Irritable Bowel Syndrome


Irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common disorders that doctors see. Yet it’s also one that many people aren’t comfortable talking about. Irritable bowel syndrome is characterized by abdominal pain or cramping and changes in bowel function — including bloating, gas, diarrhea and constipation — problems most people don’t like to discuss. What’s more, for many years irritable bowel syndrome was considered a psychological rather than a physical problem.

Up to one in five American adults has irritable bowel syndrome. The disorder accounts for more than one out of every 10 doctor visits. For most people, signs and symptoms of irritable bowel disease are mild. Only a small percentage of people with irritable bowel syndrome have severe signs and symptoms.

Fortunately, unlike more serious intestinal diseases such as ulcerative colitis and Crohn’s disease, irritable bowel syndrome doesn’t cause inflammation or changes in bowel tissue or increase your risk of colorectal cancer. In many cases, you can control irritable bowel syndrome by managing your diet, lifestyle and stress.
Signs and symptoms

The signs and symptoms of irritable bowel syndrome can vary widely from person to person and often resemble those of other diseases. Among the most common are:

* Abdominal pain or cramping
* A bloated feeling
* Gas (flatulence)
* Diarrhea or constipation — people with IBS may also experience alternating bouts of constipation and diarrhea
* Mucus in the stool

Like many people, you may have only mild signs and symptoms of irritable bowel syndrome. Sometimes these problems can be disabling, however. In some cases, you may have severe signs and symptoms that don’t respond well to medical treatment. Because symptoms of irritable bowel syndrome can be present with other diseases, it’s best to discuss these symptoms with your doctor.

For most people, IBS is a chronic condition, although there will likely be times when the signs and symptoms are worse and times when they improve or even disappear completely.

No one knows exactly what causes irritable bowel syndrome. The walls of the intestines are lined with layers of muscle that contract and relax as they move food from your stomach through your intestinal tract to your rectum. Normally, these muscles contract and relax in a coordinated rhythm. But if you have irritable bowel syndrome, the contractions are stronger and last longer than normal. Food is forced through your intestines more quickly, causing gas, bloating and diarrhea. In some cases, however, the opposite occurs. Food passage slows, and stools become hard and dry.

Some researchers believe IBS is caused by changes in the nerves that control sensation or muscle contractions in the bowel. Others believe the central nervous system may affect the colon. And because women are two to three times as likely as men to have IBS, researchers believe that hormonal changes also play a role. Also, many women find that signs and symptoms are worse during or around their menstrual periods.

Triggers bother some, not others
For reasons that still aren’t clear, if you have IBS you probably react strongly to stimuli that don’t bother other people. Triggers for IBS can range from gas or pressure on your intestines to certain foods, medications or emotions. For example:

* Foods. Many people find that their signs and symptoms worsen when they eat certain foods. For instance, chocolate, milk and alcohol might cause constipation or diarrhea. A survey found that almost two out of three people with IBS felt a dietary allergy or intolerance was to blame for their IBS. The role of food allergy or intolerance in irritable bowel syndrome hasn’t been well studied. And some researchers suspect that rather than food being a trigger, the actual process of eating may be the trigger because chewing stimulates the colon.

If you experience cramping and bloating mainly after eating dairy products, food with caffeine, or sugar-free gum or candies, the problem may not be irritable bowel syndrome. Instead, your body may not be able to tolerate the sugar (lactose) in dairy products, caffeine or the artificial sweetener sorbitol.

* Stress. If you’re like most people with IBS, you probably find that your signs and symptoms are worse or more frequent during stressful events, such as a change in your daily routine or family arguments. But while stress may aggravate symptoms, it doesn’t cause them.
* Other illnesses. Sometimes another illness, such as an acute episode of infectious diarrhea (gastroenteritis) can trigger IBS.

Risk factors

Many people have occasional symptoms of irritable bowel syndrome, but you’re more likely to have IBS if you’re young and female. IBS typically begins around age 20. Overall, two to three times as many women as men have the condition. People with IBS often report that family members also have the disorder, suggesting a possible genetic cause.
When to seek medical advice

Although as many as one in five American adults has signs and symptoms of irritable bowel syndrome, fewer than half seek medical help. Yet it’s important to see your doctor if you have a persistent change in bowel habits or if you have any other symptoms of IBS.

