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.

Irritable bowel syndrome (IBS) can occur at any age, but often begins in adolescence or early adulthood. It is more common in women. Predisposing factors may include a low-fiber diet, emotional stress, use of laxatives, a bout of infectious diarrhea, or other temporary bowel inflammation.

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

• Chronic and frequent diarrhea, usually accompanied by pain
• Chronic and frequent constipation, usually accompanied by pain
• Abdominal pain or tenderness
  • Following meals
  • Relieved by bowel movement
  • Intermittent
• Abdominal fullness, gas, bloating
• Abdominal distention
• Nausea and vomiting
• Loss of appetite
• Emotional distress
• Depression

• 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 look for inflammatory bowel disease. Irritable bowel syndrome, by contrast, is not an inflammatory condition, but the symptoms may be very similar to those of inflammatory bowel disease.

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
• Anti-diarrheal medications
• Low-dose antidepressants
• Promotility drugs such as tegaserod

A medication called tegaserod is available for patients with constipation-predominant irritable bowel syndrome.

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