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Irritable Bowel Syndrome

National Digestive Diseases Information Clearinghouse

What is irritable bowel IBS is often classified into four subtypes based on a person’s usual stool consistency. syndrome (IBS)? These subtypes are important because they is a functional affect the types of treatment that are most gastrointestinal (GI) disorder, meaning likely to improve the person’s symptoms. symptoms are caused by changes in how the The four subtypes of IBS are GI tract works. People with a functional GI disorder have frequent symptoms; however, • IBS with (IBS-C) the GI tract does not become damaged. IBS –– hard or lumpy stools at least is a group of symptoms that occur together, 25 percent of the time not a disease. In the past, IBS was called –– loose or watery stools less than , mucous colitis, spastic colon, nervous 25 percent of the time colon, and spastic bowel. The name was changed to reflect the understanding that • IBS with (IBS-D) the disorder has both physical and mental –– loose or watery stools at least causes and is not a product of a person’s 25 percent of the time imagination. –– hard or lumpy stools less than IBS is diagnosed when a person has had 25 percent of the time or discomfort at least three • Mixed IBS (IBS-M) times a month for the last 3 months without other disease or injury that could explain –– hard or lumpy stools at least the pain. The pain or discomfort of IBS 25 percent of the time may occur with a change in stool frequency –– loose or watery stools at least or consistency or be relieved by a bowel 25 percent of the time movement. • Unsubtyped IBS (IBS-U) –– hard or lumpy stools less than 25 percent of the time –– loose or watery stools less than 25 percent of the time What is the GI tract? The GI tract is a series of hollow organs joined in a long, twisting tube from the mouth to the anus—the opening through Mouth which stool leaves the body. Food is digested by the movement of muscles in the GI tract, along with the release of hormones and Stomach enzymes. Organs that make up the GI tract are the mouth, esophagus, stomach, , —which includes the , cecum, colon, and —and anus. The intestines are sometimes called the bowel. The last part of the GI tract— called the lower GI tract—consists of the Small large intestine and anus. intestine

The large intestine absorbs water and any Large remaining nutrients from partially digested intestine food passed from the small intestine. The Appendix large intestine then changes waste from Anus liquid to a solid matter called stool. Stool Rectum passes from the colon to the rectum. The rectum is located between the last part of The organs of the GI tract the colon—called the sigmoid colon—and the anus. The rectum stores stool prior to a bowel movement. During a bowel movement, stool moves from the rectum to the anus.

2 Irritable Bowel Syndrome How common is IBS and • constipation—having fewer than three bowel movements a week. During a who is affected? bowel movement, stools can be hard, Studies estimate IBS affects 3 to 20 percent dry, and small, making them difficult to of the adult population, with most studies pass. Some people find it painful and ranging from 10 to 15 percent.1 However, often have to strain to have a bowel only 5 to 7 percent of the adult population movement. has been diagnosed with the condition.2 IBS affects about twice as many women as men • feeling that a bowel movement is and is most often found in people younger incomplete. than age 45.1 • passing mucus—a clear liquid made by the intestines that coats and protects What are the symptoms tissues in the GI tract. of IBS? • abdominal . The most common symptoms of IBS are Symptoms may often occur after eating abdominal pain or discomfort, often reported a meal. To meet the definition of IBS, as cramping, along with changes in bowel symptoms must occur at least three times a habits. To meet the definition of IBS, the month. pain or discomfort will be associated with at least two of the following three symptoms: What causes IBS? • bowel movements that occur more or The causes of IBS are not well understood. less often than usual Researchers believe a combination of • stool that appears less solid and more physical and mental health problems can watery, or harder and more lumpy, than lead to IBS. usual Brain-Gut Signal Problems • bowel movements that improve the Signals between the brain and nerves of the discomfort small and large intestines, also called the gut, Other symptoms of IBS may include control how the intestines work. Problems with brain-gut signals may cause IBS • diarrhea—having loose, watery stools symptoms, such as changes in bowel habits three or more times a day and feeling and pain or discomfort. urgency to have a bowel movement. GI Motor Problems Normal , or movement, may not be present in the colon of a person who has IBS. Slow motility can lead to constipation and fast motility can lead to diarrhea. Spasms, or sudden, strong muscle contractions that 1Grundmann O, Yoon SL. Irritable bowel syndrome: come and go, can cause abdominal pain. epidemiology, diagnosis, and treatment: an update for Some people with IBS also experience health-care practitioners. Journal of and . 2010;25:691–699. hyperreactivity—a dramatic increase in bowel contractions in response to or 2 Irritable bowel syndrome. American College of eating. Gastroenterology website. www.patients.gi.org/topics/ irritable-bowel-syndrome. Accessed May 27, 2014.

