Inflammatory Bowel Disease

This is a descriptive term for a group of auto-immune disease characterised by recurrent episodes of inflammation in the gastro-intestinal tract. The two conditions ulcerative colitis and Crohn’s disease account for the majority of patients with symptomatic inflammatory bowel disease but other conditions including microscopic colitis (lymphocytic and collagenous colitis), and Bechet’s disease are also forms of inflammatory bowel disease. The symptoms and appearances of Crohn’s disease and ulcerative colitis can be very similar and in a number of cases it is very difficult to be categorical about which of these diseases an individual has, in which case the disease is sometimes labelled as indeterminate colitis.

 

Inflammatory bowel disease is thought to reflect an abnormal immune response to normal luminal(bowel) contents. Factors which increase risk of developing disease include genetics (hereditary), early exposure to a wide variety of gut organisms (which appears protective) and environmental factors such gut infection and drugs. Factors which are known to trigger relapse include gut infection, Non steroidal anti-inflammatory drug use, alcohol binge drinking and stress. Smoking appears to be protect against relapse in ulcerative colitis (although smokers with colitis still tend to die sooner than their non smoking peers) but more than doubles the risk of relapse and hospitalisation in Crohn’s disease.

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There is considerable debate about the role of gastrointestinal inflammation in several other diseases affecting the musculoskeletal system, known as spondyloarthropathies, since gastrointestinal inflammation similar to that found in Crohn’s disease is seen in over 50% of this type of musculoskeletal disorder, nevertheless they are usually regarded as being primary joint disease rather than primary gastro-intestinal ones.

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Many of the inflammatory bowel diseases have extra gastro-intestinal manifestations including, eye (iritis), skin (erythema nodosum and pyoderma gangrenosum) and joint manifestations (arthritis). Many of these resolve on treatment of the underlying gastrointestinal disease, but some do not.