Irritable Bowel Syndrome Symptoms

By the National Institute of Health

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What causes Irritable Bowel Syndrome?
Irritable Bowel Syndrome Symptoms
How is Irritable Bowel Syndrome diagnosed?
Treatment for Irritable Bowel Syndrome?
Does stress affect Irritable Bowel Syndrome?
Can changes in diet help?
Is Irritable Bowel Syndrome linked to other diseases?
Hope Through Research
Points to Remember
For More Information

Irritable bowel syndrome (Irritable Bowel Syndrome) is a disorder that interferes with the normal functions of the large intestine (colon). It is characterized by a group of symptoms--crampy abdominal pain, bloating, constipation, and diarrhea.

One in five Americans has Irritable Bowel Syndrome, making it one of the most common disorders diagnosed by doctors. It occurs more often in women than in men, and it usually begins around age 20.

Irritable Bowel Syndrome causes a great deal of discomfort and distress, but it does not permanently harm the intestines and does not lead to intestinal bleeding or to any serious disease such as cancer. Most people can control their symptoms with diet, stress management, and medications prescribed by their physician. But for some people, Irritable Bowel Syndrome can be disabling. They may be unable to work, go to social events, or travel even short distances.

What causes Irritable Bowel Syndrome?

What causes one person to have Irritable Bowel Syndrome and not another? No one knows. Symptoms cannot be traced to a single organic cause. Research suggests that people with Irritable Bowel Syndrome seem to have a colon that is more sensitive and reactive than usual to a variety of things, including certain foods and stress. Some evidence indicates that the immune system, which fights infection, is also involved. Irritable Bowel Syndrome symptoms result from the following:

The normal motility of the colon may not work properly. It can be spasmodic or can even stop temporarily. Spasms are sudden strong muscle contractions that come and go.

The lining of the colon (epithelium), which is affected by the immune and nervous systems, regulates the passage of fluids in and out of the colon. In Irritable Bowel Syndrome, the epithelium appears to work properly. However, fast movement of the colon's contents can overcome the absorptive capacity of the colon. The result is too much fluid in the stool. In other patients, colonic movement is too slow, too much fluid is absorbed, and constipation develops.

The colon responds strongly to stimuli (for example, foods or stress) that would not bother most people.

In people with Irritable Bowel Syndrome, stress and emotions can strongly affect the colon. It has many nerves that connect it to the brain. Like the heart and the lungs, the colon is partly controlled by the autonomic nervous system, which has been proven to respond to stress. For example, when you are frightened, your heart beats faster, your blood pressure may go up, or you may gasp. The colon responds to stress also. It may contract too much or too little. It may absorb too much water or too little.

Research has shown that very mild or hidden (occult) celiac disease is present in a smaller group of people with symptoms that mimic Irritable Bowel Syndrome. People with celiac disease cannot digest gluten, which is present in wheat, rye, barley, and possibly oats. Foods containing gluten are toxic to these people, and their immune system responds by damaging the small intestine. A blood test can determine whether celiac disease is present. (For information about celiac disease, see the Celiac Disease fact sheet from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).)

The following have been associated with a worsening of Irritable Bowel Syndrome symptoms:

Large meals
Bloating from gas in the colon

Medicines

Wheat, rye, barley, chocolate, milk products, or alcohol

Drinks with caffeine, such as coffee, tea, or colas

Stress, conflict, or emotional upsets

Researchers have also found that women with Irritable Bowel Syndrome may have more symptoms during their menstrual periods, suggesting that reproductive hormones can exacerbate Irritable Bowel Syndrome problems.

What does the colon do?

The colon, which is about 5 feet long, connects the small intestine with the rectum and anus. The major function of the colon is to absorb water, nutrients, and salts from the partially digested food that enters from the small intestine. Two pints of liquid matter enter the colon from the small intestine each day. Stool volume is a third of a pint. The difference in volume represents what the colon absorbs each day.

Colon motility (the contraction of the colon muscles and the movement of its contents) is controlled by nerves and hormones and by electrical activity in the colon muscle. Contractions move the contents slowly back and forth but mainly toward the rectum. During this passage, water and nutrients are absorbed into the body. What remains is stool. A few times each day, strong muscle contractions move down the colon, pushing the stool ahead of them. Some of these strong contractions result in a bowel movement. The muscles of the pelvis and anal sphincters have to relax at the right time to allow the stool to be expelled. If the muscles of the colon, sphincters, and pelvis do not contract in a coordinated way, the contents do not move smoothly, resulting in abdominal pain, cramps, constipation or diarrhea, and a sense of incomplete stool movement.