3 Irritable Bowel Syndrome Hypersensitivity IBS, and some studies have shown antibiotics People with IBS have a lower pain threshold to be effective in treating IBS. However, for bowel stretching caused by gas or stool more research is needed to show a link compared with people who do not have IBS. between small intestinal bacterial overgrowth The brain may process pain signals from the and IBS. bowel differently in people with IBS. Body Chemicals Mental Health Problems People with IBS have altered levels of Mental health, or psychological, problems neurotransmitters—chemicals in the such as panic disorder, , , body that transmit nerve signals—and GI and post-traumatic stress disorder are hormones, though the role these chemicals common in people with IBS. The link play in developing IBS is unclear. Younger between these disorders and development of women with IBS often have more symptoms IBS is unclear. GI disorders, including IBS, during their menstrual periods. Post- are often found in people who have reported menopausal women have fewer symptoms past physical or sexual abuse. Researchers compared with women who are still believe people who have been abused tend to menstruating. These findings suggest that express psychological stress through physical reproductive hormones can worsen IBS symptoms. problems. Bacterial Genetics Some people who have bacterial Whether IBS has a genetic cause, meaning gastroenteritis—an or irritation it runs in families, is unclear. Studies have of the stomach and intestines caused by shown IBS is more common in people with bacteria—develop IBS. Researchers do family members who have a history of GI not know why gastroenteritis leads to IBS problems. However, the cause could be in some people and not others, though environmental or the result of heightened abnormalities of the GI tract lining and awareness of GI symptoms. psychological problems may be factors. Food Sensitivity Small Intestinal Bacterial Many people with IBS report that symptoms Overgrowth are triggered by foods rich in , spicy or fatty foods, coffee, and alcohol. Normally, few bacteria live in the small However, people with food sensitivity intestine. Small intestinal bacterial typically do not have clinical signs of food overgrowth is an increase in the number or . Researchers have proposed that a change in the type of bacteria in the small symptoms may result from poor absorption intestine. These bacteria can produce extra of sugars or bile acids, which help break gas and may also cause diarrhea and weight down fats and get rid of wastes in the body. loss. Some researchers believe that small intestinal bacterial overgrowth may lead to

4 Irritable Bowel Syndrome How is IBS diagnosed? Additional diagnostic tests may include a , lower GI series, and flexible To diagnose IBS, a health care provider will or colonoscopy. Colonoscopy conduct a physical exam and take a complete may also be recommended for people who medical history. The medical history will are older than age 50 to screen for colon include questions about symptoms, family . history of GI disorders, recent , , and stressful events related to A stool test is the analysis of a sample of the onset of symptoms. An IBS diagnosis stool. The health care provider will give the requires that symptoms started at least person a container for catching and storing 6 months prior and occurred at least three the stool. The sample is returned to the times a month for the previous 3 months. health care provider or a commercial facility Further testing is not usually needed, though and sent to a lab for analysis. The health the health care provider may perform a care provider may also do a rectal exam, blood test to screen for other problems. sometimes during the physical exam, to Additional diagnostic tests may be needed check for blood in the stool. Stool tests can based on the results of the screening blood show the presence of parasites or blood. test and for people who also have signs such as A lower GI series is an x ray that is used to look at the large intestine. The test is • fever performed at a hospital or an outpatient • rectal bleeding center by an x-ray technician, and the images are interpreted by a radiologist—a • weight loss doctor who specializes in medical imaging. • —too few red blood cells in the Anesthesia is not needed. The health body, which prevents the body from care provider may give written bowel prep getting enough oxygen instructions to follow at home before the test. The person may be asked to follow a • family history of colon cancer clear liquid diet for 1 to 3 days before the • family history of inflammatory bowel procedure. A or an may be disease—long-lasting disorders that used before the test. A laxative is cause irritation and ulcers, or sores, in that loosens stool and increases bowel the GI tract movements. An enema involves flushing water or laxative into the anus using a special • family history of celiac disease—an squirt bottle. abnormal immune reaction to , a protein found in wheat, rye, and barley, that damages the lining of the small intestine and prevents absorption of nutrients

