Inflammatory bowel disease is a group of disorders that cause chronic inflammation of the digestive tract. Crohn’s disease and ulcerative colitis are the two most common of these diseases, affecting nearly 2 million Americans. Crohn’s disease and ulcerative colitis are similar in many ways. They both cause swelling and sores along the tissue that lines the digestive tract and can cause abdominal pain and frequent diarrhea. Crohn's disease can develop anywhere in the digestive tract, from the mouth to the rectum, and penetrates into the deep layers of the lining. Ulcerative colitis usually affects only the outermost layer of the tissue lining the colon (the large intestine). There is still much to be learned about Crohn’s disease and ulcerative colitis, and laboratory and clinical research into their causes and treatments is under way at The Cleveland Clinic Digestive Disease Center and the Lerner Research Institute.
Causes Scientists estimate that seven people out of 100,000 in the United States develop Crohn’s disease, and 10 to 15 people in 100,000 develop ulcerative colitis. The exact cause of these diseases is unknown, but the latest research suggests that they may be caused by a malfunction in the body’s immune system. Both Crohn’s disease and ulcerative colitis appear to run in families, and certain environmental factors may also increase an individual’s risk for Crohn’s disease and ulcerative colitis.
Diagnosis Crohn’s disease and ulcerative colitis are so similar that they often are mistaken for each other. Making an accurate diagnosis is important so that an individual can receive the most effective treatment for his or her disease. Cleveland Clinic gastroenterologists have extensive experience in diagnosing Crohn’s disease and ulcerative colitis and are skilled in distinguishing between the two based on symptoms and test results. They use a variety of tests to diagnose inflammatory bowel disease:
Two newer blood tests are useful in diagnosing inflammatory bowel disease. These tests check for anemia or signs of infection by identifying certain antibodies in the blood, but they are only about 80 percent accurate.
A barium enema is a test that allows the doctor to perform an X-ray examination of the lower portion of the digestive tract. To perform this test, barium, a safe dye, is placed in the colon as an enema. It coats the lining and creates a silhouette of the entire large intestine, which includes the colon, rectum and anus, and a portion of the small intestine on X-ray. For patients in whom Crohn’s disease does not affect higher sections of the digestive tract, a barium enema may be the only test needed for diagnosis.
A flexible sigmoidoscopy provides an internal, real-time view of the lowest two feet of the colon. The doctor inserts a slender, flexible, lighted tube through the rectum and examines the tissue lining this section of the colon, looking for inflammation, ulcers or other problems that signal inflammatory bowel disease. The sigmoidoscopy is very useful for diagnosing disease in the lowest portion of the colon, but it does not allow the doctor to see problems that might exist higher in the colon or in the small intestine.
A colonoscopy is the most definitive test for diagnosing inflammatory bowel disease. The doctor inserts a thin, flexible, lighted tube that is long enough to view the entire colon, from the anus to the small intestine, with the attached camera. During this procedure, the doctor also can take tissue samples from inside the colon that can be tested in the laboratory for clusters of inflamed cells called granulomas. These clusters are present in Crohn’s disease but not ulcerative colitis, so this is a very useful test for distinguishing the two diseases.
Treatment In the early stages of both Crohn’s disease and ulcerative colitis, medication is the recommended treatment. The goal of medical treatment is to suppress the abnormal inflammatory response and allow the intestinal tissues to heal. Once diarrhea and abdominal pain are under control, medical treatment can reduce the frequency of flare-ups and maintain remission. At this time, there is no medical treatment that will cure inflammatory bowel disease.
In more advanced disease, surgery is often necessary. The type of operation performed and the prognosis are specific to each disease. For details about treatments, please see the appropriate sections under Crohn’s disease and ulcerative colitis.
Medication Drugs are an effective means for treating early inflammatory bowel disease, relieving symptoms and maintaining remission. The most commonly prescribed drugs for inflammatory bowel disease are:
Corticosteroids such as prednisone and methyloprednisone. These powerful drugs reduce the inflammation in the intestines and can aid in the treatment of fistulas.
Aminosalicylates such as sulfasalazine and olsalazine. These are aspirin-like anti-inflammatory agents, often used as the first-line treatment in early disease.
Immunosuppressives such as 6-mercaptopurine and azathioprine. These drugs control the immune response and can help maintain a remission and reduce the dose of corticosteroids.
Metronidazole, an antibiotic with immune system effects. It is helpful in patients with fissures or abscesses, particularly in anal disease.