Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a group of symptoms that affect the large intestine (colon) and include pain or discomfort in your abdomen and changes in your bowel movement patterns. IBS is a functional gastrointestinal (GI) disorder, meaning that it is a disorder in which the GI tract behaves in an abnormal way without evidence of damage due to a disease. Some people with the disorder have constipation and some have diarrhea. Others experience both diarrhea and constipation. Although IBS can cause a great deal of discomfort, it does not harm the intestines.

IBS is common. It is estimated to affect 10 to 15 percent of American adults, but only 5 to 7 percent of adults in the United States have received a diagnosis of IBS. Women are twice as likely as men to have IBS. It is most often found in people younger than 45 years. No one knows the exact cause of IBS. Some people can control their symptoms by managing diet, lifestyle, and stress, but others will need medication and counseling.

The exact cause of IBS is unknown, but a variety of factors likely play a role. The walls of the intestines are lined with layers of muscle that contract and relax in a coordinated rhythm to move food from your stomach through your intestinal tract to your rectum. If you have IBS, the contractions may be stronger and last longer than normal, causing gas, bloating and diarrhea. Or the opposite may occur, with weak intestinal contractions slowing food passage and leading to hard, dry stools.

Abnormalities in your GI nervous system also may play a role, causing you to experience greater than normal discomfort when your abdomen stretches from gas or stool. Poorly coordinated signals between the brain and the intestines can make your body overreact to the changes that normally occur in the digestive process. This overreaction can cause pain, diarrhea or constipation.

Many factors can trigger symptoms in people with IBS, but not all people with the condition react to the same stimuli. Common triggers include:

• foods allergies and sensitivities
• stress
• hormones
• other illnesses or infections

IBS may also have a genetic cause. IBS is more common in people with family members who have a history of GI problems.

The link between mental health and IBS is unclear, but IBS is common in people with mental health problems such as panic disorder, anxiety, depression, and post-traumatic stress disorder.

See your doctor for ongoing abdominal pain, bloating, or changes in bowel habits. Get prompt care for warning signs such as blood in the stool, unexplained weight loss, anemia, or symptoms that wake you at night.