Constipation is present when a person has 2 of any of the following problems for more than 3 months: hard stools, straining to pass stool, sensation of not having completely emptied their bowels 25% of the time, or 2 or fewer bowel movements per week.
Constipation is the most common gastrointestinal complaint in the United States. More than 4 million Americans have frequent constipation, accounting for 2.5 million physician visits a year. Those reporting constipation most often are women and adults ages 65 and older, but it can affect people of any age, including newborns. Pregnant women may have constipation, and it is a common problem following childbirth or surgery.
Self-treatment of constipation with over-the-counter (OTC) laxatives is by far the most common aid. Around $725 million is spent on laxative products each year in America.
Constipation is not defined by whether a person has a bowel movement every day. Normal stool elimination may be three times a day or three times a week, depending on the person.<ref name=olubuyide>Olubuyide IO, Olawuyi F, Fasanmade AA. Frequency of defaecation and stool consistency in Nigerian students. J Trop Med Hyg. 1995 Aug;98(4):228-32. Abstract</ref>
Constipation is a symptom, not a disease. Almost everyone experiences constipation at some point in their life, and a poor diet is a common cause. Most constipation is temporary and not serious. Understanding its causes, prevention, and treatment will help most people find relief.
The two types of constipation are idiopathic constipation and functional constipation. Irritable bowel syndrome (IBS) with predominant symptoms of constipation is categorized separately.
Idiopathic—of unknown origin—constipation does not respond to standard treatment.
Functional constipation means that the bowel is healthy but not working properly. Functional constipation is often the result of poor dietary habits and lifestyle. It occurs in both children and adults and is most common in women. Colonic inertia, delayed transit, and pelvic floor dysfunction are three types of functional constipation. Colonic inertia and delayed transit are caused by a decrease in muscle activity in the colon. These syndromes may affect the entire colon or may be confined to the lower, or sigmoid, colon.
Pelvic floor dysfunction is caused by a weakness of the muscles in the pelvis surrounding the anus and rectum. However, because this group of muscles is voluntarily controlled to some extent, biofeedback training is somewhat successful in retraining the muscles to function normally and improving the ability to have a bowel movement.
Functional constipation that stems from problems 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.
People with IBS having predominantly constipation also have pain and bloating as part of their symptoms.
Constipation is a symptom in itself, not a disease. It can involve hard, dry stools that are difficult to push out. Sometimes the stools are painful. People may have straining, bloating, or a feeling that not all the stool has come out.
Frequency of Bowel Movements
Constipation is not defined by whether a person has a bowel movement every day. One study reported that normal bowel movements varied from three times a day to three times a week in healthy students.<ref name=olubuyide/> Studies in rural traditional cultures, however, suggest that one or more bowel movements a day is normal.<ref>Lewis EA, Kale OO. Bowel habit in a Yoruba rural community: preliminary report. Afr J Med Med Sci. 1978 Sep;7(3):157-61. Abstract </ref><ref>Ekwueme O. Bowel habits in Ugandan villagers. Trop Geogr Med. 1978 Jun;30(2):247-51. Abstract</ref>
To understand constipation, it helps to know how the colon, or large intestine, works. As food moves through the colon, the colon absorbs water from the food while it forms waste products, or stool. Muscle contractions in the colon then push the stool toward the rectum. By the time stool reaches the rectum it is solid, because most of the water has been absorbed.
Constipation occurs when the colon absorbs too much water or if the colon's muscle contractions are slow or sluggish, causing the stool to move through the colon too slowly. As a result, stools can become hard and dry. Common causes of constipation are
- not enough fiber in the diet
- lack of physical activity (especially in the elderly)
- changes in life or routine such as pregnancy, aging, and travel
- abuse of laxatives
- ignoring the urge to have a bowel movement
- specific diseases or conditions, such as stroke (most common)
- irritable bowel syndrome
- problems with the colon and rectum
- problems with intestinal function (chronic idiopathic constipation)
- problems with the nerves supplying the pelvis
People who eat a high-fiber diet are less likely to become constipated. The most common causes of constipation are a diet low in fiber or a diet high in fats, such as cheese, eggs, and meats.
Fiber—both 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 through the intestines almost unchanged. The bulk and soft texture of fiber helps prevent hard, dry stools that are difficult to pass.
Americans eat an average of 5 to 14 grams of fiber daily, which is short of the 20 to 35 grams recommended by the American Dietetic Association.<ref>National Center for Health Statistics. Dietary Intake of Macronutrients, Micronutrients, and Other Dietary Constituents: United States, 198894. Vital and Health Statistics, Series 11, Number 245. July 2002.</ref> Both children and adults often eat too many refined and processed foods from which the natural fiber has been removed.
