Crohn's disease

Crohn's disease is a chronic inflammatory disease of the digestive tract and it can involve any part of it, from the mouth to the anus. It typically affects the caecum and/or the terminal ileum as well as demarcated areas of large bowel, with other areas of the bowel being relatively unaffected. It is often associated with auto-immune disorders outside the bowel, such as aphthous stomatitis and rheumatoid arthritis. more...

Crohn's disease should not be confused with a non-progressive and non-degenerative digestive disorder called irritable bowel syndrome (IBS), which is not an autoimmune disease. Ulcerative colitis is a sibling autoimmune disease to Crohn's but only impacts the colon while Crohn's can impact any part of the digestive tract. Furthermore, Crohn's tends to affect multiple layers of the bowel lining, which can lead to many additional and hard-to-treat complications.

Symptoms

Crohn's patients typically suffer from abdominal pain, chronic diarrhea and disrupted digestion, which may make it difficult for sufferers, particularly in the acute phase of the disease, to eat and/or digest food. The inflammation can be extremely painful and debilitating. Other common complications of Crohn's include fistulas of the colon, hemorrhoids, lipid absorption problems, and anemia. Bleeding is seen in 20% cases, against 98% cases in ulcerative colitis. Rectal bleeding may be serious and persistent, leading to anemia. Bruising of the shins, varying fever symptoms, varying levels of pain, and psychological damage is seen in many cases. Children with Crohn's disease may suffer delayed development and stunted growth.

Epidemiology

The disease typically first appears in young adults in their late teens and twenties, although it is not unknown for symptoms to first appear quite late in life. Additionally, there has been an increase in cases occurring in young children. Recent studies suggest that up to 30% of all newly diagnosed cases are in children and teens under the age of 18. Estimates suggest that up to 60,000 people in the UK (about 1 in 1200) and 1,000,000 Americans have the disease (around 1 in 300). Some ethnic groups (such as Ashkenazi Jews) have a significantly higher rate of prevalence than others. Increased rates of disease have also been noted in some families, leading to speculation of a possible genetic link (see below). Epidemiological research indicates that Crohn's belongs to the group of diseases of affluence. In other words, the incidence of the disease is much higher in industrialized countries than elsewhere. However, this finding may be associated with the fact that Crohn's symptoms are typically diagnosed over a long period of time, in order to establish a pattern; in countries where medical help is less available, it may be difficult to arrive at a diagnosis.

Smoking increases the risk of Crohn's disease. Some women find that their disease is exacerbated by taking oral contraceptives, while others find it can help keep their flare ups at bay.

Causes

Barrier problem and autoimmunity to the luminal flora

The efficacy of immunosuppression, as well as scanty reports of complete disease resolution after bone marrow transplant, is highly suggestive of an autoimmune pathogenesis. A definite epitope to which the autoimmunity is directed is unknown, which also hampers the search for a virus or other pathogen that could induce molecular mimicry.

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