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Irritable Bowel Syndrome

Irritable bowel syndrome is a chronic condition marked by abdominal pain and altered bowel habits.  There are no specific known causes of irritable bowel syndrome. Some symptoms, however, may be due to excessive spasms of the large intestine. (It is also known as spastic colon, nervous bowel, irritable colon and mucous colitis.). In many people stress or feelings of anxiety, guilt or resentment seem to trigger the symptoms. It is the most common abdominal complaint brought to the attention of doctors, affecting one-fourth to one-half of all patients who seek relief from gastrointestinal specialist. In addition, many people have irritable bowel syndrome without ever consulting their doctors about it.

The condition appears in late adolescence or early adulthood. For unknown reasons, women are affected about twice as often as men.

The abdominal discomfort of an irritable bowel ranges from sharp, cramping-like pains to a continuous, dull ache. It is often relieved by a bowel movement. The lower left part of the abdomen may be tender to the touch. This abdominal pain usually appears after eating. Some food intolerances are common in people with Irritable Bowel Syndrome (IBS), which causes experts to think there may be a food sensitivity or allergy component.

There is also usually diarrhea, sometimes alternating with constipation. The diarrhea typically occurs immediately after a meal or when getting up in the morning, and there is often mucus in the stool. The diarrhea is usually preceeded by urgency to have a bowel movement and then a sensation of incomplete emptying. The constipation can last days to months and it can be hard and pellet shaped. Other bowel symptoms include bloating, belching, heartburn, and nausea. In addition, there may be other, less definite symptoms, such as fatigue, anxiety and difficulty in concentrating.

These symptoms may last for a few days or weeks and then cease for months at a time. Also, they may recur with varying degrees of intensity, over a long period.

After nutrients have been digested and absorbed in the small intestine, the waste material is propelled into the large intestine (also called the colon or bowel) for eventual elimination as a bowel movement. Under normal circumstances, regular muscular contractions (intestinal motility) move this waste matter along the five-foot length of the colon and into the rectum. When the irritable bowel syndrome is present, however, the pattern of motility becomes disordered by excessive muscular contractions, which cause the pain, diarrhea and constipation.

It is not known what causes the overactivity of the intestinal muscle. Emotional stress is believed to be a factor in a great many cases. Some researchers think that the syndrome is an allergic response to particular foods. There also is some evidence that alcohol, caffeine and heavy smoking may worsen the problem.

Irritable bowel syndrome is diagnosed after a review of the symptoms and a process of elimination of other disorders. The major symptoms are characteristic of a number of other intestinal disorders, such as colitis, diverticulitis (the inflammation of pockets that form in weakened sections of the intestinal wall) and cancer of the colon.

The excessive intestinal spasms that produce the symptoms may be detected in the course of a barium enema, a test in which a chalky liquid mixture is infused into the colon and X-ray photographs are taken. (Since barium has greater density to X-ray than the tissues of the intestines, it can make them show up on X-ray films.) The barium enema test may be done as well as other tests to rule out other colon disorders that may produce similar symptoms. Sometimes the diagnosis may be made specifically on the symptoms and exam alone and no diagnostic testing is required.  

Irritable bowel syndrome, although troublesome and at times anxiety-producing, is not medically serious. Symptoms can interfere with daily living significantly despite lack of structural abnormality of the GI tract. In general, a normal diet is best. If bloating and belching are a problem, foods such as beans and cabbage and other sources of fermentable carbohydrates should be avoided. If the major symptom is diarrhea, it is wise to stay away from laxative foods, such as fruits and fruit juices. Unprocessed bran, taken with plenty of liquid, may help relieve constipation. Often, a high fiber diet or a fiber dietary supplement may be recommended. Monitor the foods you eat and try to associate specific foods that cause distress. The food may have been ingested several days ago so keeping a dietary log may be beneficial.

In addition, people with irritable bowel syndrome should engage in regular physical exercise. This helps relieve the symptoms of anxiety and also promotes good bowel function. Efforts should be made to deal with any stresses that may be contributing to the problem.

For patients who do not respond to dietary and other life-style changes, including a reduction of stress, medications may be prescribed. These may include an anticholinergic agent to reduce the intestinal over activity, a mild tranquilizer or a sedative.

illustration of the human gastrointestinal system

The irritable bowel syndrome is a condition characterized by abdominal cramps, diarrhea and constipation. Psychological factor seem to play a major role. Less definite symptoms of IBS may include fatigue, anxiety and difficulty in concentrating. Fortunately, the disorder can be controlled by avoiding triggering foods, increasing dietary bulk, administering antispasmodic drugs, reducing stress and engaging in regular physical exercise. Certain foods can aggravate IBS including; dairy products (those that contain lactose), legumes (such as beans), and gas forming vegetables (such as broccoli, cauliflower, Brussels sprouts, and cabbage),

The irritable bowel syndrome is a common intestinal disorder characterized by diarrhea, cramps and other symptoms. These symptoms are distressing, but irritable bowel syndrome is not a disease. While the causes of the irritable bowel syndrome are unknown, emotional factor seems to play a major role. Life-style changes and attention to diet may provide sufficient relief; if not, medications may be prescribed.

Cecil's Textbook of Information - 21st edition (2000). pp 687-691
Wald, A. (2006) Patient information: Irritable bowel syndrome.

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