by inflammalion, fistulas 
  • Barium swallow –  inflammation and narrowing of the small bowel

Treatment 7) Wikipedia

  • Antibiotics  used to treat any infection 
  • Aminosalicylate anti-inflammatory drugs and corticosteroids  to reduce inflammation 
  • Surgery – may also be required for complications such as obstructions, fistulas, or abscesses, or if the disease does not respond to drugs

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