Irritable Bowel Syndrome (IBS)
Key points
- Irritable bowel syndrome (IBS) is a common but poorly understood disorder that causes a variety of bowel symptoms including abdominal pain, diarrhea and/or constipation, bloating, gassiness and cramping.
- Although the symptoms of IBS often change over time, people tend to develop their own particular pattern such as mostly diarrhea, mostly constipation, or abdominal pain without a major change in bowel movements.
- No single test — or even a battery of tests — can offer a definite diagnosis of IBS because there are no measurable physical changes that occur with the syndrome.
- IBS symptoms may be a daily problem throughout a person's life, or they may occur sporadically and last a day, a week or a month before disappearing.
What Is It?
Irritable bowel syndrome (IBS) is a common but poorly understood disorder that causes a variety of bowel symptoms including abdominal pain, diarrhea and/or constipation, bloating, gassiness and cramping. While these symptoms may be caused by a number of different bowel diseases, IBS is usually diagnosed only after your doctor has ruled out the possibility of a more serious problem.
The severity of the disorder varies from person to person. Some patients experience symptoms that come and go and are just mildly annoying, while others have such severe daily bowel problems that IBS affects their ability to work, sleep and enjoy life. In addition, symptoms may change over time. A person may have severe symptoms for several weeks and then feel well for months, or even years. Most people are never cured of IBS, but the disorder is not related to any other disease, and does not develop into any other disease, such as ulcerative colitis or colon cancer.
IBS usually starts in early adulthood, and affects twice as many women as men. Approximately 10 percent to 20 percent of the population suffers from IBS, but at least half of all people with the condition never seek medical care for their symptoms. IBS also has been called irritable colon, spastic colon, mucous colitis and functional bowel disease.
No one knows what causes IBS. In people with IBS, doctors cannot easily identify specific abnormalities of the bowel that produce the symptoms of IBS. Some studies suggest that in people with IBS, the nerves of the colon may be much more sensitive than usual. The normal movement of food and gas through the colon causes greater-than-usual pain, intestinal spasms and an irregular pattern of bowel movements.
In the past, it was thought that stress might cause IBS. That is no longer the case. Stress does not cause IBS, but stress can increase the symptoms, especially pain.
Symptoms
People with IBS may have some or all of these symptoms:
- Mild or severe abdominal pain, discomfort or cramping, usually relieved after a bowel movement
- Periods of diarrhea, constipation or alternating diarrhea and constipation
- Bloating, gassiness or a feeling of having a distended abdomen
- Mucus in bowel movements
- Feeling as though a bowel movement is incomplete
- In extreme cases, nausea, dizziness or fainting
Although the symptoms of IBS often change over time, people tend to develop their own particular pattern such as mostly diarrhea, mostly constipation, or abdominal pain without a major change in bowel movements.
Diagnosis
Written and revised by
David Cohen, M.D.
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