Your doctor may be able to help you find ways to relieve symptoms as well as rule out other more serious colon conditions, such as ulcerative colitis and Crohn’s disease, which are forms of inflammatory bowel disease, and colon cancer. He or she can also help you avoid possible complications from problems such as chronic diarrhea.
Screening and diagnosis

A diagnosis of irritable bowel syndrome depends largely on a complete medical history and physical exam. Your doctor may also recommend conducting several tests, including stool studies to check for infection or malabsorption problems. Among the tests that you may undergo to rule out other causes for your symptoms are the following:

* Flexible sigmoidoscopy. This test examines the lower part of the colon (sigmoid) with a flexible, lighted tube (sigmoidoscope).
* Colonoscopy. In some cases, your doctor may perform this diagnostic test, in which a small, flexible tube is used to examine the entire length of the colon.
* Computerized tomography (CT) scan. CT scans produce cross-sectional X-ray images of internal organs. CT scans of your abdomen and pelvis may help your doctor rule out other causes of your symptoms.
* Lactose intolerance tests. Lactase is an enzyme you need to digest the sugar found in dairy products. If you lack this enzyme, you may have problems similar to those caused by irritable bowel syndrome, including abdominal pain, gas and diarrhea. To find out if this is the cause of your symptoms, your doctor may order a breath test or ask you to exclude milk and milk products from your diet for several weeks.
* Blood tests. Celiac disease (nontropical sprue) is sensitivity to wheat protein that also may cause symptoms like those of irritable bowel syndrome. Blood tests may help rule out that disorder.

Criteria for making a diagnosis
Because there are usually no physical signs to definitively diagnose irritable bowel syndrome, diagnosis is often a process of elimination. To help in this process, researchers have developed diagnostic criteria, known as Rome criteria, for IBS and other functional gastrointestinal disorders — conditions in which the bowel appears normal but doesn’t function normally.

According to these criteria, you must have certain signs and symptoms before a doctor diagnoses irritable bowel syndrome. The most important are abdominal pain and diarrhea or constipation lasting at least 12 weeks, though they don’t have to occur consecutively. You also need to have at least two of the following:

* A change in the frequency or consistency of your stool. For example, you may change from having one normal, formed stool every day to three or more loose stools daily. Or you may have only one hard stool every three to four days.
* Straining, urgency or a feeling that you can’t empty your bowels completely.
* Mucus in your stool.
* Bloating or abdominal distension.


Both diarrhea and constipation can aggravate hemorrhoids. In addition, signs and symptoms of irritable bowel syndrome can interfere with your work, your relationships with friends and family, and your ability to live your life to the fullest. At times, you may feel discouraged or depressed.

Because it’s still not clear what causes irritable bowel syndrome, treatment focuses on the relief of symptoms so that you can live your life as fully and normally as possible.

In most cases, you can successfully control mild symptoms of irritable bowel syndrome by learning to manage stress and making changes in your diet and lifestyle. But if your problems are moderate or severe, you may need more help than lifestyle changes alone can offer. Your doctor may suggest:

* Fiber supplements. Taking fiber supplements such as psyllium (Metamucil) or methylcellulose (Citrucel) with fluids may help control constipation.
* Anti-diarrheal medications. Over-the-counter medications such as loperamide (Imodium) can help control diarrhea.
* Eliminating high-gas foods. If you have significant bloating or are passing significant amounts of gas, your doctor may also ask you to cut out such items as carbonated beverages, salads, raw fruits and vegetables, cabbage, broccoli and cauliflower.
* Anticholinergic medications. Some people need drugs that affect certain activities of the nervous system (anticholinergics) to relieve painful bowel spasms.
* Antidepressant medications. If your symptoms include pain and depression, your doctor may recommend a tricyclic antidepressant or a selective serotonin reuptake inhibitor (SSRI). These medications help relieve depression as well as inhibit the activity of neurons that control the intestines. For diarrhea and abdominal pain, your doctor may suggest tricyclic antidepressants, such as imipramine (Tofranil) and amitriptyline. Side effects of these drugs include drowsiness and constipation. SSRIs such as fluoxetine (Prozac, Sarafem) or paroxetine (Paxil) may be helpful if you’re depressed and have pain and constipation.
* Counseling. If antidepressant medications don’t work, you may have better results from counseling if stress tends to exacerbate your symptoms.

Drugs specifically for IBS
There are currently two drugs available to treat IBS: alosetron (Lotronex) and tegaserod (Zelnorm).

* Alosetron. This drug is a nerve receptor antagonist that’s supposed to relax the colon and slow the movement of waste through the lower bowel. But the drug was removed from the market just nine months after its approval when it was linked to at least four deaths and severe side effects in 197 people. In June 2002, the Food and Drug Administration (FDA) decided to allow alosetron to be sold again — with restrictions. The drug can be prescribed only by doctors enrolled in a special program and is intended for severe cases of diarrhea-predominant IBS in women who haven’t responded to other treatments. Alosetron is not approved for use by men.
* Tegaserod. For women who have IBS with constipation, the FDA has approved the medication tegaserod (Zelnorm). It’s approved for short-term use in women and has not been shown to be effective for treating men with IBS. Tegaserod imitates the action of the neurotransmitter serotonin and helps to coordinate the nerves and muscles in the intestine. Some reports have suggested a risk of rare, dangerous side effects similar to those of alosetron, but the drug is still available.