A low-fiber diet also plays a key role in constipation among older adults, who may lose interest in eating and choose foods that are quick to make or buy, such as fast foods, or prepared foods, both of which are usually low in fiber. Also, difficulties with chewing or swallowing may cause older people to eat soft foods that are processed and low in fiber.
A study of Japanese women and their diets found that those who ate a traditional diet, high in rice, miso soup, and soy products, and low in bread and confectionaries, had a significantly lower chance of having constipation.<ref>Okubo H, Sasaki S, Murakami K, et al. Freshmen in Dietetic Courses Study II Group. Dietary patterns associated with functional constipation among Japanese women aged 18 to 20 years: a cross-sectional study. J Nutr Sci Vitaminol (Tokyo). 2007 Jun;53(3):232-8. Abstract</ref>
Research shows that although increased fluid intake does not necessarily help relieve constipation, many people report some relief from their constipation if they drink fluids such as water and juice and avoid dehydration. Liquids add fluid to the colon and bulk to stools, making bowel movements softer and easier to pass. People who have problems with constipation should try to drink liquids every day. However, liquids that contain caffeine, such as coffee and cola drinks, will worsen symptoms by leading to dehydration. Alcohol is another beverage that causes dehydration. It is important to drink fluids that hydrate the body, especially when consuming caffeine-containing drinks or alcoholic beverages.
A lack of physical activity 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. Lack of physical activity is thought to be one of the reasons constipation is common in older people.
Some medications can cause constipation, including
- pain medications (especially narcotics, such as Vicodin and Percocet)
- antacids that contain aluminum and calcium
- Blood Pressure medications (calcium channel blockers and beta-blockers)
- antiparkinson drugs
- muscle relaxants
- iron supplements
If a patient must take these medications, constipation may be anticipated and prevented through increased fiber intake or other measures.<ref>National Digestive Diseases Clearinghouse. Constipation. Available here.</ref><ref name=natmed>Murray and Pizzorno. "Intestinal dysbiosis and dysfunction." Textbook of Natural Medicine, 2nd edition. 1999. p. 490-1.</ref>
Changes in life or routine
During pregnancy, women may be constipated because of hormonal changes or because the 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 routine are disrupted and because they may become dehydrated.
Abuse of laxatives
Because many people mistakenly believe they should be having daily bowel movements, they often inappropriately take over-the-counter laxatives. Although people may feel relief when they use laxatives, they often have to increase the dose over time because the body starts to rely on laxatives in order to have a bowel movement. As a result, laxatives may become habit-forming.
Ignoring the urge to go
People who ignore the urge to have a bowel movement may eventually stop feeling the need to have one, 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 stop playing.
Specific diseases and conditions: non-gastrointestinal
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.
- Neurological disorders
- Metabolic and endocrine conditions
- Systemic disorders
Specific diseases and conditions: gastrointestinal
Intestinal obstruction, scar tissue (adhesions), diverticulosis, tumors, colorectal stricture, Hirschsprung's disease, or cancer can compress, squeeze, or narrow the intestine and rectum and cause constipation.
Problems with intestinal function
Functional constipation: Functional means that the bowel is healthy but still not working properly. Functional constipation is often the result of poor dietary habits and lifestyle. It occurs in both children and adults and is most common in women. Colonic inertia, delayed transit, and pelvic floor dysfunction are three types of functional constipation.
- Colonic inertia and delayed transit are caused by a decrease in muscle activity in the colon. These syndromes may affect the entire colon or may be confined to the lower, or sigmoid, colon.
- Pelvic floor dysfunction is caused by a weakness of the muscles in the pelvis surrounding the anus and rectum. However, because this group of muscles is voluntarily controlled to some degree, biofeedback training is somewhat successful in retraining the muscles to function normally and improving the ability to have a bowel movement.
- Functional constipation that stems from problems 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.
People with irritable bowel syndrome, or IBS, may experience a great deal of constipation.
It is important to figure out what exactly is causing the symptom of constipation, so treatment can be aimed at that cause (or causes). The tests the doctor performs depend on how long the constipation has lasted and how bad it has been, the person's age, and whether blood in stools, changes in bowel habits, or weight loss have occurred. Most people with constipation do not need much testing and can be treated with changes in diet and exercise. For example, in young people with mild symptoms, a medical history and physical exam may be all that is needed for diagnosis and treatment.
Exams and tests
Extensive testing usually is done only for people with severe symptoms, for those with sudden changes in the number and consistency of bowel movements or blood in the stool, and older adults.
