Constipation is passage of small amounts of hard, dry bowel movements, usually fewer than three times a week. People who are constipated may find it difficult and painful to have a bowel movement. Other symptoms of constipation include feeling bloated, uncomfortable, and sluggish.

Many people think they are constipated when, in fact, their bowel movements are regular. For example, some people believe they are constipated, or irregular, if they do not have a bowel movement every day. However, there is no right number of daily or weekly bowel movements. Normal may be three times a day or three times a week depending on the person. In addition, some people naturally have firmer stools than others.

At one time or another almost everyone gets constipated. Poor diet and lack of exercise are usually the causes. In most cases, constipation is temporary and not serious. Understanding causes, prevention, and treatment will help most people find relief.

Who Gets Constipated?

According to the 1991 National Health Interview Survey, about 4 1/2 million people in the United States say they are constipated most or all of the time. Those reporting constipation most often are women, children, and adults age 65 and over. Pregnant women also complain of constipation, and it is a common problem following childbirth or surgery.

Constipation is the most common gastrointestinal complaint in the United States, resulting in about 2 million annual visits to the doctor. However, most people treat themselves without seeking medical help, as is evident from the $725 million Americans spend on laxatives each year.

What Causes Constipation?

The hard and dry stools of constipation occur when the colon absorbs too much water. This happens because the colon's muscle contractions are slow or sluggish, causing the stool to move through the colon too slowly. Figure 2 lists the most common causes of constipation.

Common Causes of Constipation

• Not enough fiber in diet
• Not enough liquids
• Lack of exercise
• Medications
• Irritable bowel syndrome
• Changes in life or routine such as pregnancy, older age, and travel
• Abuse of laxatives
• Ignoring the urge to have a bowel movement
• Specific diseases such as multiple sclerosis and lupus
• Problems with the colon and rectum
• Problems with intestinal function (Chronic idiopathic constipation).

Diet

Fiber--soluble and insoluble--is the part of fruits, vegetables, and grains that the body cannot digest. Soluble fiber dissolves easily in water and takes on a soft, gel-like texture in the intestines. Insoluble fiber passes almost unchanged through the intestines. The bulk and soft texture of fiber help prevent hard, dry stools that are difficult to pass.

On average, Americans eat about 5 to 20 grams of fiber daily, short of the 20 to 35 grams recommended by the American Dietetic Association. Both children and adults eat too many refined and processed foods in which the natural fiber is removed.

A low-fiber diet also plays a key role in constipation among older adults. They often lack interest in eating and may choose fast foods low in fiber. In addition, loss of teeth may force older people to eat soft foods that are processed and low in fiber.

Not Enough Liquids Liquids like water and juice add fluid to the colon and bulk to stools, making bowel movements softer and easier to pass. People who have problems with constipation should drink enough of these liquids every day, about eight 8-ounce glasses. Other liquids, like coffee and soft drinks, that contain caffeine seem to have a dehydrating effect.

Lack of Exercise Lack of exercise can lead to constipation, although doctors do not know precisely why. For example, constipation often occurs after an accident or during an illness when one must stay in bed and cannot exercise.

Medications Pain medications (especially narcotics), antacids that contain aluminum, antispasmodics, antidepressants, iron supplements, diuretics, and anticonvulsants for epilepsy can slow passage of bowel movements.

Irritable Bowel Syndrome (IBS) Some people with IBS, also known as spastic colon, have spasms in the colon that affect bowel movements. Constipation and diarrhea often alternate, and abdominal cramping, gassiness, and bloating are other common complaints. Although IBS can produce lifelong symptoms, it is not a life-threatening condition. It often worsens with stress, but there is no specific cause or anything unusual that the doctor can see in the colon.

Changes in Life or Routine During pregnancy, women may be constipated because of hormonal changes or because the heavy uterus compresses the intestine. Aging may also affect bowel regularity because a slower metabolism results in less intestinal activity and muscle tone. In addition, people often become constipated when traveling because their normal diet and daily routines are disrupted.

Abuse of Laxatives Myths about constipation have led to a serious abuse of laxatives. This is common among older adults who are preoccupied with having a daily bowel movement.

