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Irritable Bowel Syndrome

GENERAL CHARACTERISTICS

Irritable bowel syndrome is a chronic condition marked by chronic abdominal pain and altered bowel habits in the absence of any organic cause. 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 commonly diagnosed abdominal condition, affecting 10-15% of the North American population. Only about 15% of those affected seek medical care for the condition.

The condition is usually diagnosed in late adolescence or early adulthood, but affects people of all ages. For unknown reasons, women are affected about twice as often as men.

SYMPTOMS

The abdominal discomfort of an irritable bowel ranges from sharp, cramping-like pains to a continuous, dull ache. It is sometimes alleviated 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, and/or 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 preceded 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 body aches. 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.

Rectal bleeding, weight loss, or abdominal pain that awakens a person at night are not symptoms of IBS and should be reported to your provider.

INTESTINAL MOTILITY

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. In irritable bowel syndrome, 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 disordered activity of the intestinal muscle. Emotional stress is believed to be a factor. Some researchers think that the syndrome is an allergic response to particular foods. Smoking increases intestinal motility.

DIAGNOSIS

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, celiac disease, diverticulitis (the inflammation of pockets that form in weakened sections of the intestinal wall) and cancer of the colon.

Sometimes lab tests are ordered to rule out these other disorders; often the diagnosis may be made on the symptoms and exam alone.

TREATMENT

Irritable bowel syndrome, although troublesome and at times anxiety-producing, is not medically serious. Symptoms can, however, interfere with daily living significantly. In general, a normal diet is best. If bloating and belching are a problem, foods such as beans and cabbage, dairy products, some fruits, 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 for constipation. Monitor the foods you eat and try to identify 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 get regular physical exercise. This helps relieve anxiety and 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 stress reduction, medications may be prescribed. These may include anticholinergic agents to reduce intestinal motility, mild sedatives, antidepressants, or antidiarrheal agents. Medications should be taken on a short-term basis only. Peppermint oil may be helpful but can cause or worsen heartburn.

CONCLUSION

Irritable bowel syndrome is a common intestinal disorder characterized by abdominal pain, diarrhea, and/or constipation. These symptoms are distressing, but not serious. While the causes of irritable bowel syndrome are unknown, emotional factors seem to play a major role. Life-style changes and attention to diet often provide sufficient relief; if not, medications may help.

References

Cecil's Textbook of Information - 21st edition (2000). pp 687-691
Wald, A. (2010). Clinical manifestations and diagnosis of irritable bowel syndrome. Retrieved from the UpToDate web site.
Wald, A. (2010). Patient information: Irritable bowel syndrome. Retrieved from the UpToDate web site
Wald, A. (2010). Treatment of irritable bowel syndrome. Retrieved from the UpToDate web site