Bowel Movement Disorders
Bowel (intestinal) function varies greatly not only from one person to another but also for any one person at different times. It can be affected by diet, stress, drugs, disease, and even social and cultural patterns. In most Western societies, the normal number of bowel movements ranges from two or three a week to as many as two or three a day. Changes in the frequency, consistency, or volume of bowel movements or the presence of blood, mucus, pus, or excess fatty material (oil, grease) in the stool may indicate a disease.
Constipation is a condition in which a person has uncomfortable or infrequent bowel movements. A person with constipation produces hard stools that may be difficult to pass. The person also may feel as though the rectum has not been completely emptied. Acute constipation begins suddenly and noticeably. Chronic constipation, on the other hand, may begin insidiously and persist for months or years.
Often the cause of acute constipation is nothing more than a recent change in diet or a decrease in physical activity, for example, when a person stays in bed for a day or two during an illness. Many drugs-for example, aluminum hydroxide (common in over-the-counter antacids), bismuth salts, iron salts, anticholinergics, antihypertensives, narcotics, and many tranquilizers and sedatives-can cause constipation. Acute constipation occasionally may be caused by serious problems such as an obstruction of the large intestine, poor blood supply to the large intestine, and nerve or spinal cord injury.
Too little physical activity and too little fiber in the diet are common causes of chronic constipation. Other causes include an underactive thyroid gland (hypothyroidism), high blood calcium levels (hypercalcemia), and Parkinson’s disease. A decrease in the contractions in the large intestine (inactive colon) and discomfort during defecation also lead to chronic constipation. Psychological factors are common causes of acute and chronic constipation.
When a disease is causing constipation, the disease must be treated. Otherwise, constipation is best prevented and treated with a combination of adequate exercise, a high-fiber diet, and the occasional use of appropriate medications.
Vegetables, fruits, and bran are excellent sources of fiber. Many people find it convenient to sprinkle 2 or 3 teaspoons of unrefined miller’s bran or high-fiber cereal on fruit two or three times a day. To work well, fiber must be consumed with plenty of fluids.
Recovery is proposed to improve quality of life in conditions associated with pain, inflammation, spasm, fatigue and tissue damage such as: aging, arthritis (osteo and rheumatoid), autoimmune disease, bursitis, diabetes, eczema, fasciitis, fibromyalgia, muscle spasm, osteoporosis, psoriasis, surgery recovery, tendonitis and wound healing.
In addition to its proposed benefits for conditions with chronic pain and inflammation, Recovery is very safe and is safe to combine with other drugs.
Many people use laxatives to relieve constipation. Some are safe for long-term use; others should be used only occasionally. Some are good for preventing constipation; others can be used to treat it.
Bulking agents (bran, psyllium, calcium polycarbophil, and methylcellulose) add bulk to the stool. The increased bulk stimulates the natural contractions of the intestine, and bulkier stools are softer and easier to pass. Bulking agents act slowly and gently and are among the safest ways to promote regular bowel movements. These agents generally are taken in small amounts at first. The dose is increased gradually until regularity is achieved. People who use bulking agents should always drink plenty of fluids.
Stool softeners, such as docusate, increase the amount of water that the stool can hold. Actually, these laxatives are detergents that decrease the surface tension of the stool, allowing water to penetrate the stool more easily and soften it. The increased bulk stimulates the natural contractions of the large intestine and helps the softened stools to move more easily out of the body.
Mineral oil softens the stool and facilitates its passage out of the body. However, mineral oil may decrease the absorption of certain fat-soluble vitamins. Also, if a person-for instance, someone who is debilitated-accidently inhales (aspirates) mineral oil, serious lung irritation can develop. Plus, mineral oil seeps from the rectum.
Osmotic agents pull large amounts of water into the large intestine, making the stool soft and loose. The excess fluid also stretches the walls of the large intestine, stimulating contractions. These laxatives consist of either salts-usually phosphate, magnesium, or sulfate-or sugars that are poorly absorbed-for example, lactulose and sorbitol. Some osmotic agents contain sodium. They may cause fluid retention in people with kidney disease or heart failure, especially when given in large or frequent doses. Osmotic agents containing magnesium and phosphate are partially absorbed into the bloodstream and can be harmful in people with kidney failure. These laxatives, which generally work within 3 hours, are better for treating constipation than for preventing it. They’re also used to clear stool from the intestine before x-rays of the digestive (gastrointestinal) tract are taken and before colonoscopy (an examination of the large intestine using a flexible viewing tube) (see page 485 in Chapter 100, Diagnostic Tests for Digestive Disorders) is performed.