Irritable bowel syndrome symptoms - What are they?

Abdominal pain or discomfort in association with bowel dysfunction is the main symptom. Symptoms may vary from person to person. Some people have constipation (hard, difficult-to-pass, or infrequent bowel movements); others have diarrhea (frequent loose stools, often with an urgent need to move the bowels); and still others experience alternating constipation and diarrhea. Some people experience bloating, which is gas building up in the intestines and causing the feeling of pressure inside the abdomen.

Irritable bowel syndrome affects the motility or movement of stool and gas through the colon and how fluids are absorbed. When stool remains in the colon for a long time, too much water is absorbed from it. Then it becomes hard and difficult to pass. Or spasms push the stool through the colon too fast for the fluid to be absorbed, resulting in diarrhea. In addition, with spasms, gas may get trapped in one area or stool may collect in one place, temporarily unable to move forward.

Sometimes people with Irritable Bowel Syndrome have a crampy urge to move their bowels but cannot do so or pass mucus with their bowel movements.

Bleeding, fever, weight loss, and persistent severe pain are not symptoms of Irritable Bowel Syndrome and may indicate other problems such as inflammation or rarely cancer.

How is Irritable Bowel Syndrome diagnosed?

If you think you have Irritable Bowel Syndrome, seeing your doctor is the first step. Irritable Bowel Syndrome is generally diagnosed on the basis of a complete medical history that includes a careful description of symptoms and a physical examination.

No particular test is specific for Irritable Bowel Syndrome. However, diagnostic tests may be performed to rule out other diseases. These tests may include stool or blood tests, x rays, or endoscopy (viewing the colon through a flexible tube inserted through the anus). If these tests are all negative, the doctor may diagnose Irritable Bowel Syndrome based on your symptoms: that is, how often you have had abdominal pain or discomfort during the past year, when the pain starts and stops in relation to bowel function, and how your bowel frequency and stool consistency are altered.

Criteria for Diagnosis

Abdominal pain or discomfort for at least 12 weeks out of the previous 12 months. These 12 weeks do not have to be consecutive.

The abdominal pain or discomfort has two of the following three features:

It is relieved by having a bowel movement.

When it starts, there is a change in how often you have a bowel movement.

When it starts, there is a change in the form of the stool or the way it looks.

What is the treatment for Irritable Bowel Syndrome?

No cure has been found for Irritable Bowel Syndrome, but many options are available to treat the symptoms. Your doctor will give you the best treatments available for your particular symptoms and encourage you to manage stress and make changes to your diet.

Medications are an important part of relieving symptoms. Your doctor may suggest fiber supplements or occasional laxatives for constipation, as well as medicines to decrease diarrhea, tranquilizers to calm you, or drugs that control colon muscle spasms to reduce abdominal pain. Antidepressants may also relieve some symptoms. Medications available to treat Irritable Bowel Syndrome specifically are the following:

Alosetron hydrochloride (Lotronex) has been re-approved by the U.S. Food and Drug Administration (FDA) for women with severe Irritable Bowel Syndrome who have not responded to conventional therapy and whose primary symptom is diarrhea. However, even in these patients, it should be used with caution because it can have serious side effects, such as severe constipation or decreased blood flow to the colon.

Tegaserod maleate (Zelnorm) has been approved by the FDA for the short-term treatment (usually 4 weeks) of women with Irritable Bowel Syndrome whose primary symptom is constipation.

With any medication, even over-the-counter medications such as laxatives and fiber supplements, it is important to follow your doctor's instructions. Laxatives can be habit forming if they are not used carefully or are used too frequently.

It is also important to note that medications affect people differently and that no one medication or combination of medications will work for everyone with Irritable Bowel Syndrome. You need to work with your doctor to find the best combination of medicine, diet, counseling, and support to control your symptoms.

How does stress affect Irritable Bowel Syndrome?

