Introduction

Irritable bowel syndrome (IBS) is a common disorder that affects the large intestine (colon). Irritable bowel syndrome commonly causes cramping, abdominal pain, bloating, gas, diarrhea and constipation. IBS is a chronic condition that you will need to manage long term.

Even though signs and symptoms are uncomfortable, IBS doesn't cause changes in bowel tissue or increase your risk of colorectal cancer.

Only a small number of people with irritable bowel syndrome have severe signs and symptoms. Some people can control their symptoms by managing diet, lifestyle and stress. Others will need medication and counseling.

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
• Diarrhea or constipation — sometimes alternating bouts of constipation and diarrhea
• Mucus in the stool

  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.

  Diagnosis

  Because there are usually no physical signs to definitively diagnose IBS, diagnosis is often a process of ruling out other conditions. To help this process, researchers have developed diagnostic criteria for IBS and other functional gastrointestinal disorders — conditions in which the bowel appears normal but doesn't work (function) normally.

• Rome criteria. 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 three days a month in the last three months, associated with two or more of following: improvement with defecation, altered frequency of stool or altered consistency of stool.

   

  Your doctor will 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 suggest a need for additional testing include:

• New onset after age 50
• Weight loss
• Rectal bleeding
• Fever
• Nausea or recurrent vomiting
• Abdominal pain, especially if it's not completely relieved by a bowel movement, or occurs at night
• Diarrhea that is persistent or awakens you from sleep
• Anemia related to iron deficiency

  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'll likely require more tests.

  Additional tests

  Your doctor may recommend several tests, including stool studies to check for infection or problems with your intestine's ability to take in the nutrients from food (malabsorption). You may undergo a number of tests to rule out other causes for your symptoms.

  Imaging tests:

• Colonoscopy. In some cases, especially if you are age 50 or older or have other signs of a potentially more serious condition, 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, especially if you have abdominal pain.
• Lower GI series. In this test, doctors fill your large intestine with a liquid (barium) to make it easier to see any problems on the X-ray.

• Blood tests. Blood tests can help rule out endocrine disorders or celiac disease.
• Stool tests. If you have chronic diarrhea, doctors may want to examine your stool for bacteria or parasites.

  Treatment

  Because it's not clear what causes irritable bowel syndrome, treatment focuses on the relief of symptoms so that you can live 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. Try to avoid foods that trigger your symptoms. Also try to get enough exercise, drink plenty of fluids and get enough sleep.

  If your problems are moderate or severe, you may need more than lifestyle changes. Your doctor may suggest medications.

  Dietary changes:

• Eliminating high-gas foods. If you have bothersome bloating or are passing considerable amounts of gas, your doctor may suggest that you cut out such items as carbonated beverages, vegetables — especially cabbage, broccoli and cauliflower — and raw fruits.
• Eliminating gluten. Research shows that some people with IBS report improvement in diarrhea symptoms if they stop eating gluten (wheat, barley and rye). This recommendation remains controversial, and the evidence is not clear.
• Eliminating FODMAPs. Some people are sensitive to types of carbohydrates such as fructose, fructans, lactose and others, called FODMAPs (fermentable oligo-, di-, and monosaccharides and polyols). FODMAPs are found in certain grains, vegetables, fruits and dairy products. However, often people are not bothered by every FODMAP food. You may be able to get relief from your IBS symptoms on a strict low FODMAP diet and then reintroduce foods one at time.

   

  Medications:

• Fiber supplements. Taking fiber supplements with fluids may help control constipation. Fiber obtained from food may cause much more bloating compared with a fiber supplement. If fiber doesn't help symptoms, your doctor may prescribe an osmotic laxative.
• Anti-diarrheal medications. Anti-diarrheal medications, such as loperamide or smecta, can help control diarrhea.
• Anticholinergic and antispasmodic medications. These medications, such as delibs and catilon, can help 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.
• Counseling. You may benefit from counseling if you have depression or if stress tends to worsen your symptoms.

   

  Life style modification

  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 slowly 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 as Metamucil or Citrucel, be sure to introduce it slowly and drink plenty of water every day to reduce 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. These may 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 also may be a problem for some people. Chewing gum or drinking through a straw can lead to swallowing air, 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 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 stop eating 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.