Diagnosis and Treatment of Constipation

What Diagnostic Tests Are Used For Constipation?

Most people do not need extensive testing and can be treated with changes in diet and exercise for their constipation. For example, in young people with mild symptoms, a medical history and physical examination may be all the doctor needs to suggest successful treatment. The tests the doctor performs depends on the duration and severity of the constipation, the person's age, and whether there is blood in stools, recent changes in bowel movements, or weight loss.

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.

Barium Enema X-Ray

A barium enema x-ray involves viewing the rectum, colon, and lower part of the small intestine to locate any problems. This part of the digestive tract is known as the bowel. This test may show intestinal obstruction and Hirschsprung's disease, a lack of nerves within the colon.

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 at bedtime. 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?

Although treatment depends on the cause, severity, and duration, in most cases dietary and lifestyle changes will help relieve symptoms and help prevent constipation.

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®, and Serutan®.

• Stimulants cause rhythmic muscle contractions in the intestines. Brand names include Correctol®, Ex-Lax®, 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 (FDA) 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®.

People who are dependent on laxatives need to slowly stop using the medications. A doctor can assist in this process. In most people, this restores the colon's natural ability to contract.

Other Treatment

Treatment may be directed at a specific cause. For example, the doctor may recommend discontinuing medication or performing surgery to correct an anorectal problem such as rectal prolapse.

People with chronic constipation caused by anorectal dysfunction can use biofeedback to retrain the muscles that control release of bowel movements. Biofeedback involves using a sensor to monitor muscle activity that at the same time can be displayed on a computer screen allowing for an accurate assessment of body functions. A health care professional uses this information to help the patient learn how to use these muscles.

Surgical removal of the colon may be an option for people with severe symptoms caused by colonic inertia. However, the benefits of this surgery must be weighed against possible complications, which include abdominal pain and diarrhea.

Can Constipation Be Serious?

Sometimes constipation can lead to complications. These complications include hemorrhoids caused by straining to have a bowel movement or anal fissures (tears in the skin around the anus) caused when hard stool stretches the sphincter muscle. As a result, rectal bleeding may occur that appears as bright red streaks on the surface of the stool. Treatment for hemorrhoids may include warm tub baths, ice packs, and application of a cream to the affected area. Treatment for anal fissure may include stretching the sphincter muscle or surgical removal of tissue or skin in the affected area.

Sometimes straining causes a small amount of intestinal lining to push out from the anal opening. This condition is known as rectal prolapse and may lead to secretion of mucus from the anus. Usually, eliminating the cause of the prolapse such as straining or coughing is the only treatment necessary. Severe or chronic prolapse requires surgery to strengthen and tighten the anal sphincter muscle or to repair the prolapsed lining.

Constipation may also cause hard stool to pack the intestine and rectum so tightly that the normal pushing action of the colon is not enough to expel the stool. This condition, called fecal impaction, occurs most often in children and older adults. An impaction can be softened with mineral oil taken by mouth and an enema. After softening the impaction, the doctor may break up and remove part of the hardened stool by inserting one or two fingers in the anus.

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.