Irritable Bowel Syndrome

[David Baxter PhD]

Irritable bowel syndrome
By Mayo Clinic Staff
May 9, 2008

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 because the signs and symptoms may be embarrassing. Some signs and symptoms of irritable bowel syndrome are:

• Abdominal cramping
• Bloating and gas
• Diarrhea, constipation or both

As many as one in five American adults has irritable bowel syndrome. Most people with IBS find signs and symptoms improve as they learn to control the condition. 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 ? sometimes 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.

Causes
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 may be 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. People with IBS may have a heightened sensitivity to stretching of the bowel with gas leading to pain or bloating. Others believe the central nervous system may affect the colon. And because women are twice as likely 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. Carbonated beverages and some fruits and vegetables may lead to more bloating and discomfort in some people with IBS. The role of food allergy or intolerance in irritable bowel syndrome hasn't been well studied.
  
  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 signs and symptoms of irritable bowel syndrome, but you're more likely to have IBS if you're young and female. IBS begins before the age of 35 for 50 percent of people. Overall, about twice as many women have the condition. Genetics or heredity also may play a role.

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 signs or symptoms of IBS, because these may be an indication of a more serious condition such as colon cancer.

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.

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 discomfort lasting at least 12 weeks, though the weeks 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.

Your doctor will likely assess how you fit these criteria, as well as whether you have any other signs or symptoms that might suggest another, more serious condition. Some red flag signs and symptoms that might prompt your doctor to do additional testing include:

• New onset after age 50
• Weight loss
• Fever
• Recurrent vomiting

If you have these or other red flag signs or symptoms, you'll need additional testing to further assess your condition.

If you fit the IBS criteria and don't have any red flag signs or symptoms, your doctor may suggest a course of treatment without doing additional testing. But if you don't respond to that treatment, you will likely require more tests.

Additional tests
Your doctor may recommend 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 don?t produce 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 signs and symptoms like those of irritable bowel syndrome. Blood tests may help rule out that disorder.

Complications
Diarrhea and constipation, both signs of irritable bowel syndrome, can aggravate hemorrhoids. In addition, 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. If you avoid certain foods, you also may not get enough of the nutrients you need, leading to malnourishment.

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

In most cases, you can successfully control mild signs and 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 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 bothersome 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 medications that affect certain activities of the nervous system (anticholinergics) to relieve painful bowel spasms.
• Antidepressant medications. If your symptoms include pain or 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 worsen your symptoms.

Some research has shown that some people with IBS might benefit from antibiotic treatment, but this remains unproved.

Medication specifically for IBS
Two medications for IBS exist.

• Alosetron (Lotronex). Alosetron 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 two deaths and severe side effects in 113 people. In June 2002, the Food and Drug Administration (FDA) allowed 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.
  
  Generally, alosetron should only be used if usual therapy for IBS has failed. Additionally, it should only be prescribed by a gastroenterologist with expertise in IBS because of the potential side effects.
  
• Lubiprostone (Amitiza). The FDA approved Amitiza in April 2008 to treat women age 18 and older who have IBS with constipation. Its effectiveness in men is not proved. Amitiza is a chloride channel activator that you take twice a day. It works by increasing fluid secretion in your small intestine to help with the passage of stool. Common side effects include nausea, diarrhea and abdominal pain.

Prevention
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 may be helpful in preventing or alleviating symptoms:

• Counseling. In some cases, a psychologist or psychiatrist can help you learn to reduce stress by looking at how you respond to events 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.
• 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 videos.
• 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 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. 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 in relaxing your abdominal muscles.
• 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.

Self-care
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 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. Some people do better limiting dietary fiber and instead take a fiber supplement that causes less gas and bloating. 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. If gas is a problem for you, foods that might make symptoms worse include beans, cabbage, cauliflower and broccoli. Fatty foods may also be a problem for some people. Chewing gum or drinking through a straw can lead to air swallowing, causing more gas.
• 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 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. If you have other medical problems, check with your doctor before starting an exercise program.
• 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 or pharmacist.

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 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. 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 problems caused by IBS. Not all studies on probiotics have had positive results, however.