5 Irritable Bowel Syndrome For the test, the person will lie on a table In most cases, light anesthesia and possibly while the radiologist inserts a flexible tube pain medication help people relax during into the person’s anus. The large intestine colonoscopy. For either test, the person will is filled with barium, making signs of lie on a table while the gastroenterologist underlying problems show up more clearly inserts a flexible tube into the anus. A small on x rays. camera on the tube sends a video image of the intestinal lining to a computer screen. For several days, traces of barium in the The tests can show signs of problems in the large intestine cause stools to be white or lower GI tract. light colored. and frequent bowel movements may cause anal soreness. A The gastroenterologist may also perform health care provider will provide specific a , a procedure that involves taking instructions about eating and drinking after a piece of intestinal lining for examination the test. with a microscope. The person will not feel the biopsy. A pathologist—a doctor who Flexible sigmoidoscopy and colonoscopy specializes in diagnosing diseases—examines are similar, although colonoscopy is used the tissue in a lab. to view the rectum and entire colon, while flexible sigmoidoscopy is used to view just Cramping or bloating may occur during the the rectum and lower colon. These tests first hour after either test. Driving is not are performed at a hospital or an outpatient permitted for 24 hours after a colonoscopy to center by a gastroenterologist—a doctor allow the sedative time to wear off. Before who specializes in digestive diseases. Before the appointment, a person should make either test, a health care provider will give plans for a ride home. Full recovery is written bowel prep instructions to follow at expected by the next day. home. The person may be asked to follow a clear liquid diet for 1 to 3 days before either How is IBS treated? test. The night before either test, the person may need to take a laxative or one or more Though IBS does not have a cure, enemas. One or more enemas may also the symptoms can be treated with a be required about 2 hours before a flexible combination of sigmoidoscopy. • changes in eating, diet, and nutrition • medications • • therapies for mental health problems

