Irritable Bowel Syndrome

What is irritable bowel syndrome?
Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder of the colon (large intestine) that causes abdominal pain, bloating, constipation and diarrhea.  No structural or biochemical cause can be found to explain the symptoms, therefore IBS is diagnosed often after other possible digestive disorders and diseases have been ruled out.

What causes IBS?
Muscles in the colon typically contract many times a day, moving feces along and resulting in a bowel movement. With IBS, these muscles are exceptionally sensitive to certain stimuli or triggers.  Researchers are not sure exactly why the muscles in the colon of a person with IBS are more sensitive, but they do know that IBS is not caused by stress or strong emotions.

What are the symptoms of IBS?
The symptoms of IBS can include gas, pain, bloating, nausea, vomiting, mucus in the stool, constipation, and diarrhea. Cramps are often relieved by a bowel movement, but some people with IBS may have cramps and be unable to pass anything. The severity of symptoms varies and could be anywhere from mild annoyance to debilitating. IBS does not lead to Crohn’s disease, ulcerative colitis, or any type of bowel cancer.

How is IBS diagnosed?
IBS is often diagnosed after excluding organic diseases such as infection or other causes of the symptoms.  Testing includes:

  • Blood tests: To determine the white blood cell count or if anemia is present.
  • Fecal occult blood test: Detect bleeding from anywhere in the digestive tract.
  • Stool culture: Collected and tested for bacteria, parasites, and white blood cells.
  • Barium enema: Barium sulfate and air will outline the rectum and colon, and abnormalities will appear as dark silhouettes on the x-ray.
  • Sigmoidoscopy: A flexible, lighted tube is used to determine inflammation.
  • Colonoscopy: A flexible, lighted tube is used to view the whole colon, the lower small bowel, and sample tissue.

Some gastroenterologists use a pattern of symptoms called Rome criteria to aid in diagnosing IBS.  In low-risk circumstances with typical symptoms, these may help limit testing to the most necessary studies.

What medications are used to treat IBS?
Medications are used to lessen IBS symptoms such as diarrhea, cramping, pain, or constipation.