Definition of Irritable bowel syndrome:

Irritable bowel syndrome (IBS) refers to a complex disorder of the lower intestinal tract. It is mainly characterized by a pattern of symptoms that is often worsened by emotional stress.

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

Causes, incidence, and risk factors:

IBS involve a combination of abdominal pain and alternating constipation and diarrhea. There are many possible causes. For instance, 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 in the structure of the intestine.

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

IBS can occur at any age, but often begins in adolescence or early adulthood. It is more common in women. The condition is the most common intestinal complaint that leads to referral to a gastroenterologist.