Inflammatory Bowel Disease: Intestinal Problems

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Intestinal Complications
of
Inflammatory Bowel Disease

Digestive Disease Myths Slideshow

Medical Author: Lori Kam, MD
Medical Editor: Leslie J. Schoenfield, MD, PhD

What are the intestinal complications of IBD?
- Are the intestinal complications of ulcerative colitis and Crohn's disease different?
- Patient Discussions: Inflammatory Bowel Disease: Intestinal Problems - Describe Your Experience
Do intestinal ulcers occur in IBD?
- How are ulcers in IBD diagnosed and treated?
Does gastrointestinal bleeding occur in IBD?
- How is gastrointestinal bleeding in IBD diagnosed and treated?
How do intestinal strictures form in IBD?
- What symptoms do intestinal strictures cause and how are they diagnosed?
- How are intestinal strictures in IBD treated?
What are intestinal fistulas?
- What symptoms do fistulas cause and how are they diagnosed?
- How are fistulas in IBD treated?
What are fissures and how are they treated?
What is small intestinal bacterial overgrowth (SIBO)?
- How is SIBO diagnosed and treated?
Does colon cancer occur in IBD?
- How does colon cancer develop in IBD?
- How can colon cancer in IBD be prevented?
- Does small bowel cancer occur in IBD?
What should be done about polyps in IBD?
What is toxic megacolon and what are its causes?
What kind of malabsorption occurs in IBD?
- How is malabsorption in IBD treated?
Intestinal Problems At A Glance
Related inflammatory bowel disease articles:
Inflammatory bowel disease - on WebMD
Read what your doctor is reading:
Inflammatory Bowel Disease - on Medscape

What are the intestinal complications 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.

Are the intestinal complications of ulcerative colitis and Crohn's disease different?

Some intestinal complications of IBD occur in both ulcerative colitis and Crohn's disease. For example, ulceration of the inflamed inner intestinal lining (mucosa), which causes abdominal pain and intestinal bleeding, may complicate both diseases. Since both ulcerative colitis and Crohn's disease involve the colon, complications that are associated with the colon, such as toxic megacolon and colon cancer, occur in both diseases. Additionally, there are no intestinal complications that occur only in ulcerative colitis and not in Crohn's disease. On the other hand, certain intestinal complications of IBD occur predominantly in Crohn's disease (for example, fistulas) or exclusively in Crohn's disease and not in ulcerative colitis (for example, malabsorption and SIBO).

The differences in intestinal complications between ulcerative colitis and Crohn's disease depend on the characteristically dissimilar behaviors of the inflammation associated with these diseases. In Crohn's disease, the inflammation usually extends from the inner lining (mucosa) through the entire thickness of the bowel wall. This spreading inflammatory process may thereby lead to fistulas, abscesses, or strictures of the bowel. By contrast, the inflammation in ulcerative colitis is limited to the inner lining of the colon. The development of these particular complications is, therefore, much less common in ulcerative colitis. Also, Crohn's disease can affect any area of the GI tract from the mouth to the anus, whereas ulcerative colitis is limited to the colon. Therefore, complications involving the small intestine, such as malabsorption and SIBO, as previously noted, occur only in Crohn's disease and not in ulcerative colitis.