Ulcerative colitis
Description
An in-depth report on the causes, diagnosis, treatment, and prevention of ulcerative colitis.
Alternative Names
Inflammatory bowel disease; Colitis - ulcerative
Diagnosis
The doctor will take your medical history and perform a thorough physical examination. The disease is particularly difficult to diagnose in children, in whom IBD may be mistaken for an infection or even depression if other characteristic symptoms, such as bloody diarrhea and weight loss, are not present. Slow growth may be a key feature in making a diagnosis, particularly of Crohn's disease, in children.
Several laboratory tests may be taken, such as the following:
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Blood tests are used for various purposes. An increased number of white blood cells may indicate the presence of inflammation. Blood tests are used to determine the presence of anemia and to measure liver enzymes. (They are abnormal in about 3% of ulcerative colitis cases.) New blood tests that measure certain antibodies may make it easier to differentiate Crohn's disease from ulcerative colitis in children.
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A stool sample is taken and examined for blood, infectious organisms, or both.
Imaging Procedures Used for Diagnosis
Endoscopic Procedures.
Flexible sigmoidoscopy and colonoscopy are endoscopic procedures. They are important in the diagnosis of both ulcerative colitis and Crohn's disease. Both procedures involve snaking a fiberoptic tube called an endoscope through the rectum to view the lining of the colon. The doctor may also insert instruments through the endoscope to remove a tissue sample for a biopsy.
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Sigmoidoscopy, which is used to examine the rectum and left (sigmoid) colon, lasts about 10 minutes and is done without sedation. It may be mildly uncomfortable, but it is not painful. Ulcerative colitis almost always involves the lower left colon and rectum and is diagnosed using sigmoidoscopy. The doctor usually observes an evenly distributed inflamed surface lining the intestine, and the bowel wall bleeds easily when touched with a swab.
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Colonoscopy allows a view of the entire colon and requires a sedative, but it is still performed on an outpatient basis. It is helpful for distinguishing between Crohn's disease and ulcerative colitis and in screening for colon cancer.
Patients diagnosed with UC may also need periodic endoscopies to evaluate their condition when symptoms flare up. However, a 2005 study suggested that these routine endoscopies may not be necessary. The study found that people self-reporting symptoms provides as much information as the endoscopies.
X-rays and Barium Enema.
The double-contrast barium enema, which uses an x-ray image, is less expensive than a colonoscopy for viewing the entire colon. Although not as accurate as colonoscopy, it is very valuable in diagnosing both Crohn's disease and ulcerative colitis in early stages. In patients with active ulcerative colitis, this procedure may increase the risk for toxic megacolon.
A barium enema is a valuable diagnostic tool that helps detect abnormalities in the large intestine (colon). A barium enema, along with colonoscopy, remain standards in the diagnosis of colon cancer, ulcerative colitis, and other diseases of the colon.
X-rays of the abdomen are also useful when a patient has a severe attack of ulcerative colitis. In such cases, the edges of the colon are swollen and irregular. X-rays may also reveal thickened walls and other signs of severity.
Ultrasound.
Intestinal wall ultrasound may be useful for identifying the extent and severity of Crohn's disease. Although it is unclear if ultrasound is useful for an initial diagnosis, one study indicated that, when used by experienced professionals, it is effective for identifying Crohn's disease or ulcerative colitis.
Other Imaging Procedures.
Magnetic resonance spectroscopy (MRS) is a variant of magnetic resonance imaging (MRI) that may prove to be useful for differentiating between Crohn's disease and ulcerative colitis.
Computed tomography (CT) scans may be useful for determining the extent of the disease on the intestine and for detecting abscesses and other complications of advanced IBD.
A promising experimental technique called virtual colonoscopy allows three-dimensional imaging of the colon without using invasive instruments. The procedure involves pumping air into the colon and scanning the intestine using computed tomography (CT) or magnetic resonance imaging (MRI). It is very safe, requires no sedation, and takes only about 10 minutes.
Using Tests to Differentiate Between Crohn's Disease and Ulcerative Colitis
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Endoscopy
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Ulcerative colitis almost always involves the lower left colon and rectum and can be diagnosed using sigmoidoscopy. Crohn's disease may require colonoscopy as well. Endoscopy often reveals ulcers, diseased regions that have a cobblestone-like appearance in Crohn's disease, but not in ulcerative colitis.
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X-Rays (Barium Enema) or Computed Tomography Scans
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In ulcerative colitis, inflammation is usually evenly distributed on the surface lining of the intestine, and the bowel wall bleeds easily when touched with a swab. The pattern observed in Crohn's disease is usually one of scattered patches of ulcers that are deep, thick, and large.
Crohn's disease produces pockets (fissures) or channels (fistulas). They do not occur with UC.
In ulcerative colitis the ileum (the lower part of the small intestine) is often dilated while it is narrowed in Crohn's disease.
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Laboratory Tests
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Tissue samples obtained from a patient with Crohn's disease may reveal granulomas, small collections of inflammatory cells. Granulomas may also be present in other conditions, however. Tissue samples should also be examined for the presence of cancerous cells.
About 70% of tests for antibodies in people with UC will show perinuclear-staining antineutrophil cytoplasmic antibodies. Over 50% of Crohn's people have
anti-Saccharomyces cerevisiae
antibodies. Such tests are expensive and infrequently performed, but they may be useful in cases of uncertainty.
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Ruling Out Diseases Resembling Inflammatory Bowel Disease
Irritable Bowel Syndrome.
Irritable bowel syndrome (IBS), also known as spastic colon, functional bowel disease, and spastic colitis, causes many of the same symptoms as inflammatory bowel disease. Bloating, diarrhea, constipation, and abdominal cramps are all symptoms of IBS. Irritable bowel syndrome is not caused by inflammation, however, and no fever or bleeding occurs. Behavioral therapy may be helpful in treating IBS. (Psychological therapy does not improve inflammatory bowel disease.)
Microscopic Colitis.
Microscopic colitis causes chronic watery diarrhea, but the colon lining shows little or no signs of inflammation. It may be genetically linked to celiac sprue. Most patients can expect to improve.
Celiac Sprue.
Celiac sprue, or celiac disease, is an intolerance to gluten (found in wheat) that triggers inflammation in the small intestine and causes diarrhea, vitamin deficiencies, and stool abnormalities. It occurs in a significant number of people with IBD and is usually first noticed in children.
Interstitial Cystitis.
Interstitial cystitis (IC) is an inflammation of the bladder wall that occurs almost exclusively in women. Some evidence suggests that the risk for IBD in these patients is 100 times above that in the general population and that there may be some common factor to both conditions. The average age of patients with IC is 40, but 25% of cases occur in women under 30. Symptoms are very similar to urinary tract infections, but no bacteria are present. Pain during sex is a very common complaint in these patients, and stress may intensify symptoms.
Infections.
If endoscopy reveals inflammation, a doctor must always rule out possible infections before a diagnosis of inflammatory bowel disease can be confirmed.
Acute Appendicitis.
Crohn's disease may cause tenderness in the right lower part of the abdomen where the appendix is located and resembles appendicitis.
Cancer.
Colon or rectal cancers must always be ruled out when symptoms of IBD occur.
Intestinal Ischemia.
Symptoms similar to IBS can be caused by blockage of blood flow in the intestine. This is more likely to occur in elderly people.
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Review Date: 8/23/2006
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Reviewed By: Harvey Simon, M.D., Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital
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