IRRITABLE BOWEL SYNDROME

DEFINITION

Irritable bowel syndrome (IBS) is a common intestinal condition. Its cause is unknown and there is currently no cure. IBS is characterized by abdominal pain, changes in bowel movements, gassiness, nausea, and other symptoms.

DESCRIPTION

Irritable bowel syndrome is a poorly understood condition even though, by some estimates, as many as 30 percent of Americans have had IBS at one time in their life. IBS is responsible for more time lost at work and school than any other medical problem except the common cold. It is a major reason that patients see gastroenterologists (doctors who specialize in the digestive system; pronounced GAS-troe-EN-tuh-ROL-uh-jist). Yet no more than half of the people who experience IBS ever see a doctor.

IBS normally does not appear until after adolescence. It affects women about twice as often as men. Researchers do not know the reason for these patterns.

CAUSES

The food a person eats passes through various stages of digestion. In the stomach and small intestine, food is changed into a liquid. In the large intestine (colon), water and salts in this liquid pass through the walls of the colon into the bloodstream. The semisolid material that remains is passed on to the rectum.

Food is passed through the digestive system by means of peristalsis (pronounced per-i-STOL-sis). Peristalsis is a wave-like series of movements made by muscles in the walls of the digestive system. Peristalsis in the colon usually occurs only after meals.

In people who have IBS, peristalsis occurs in unusual patterns. It may go on for extended periods of time, or it may take place much more slowly than usual. In the first case, watery solids are continually passed to the rectum, which results in diarrhea. In the second case, very dry solids are passed to the rectum, which leads to constipation. Irritable bowel syndrome is any condition in which the colon does not function normally.

Certain foods seem to cause IBS in some people. They include chocolate, milk products, caffeine, and large quantities of alcohol. Some individuals are affected by very specific foods. Stress is also related to IBS. People who have IBS are likely to develop symptoms when they feel anxious. Researchers do not yet know why this connection exists.

SYMPTOMS

Some typical symptoms of IBS include the following:

• Abdominal pain
• Diarrhea and/or constipation
• Cramps
• Gassiness
• Bloating

Illustration of the large intestine with irritable bowel syndrome. Darker center shows abnormal colon, showing areas of constriction which cause constipation, and areas of distention which causes diarrhea. (© 1995

John Bavosi/Science Photo Library

. Reproduced by permission of

Custom Medical Stock Photo

.)

• Nausea
• A strong desire to defecate (have a bowel movement)
• A feeling that the bowels are not empty after a bowel movement

DIAGNOSIS

Many medical conditions produce symptoms similar to irritable bowel syndrome. A doctor needs to make sure that another condition is not causing the patient's symptoms. Eliminating other causes usually requires taking a medical history and conducting a general physical examination. Laboratory tests may also be needed. A stool sample can be tested for the presence of blood or parasites that may be causing an infection in the colon.

When other possible causes have been eliminated, a doctor may diagnose IBS. A positive diagnosis is based on a set of standards known as the Rome criteria. According to the Rome criteria an individual must have experienced continuous or recurrent symptoms for a period of three months. The diagnosis may also rate one of three levels for the disorder: mild, moderate, or severe.

About 70 percent of all patients have mild IBS. The symptoms of mild IBS are slight and do not interfere with the patient's daily life. Moderate IBS may interfere with some normal activities. It may also cause the patient some psychological problems. This level of IBS is seen in about 25 percent of all patients. Severe IBS causes a severe disruption of a patient's life. In some cases, patients suffer constant and intense pain. They usually cannot live normal lives or hold regular jobs. About 5 percent of all patients with IBS have this form of the disorder.

TREATMENT

The treatment recommended for IBS depends on the severity of the disorder. Patients with mild or moderate symptoms should identify foods that lead to the symptoms of IBS and avoid them. Over-the-counter medications can be used to control both diarrhea and constipation. If those medications do not work, other drugs can be prescribed. Drugs are also available to control the abdominal pain that often accompanies IBS. People with constipation can sometimes be helped by setting specific times for meals and bowel movements.

Psychological counseling may also be helpful. The purpose of counseling is to help patients reduce anxiety and learn to deal with the pain and other symptoms of IBS. Patients with severe symptoms need more aggressive treatment. They may be given antidepressant drugs to help reduce the worst pain associated with the disorder.

Alternative Treatment

Alternative practitioners recommend a variety of techniques to help patients deal with stress. These techniques include yoga, meditation, hypnosis biofeedback, and reflexology. Reflexology is a form of foot massage that some people think relieves diarrhea, constipation, and other symptoms of IBS.

Certain herbal remedies are also thought to be helpful in controlling the symptoms of IBS. For example, ginger, buckthorn, and peppermint oil are recommended to avoid irritation in the upper part of the digestive tract. Chamomile, valerian, rosemary, and lemon balm are thought to calm the digestive system and prevent abnormal peristaltic movements.

PROGNOSIS

Irritable bowel syndrome is not a life-threatening disorder. Nor is it likely to lead to more serious medical conditions, such as cancer (see cancer entry). In the majority of patients, the symptoms of IBS never disappear. However, those symptoms can usually be treated effectively and the condition is viewed as a temporary, if annoying, inconvenience.

PREVENTION

While there is no single known cause of IBS, there are some habits that an individual can develop to maintain good digestive health. Specifically, a well-balanced diet, low in fats, is recommended. Ensuring that your diet includes enough fiber is also a positive step; this means monitoring your intake of fresh fruits and vegetables, whole grains, and bran. Regular exercise, quitting smoking, and avoiding excessive amounts of caffeine are also encouraged.

FOR MORE INFORMATION

Books

Peikin, Steven R. Gastrointestinal Health: A Self-Help Nutritional Program to Prevent, Cure, or Alleviate Irritable Bowel Syndrome, Ulcers, Heartburn, Gas, and Constipation, revised edition. New York: HarperCollins, 1999.

Organizations

International Foundation for Functional Gastrointestinal Disorders. PO Box 17864, Milwaukee, WI 53217. (888) 964-2001. http://www.iffgd.org.

National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health. 2 Information Way, Bethesda, MD 20892-3570. http://www.niddk.nih.gov.