Crohn's disease

Definition

• • Inflammatory disease of the intestines that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms

Risk Factors

• • FHx

  • Smoking

Differential diagnosis

Epidemiology

• • Tends to present initially in the teens and twenties, with another peak incidence in the fifties to seventies

  • Prevalence ( Northern Europe): 27–48 per 100,000

  • Higher incidence in western industrialized nations compared to other parts of the world

  • Males and females are equally affected

  • Smokers are two times more likely to develop Crohn's disease than nonsmokers.^[5]

  • Genetic link

Aetiology

• • autoimmune disease of the gastrointestinal tract

  • Inflammation stimulated by an overactive T_h1 cytokine response

  • T_h17 is of greater importance in the disease?^[54]

  • ATG16L1 may induce autophagy and hinder the body's ability to attack invasive bacteria

  • Increasing body of evidence in favor of the hypothesis that Crohn's disease results from an impaired innate immunity

Clinical features

• abdominal pain

  • diarrhoea

    • may be bloody if inflammation is at its worst

    • Often porridge-like^[18], sometimes steatorrhea

• vomiting

  • weight loss^[1][2][3]

  • Perianal discomfort

    • inflammation

  • fistulization

    • abscess around the anal area^[1]

  • anal fissure

    • Skin tags

  • Fecal incontinence

  • May also cause complications outside the gastrointestinal tract:

  • skin rashes

  • arthritis

  • inflammation of the eye

    • tiredness

    • lack of concentration

Pathophysiology

• • Transmural pattern of inflammation

  • Ulceration is an outcome seen in highly active disease

  • Usually an abrupt transition between unaffected tissue and the ulcer.

  • Mucosal inflammation, characterized by focal infiltration of neutrophils into the epithelium

  • Neutrophils, along with mononuclear cells, may infiltrate the crypts, leading to inflammation (crypititis) or abscess (crypt abscess)

  • Granulomas are found in 50% of cases and are most specific for Crohn's disease

    • Do not show "caseation"

  • 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)

Investigations

Management

a) conservative

b) medical

• • 5-aminosalicylic acid (5-ASA) formulations, prednisone, immunomodulators

  • No known pharmaceutical or surgical cure

c) surgical

• • used when partial or a full blockage of the intestine occurs

Prognosis