Irritable bowel syndrome (IBS) is a disorder of intestinal movement and sensation. IBS is not associated with inflammation, and it does not lead to more permanent harm or progress to more serious conditions.
The cause of irritable bowel syndrome is not known. The colon normally contracts in response to eating. With irritable bowel syndrome, the muscles in the colon do not function normally and may spasm. Individuals with IBS may possess a colon that is more sensitive than normal and reacts more strongly to food, medication, and other factors.
Despite these uncertainties, there is increasing evidence that the causes may be different in different people and that both food allergies and “overgrowth” of certain bowel bacteria may contribute to the symptoms. There is also fairly strong evidence that irritable bowel syndrome can follow an episode of infectious diarrhea (often called gastroenteritis or “food poisoning”). While it is not yet certain that infection actually causes irritable bowel syndrome, many gastroenterologists think that this might be the case.
Once established in susceptible people, the following may worsen symptoms of IBS:
A risk factor is something that increases your chance of getting a disease or condition.
Risk factors for IBS include:
Irritable bowel syndrome symptoms usually come and go. Symptoms range in intensity from mild to severe.
The doctor will ask about your symptoms and medical history, and perform a physical exam. In many cases this is sufficient to make the diagnosis. Since there is no diagnostic test for irritable bowel syndrome doctors have developed standardized criteria for deciding who does and who does not have the disorder. However, diagnostic tests are often performed to rule out other diagnoses having similar symptoms. These may include:
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There is no cure for IBS. Treatment focuses on controlling symptoms.
The following dietary interventions may help control your symptoms:
Techniques to reduce stress include:
Exercise not only helps reduce stress, but it may also directly improve bowel function.
Depending on the severity of your symptoms and whether you predominantly suffer from diarrhea or constipation, your doctor may recommend one or more of the following types of medications:
Many doctors favor a newer class of medications called serotonin receptor agonists and antagonists for the most serious cases, particularly in women. Tegaserod is prescribed for constipation and alosetron for diarrhea (but under limited circumstances). Note: Tegaserod was withdrawn from the market in March 2007 due to a slightly increased risk of heart attack, angina, and stroke in patients taking the medication. *2
Probiotics (preparations containing “helpful” bacteria and yeasts) have been shown to be helpful in some people and could be tried under medical supervision.
There are no guidelines for preventing IBS because the cause is unknown.
What's Your Indigestion IQ?
Painful burning. Belching and gas. Abdominal pain. Far too many of us are familiar with the lingering discomforts associated with indigestion, heartburn, acid reflux, and other gastrointestinal issues. The good news is that you can take steps to prevent the unnecessary side effects brought on by certain behaviors. It's all about keeping your stomach happy. Do you know how? Take this indigestion quiz to find out.
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*1Updated Treatment section on Medication on 9/26/06 according to the following study, as cited by DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Mueller-Lissner S, Tytgat GN, Paulo LG, Quigley EM, Bubeck J, Peil H, et al. Placebo-and paracetamol-controlled study on the efficacy and tolerability of hyoscine butylbromide in the treatment of patients with recurrent crampy abdominal pain. Alimentary Pharmacology and Therapeutics. 2006;23(12):1741-8.
*2Updated Treatment section on Medication on 4/10/07 according to the following study, as cited by DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : US Food and Drug Administration. FDA announces discontinued marketing of GI drug, Zelnorm, for safety reasons [press release]. March 30, 2007. US Food and Drug Administration website. Available at: http://www.fda.gov/bbs/topics/news/2007/new01597.html.