Generally, alosetron and tegaserod should only be used if you have failed usual therapy for your IBS. Additionally, they should only be prescribed by a gastroenterologist with expertise in IBS because of the potential side effects.

Anyone can experience digestive upset from worry or anxiety. But if you have irritable bowel syndrome, stress-related problems such as abdominal pain and diarrhea tend to occur with greater frequency and intensity. Finding ways to deal with stress can be extremely helpful in preventing or alleviating symptoms:

* Counseling. In some cases, a health care professional such as a psychologist or psychiatrist can help you learn to reduce stress by looking at how you respond to events in your life and then working with you to modify or change that response.
* Biofeedback. This stress-reduction technique helps you reduce muscle tension and slow your heart rate with the feedback help of a machine. You’re then taught how to produce these changes yourself. The goal is to help you enter a relaxed state so that you can cope more easily with stress. Biofeedback is usually taught in hospitals and medical centers.
* Regular exercise, yoga, massage or meditation. These can all be effective ways to relieve stress. You can take classes in yoga and meditation or practice at home using books or tapes.
* Progressive relaxation exercises. These help you relax muscles in your body, one by one. Start by tightening the muscles in your feet, then concentrate on slowly letting all of the tension go. Next, tighten and relax your calves. Continue until the muscles in your body, including those in your eyes and scalp, are completely relaxed.
* Deep breathing. Most adults breathe from their chests. But you become calmer when you breathe from your diaphragm, the muscle that separates your chest from your abdomen. When you inhale, allow your belly to expand with air; when you exhale, your belly naturally contracts. Deep breathing can also help relax your abdominal muscles, which may lead to more-normal bowel activity.
* Hypnosis. Hypnosis may reduce abdominal pain and bloating. A trained professional teaches you how to enter a relaxed state and then guides you as you imagine your intestinal muscles becoming smooth and calm.
* Other techniques. Set aside at least 20 minutes a day for any activity you find relaxing — listening to music, reading, playing computer games or just soaking in a warm bath.


In many cases, simple changes in your diet and lifestyle can provide relief from irritable bowel syndrome. Although your body may not respond immediately to these changes, your goal is to find long-term, not temporary, solutions:

* Experiment with fiber. When you have irritable bowel syndrome, fiber can be a mixed blessing. Although it helps reduce constipation, it can also make diarrhea, gas and cramping worse. The best approach is to gradually increase the amount of fiber in your diet over a period of weeks. Examples of foods that contain fiber are whole grains, fruits, vegetables and beans. If your signs and symptoms remain the same or worse, tell your doctor. You may also want to talk to a dietitian. If you take a fiber supplement, such Metamucil or Citrucel, be sure to introduce it gradually and drink plenty of water every day to minimize gas, bloating and constipation. If you find that taking fiber helps your IBS, use it on a regular basis for best results.
* Avoid problem foods. If certain foods make your signs and symptoms worse, don’t eat them. Common culprits include alcohol, chocolate, caffeinated beverages such as coffee and sodas, medications that contain caffeine, dairy products, and sugar-free sweeteners such as sorbitol or mannitol. For some people, fats such as butter and margarine or foods high in fat such as mayonnaise, nuts, cream, ice cream and red meat also may aggravate symptoms. Be careful that your diet doesn’t become too restricted, though. If you need help, talk to a dietitian. Large meals also may make your symptoms worse.
* Eat at regular times. Don’t skip meals, and try to eat about the same time each day to help regulate bowel function. If you have diarrhea, you may find that eating small, frequent meals makes you feel better. But if you’re constipated, eating larger amounts of high-fiber foods may help move food through your intestines.
* Take care with dairy products. If you’re lactose intolerant, try substituting yogurt for milk. Or use an enzyme product, such as Lactaid, to help break down lactose. Consuming small amounts of milk products or combining them with other foods to slow digestion also may help. In some cases, though, you may need to eliminate dairy foods completely. If so, be sure to get enough protein, calcium and B vitamins from other sources.
* Drink plenty of liquids. Try to drink plenty of fluids every day. Water is best. Alcohol and beverages that contain caffeine stimulate your intestines and can make diarrhea worse, and carbonated drinks can produce gas.
* Exercise regularly. Exercise helps relieve depression and stress, stimulates normal contractions of your intestines and can help you feel better about yourself. If you’ve been inactive, start slowly and gradually increase the amount of time you exercise.
* Use anti-diarrheal medications and laxatives with caution. If you try over-the-counter anti-diarrheal medications, such as Imodium or Kaopectate, use the lowest dose that helps. In the long run, these medications can cause problems if you don’t use them appropriately. The same is true of laxatives. If you have any questions about them, check with your doctor.

