The intestine, divided into the small and large intestine, plays an essential role in the digestive system with its functions of mixing food, transporting food, splitting and absorbing food components and regulating the fluid balance. In particular, the large intestine takes over the task of thickening (by dehydration) and storage of the intestinal contents as well as their further transport up to excretion. However, if an inflammatory disease occurs in this area, the sensitive system is disturbed.
In this case, however, colitis does not initially mean that it is a disease of the colon as a whole functional system, but rather an isolated inflammation of and damage to the colon mucosa. In some cases, however, it is possible that the inflammatory process can spread beyond the mucosal barrier into the colon muscles. Inflammations of the colon are divided into three major groups: “acute”, “chronic” and “ischemic”.
Causes
Acute colitis is one of the most common forms of intestinal inflammation (2007 approx. 400,000 cases in Germany) and usually occurs in combination with inflammation of the small intestine (enterocolitis) and/or stomach (gastroenteritis). It is usually triggered by viruses, bacteria (Salmonella, Shigella, Campylobacter, Escherichia coli, Clostridia, Staphylococcus), fungi or parasites/protozoa (amoebae), which are usually transmitted faecal-orally, so that infection occurs through the intake of contaminated drinking water, infected food or contact with excretion products of sick persons.
However, taking medication (antibiotics-induced pseudomembranous colitis) and radiation of abdominal tumors can also trigger acute colitis. Chronic inflammation of the colon (CED; chronic inflammatory bowel disease) primarily includes Crohn’s disease and ulcerative colitis. Ulcerative colitis is an inflammation of the colon mucosa alone, which usually begins in the last section of the rectum and rises without interruption and can affect other sections of the colon.
However, the inflammation remains strictly limited to the large intestine, the small intestine is not affected. In 50% of cases, both the rectum and the sigmoid (colon) are affected, in 25% the entire colon. The situation is different in Crohn’s disease, which also has a relapsing course, but on the one hand shows inflammation beyond the mucous membrane (up to the colon muscles) and on the other hand can affect not only the colon, but all structures of the digestive tract from the mouth to the anus.
The spread of inflammation is not continuous as in ulcerative colitis, but rather discontinuous, so that healthy and diseased, inflamed sections of the intestine coexist. The ileum and the colon are most frequently affected. The number of new patients for both forms of the disease is approx.
5/100,000 inhabitants/year and the peak frequency of the initial manifestation is also identical – it is between the ages of 20 and 40. The cause of neither ulcerative colitis nor Crohn’s disease has been conclusively clarified. However, a disturbance in the immune system (autoimmune reaction) is suspected, which leads to a dysregulation of the body’s own defense system and results in an uncontrolled, permanent inflammatory reaction with subsequent destruction of the mucous membrane.
The main risk factor for the development of Crohn’s disease is smoking (2-fold increased risk), whereas in ulcerative colitis it has a more protective effect (smokers are less likely to develop the disease). In both chronic inflammatory colon diseases, there is often a familial predisposition. The so-called “ischemic” colitis is a non-infectious disease that develops at the base of circulatory disorders in the colon. It is usually caused by an increasing calcification of the intestinal vessels (in generalized arteriosclerosis), which leads to constrictions or blockages and causes a reduced blood flow in the intestinal sections they serve.