Inflammatory Bowel Disease (IBD)
(Intestinal Problems of IBD)

Ulcerative colitis (UC) and Crohn's disease (CD) are known as the inflammatory bowel diseases (IBD). The precise cause of IBD remains unknown. These diseases are believed to be caused by a combination of genetic and non-genetic, or environmental factors (for example, infections) that interact with the body's immune (defense) system. When the intestinal immune system does not function properly, many white blood cells accumulate in the inner lining (mucosa) of the gut. The white cells then release chemicals that lead to tissue injury (inflammation). This inflammation of the mucosa can cause diarrhea, which is the most common symptom of ulcerative colitis and Crohn's disease, with or without the intestinal complications.

The intestinal complications of IBD occur when the intestinal inflammation is severe, extends beyond the inner lining (mucosa) of the intestines, is widespread, and/or is of long duration (chronic). For example, severe mucosal inflammation can cause ulcers, bleeding, and toxic megacolon (a condition in which the colon widens, or dilates, and loses its ability to properly contract). Inflammation that extends beyond the inner lining and through the intestinal wall is responsible for strictures (scarring that causes narrowing of the intestinal wall) and fistulas (tubular passageways originating from the bowel wall and connecting to other organs or the skin). Strictures, in turn, can lead to bacterial overgrowth of the small intestine (SIBO). If the inflammation of the small bowel is widespread, malabsorption of nutrients can be a complication. Chronic inflammation can also be associated with colon cancer.

The majority of IBD patients experience periods during which their disease intensifies (flares) or subsides (remissions). Although most patients require medication for IBD, they are able to live normal, productive lives. Some patients, but certainly not all, will develop intestinal complications of IBD. When these complications occur, they should be recognized and usually treated. Some patients with IBD develop complications outside of the intestine (extraintestinal), such as certain kinds of arthritis, skin rashes, eye problems, and liver disease. These extraintestinal complications are discussed in other articles on IBD.

This review will describe the various types of intestinal complications that are associated with IBD, and will also summarize methods for their diagnosis and treatment. Please note that the terms bowel, intestine, and gut are used synonymously. The small bowel, or intestines, includes from top to bottom, the duodenum, jejunum, and ileum. The large bowel is also called the colon.

Source: MedicineNet.com
http://www.medicinenet.com/inflammatory_bowel_disease_intestinal_problems/article.htm