About Irritable Bowel Syndrome

Introduction

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.

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 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.

Complications

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.

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.

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. There are a number of clinical studies that have shown significant reduction in symptoms of IBS with probiotics. Symbion™ is the only one on the market that contains all three of the most effective probiotic strains. See the Q&A page for much more information on probiotics.

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 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.

Web Resources

• Irritable Bowel Syndrome Self Help and Support Group
• National Institute of Diabetes & Digestive & Kidney Diseases
• National Center for Complementary and Alternative Medicine: Acupuncture
• Acupuncture and Oriental Medicine Alliance
• International Foundation for Functional Gastrointestinal Disorders: About IBS

Excerpt from: Diagnosing the Patient with Abdominal Pain and Altered Bowel Habits: Is It Irritable Bowel Syndrome?

http://www.aafp.org/afp/20030515/2157.html

KEITH B. HOLTEN, M.D., and ANTHONY WETHERINGTON, M.D., University of Cincinnati College of Medicine, Cincinnati, Ohio ,LAURIE BANKSTON, M.D., Clinton Memorial Hospital, Wilmington, Ohio

Epidemiology

Americans spend $8 billion each year on medical costs related to IBS,³ and absenteeism resulting from IBS significantly affects the work force. Studies have shown that IBS affects 3 to 22 percent of persons worldwide.⁴ Symptoms are reported by 12 percent of Americans and are the cause of 20 to 50 percent of referrals to gastroenterology clinics.^5,6 Most people with IBS do not seek medical care.

OTHER FACTORS

Rates of IBS among patients with chronic fatigue syndrome, fibromyalgia, and temporomandibular joint (TMJ) syndrome are high (92, 77, and 64 percent, respectively).¹⁸

3. Talley NJ, Gabriel SE, Harmsen WS, Zinsmeister AR, Evans RW. Medical costs in community subjects with irritable bowel syndrome. Gastroenterology 1995;109:1736-41.

4. Locke GR 3d, Zinsmeister AR, Talley NJ, Fett SL, Melton LJ. Risk factors for irritable bowel syndrome: role of analgesics and food sensitivities. Am J Gastroenterol 2000;95:157-65.

5. Locke GR 3d. The epidemiology of functional gastrointestinal disorders in North America. Gastroenterol Clin North Am 1996;25:1-19.

6. Maxwell PR, Mendall MA, Kumar D. Irritable bowel syndrome. Lancet 1997;350:1691-5.

18. Aaron LA, Burke MM, Buchwald D. Overlapping conditions among patients with chronic fatigue syndrome, fibromyalgia, and temporomandibular disorder. Arch Intern Med 2000;160:221-7.