1. Inflammatory Bowel Disease Slideshow Pictures
2. Take the Tummy Trouble Quiz
3. Ulcerative Colitis Slideshow Pictures

Medical Author:

Lori Kam, MD

Medical Editor:

Leslie J. Schoenfield, MD, PhD

Leslie J. Schoenfield, MD, PhD

Dr. Schoenfield served as associate professor of medicine and consultant in gastroenterology on the faculty of the Mayo Clinic for seven years. He became a professor of medicine in residence at UCLA from 1972 to 1999 (now emeritus). He was the director of gastroenterology at Cedars-Sinai Medical Center in Los Angeles for 25 years, where he received the chief resident's teaching award, the president's award, and the pioneer of medicine award.

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In this Article

• What is inflammatory bowel disease?
• What are the intestinal complications of IBD?
• Are the intestinal complications of ulcerative colitis and Crohn's disease different?
• Do intestinal ulcers occur in IBD?
• Does gastrointestinal bleeding occur in IBD?
• How do intestinal strictures form in IBD?
• What are the symptoms of intestinal strictures, and how are they diagnosed and treated?
• What are intestinal fistulas?
• What symptoms do fistulas cause and how are they diagnosed and treated?
• What are fissures and how are they treated?
• What is small intestinal bacterial overgrowth (SIBO)?
• Does colon 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?
• Intestinal Problems in IBD At A Glance
• Patient Comments: Inflammatory Bowel Disease (IBD) - Treatments
• Patient Comments: Inflammatory Bowel Disease - Experience
• Find a local Gastroenterologist in your town
• Inflammatory Bowel Disease: Intestinal Problems Index

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.