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. A record of eating habits, medication, and level of physical activity will also help the doctor determine the cause of constipation.
The doctor may press on the belly. He or she may also need to do a rectal exam with a gloved, lubricated finger to evaluate the muscle that closes off the anus—the anal sphincter—and to detect tenderness, obstruction, or blood.
Colorectal transit study
The colorectal transit study shows how well food moves through the colon. The patient swallows capsules containing small markers that are visible on an x ray. The movement of the markers through the colon is monitored by abdominal x rays taken several times 3 to 7 days after the capsule is swallowed. The patient eats a high-fiber diet during the course of this test.
Anorectal function tests
Anorectal function tests diagnose constipation caused by abnormal functioning of the anus or rectum.
- Anorectal manometry evaluates how well the anal sphincter muscle is functioning. For this test, a catheter or air-filled balloon is inserted into the anus and slowly pulled back through the sphincter muscle to measure muscle tone and contractions.
- Balloon expulsion testing involve inserting a balloon into the rectum, then filling it with varying amounts of water. Then the patient is asked to expel the balloon. The inability to expel a balloon filled with less than 150 mL of water may indicate a decrease in bowel function.
Defecography is an x-ray of the anorectal area that evaluates how completely stool is expelled, identifies any anorectal abnormalities, and evaluates rectal muscle contraction 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, then relaxes and squeezes the anus to expel the paste. The doctor studies the x rays for anorectal problems that occurred as the paste was expelled.
Because of an increased risk of colorectal cancer in older adults, the doctor may want to rule out a diagnosis of cancer, and may obtain:
Barium enema x-ray
The barium enema x-ray is an x-ray of the rectum, colon, and lower part of the small intestine. This part of the digestive tract is known as the bowel. This test may show intestinal obstruction and Hirschsprung's disease, which is an inborn lack of nerves within the colon that is usually diagnosed in newborns.
- The night before the test, bowel cleansing, also called bowel prep, is necessary to clear the lower digestive tract. The patient drinks a special liquid to flush 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 incomplete exam.
- Because the colon does not show up well on x-rays, the doctor fills it with barium, a chalky liquid that makes the area visible. Once the mixture coats the inside of the colon and rectum, x-rays are taken that show 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 white in color for a few days after the exam.
Sigmoidoscopy and colonoscopy
Sigmoidoscopy is an examination of the rectum and the lower, or sigmoid, colon. Colonoscopy is an examination of the rectum and entire colon, including the sigmoid and upper colon. These tests are done with slender, flexible cameras inserted into the rectum.
- The person usually has a liquid dinner the night before a colonoscopy or sigmoidoscopy and takes an enema early the next morning. An 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. The patient is lightly sedated before the exam so as not be uncomfortable or afraid. 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 abdominal pressure and a mild sensation of wanting to move the bowels. The doctor may fill the colon with air to get a better view. The air can 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. During the exam, the patient lies on his or her side, and is sedated. 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.
Because constipation can be a symptom of a wide variety of problems, treatment depends on identifying the cause, as well as determining how severe and long-lasting it has been. In most cases, dietary and lifestyle changes will help relieve constipation and help prevent it from recurring.
Holistic and alternative treatments
People with constipation often benefit from a holistic treatment approach involving many of the approaches mentioned in the Therapies section.
Natural ways of increasing dietary fiber include taking bran cereal, and increasing from a half a cup to 1.5 cups over several weeks. Whole prunes and prune juice (8 oz) are also effective laxatives. It's important to also increase other sources of fiber and water intake.
Fiber supplements can come from natural plant sources such as psyllium, kelp, and pectin.<ref name=natmed/>
Most people who are mildly constipated do not need laxatives, and can get better by increasing the amount of fiber in their diets. However, for those who have made diet and lifestyle changes and are still constipated, a doctor 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, helps prevent chronic constipation.
Laxatives taken by mouth are available in liquid, tablet, gum powder, and granule forms. They work in various ways:
- Bulk-forming laxatives: These are also known as fiber supplements, and are always taken with water. They work by absorbing water in the intestine and making the stool softer. Brand names include Metamucil, Fiberall, Citrucel, Konsyl, and Serutan. They must be taken with water or they can make constipation worse. These laxatives generally are considered the safest kind, but they can interfere with absorption of some medicines. Many people also report no relief after taking bulking agents and suffer from a worsening in bloating and abdominal pain.
