Section 9. Digestive Disorders

Chapter 129. Bowel Movement Disorders

Topics: Introduction | Constipation | Diarrhea | Irritable Bowel Syndrome | Fecal Incontinence | Flatulence

Irritable Bowel Syndrome

Irritable bowel syndrome is a disorder of motility of the entire digestive tract that causes abdominal pain, constipation, or diarrhea.

In this disorder, the digestive tract is especially sensitive to many stimuli. Stress, diet, drugs, hormones, or minor irritants may cause the digestive tract to contract abnormally, usually leading to diarrhea. Periods of constipation may occur between bouts of diarrhea. Irritable bowel syndrome affects women 3 times more often than men.

The brain has enormous control over the digestive system. Stress, anxiety, depression, fear, and virtually any strong emotion can lead to diarrhea, constipation, and other changes in bowel function and can further worsen a flare-up (bout or attack) of irritable bowel syndrome.

During a flare-up, the contractions of the digestive tract become stronger and more frequent, and the resulting rapid transit of food and stool through the large intestine often leads to diarrhea. Crampy pain seems to result from the strong contractions of the large intestine and increased sensitivity of the receptors in the large intestine that sense stretching and pressure. Flare-ups almost always occur when a person is awake; they rarely wake a person from sleep.

For some people, high-calorie meals or a high-fat diet may be to blame. For other people, wheat, dairy products, coffee, tea, or citrus fruits appear to aggravate the symptoms, but it is not clear whether these foods are actually the cause. Others find that eating too quickly or eating after too long a period without food stimulates a flare-up of irritable bowel syndrome.

Symptoms

Symptoms are commonly triggered by eating, often by eating too quickly or too much. A few minutes later, diarrhea with pain occurs. The diarrhea may begin very suddenly and with extreme urgency. Sometimes the urgency is so strong that the person loses control and cannot reach a bathroom in time. Diarrhea during the night is rare. Sometimes constipation and diarrhea alternate. Mucus often appears in the stool. The pain may come in bouts of continuous dull aching or cramps, usually over the lower abdomen. The person may experience bloating, gas, nausea, headaches, fatigue, depression, anxiety, and difficulty concentrating. Having a bowel movement often relieves the pain. Periods of stress may worsen symptoms.

Diagnosis

Most people with irritable bowel syndrome appear healthy. A physical examination generally does not reveal anything unusual except sometimes tenderness over the large intestine. Doctors generally perform some tests--for example, blood tests, a stool examination, and a sigmoidoscopy--to differentiate irritable bowel syndrome from Crohn's disease, ulcerative colitis, collagenous and lymphocytic colitis, and the many other diseases that can cause abdominal pain and changes in bowel habits. These test results are usually normal, although the stool may be watery. The results of a sigmoidoscopy, which may cause spasms and pain, are normal. Sometimes other tests--such as abdominal ultrasound, x-rays of the intestines, or a colonoscopy--are used.

Treatment

The treatment for irritable bowel syndrome differs from person to person. People who can identify particular foods or types of stress that bring on the problem should avoid them if possible. For most people, especially those who tend to be constipated, regular physical activity helps keep the digestive tract functioning normally.

In general, a normal diet is best. Many people do better eating frequent, smaller meals rather than less frequent, larger meals (for example, five or six small meals rather than three large meals a day). People with abdominal expansion (distention) and increased gas (flatulence) should avoid beans, cabbage, and other foods that are difficult to digest. Sorbitol, an artificial sweetener used in dietetic foods and in some drugs and chewing gums, should not be consumed in large amounts. Fructose, a common constituent of fruits, berries, and some plants, should be eaten only in small amounts. A low-fat diet helps some people. People who have both irritable bowel syndrome and lactase deficiency should not eat dairy products.

Some people with irritable bowel syndrome can improve their condition by eating more fiber. They can take a tablespoon of raw bran with plenty of water and other fluids at each meal, or they can take psyllium mucilloid supplements with two glasses of water. However, increasing the dietary fiber may aggravate some symptoms, such as flatulence and bloating.

Antispasmodic drugs, which slow the function of the digestive tract, are frequently prescribed but have not been proved effective in all people with irritable bowel syndrome. Antidiarrheal drugs help people with diarrhea. Aromatic oils, such as oil of peppermint, often help symptoms of flatulence and cramping.

If an emotional disorder is identified as the cause, treatment of the disorder may relieve irritable bowel syndrome symptoms. Such treatment may include the use of antidepressants, mild tranquilizers, psychotherapy, hypnosis, and behavior modification techniques.