Laxatives usually are not necessary and can be habit-forming. The colon begins to rely on laxatives to bring on bowel movements. Over time, laxatives can damage nerve cells in the colon and interfere with the colon's natural ability to contract. For the same reason, regular use of enemas can also lead to a loss of normal bowel function.

Ignoring the Urge to Have a Bowel Movement People who ignore the urge to have a bowel movement may eventually stop feeling the urge, which can lead to constipation. Some people delay having a bowel movement because they do not want to use toilets outside the home. Others ignore the urge because of emotional stress or because they are too busy. Children may postpone having a bowel movement because of stressful toilet training or because they do not want to interrupt their play.

Specific Diseases Diseases that cause constipation include neurological disorders, metabolic and endocrine disorders, and systemic conditions that affect organ systems. These disorders can slow the movement of stool through the colon, rectum, or anus. Figure 3 lists the diseases that cause constipation.

Diseases That Cause Constipation

• Multiple sclerosis
• Parkinson's disease
• Chronic idiopathic intestinal pseudo-obstruction
• Stroke
• Spinal cord injuries.

• Diabetes
• Underactive or overactive thyroid gland
• Uremia.

• Amyloidosis
• Lupus
• Scleroderma.

Problems with Intestinal Function (Chronic Idiopathic Constipation) Also known as functional constipation, chronic idiopathic (of unknown origin) constipation is rare. However, some people are chronically constipated and do not respond to standard treatment. This chronic constipation may be related to multiple problems with hormonal control or with nerves and muscles in the colon, rectum, or anus. Functional constipation occurs in both children and adults and is most common in women.

Colonic inertia and delayed transit are two types of functional constipation caused by decreased muscle activity in the colon. These syndromes may affect the entire colon or may be confined to the left or lower (sigmoid) colon.

Functional constipation that stems from abnormalities in the structure of the anus and rectum is known as anorectal dysfunction, or anismus. These abnormalities result in an inability to relax the rectal and anal muscles that allow stool to exit.

What Diagnostic Tests Are Used?

Medical History The doctor may ask a patient to describe his or her constipation, including duration of symptoms, frequency of bowel movements, consistency of stools, presence of blood in the stool, and toilet habits (how often and where one has bowel movements). Recording eating habits, medication, and level of physical activity or exercise also helps the doctor determine the cause of constipation.

Physical Examination A physical exam may include a digital rectal exam with a gloved, lubricated finger to evaluate the tone of the muscle that closes off the anus (anal sphincter) and to detect tenderness, obstruction, or blood. In some cases, blood and thyroid tests may be necessary.

Extensive testing usually is reserved for people with severe symptoms, for those with sudden changes in number and consistency of bowel movements or blood in the stool, and for older adults. Because of an increased risk of colorectal cancer in older adults, the doctor may use these tests to rule out a diagnosis of cancer:

• Barium enema x-ray
• Sigmoidoscopy or colonoscopy
• Colorectal transit study
• Anorectal function tests.

The night before the test, bowel cleansing, also called bowel prep, is necessary to clear the lower digestive tract. The patient drinks 8 ounces of a special liquid every 15 minutes for about 4 hours. This liquid flushes out the bowel. A clean bowel is important, because even a small amount of stool in the colon can hide details and result in an inaccurate exam.

Because the colon does not show up well on an x-ray, the doctor fills the organs with a barium enema, a chalky liquid to make the area visible. Once the mixture coats the organs, x-rays are taken that reveal their shape and condition. The patient may feel some abdominal cramping when the barium fills the colon, but usually feels little discomfort after the procedure. Stools may be a whitish color for a few days after the exam.

Sigmoidoscopy or Colonoscopy An examination of the rectum and lower colon (sigmoid) is called a sigmoidoscopy. An examination of the rectum and entire colon is called a colonoscopy.

The night before a sigmoidoscopy, the patient usually has a liquid dinner and takes an enema in the early morning. A light breakfast and a cleansing enema an hour before the test may also be necessary.

To perform a sigmoidoscopy, the doctor uses a long, flexible tube with a light on the end called a sigmoidoscope to view the rectum and lower colon. First, the doctor examines the rectum with a gloved, lubricated finger. Then, the sigmoidoscope is inserted through the anus into the rectum and lower colon. The procedure may cause a mild sensation of wanting to move the bowels and abdominal pressure. Sometimes the doctor fills the organs with air to get a better view. The air may cause mild cramping.

