Irritable bowel syndrome (IBS) refers to a disorder that involves abdominal pain and cramping, as well as changes in bowel movements.
There are many possible causes of IBS. For example, there may be a problem with muscles in the intestine, or the intestine may be more sensitive to stretching or movement. 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.
Stress can worsen IBS. The colon is connected to the brain through nerves of the autonomic nervous system. These nerves become more active during times of stress, and can cause the intestines to squeeze or contract more. People with IBS may have a colon that is over-responsive to these nerves.
IBS can occur at any age, but it often begins in adolescence or early adulthood. It is more common in women. About 1 in 6 people in the U.S. have symptoms of IBS. It is the most common intestinal complaint for which patients are referred to a gastroenterologist.
Symptoms range from mild to severe. Most people have mild symptoms. Symptoms vary from person to person.
Abdominal pain, fullness, gas, and bloating that have been present for at least 6 months are the main symptoms of IBS. The pain and other symptoms will often:
• Occur after meals
• Come and go
• Be reduced or go away after a bowel movement
People with IBS may switch between constipation and diarrhea, or mostly have one or the other.
• People with diarrhea will have frequent, loose, watery stools. They will often have an urgent need to have a bowel movement, which is difficult to control.
• Those with constipation will have difficulty passing stool, as well as less frequent bowel movements. They will often need to strain and will feel cramping with a bowel movement. Often, they do not eliminate any stool, or only a small amount.
For some people, the symptoms may get worse for a few weeks or a month, and then decrease for a while. For other people, symptoms are present most of the time and may even slowly increase.