Stress--feeling mentally or emotionally tense, troubled, angry, or overwhelmed--stimulates colon spasms in people with Irritable Bowel Syndrome. The colon has a vast supply of nerves that connect it to the brain. These nerves control the normal rhythmic contractions of the colon and cause abdominal discomfort at stressful times. People often experience cramps or "butterflies" when they are nervous or upset. But with Irritable Bowel Syndrome, the colon can be overly responsive to even slight conflict or stress. Stress also makes the mind more tuned to the sensations that arise in the colon and makes the stressed person perceive these sensations as unpleasant.

Some evidence suggests that Irritable Bowel Syndrome is affected by the immune system, which fights infection in the body. The immune system is also affected by stress. For all these reasons, stress management is an important part of treatment for Irritable Bowel Syndrome. Stress management comprises stress reduction (relaxation) training and relaxation therapies, such as meditation counseling and support regular exercise such as walking or yoga
changes to the stressful situations in your life adequate sleep.

Can changes in diet help Irritable Bowel Syndrome?

For many people, careful eating reduces Irritable Bowel Syndrome symptoms. Before changing your diet, keep a journal noting the foods that seem to cause distress. Then discuss your findings with your doctor. You may also want to consult a registered dietitian, who can help you make changes to your diet. For instance, if dairy products cause your symptoms to flare up, you can try eating less of those foods. You might be able to tolerate yogurt better than other dairy products because it contains bacteria that supply the enzyme needed to digest lactose, the sugar found in milk products. Dairy products are an important source of calcium and other nutrients. If you need to avoid dairy products, be sure to get adequate nutrients in the foods you substitute or take supplements.

In many cases, dietary fiber may lessen Irritable Bowel Syndrome symptoms, particularly constipation. However, it may not help pain or diarrhea. Whole grain breads and cereals, fruits, and vegetables are good sources of fiber. High-fiber diets keep the colon mildly distended, which may help prevent spasms. Some forms of fiber also keep water in the stool, thereby preventing hard stools that are difficult to pass. Doctors usually recommend a diet with enough fiber to produce soft, painless bowel movements. High-fiber diets may cause gas and bloating, but these symptoms often go away within a few weeks as your body adjusts. (For information about diets for people with celiac disease, please see the Celiac Disease fact sheet from NIDDK.)

Drinking six to eight glasses of plain water a day is important, especially if you have diarrhea. But drinking carbonated beverages, such as sodas, may result in gas and cause discomfort. Chewing gum and eating too quickly can lead to swallowing air, which again leads to gas.

Also, large meals can cause cramping and diarrhea, so eating smaller meals more often or eating smaller portions should help Irritable Bowel Syndrome symptoms. It may also help if your meals are low in fat and high in carbohydrates, such as pasta, rice, whole-grain breads and cereals (unless you have celiac disease), fruits, and vegetables.

Is Irritable Bowel Syndrome linked to other diseases?

Irritable Bowel Syndrome itself is not a disease. As its name indicates, it is a syndrome--a combination of signs and symptoms. But Irritable Bowel Syndrome has not been shown to lead to any serious, organic diseases, including cancer. Through the years, Irritable Bowel Syndrome has been called by many names, among them colitis, mucous colitis, spastic colon, or spastic bowel. However, no link has been established between Irritable Bowel Syndrome and inflammatory bowel diseases such as Crohn's disease or ulcerative colitis.

Hope Through Research

The NIDDK conducts and supports research into many kinds of digestive disorders, including Irritable Bowel Syndrome. Researchers are studying gastrointestinal motility and sensitivity to find possible treatments for Irritable Bowel Syndrome. These studies include the structure and contraction of gastrointestinal muscles as well as the mechanics of fluid movement through the intestines. Understanding the influence of the nerves, hormones, and inflammation in Irritable Bowel Syndrome may lead to new treatments to better control the symptoms.

Points to Remember

Irritable Bowel Syndrome is a disorder that interferes with the normal functions of the colon. The symptoms are crampy abdominal pain, bloating, constipation, and diarrhea.

Irritable Bowel Syndrome is a common disorder found more often in women than in men and usually begins around age 20.

People with Irritable Bowel Syndrome have colons that are more sensitive and react to things that might not bother other people, such as stress, large meals, gas, medicines, certain foods, caffeine, or alcohol.

Irritable Bowel Syndrome is diagnosed by its symptoms and by the absence of other diseases.

