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Irritable bowel syndrome (functional bowel): Irritable bowel syndrome includes a group of gastrointestinal symptoms for which a cause is not known. The symptoms are often worsened by emotional stress.

Alternative Names: Pylorospasm; Nervous indigestion; Spastic colon; Intestinal neurosis; Functional colitis; Irritable colon; Mucous colitis; Laxative colitis; Functional dyspepsia

Causes, incidence, and risk factors: Irritable bowel syndrome is characterized by a combination of abdominal pain and altered bowel function. There are many possible causes. For instance, there may be a disturbance in the muscle movement of the intestine or a lower tolerance for stretching and movement of the intestine. There is no abnormality in the structure of the intestine.

The condition occurs more frequently in women and usually begins between the ages of 20 and 30. Predisposing factors may be a low-fiber diet, emotional stress, and use of laxatives.

Irritable bowel syndrome is extremely common, but only a small proportion of people seek treatment.


  • Diarrhea alternating with constipation for 6 months or more
  • Abdominal pain
    1. Following meals
    2. Relieved by bowel movement
    3. Intermittent
  • Abdominal tenderness
  • Abdominal fullness, gas, bloating
  • Abdominal distention
  • Nausea
  • Vomiting
  • Loss of appetite
  • Emotional distress
  • Depression

Signs and tests:

  • Tests usually reveal no abnormalities.
  • Not all patients require endoscopy, especially if symptoms begin early in life and have been stable. Patients who have irritable bowel symptoms beginning later in life usually require endoscopy.
  • Patients over age 50 should be screened for colon cancer.
  • Younger patients with persistent diarrhea may require endoscopy to rule out inflammatory bowel disease, which is an autoimmune disorder and is not the same as irritable bowel syndrome.

Treatment: The objective of treatment is to relieve symptoms. Changes in diet may help alleviate symptoms in some patients. No diet is applicable to all patients.

Increasing dietary fiber and eliminating gastrointestinal stimulants such as caffeine may be beneficial. Other possible treatment may include:

  • Anxiety-reducing measures, such as regular exercise.
  • Anticholinergic medications before meals.
  • Counseling in cases of severe anxiety or depression.
A medication called Tegaserod is available for patients with constipation-predominant irritable bowel syndrome. Your doctor can decide if this medication is appropriate for you.

Expectations (prognosis): Irritable bowel syndrome may be a life-long chronic condition, but symptoms can often be improved or relieved through treatment.


  • Discomfort
  • Dehydration
  • Malnutrition resulting from food avoidance
  • Depression

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