6 Irritable Bowel Syndrome Eating, Diet, and Nutrition Medications Large meals can cause cramping and A health care provider will select diarrhea, so eating smaller meals more often, medications based on a person’s symptoms. or eating smaller portions, may help IBS • Fiber supplements may be symptoms. Eating meals that are low in fat recommended to relieve constipation and high in carbohydrates, such as pasta, when increasing is rice, whole-grain breads and cereals, fruits, ineffective. and vegetables, may help. • may help constipation. Certain foods and may cause IBS Laxatives work in different ways, and symptoms in some people, such as a health care provider can provide • foods high in fat information about which type is best for each person. Read more in Constipation • some milk products at www.digestive.niddk.nih.gov. • drinks with alcohol or caffeine • is an antidiarrheal that has • drinks with large amounts of artificial been found to reduce diarrhea in people sweeteners, which are used in place of with IBS, though it does not reduce sugar pain, bloating, or other symptoms. Loperamide reduces stool frequency • beans, cabbage, and other foods that and improves stool consistency by may cause gas slowing the movement of stool through People with IBS may want to limit or avoid the colon. these foods. Keeping a food diary is a good • , such as hyoscine, way to track which foods cause symptoms so cimetropium, and pinaverium, help to they can be excluded from or reduced in the control colon muscle spasms and reduce diet. abdominal pain. Dietary fiber may improve constipation • , such as low doses of symptoms in people with IBS, although it tricyclic antidepressants (TCAs) and may not help with reducing pain. Fiber selective serotonin reuptake inhibitors softens stool so it moves smoothly through (SSRIs), can help relieve IBS symptoms, the colon. Adults are advised to consume including abdominal pain. In theory, 21 to 38 grams of fiber a day.3 Fiber may TCAs should be better for people with cause gas and trigger symptoms in some IBS-D and SSRIs should be better for people with IBS. Increasing fiber intake people with IBS-C due to the effect slowly, by 2 to 3 grams a day, may help on colon transit, although this theory reduce the risk of increased gas and bloating. has not been confirmed in clinical studies. TCAs work in people with IBS by reducing sensitivity to pain in the GI tract as well as normalizing GI motility and secretion. 3Dietary reference intakes: recommended dietary allowances and adequate intakes, total water and macronutrients. In: Ross AC, Taylor CL, Yaktine AL, Del Valle HB, eds. Dietary Reference Intakes for Calcium and . Washington, D.C.: The National Academies Press; 2011: 1110. 7 Irritable Bowel Syndrome • (Amitiza) is prescribed and safe care, people should discuss their for people who have IBS-C. The use of complementary and alternative medication has been found to improve medical practices, including their use of abdominal pain or discomfort, stool dietary supplements and probiotics, with consistency, straining, and constipation their health care provider. Read more at severity. www.nccam.nih.gov/health/probiotics. • (Linzess) is also prescribed Therapies for Mental Health for people who have IBS-C. Linzess has been found to relieve abdominal pain Problems and increase the frequency of bowel The following therapies can help improve movements. IBS symptoms due to mental health problems: The antibiotic can reduce abdominal bloating by treating small • Talk therapy may reduce stress and intestinal bacterial overgrowth; however, improve IBS symptoms. Two types scientists are still debating the use of of talk therapy used to treat IBS are antibiotics to treat IBS and more research is cognitive behavioral therapy and needed. psychodynamic, or interpersonal, therapy. Cognitive behavioral therapy Probiotics focuses on a person’s thoughts and Probiotics are live microorganisms, actions. Psychodynamic therapy focuses usually bacteria, that are similar to on how emotions affect IBS symptoms. microorganisms normally found in This type of therapy often involves the GI tract. Studies have found that relaxation and stress management when taken in large enough amounts, techniques. probiotics, specifically Bifidobacteria and • may help a person relax certain combinations, improve the muscles in the colon. symptoms of IBS. However, more research is needed. Probiotics can be found in • Mindfulness training teaches people dietary supplements, such as capsules, to focus their attention on sensations tablets, and powders, and in some foods, occurring at the moment and avoid such as . A health care provider can catastrophizing, or worrying about the give information about the right kind and meaning of those sensations. amount of probiotics to take to improve IBS symptoms. To help ensure coordinated

8 Irritable Bowel Syndrome What other conditions are • depression associated with IBS? • anxiety People with IBS often suffer from other • somatoform disorders—chronic pain GI and non-GI conditions. GI conditions or other symptoms with no physical such as gastroesophageal reflux disease cause that are thought to be due to (GERD) and dyspepsia are more common psychological problems in people with IBS than the general population. GERD is a condition in How does stress affect IBS? which stomach contents flow back up into the esophagus—the organ that connects Stress can stimulate colon spasms in people the mouth to the stomach—because the with IBS. The colon has many nerves that muscle between the esophagus and the connect it to the brain. These nerves control stomach is weak or relaxes when it should the normal contractions of the colon and not. Dyspepsia, or , is upper cause abdominal discomfort at stressful abdominal discomfort that often occurs times. In people with IBS, the colon can be after eating. Dyspepsia may be accompanied overly responsive to even slight conflict or by fullness, bloating, , or other GI stress. Stress makes the mind more aware symptoms. Read more in Gastroesophageal of the sensations that arise in the colon. IBS Reflux (GER) and Gastroesophageal Reflux symptoms can also increase a person’s stress Disease (GERD) in Adults and Indigestion at level. Some options for managing stress www.digestive.niddk.nih.gov. include Non-GI conditions often found in people • participating in stress reduction and with IBS include relaxation therapies such as • getting counseling and support • chronic syndrome—a disorder that causes extreme fatigue, which is • taking part in regular such as tiredness that lasts a long time and walking or yoga limits a person’s ability to do ordinary • minimizing stressful life situations as daily activities much as possible • chronic • getting enough sleep • temporomandibular joint disorders— problems or symptoms of the chewing muscles and joints that connect the lower jaw to the skull