Most people can control their symptoms by taking medicines (laxatives, antidiarrhea medicines, tranquilizers, or antidepressants), reducing stress, and changing their diet.

Irritable Bowel Syndrome does not harm the intestines and does not lead to cancer. It is not related to Crohn's disease or ulcerative colitis.

For More Information

International Foundation for Functional Gastrointestinal Disorders
P.O. Box 170864
Milwaukee, WI 53217
Phone: 1-888-964-2001 or (414) 964-1799
Fax: (414) 964-7176
Email: iffgd@iffgd.org
Internet: www.iffgd.org

The U.S. Government does not endorse or favor any specific commercial product or company. Trade, proprietary, or company names appearing in this document are used only because they are considered necessary in the context of the information provided. If a product is not mentioned, this does not mean or imply that the product is unsatisfactory.

National Digestive Diseases Information Clearinghouse

2 Information Way
Bethesda, MD 20892-3570
Email: nddic@info.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 under 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. NDDIC answers inquiries, develops and distributes publications, and works closely with professional and patient organizations and Government agencies to coordinate resources about digestive diseases.

Publications produced by the clearinghouse are carefully reviewed by both NIDDK scientists and outside experts. This fact sheet was reviewed by Michael Camilleri, M.D., Mayo Clinic Rochester.

This e-text is not copyrighted. The clearinghouse encourages users of this e-pub to duplicate and distribute as many copies as desired.

NIH Publication No. 03-693
April 2003

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The National Digestive Diseases Information Clearinghouse (NDDIC) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). NIDDK is part of the National Institutes of Health under 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 National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) is 1 of the 27 institutes and centers that make up the National Institutes of Health (NIH). The NIDDK conducts and supports research on many of the most serious diseases affecting public health, including digestive diseases.

The National Organization for Rare Disorders (NORD) is a unique federation of voluntary health organizations dedicated to helping people with rare "orphan" diseases and assisting the organizations that serve them. NORD is committed to the identification, treatment, and cure of rare disorders through programs of education, advocacy, research, and service.

The UCLA Center for Neurovisceral Sciences & Women's Health is an NIH-funded, interdisciplinary basic and translational research program focused on various aspects of mind brain body interactions in health and disease. The Center seeks better understanding of such common gastrointestinal disorders as irritable bowel syndrome, functional dyspepsia, and common urological disorders such as irritable bladder syndrome (interstitial cystitis).

The University of North Carolina (UNC) Center for Functional GI & Motility Disorders is a multidisciplinary facility dedicated to advancing the understanding and care of patients with functional disorders. Their web site offers up-to-date information on Functional GI and Motility Disorders for both the professional and the patient, and provides information on the Center and its research, training, patient education and clinical treatment.

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Professional Organizations

The American Academy of Family Physicians provides a wealth of health information for the entire family.

The American College of Gastroenterology was founded in 1932 to advance the study and medical treatment of disorders of the gastrointestinal tract.

Founded in 1917, the American Dietetic Association (ADA) is the largest organization of food and nutrition professionals in the USA.

The American Gastroenterological Association (AGA) was founded in 1897 and is the oldest nonprofit specialty medical society in the country.

TheAmerican Society of Colon and Rectal Surgeons is the leading professional society representing more than 1000 board certified Colon and Rectal surgeons and other surgeons dedicated to advancing and promoting the science and practice of the treatment of patients with diseases and disorders affecting the colon, rectum, and anus.

The American Society for Gastrointestinal Endoscopy represents over 7,000 gastroenterologists, surgeons, and other digestive health specialists who remain committed to furthering the knowledge of the diagnosis and treatment of GI disease through the appropriate use of endoscopic techniques.

The North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) strives to improve the care of infants, children and adolescents with digestive disorders by promoting advances in clinical care, research and education.

The Society of American Gastrointestinal Endoscopic Surgeons (SAGES) provides several resources for patients and the general public to educate themselves about surgical options.

Society of Gastroenterology Nurses and Associates. Gastroenterology (GI) nursing is a specialty practice area in which nurses and associates provide care to patients with known or suspected gastrointestinal problems who are undergoing diagnostic or therapeutic treatment and/or procedures.

Founded in 1968, the Wound, Ostomy and Continence Nurses Society (WOCN) is a professional, international nursing society of more than 3,700 nurse professionals who are experts in the care of patients with wound, ostomy and continence problems.