Irritable bowel syndrome

Also known as: Spastic colon, Irritable colon, Mucous colitis or Spastic colitis

Definition

Irritable bowel syndrome (IBS) is a disorder that leads to abdominal pain and cramping, changes in bowel movements, and other symptoms.

IBS is not the same as inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis. In IBS, the structure of the bowel is not abnormal.

A common sign of IBS is frequent:The correct answer is all of the above. IBS symptoms vary from person to person and can range from mild to severe. Talk to your doctor if you have had IBS symptoms on 3 or more days a month for the past 3 months.Irritable bowel syndrome (IBS) is the same as inflammatory bowel disease (IBD).The correct answer is myth. IBD includes Crohn's disease and ulcerative colitis, conditions that damage the lining of the digestive tract. IBS causes belly pain and abnormal bowel movements but does not harm the intestines.IBS is a common disorder.The correct answer is fact. About 1 in 6 people in the U.S. have symptoms of IBS. It is the most common intestinal problem that brings patients to a bowel specialist (gastroenterologist).Everyone with IBS has diarrhea.The correct answer is myth. Some people with IBS have frequent diarrhea, while others tend to have hard stools and be constipated. It's also common to switch between diarrhea and constipation. Bowel problems may get worse for a few weeks and then clear up for awhile. Discuss any changes in your bowel movements with your doctor.Doctors need to run a lot of tests to diagnose IBS.The correct answer is myth. There is no test to diagnose IBS, although tests may be done to rule out other problems. Most of the time, your doctor can diagnose IBS based on your symptoms, with few or no tests.Stress plays a role in triggering IBS symptoms.The correct answer is fact. Signals go back and forth between the bowel and brain. These signals affect bowel movements. Stress may cause the intestines to be more sensitive and to squeeze more often. Finding ways to relieve stress can help keep symptoms at bay.There is a special IBS diet that relieves symptoms for most people.The correct answer is myth. Dietary changes can be helpful. However, no specific diet works for everyone with IBS. This is because the symptoms differ from one person to another. Keeping a food diary can help you figure out which foods make your symptoms worse.Which foods or drinks are most likely to cause IBS symptoms?The correct answer is any of the above. These are common triggers, although not everyone with IBS will react to all of these foods. Avoiding caffeine is a good idea for most people with IBS. Caffeine can make the intestines more active.What type of medicines can treat IBS?The correct answer is all of the above. Your doctor will recommend medicines based on your symptoms. Always follow your doctor’s instructions when using medicines for IBS. You should not take a different amount or take the medicine more or less often. Doing so can lead to further problems. Low doses of tricyclic antidepressants can help relieve pain and discomfort even if you are not depressed.It's normal to lose a lot of weight when IBS flares up.The correct answer is myth. Unexpected weight loss of more than 5 to 10 pounds could be a sign of a more serious problem. Contact your doctor right away if you have weight loss when you are not trying, bloody stools, fever, or severe pain.

Causes, incidence, and risk factors

It is not clear why patients develop IBS. Sometimes it occurs after an infection of the intestines. This is called postinfectious IBS. There may also be other triggers.

The intestine is connected to the brain. Signals go back and forth between the bowel and brain. These signals affect bowel function and symptoms. The nerves can become more active during stress, causing the intestines to be more sensitive and squeeze (contract) more.

IBS can occur at any age, but it often begins in the teen years or early adulthood. It is twice as common in women as in men.

About 1 in 6 people in the U.S. have symptoms of IBS. It is the most common intestinal problem that causes patients to be referred to a bowel specialist (gastroenterologist).

Symptoms

Symptoms range from mild to severe. Most people have mild symptoms. Symptoms are different from person to person.

The main symptoms of IBS are abdominal pain, fullness, gas, and bloating that have been present for at least 3 days a month for the last 3 months. The pain and other symptoms will often:

  • Be reduced or go away after a bowel movement
  • Occur when there is a change in how often you have bowel movements

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 may be hard to control.
  • Those with constipation will have a hard time passing stool, as well as fewer bowel movements. They will often need to strain and will feel cramps with a bowel movement. Often, they do not release 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.

People with IBS may also lose their appetite.

Signs and tests

Most of the time, your doctor can diagnose IBS based on your symptoms, with few or no tests. Eating a lactose-free diet for 2 weeks may help the doctor check for a possible lactase deficiency.

There is no test to diagnose IBS. Tests may be done to rule out other problems:

  • Blood tests to see if you have celiac disease or a low blood count (anemia)
  • Stool cultures to check for an infection

Some patients will have a colonoscopy. During this test, a flexible tube is inserted through the anus to examine the colon. You may need this test if:

  • Symptoms began later in life (over age 50)
  • You have symptoms such as weight loss or bloody stools
  • You have abnormal blood tests (such as a low blood count)

Other disorders that can cause similar symptoms include:

Treatment

The goal of treatment is to relieve symptoms.

Lifestyle changes can help in some cases of IBS. For example, regular exercise and improved sleep habits may reduce anxiety and help relieve bowel symptoms.

Dietary changes can be helpful. However, no specific diet can be recommended for IBS, because the condition differs from one person to another.

The following changes may help:

  • Avoid foods and drinks that stimulate the intestines (such as caffeine, tea, or colas)
  • Avoid large meals
  • Increase fiber in the diet (this may improve constipation but make bloating worse)

Talk with your doctor before taking over-the-counter medications.

No one medication will work for everyone. Medications your doctor might try include:

  • Anticholinergic medications (dicyclomine, propantheline, belladonna, and hyoscyamine) taken about a half-hour before eating to control intestinal muscle spasms
  • Bisacodyl to treat constipation
  • Loperamide to treat diarrhea
  • Low doses of tricyclic antidepressants to help relieve intestinal pain
  • Lubiprostone for constipation symptoms
  • Rifaximin, an antibiotic

Therapy may help in cases of severe anxiety or depression.

Expectations (prognosis)

Irritable bowel syndrome may be a lifelong condition. For some people, symptoms are disabling and reduce the ability to work, travel, and attend social events.

Symptoms can often be improved or relieved through treatment.

IBS does not cause permanent harm to the intestines, and it does not lead to a serious disease, such as cancer.

Calling your health care provider

Call your health care provider if you have symptoms of irritable bowel syndrome or if you notice a change in your bowel habits that does not go away.

References

Irritable Bowel Syndrome. Bethesda, MD: The National Digestive Diseases Information Clearinghouse; 2007. NIH Publication No. 07-693.

Talley NJ. Irritable bowel syndrome. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger & Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 118.

Review date:
September 11, 2013
Reviewed by:
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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