To perform a colonoscopy, the doctor uses a flexible tube with a light on the end called a colonoscope to view the entire colon. This tube is longer than a sigmoidoscope. The same bowel cleansing used for the barium x-ray is needed to clear the bowel of waste. The patient is lightly sedated before the exam. During the exam, the patient lies on his or her side and the doctor inserts the tube through the anus and rectum into the colon. If an abnormality is seen, the doctor can use the colonoscope to remove a small piece of tissue for examination (biopsy). The patient may feel gassy and bloated after the procedure.

Colorectal Transit Study This test, reserved for those with chronic constipation, shows how well food moves through the colon. The patient swallows capsules containing small markers, which are visible on x-ray. The movement of the markers through the colon is monitored with abdominal x-rays taken several times 3 to 7 days after the capsule is swallowed. The patient follows a high-fiber diet during the course of this test.

Anorectal Function Tests These tests diagnose constipation caused by abnormal functioning of the anus or rectum (anorectal function). Anorectal manometry evaluates anal sphincter muscle function. A catheter or air-filled balloon inserted into the anus is slowly pulled back through the sphincter muscle to measure muscle tone and contractions.

Defecography is an x-ray of the anorectal area that evaluates completeness of stool elimination, identifies anorectal abnormalities, and evaluates rectal muscle contractions and relaxation. During the exam, the doctor fills the rectum with a soft paste that is the same consistency as stool. The patient sits on a toilet positioned inside an x-ray machine and then relaxes and squeezes the anus and expels the solution. The doctor studies the x-rays for anorectal problems that occurred while the patient emptied the paste.

How Is Constipation Treated?

Diet A diet with enough fiber (20 to 35 grams each day) helps form soft, bulky stool. A doctor or dietitian can help plan an appropriate diet. High-fiber foods include beans; whole grains and bran cereals; fresh fruits; and vegetables such as asparagus, brussels sprouts, cabbage, and carrots. For people prone to constipation, limiting foods that have little or no fiber such as ice cream, cheese, meat, and processed foods is also important.

Lifestyle Changes Other changes that can help treat and prevent constipation include drinking enough water and other liquids such as fruit and vegetable juices and clear soup, engaging in daily exercise, and reserving enough time to have a bowel movement. In addition, the urge to have a bowel movement should not be ignored.

Laxatives Most people who are mildly constipated do not need laxatives. However, for those who have made lifestyle changes and are still constipated, doctors may recommend laxatives or enemas for a limited time. These treatments can help retrain a chronically sluggish bowel. For children, short-term treatment with laxatives, along with retraining to establish regular bowel habits, also helps prevent constipation.

A doctor should determine when a patient needs a laxative and which form is best. Laxatives taken by mouth are available in liquid, tablet, gum, powder, and granule forms. They work in various ways:

• Bulk-forming laxatives generally are considered the safest but can interfere with absorption of some medicines. These laxatives, also known as fiber supplements, are taken with water. They absorb water in the intestine and make the stool softer. Brand names include Metamucil^®, Citrucel^®, Konsyl^®, and Serutan^®.

• Stimulants cause rhythmic muscle contractions in the intestines. Brand names include Correctol^®, Dulcolax^®, Purge^®, Feen-A-Mint^®, and Senokot^®. Studies suggest that phenolphthalein, an ingredient in some stimulant laxatives, might increase a person's risk for cancer. The Food and Drug Administration has proposed a ban on all over-the-counter products containing phenolphthalein. Most laxative makers have replaced or plan to replace phenolphthalein with a safer ingredient.

• Stool softeners provide moisture to the stool and prevent dehydration. These laxatives are often recommended after childbirth or surgery. Products include Colace^®, Dialose^®, and Surfak^®.

• Lubricants grease the stool enabling it to move through the intestine more easily. Mineral oil is the most common lubricant.

• Saline laxatives act like a sponge to draw water into the colon for easier passage of stool. Laxatives in this group include Milk of Magnesia^®, Citrate of Magnesia^®, and Haley's M-O^®.