- Stool softeners: These moisten the stool. Brand names include Colace and Surfak. These products are suggested for people who need to avoid straining in order to pass a bowel movement, so they are often recommended after childbirth or surgery. Using this type of medication for too long can cause electrolyte imbalances, or abnormal levels of important substances in the blood.
- Stimulants: These cause the intestine to contract and squeeze stool along. Brand names include Correctol, Dulcolax, Purge, and Senokot. Phenolphthalein, an ingredient in some stimulant laxatives, might increase a person's risk for cancer, and 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.
- Osmotics: These cause fluids to flow toward the stool, which makes stool size grow and stimulates the bowel to squeeze. This class of drugs is useful for people with idiopathic constipation. Drugs include milk of magnesia, Cephulac, Sorbitol, and Miralax. People with diabetes who take osmotic laxatives should be checked for electrolyte imbalances by getting blood tests.
- Lubricants: These grease the stool, enabling it to move through the intestine more easily. Mineral oil is the most common example. Brand names include Fleet and Zymenol. Lubricants typically stimulate a bowel movement within 8 hours.
- Saline laxatives: These act like a sponge to draw water into the colon for easier passage of stool. Brand names include Milk of Magnesia and Haley's M-O. Saline laxatives are used to treat acute constipation if there is no indication of bowel obstruction. Electrolyte imbalances have been reported with extended use, especially in small children and people with renal deficiency.
- Chloride channel activators: These increase intestinal fluid and movement to help stool pass, reducing the symptoms of constipation. One such agent is Amitiza, which has been shown to be safely used for up to 6 to 12 months. After that, a doctor should decide whether continued use is necessary.
People who are dependent on laxatives need to stop using them gradually. A doctor can assist in this process.
A diet with enough fiber (20 to 35 grams each day) helps the body 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.
Other changes that may help treat and prevent constipation include drinking enough water and other liquids, such as fruit and vegetable juices and clear soups, so as not to become dehydrated; exercising every day; and setting aside enough time to have a bowel movement. People should get into the habit of using the bathroom as soon as they feel the urge to have a bowel movement, rather than ignoring the urge to go.
Some causes of constipation require other specific treatments. For example, if constipation is caused by rectal prolapse, a condition in which the lower portion of the colon turns inside out, the doctor may recommend stopping certain medications or performing surgical repair.
People with chronic constipation caused by anorectal dysfunction can use biofeedback to retrain the muscles that control bowel movements. Biofeedback involves using a sensor to monitor muscle activity, which is 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 retrain 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.
Sometimes constipation can lead to complications. Examples 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, appearing as bright red streaks on the surface of the stool. Treatment for hemorrhoids may include warm tub baths, ice packs, and application of a special cream to the affected area. Treatment for anal fissures may include stretching the sphincter muscle or surgically removing the tissue or skin in the affected area.
Sometimes straining causes a small amount of intestinal lining to push inside-out from the anal opening. This condition, known as rectal prolapse, 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 by an enema. After softening the impaction, the doctor may break up and remove part of the hardened stool by inserting one or two fingers into the anus.
The Division of Digestive Diseases and Nutrition at the National Institute of Diabetes and Digestive and Kidney Diseases supports research into gastrointestinal conditions, including constipation. Researchers are studying the anatomical and physiological characteristics of rectoanal motility and the use of new medications and behavioral techniques, such as biofeedback, to treat constipation.
Points to Remember
- Constipation affects almost everyone at one time or another.
- The most common causes of constipation are poor diet and lack of exercise.
- Other causes of constipation include medications, irritable bowel syndrome, abuse of laxatives, and specific diseases.
- A medical history and physical exam may be the only diagnostic tests needed before the doctor suggests treatment.
- In most cases, following these simple tips will help relieve symptoms and prevent recurrence of constipation:
- Eat a well-balanced, high-fiber diet that includes beans, bran, whole grains, fresh fruits, and vegetables.
- Drink plenty of liquids.
- Exercise regularly.
- Set aside time after breakfast or dinner for undisturbed visits to the toilet.
- Do not ignore the urge to have a bowel movement.
- Understand that normal bowel habits vary.
- A significant or prolonged change in bowel habits can be a warning sign of more serious underlying disease.
- Most people with mild constipation do not need laxatives. However, a doctor may recommend laxatives for a limited time for people with chronic constipation.
- American Gastroenterological Association: Patient Center: Constipation
- IFFGD: Common Questions About Constipation; Myths and Misconceptions
- IFFGD: Characteristics of Chronic Constipation
- WebMD: Constipation
Constipation in children
- IFFGD: Functional Constipation in Children
- American Academy of Pediatrics: Constipation in Children
- Mayo Clinic: Constipation in children