Updated guidelines for irritable bowel syndrome

Dec 18 2008

Although irritable bowel syndrome (IBS) is the most common disease diagnosed by gastroenterologists, it's also one of the most misunderstood.

That's why updated guidelines addressing the management of the condition are being released by the American College of Gastroenterology.

Through a comprehensive review of the latest medical research and expert consensus, the updated guidelines provide clinicians with a comprehensive and practical set of recommendations for the diagnosis and treatment of IBS.

“The last time the American College of Gastroenterology published guidelines for the management of IBS was in 2002, and the College recognized that in the span of five to six years there has been a remarkable explosion in knowledge that's become available that's helped us to understand the cause and management of IBS,” says William Chey, M.D., professor of medicine and director of the Gastrointestinal Physiology Laboratory at the University of Michigan Health System.

Along with Philip Schoenfeld, M.D., also of the U-M Division of Gastroenterology, Chey has helped to develop the new evidence-based recommendations.
IBS is a chronic disorder of the lower intestine that causes cramping, abdominal pain, bloating, constipation and/or diarrhea that affects 10 to 15 percent of the U.S. population. The new recommendations show that “there really are things to do for these patients; it's not a hopeless situation,” says Chey.

Some of the most significant evidence-based recommendations from the guideline include:

• Most patients with typical IBS symptoms and no alarm features such as bleeding, weight loss, or a family history of colon cancer, inflammatory bowel disease or celiac sprue, do not need extensive diagnostic testing before confidently diagnosing IBS.
• IBS patients with diarrhea or a mixture of diarrhea and constipation should be screened with blood tests for celiac disease, a condition in which one cannot tolerate the gluten protein found in wheat and other grains.
• When patients with IBS and diarrhea undergo colonoscopy, biopsies should be obtained to rule out a rare disease called microscopic colitis.
• The use of anti-depressants, tricyclic agents and selective serotonin reuptake inhibitors, can be helpful for some patients with IBS. “There is a stronger recommendation that tricyclic antidepressants, used in low doses before people go to sleep at night, are an effective medicine for irritable bowel syndrome,” says Schoenfeld, associate professor of internal medicine at the U-M Medical School. The agents in these antidepressants can reduce bloating and discomfort by altering brain-gut signaling about motility and distention. He adds that constipation, a side effect of tricyclic antidepressants, is actually beneficial to many people in this population.
• The drug lubiprostone, a chloride channel activator, benefits a subset of women with IBS and constipation.
• Evidence suggests that a specific probiotic called Bifidobacter infantis offers benefit to some patients with IBS and diarrhea.
• The non-absorbable antibiotic called rifaximin has been found to be of benefit for selected patients with IBS, in particular those with bloating and diarrhea.
• women with more severe IBS and diarrhea who have not responded to standard therapies, alosetron, a drug which alters an important neurotransmitter called serotonin, can be considered.

IBS usually begins in young adulthood, and women are twice as likely as men to be diagnosed with IBS in the United States. Despite intensive research, the precise cause of IBS is not clear. Suggested contributors to IBS include abnormal contractile activity of the intestines and colon, altered sensation within the gastrointestinal tract, exaggerated reactions to stress or anxiety, and/or problems arising from the interaction between the bacteria and immune system within the intestines and colon.

Treatments are often combined to reduce the pain and bowel-related symptoms of IBS, and it may be necessary to try more than one combination to find the one that is most helpful, Chey and Schoenfeld note.

Before newer therapies and medications were available, much of the effort to treat IBS symptoms focused on lifestyle, diet and reduction of stress. Some dietary changes that many patients have found helpful:

• Avoid or limit the amount of gas-producing foods such as beans, onions, broccoli, cabbage or any other foods that will commonly aggravate IBS symptoms.
• Try to slow down when you eat and avoid overeating.
• Avoid carbonated drinks. These can introduce gas into the intestines and cause bloating or abdominal discomfort.
• Intolerance to milk sugar, or lactose, is seen in up to 40 percent of patients with IBS. Avoiding dairy products may be helpful in reducing symptoms of IBS such as gas, bloating, cramping and diarrhea.
• Avoid large quantities of other sugars such as fructose or sorbitol which can also worsen IBS symptoms.
• The addition of fiber in the form of psyllium can help with constipation related symptoms in IBS patients.

A structured, focused diagnostic evaluation will lead to a confident diagnosis of IBS says Chey. There are some good treatment options for people diagnosed with IBS. With effective counseling, dietary and lifestyle intervention, and use of over-the-counter and/or prescription medications, IBS can be effectively managed in the vast majority of patients, Chey notes.