Coping skills

Living with irritable bowel syndrome presents daily challenges. It may be painful or embarrassing and can seriously affect the quality of your life. These suggestions may help you cope more easily:

* Learn as much about IBS as you can. Talk to your doctor, look for information on the Internet from reputable sources such as the National Institutes of Health and major medical centers or medical schools, and read books and pamphlets. Being informed about your condition can help you take better charge of it.
* Identify the factors that trigger IBS. This is a key step both in managing your condition and in helping you feel you have control of your life.
* Seek out others with IBS. Talking to people who know what you’re going through can be reassuring. Try Internet chat rooms or IBS support groups in your community. Your doctor may be able to refer you to a support group, or you may find one through your local paper or on Internet sites.

Complementary and alternative medicine

The following nontraditional therapies may help relieve symptoms of irritable bowel syndrome:

* Acupuncture. Researchers at the National Institutes of Health (NIH) have found that acupuncture can provide relief from chronic pain. Although study results on the effects of acupuncture on symptoms of irritable bowel syndrome have been mixed, some people use acupuncture to help relax muscle spasms and improve bowel function.
* Herbs. Peppermint is a natural antispasmodic that relaxes smooth muscles in the intestines. Study results haven’t been consistently encouraging, but if you’d like to try peppermint be sure to use enteric-coated capsules. Peppermint may aggravate heartburn. Before taking any herbs, check with your doctor to be sure they won’t interact or interfere with other medications you may be taking.
* Probiotics. Probiotics are “good” bacteria that normally live in your intestines and are found in certain foods, such as yogurt, and in dietary supplements. It’s been suggested that people with irritable bowel syndrome may not have enough good bacteria, and that adding probiotics to your diet may help ease your symptoms. Some studies have shown that probiotics can decrease IBS exacerbations. Not all studies on probiotics have had positive results, however.

Jul 27, 2005
© 1998-2006 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved.

What is irritable bowel syndrome (IBS)?

Irritable bowel syndrome (IBS) is a term used to describe discomfort in the bowel (the colon, or large intestine). Symptoms of IBS may include crampy pain, bloating, gas, mucus in the stool, and changes in bowel habits. Some people with IBS have constipation—infrequent stools that may be hard, dry and painful. Others have diarrhea—frequent loose stools. Some people having alternating constipation and diarrhea. Sometimes a person with IBS has a crampy urge to move the bowels but cannot do so.

You may have heard IBS referred to as “spastic colon” or “spastic bowel.” Sometimes IBS is confused with inflammatory bowel diseases such as ulcerative colitis. But IBS is not a disease and does not cause inflammation, bleeding, damage to the bowel, or cancer or other serious diseases. It is called a functional disorder, which means that there is no sign of disease when the colon is examined, but the bowel doesn’t work as it should. The cause of IBS is not known, and as yet there is no cure.

Often IBS is just a mild annoyance, but for some people it can be disabling. They may be unable to go to social events, to go out to a job, or to travel even short distances. Most people with IBS, however, are able to control their symptoms through diet, stress management, and medicines.
Who gets IBS?

IBS is a common problem, affecting up to one in five people. However, estimates of the number of people with IBS vary. The majority of people with IBS (perhaps 75 percent) are women. IBS often begins in the teen years or young adulthood but can affect people of any age.
What are the symptoms of IBS?

Symptoms of IBS may include:


Crampy pain in the abdomen



Alternating constipation and diarrhea

Feeling that you haven’t finished a bowel movement



Mucus in the stool

What causes IBS symptoms?

The colon or large intestine is a muscular tube about 6 feet long. It connects the small intestine with the rectum and anus (see image below).

The colon absorbs water and salts from digested food after it has traveled from the stomach through the small intestine. The muscles of the colon contract (tighten or squeeze) and gradually move the material toward the rectum. Strong contractions then lead to a bowel movement. Colon contractions are controlled by nerves, hormones, and by electrical activity in the muscles.

Researchers have found that, for unknown reasons, the colons of people with IBS are more sensitive than usual, and react to things that would not bother other people. For example, the muscles may contract too much after eating. These contractions can cause cramping and diarrhea during or shortly after a meal. The nerves can be overly sensitive to the stretching of the bowel (because of gas, for example), causing cramping or pain. Diet and stress play a role in IBS for many people, causing symptoms or making them worse.

