Complications in the Intestine
Intestinal Blockage. Blockage or obstruction in the intestinal tract is a common complication of Crohn’s disease. Inflammation from Crohn's disease produces scar tissue known as strictures that can constrict the intestines, causing bowel obstruction with severe cramps and vomiting. Strictures usually occur in the small intestine but can also occur in the large intestine.
Fistulas and Abscesses. Between 30 - 40% of patients with Crohn's disease have complications around the anal area from inflammation. Fistulas (abnormal channels between tissues) frequently develop from the deep ulcers that can form with Crohn's. If fistulas develop between the loops of the small and large intestines, they can interfere with absorption of nutrients. They often form pockets of infection, or abscesses, which may become life threatening if not treated.
Malabsorption and Malnutrition. Malabsorption is the inability of the intestines to absorb nutrients. In IBD, this occurs as a result of bleeding and diarrhea, as a side effect from some of the medications, or as a result of surgery. Malnutrition usually develops slowly and tends to become severe, with multiple nutritional deficiencies. It is very common in patients with Crohn's disease.
Toxic Megacolon. Toxic megacolon is a serious complication that can occur if inflammation spreads into the deeper layers of the colon. In such cases, the colon enlarges and becomes paralyzed. In severe cases, it may rupture, which is a life-threatening event needing emergency surgery.
Colorectal Cancers. Inflammatory bowel disease increases the risk for colorectal cancer. The risk is highest for patients who have had the disease for at least 8 years or who have extensive areas of colon involvement. The more severe the disease, and the more it has spread throughout the colon, the higher the risk. Having a family history of colorectal cancer also increases risk. Patients with Crohn's disease also have an increased risk for small bowel cancer. (However, small bowel cancer is a very rare type of cancer.)
Patients with IBD should discuss with their doctors how often they should have colonoscopies (screening tests for colorectal cancer). Current guidelines recommend that patients receive an initial colonscopy within 8 years after IBD is diagnosed, and have follow-up colonoscopies every 1 to 2 years if results are negative. The colonoscopy should include biopsies to test for dysplasia (precancerous changes in cells). [For more information, see In-Depth Report #55: Colon and rectal cancers.]
Review Date: 09/28/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.