9 Irritable Bowel Syndrome Points to Remember –– passing mucus • Irritable bowel syndrome (IBS) is –– abdominal bloating a functional gastrointestinal (GI) • The causes of IBS are not well disorder, meaning symptoms are understood. Researchers believe a caused by changes in how the GI tract combination of physical and mental works. People with a functional GI health problems can lead to IBS. disorder have frequent symptoms; • To diagnose IBS, a health care however, the GI tract does not provider will conduct a physical become damaged. exam and take a complete medical • IBS is a group of symptoms that occur history. The medical history will together, not a disease. include questions about symptoms, • Studies estimate IBS affects 3 to family history of GI disorders, 20 percent of the adult population, recent infections, medications, and with most studies ranging from stressful events related to the onset of 10 to 15 percent. However, only 5 to symptoms. 7 percent of the adult population has • Though IBS does not have a cure, been diagnosed with the condition. the symptoms can be treated with a • The most common symptoms of IBS combination of are abdominal pain or discomfort, –– changes in eating, diet, and often reported as cramping, along nutrition with changes in bowel habits. Other –– medications symptoms of IBS may include –– probiotics –– diarrhea –– therapies for mental health –– constipation problems –– feeling that a bowel movement is incomplete

10 Irritable Bowel Syndrome Hope through Research Acknowledgments The National Institute of and Publications produced by the Clearinghouse Digestive and Kidney Diseases’ (NIDDK’s) are carefully reviewed by both NIDDK Division of Digestive Diseases and Nutrition scientists and outside experts. This conducts and supports basic and clinical publication was reviewed by William E. research into many digestive disorders. Whitehead, Ph.D., University of North Carolina Center for Functional GI and Clinical trials are research studies involving Motility Disorders. people. Clinical trials look at safe and effective new ways to prevent, detect, or treat disease. Researchers also use clinical You may also find additional information about this trials to look at other aspects of care, such topic by visiting MedlinePlus at www.medlineplus.gov. as improving the quality of life for people This publication may contain information about with chronic illnesses. To learn more about medications and, when taken as prescribed, the clinical trials, why they matter, and how to conditions they treat. When prepared, this publication included the most current information available. participate, visit the NIH Clinical Research For updates or for questions about any medications, Trials and You website at www.nih.gov/health/ contact the U.S. Food and Drug Administration toll- clinicaltrials. For information about current free at 1–888–INFO–FDA (1–888–463–6332) or visit www.fda.gov. Consult your health care provider for studies, visit www.ClinicalTrials.gov. more information. For More Information American Neurogastroenterology and The U.S. Government does not endorse or favor any Motility Society specific commercial product or company. Trade, proprietary, or company names appearing in this 45685 Harmony Lane document are used only because they are considered Belleville, MI 48111 necessary in the context of the information provided. Phone: 734–699–1130 If a product is not mentioned, the omission does not mean or imply that the product is unsatisfactory. Fax: 734–699–1136 Email: [email protected] Internet: www.motilitysociety.org International Foundation for Functional Gastrointestinal Disorders 700 West Virginia Street, Suite 201 Milwaukee, WI 53204 Phone: 1–888–964–2001 or 414–964–1799 Fax: 414–964–7176 Email: [email protected] Internet: www.iffgd.org Rome Foundation, Inc. P.O. Box 6524 Raleigh, NC 27628 Phone: 919–539–3051 Fax: 919–900–7646 Email: [email protected] Internet: www.romecriteria.org

11 Irritable Bowel Syndrome National Digestive Diseases Information Clearinghouse 2 Information Way Bethesda, MD 20892–3570 Phone: 1–800–891–5389 TTY: 1–866–569–1162 Fax: 703–738–4929 Email: [email protected] Internet: www.digestive.niddk.nih.gov The National Digestive Diseases Information Clearinghouse (NDDIC) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The NIDDK is part of the National Institutes of Health of the U.S. Department of Health and Human Services. Established in 1980, the Clearinghouse provides information about digestive diseases to people with digestive disorders and to their families, health care professionals, and the public. The NDDIC answers inquiries, develops and distributes publications, and works closely with professional and patient organizations and Government agencies to coordinate resources about digestive diseases.

This publication is not copyrighted. The Clearinghouse encourages users of this publication to duplicate and distribute as many copies as desired. This publication is available at www.digestive.niddk.nih.gov.

NIH Publication No. 13–693 September 2013

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