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.
Causes
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:
Urge to move bowels again immediately following a bowel movement
Mucus in the stool
Diagnosis
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:
Analysis of a stool sample to check for blood or evidence of inflammation
Blood tests
Barium enema—injection of fluid into the rectum that makes your colon show up on an an x-ray so the doctor can see abnormal spots in your colon
Flexible sigmoidoscopy—a thin, lighted tube inserted into the rectum to examine the rectum and the lower colon
Colonoscopy—a thin, lighted tube inserted through the rectum and into the colon to examine the lining of the entire colon
There is no cure for IBS. Treatment focuses on controlling symptoms.
Diet
The following dietary interventions may help control your symptoms:
Keep a food diary, listing what you eat and what reaction occurs. Discuss the findings with your doctor or a dietitian. Since food allergy probably plays a role in the symptoms that some people with irritable bowel experience, you may wish to consult an allergist or a gastroenterologist familiar with diagnosis of food allergies. In most cases, a careful food diary will be most useful in diagnosing allergies.
Make gradual changes to your diet and record the results.
Avoid foods that have provoked symptoms more than once. A dietitian can help you choose substitutes for offending foods.
Avoid the following foods and drinks that may provoke symptoms:
High fat foods
Spicy foods
Dairy products
Onions
Cabbage
Other gas-producing foods
Large amounts of alcohol or caffeine
Eat foods that may reduce the chance of spasm, such as:
Fruits and vegetables
Whole grains and other high-fiber foods (Note: More fiber may increase gas and bloating until your body adjusts.)
Eat smaller meals more often or smaller portions.
Eat slowly and try not to swallow air.
Drink plenty of water (at least two liters per day) to help reduce constipation.
Stress Management
Techniques to reduce stress include:
Stress management techniques
Relaxation techniques
Biofeedback
Counseling to help develop coping skills
Exercise
Exercise
Exercise not only helps reduce stress, but it may also directly improve bowel function.
Medication
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:
An antibiotic—recent data suggests that brief treatment with the nonabsorbed antibiotic, Rifaximin, can improve symptoms for at least several months. More studies will be necessary to see whether benefit persists or retreatment is necessary.
An antispasmotic agent (eg, dicyclomine)
A high-fiber bulking agent (eg, psyllium)
An antidiarrheal agent (eg, loperamide)
A low-dose antidepressant
A pain reliever, such as acetaminophen (eg, Tylenol)
Findings from a recent clinical trial showed modest benefit of acetaminophen for treatment of crampy abdominal pain in 2000 patients with IBS.
*1
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.
Prevention
There are no guidelines for preventing IBS because the cause is unknown.
RESOURCES:
American College of Gastroenterology http://www.acg.gi.org
American Gastroenterological Association http://www.gastro.org
IBS Association http://www.ibsassociation.org
CANADIAN RESOURCES
Health Canada http://chp-pcs.gc.ca
Crohn's and Colitis Foundation of Canada http://www.ccfc.ca
References:
American Society of Colon and Rectal Surgeons website. Available at:
http://www.fascrs.org/.
Conn's Current Therapy. WB Saunders Co.; 2001.
Griffith's 5-Minute Clinical Consult. Lippincott Williams & Wilkins; 1999.
Drossman DA.
Treatment for bacterial overgrowth in the irritable bowel syndrome.
Ann Intern Med. 2006;145(8):626-628.
Halvorson HA, Schlett CD, Riddle MS.
Postinfectious irritable bowel syndrome—a meta-analysis.
Am J Gastroenterol. 2006;101(8):1894-1899.
Murch S. Allergy and intestinal dysmotility—evidence of genuine causal linkage?
Curr Opin Gastroenterol. 2006;22(6):664-668.
National Institute of Diabetes and Digestive and Kidney Diseases website. Available at:
http://www.niddk.nih.gov/.
Rubin G, De Wit N, Meineche-Schmidt V, Seifert B, Hall N, Hungin P.
The diagnosis of IBS in primary care: consensus development using nominal group technique.
Family Practitioner. 2006 Oct 24.
Yan F, Polk DB. Probiotics as functional food in the treatment of diarrhea.
Current Opinion in Clinincal Nutrition and Metabolic Care. 2006 Nov;9(6):717-721.
*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.
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
