CROHN'S DISEASE
Crohn's disease is a form of inflammatory bowel disease (IBD), which involves ongoing (chronic) inflammation of the gastrointestinal tract. Crohn's-related inflammation usually affects the intestines, but may occur anywhere from the mouth to the anus (the end of the rectum). The exact chain of events that lead to Crohn's disease is unknown but there is evidence that the condition is linked to a problem with the body's immune system response.
Normally the immune system helps protect the body from harmful substances. But in patients with Crohn's disease and other types of inflammatory bowel disease (IBD), the immune system can't tell the difference between good substances and foreign invaders. The result is an overactive immune response that leads to chronic inflammation. This is called an autoimmune disorder. There are five different types of Crohn's disease:
- Ileocolitis is the most common form. It affects the lowest part of the small intestine (ileum) and the large intestine (colon).
- Ileitis affects the ileum.
- Gastroduodenal Crohn's disease causes inflammation in the stomach and first part of the small intestine, called the duodenum.
- Jejunoileitis causes spotty patches of inflammation in the top half of the small intestine (jejunum).
- Crohn's (granulomatous) colitis only affects the large intestine.
A person's genes and environmental factors seem to play a role in the development of Crohn's disease.
(Source: NIH, MedlinePlus medical Encyclopedia 2008)
