Definition of Irritable bowel syndrome:

Irritable bowel syndrome (IBS) refers to a disorder of the lower intestinal tract. It involves abdominal pain and abnormal bowel movements. Emotional stress often makes the symptoms worse.

It is not the same as inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis.

Causes, incidence, and risk factors:

IBS involves a combination of abdominal pain and constipation, diarrhea, or an alternating pattern of these problems.

There are many possible causes. For example, there may be a problem with muscle movement in the intestine or a lower tolerance for stretching and movement of the intestine. There is no problem with the structure of the intestine.

It is not clear why patients develop IBS, but in some instances, it occurs after an intestinal infection. This is called postinfectious IBS. There may also be other triggers.

IBS can occur at any age, but it often begins in adolescence or early adulthood. It is more common in women. The condition is the most common intestinal complaint for which patients are referred to a gastroenterologist.