In women, IBS symptoms may be worse during their menstrual periods, so hormone changes may be involved. Sometimes IBS symptoms appear after another illness.
How is IBS diagnosed?

IBS usually is diagnosed after bowel disease has been ruled out. Your doctor will probably take a complete medical history, do a physical exam, and check for blood in your stool. Other diagnostic tests such as blood tests, x-rays or a colonoscopy (viewing the colon through a flexible tube inserted through the anus) may be done if needed.
How do diet and stress affect IBS?

In people with IBS, diet and stress often seem to cause symptoms. Many people report that their symptoms occur after a meal or when they are under stress. No one is sure why this happens, but scientists have some clues.

Eating causes contractions or spasms of the colon. Normally, this response may cause an urge to have a bowel movement within 30 to 60 minutes after a meal. In people with IBS, the urge may come sooner with cramps and diarrhea. Contractions may be stronger after a large meal or a meal with a lot of fat in it. Many people with IBS learn to avoid certain foods, beverages, and medicines that seem to make their symptoms worse.

Stress can cause contractions of the colon in people with IBS. The reasons for this are not clear, but scientists point out that the colon is controlled partly by the nervous system. Learning relaxation methods and other ways to reduce stress can be helpful. Counseling and support help relieve IBS symptoms in many people.
What foods may cause IBS symptoms?

Some foods that may cause symptoms include:


Fatty foods like french fries

Milk products like cheese or ice cream (especially in people who have trouble digesting lactose, or milk sugar)



Caffeine (found in coffee, tea, and some sodas)

Carbonated drinks like soda

Sorbitol, a sweetener found in dietetic foods and in some chewing gums

Gas-producing foods including beans and certain vegetables like broccoli or cabbage.

You may want to keep a journal keeping track of the foods that seem to cause trouble. If certain foods cause your symptoms to flare up, you can try eating less of those foods. Discuss your findings with your doctor. You also may want to consult a registered dietitian, who can help you make changes in your diet.
What can I do to help my IBS besides avoiding problem foods and beverages?

Drinking lots of water and increasing your fiber intake may help, especially if constipation is a problem. Fiber is found in bran, bread, cereal, beans, fruits, and vegetables. It’s a good idea to increase the fiber in your diet gradually to avoid causing gas and pain. Many people with IBS also use a fiber supplement to add soluble fiber, often from psyllium seeds, to the diet.

Regular exercise can help with constipation and improve your health in other ways. Look into support groups, stress reduction methods or counseling if you think they might be helpful. Be careful about using laxatives, anti-diarrhea or other over-the-counter medicines to treat yourself. They can cause problems if misused. Other kinds of medicines sometimes make IBS symptoms worse, too.
What medicines are used to treat IBS?

Medicines sometimes used for IBS symptoms include:


fiber supplements and occasional use of laxatives (for constipation)

antispasmodics—drugs that control colon muscle spasms and help with diarrhea and pain

tranquilizers and antidepressants to help with stress, anxiety, and depression.

Be sure to follow your doctor’s instructions for use of all medicines. Some medicines including laxatives can be habit-forming, and all drugs have side effects. Tell your doctor about any over-the-counter medicines that you use. New drugs are being developed for IBS—ask your doctor about new treatment options.
For more information…

For more information about irritable bowel syndrome, contact the National Women’s Health Information Center at (800) 994-WOMAN (9662) or the following organizations:

National Digestive Diseases Information Clearinghouse, NIDDK, NIH HHS
Phone Number(s):(301) 654-3810, (800) 891-5389
Web Site: http://www.niddk.nih.gov/health/digest/nddic.htm

National Library of Medicine—Medlineplus
Web site: http://www.nlm.nih.gov/medlineplus/irritablebowelsyndrome.html

American Society of Colon and Rectal Surgeons
Phone Number(s): (847) 290-9184
Web Site: http://www.fascrs.org/

American College of Gastroenterology
Phone Number(s): (703) 820-7400
Web Site: http://www.acg.gi.org/

The information in this FAQ was adapted primarily from materials from the National Institute of Diabetes & Digestive & Kidney Diseases (NIDDK), including “Irritable Bowel Syndrome” and “What I Need to Know about Irritable Bowel Syndrome.”

All material contained in the FAQs is free of copyright restrictions, and may be copied, reproduced, or duplicated without permission of the Office on Women’s Health in the Department of Health and Human Services; citation of the source is appreciated.

Publication date: February 2002

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