Stimulant laxatives directly stimulate the walls of the large intestine, causing it to contract and move the stool. These laxatives contain irritating substances such as senna, cascara, phenolphthalein, bisacodyl, or castor oil. They generally cause a semisolid bowel movement in 6 to 8 hours but often cause cramping as well. In suppositories, these laxatives often work in 15 to 60 minutes. Prolonged use of stimulant laxatives can damage the large intestine. Also, people can become addicted to stimulant laxatives, developing lazy bowel syndrome, which creates a dependency on the laxatives. Stimulant laxatives are often used to empty the large intestine before diagnostic procedures and to prevent or treat constipation caused by drugs that slow the contractions of the large intestine, such as narcotics.
Many people believe they have constipation if they don’t have a bowel movement every day. Other people think they have constipation if the appearance or consistency of their stool seems abnormal to them. However, daily bowel movements aren’t necessarily normal, and less frequent bowel movements don’t necessarily indicate a problem unless they represent a substantial change from previous patterns. The same is true of the color and consistency of stool; unless there’s a substantial change in them, the person probably doesn’t have constipation.
Such misconceptions about constipation can lead to overzealous treatment, especially the long-term use of stimulant laxatives, irritant suppositories, and enemas. Such treatment can severely damage the large intestine or induce lazy bowel syndrome and melanosis coli (abnormal changes in the lining of the large intestine caused by deposits of a pigment).
Before making a diagnosis of psychogenic constipation, a doctor first ensures that an underlying physical problem isn’t causing irregular bowel movements. Diagnostic tests, such as a sigmoidoscopy (an examination of the sigmoid colon using a flexible viewing tube) or a barium enema, may be needed. If there’s no underlying physical problem, the person needs to accept the existing pattern of bowel movements and not insist on a more regular pattern.
Colonic inertia (inactive colon) is a decrease in contractions in the large intestine or an insensitivity of the rectum to the presence of stool, resulting in chronic constipation.
Colonic inertia often occurs in people who are elderly, debilitated, or bedridden, but it also occurs in otherwise healthy younger women. The large intestine stops responding to the stimuli that usually cause bowel movements: eating, a full stomach, a full large intestine, and stool in the rectum. Drugs used to treat medical conditions frequently cause or worsen the problem, especially narcotics (such as codeine) and drugs with anticholinergic properties (such as amitriptyline for depression or propantheline for diarrhea). Colonic inertia sometimes occurs in people who habitually delay defecation or who have used laxatives or enemas for a long time.
Constipation is a long-term, day-to-day problem; the person may or may not have abdominal discomfort. Often a doctor finds the rectum filled with soft stool, even though the person has no urge to defecate and can do so only with difficulty.
People with this condition may develop fecal impaction, in which the stool in the last part of the large intestine and rectum hardens and blocks the passage of other stool. This blockage leads to cramps, rectal pain, and strong but futile efforts to defecate. Often, watery mucus material oozes around the blockage, sometimes giving the false impression of diarrhea.
For colonic inertia, doctors sometimes recommend suppositories or enemas with 2 to 3 ounces of water, water and salts (saline enemas), or oils such as olive oil. For fecal impaction, laxatives-usually osmotic agents-are needed as well. Sometimes a doctor or nurse must remove hard impacted stool with a gloved finger or probe.
People who have colonic inertia should try to defecate daily, preferably 15 to 45 minutes after a meal because eating stimulates a bowel movement. Exercise often helps.
Dyschezia is difficulty in defecating caused by an inability to control the pelvic and anal muscles.
Having a normal bowel movement requires relaxation of the muscles in the pelvis and the circular muscles (sphincters) that keep the anus closed. Otherwise, efforts to defecate are futile, even with severe straining. People with dyschezia sense the need to have a bowel movement, but they can’t have one. Even stool that isn’t hard may be difficult to pass.
Conditions that can interfere with muscle movement include pelvic floor dyssynergia (a disturbance of muscle coordination), anismus (a condition in which the muscles fail to relax or paradoxically contract during defecation), a rectocele (hernia of the rectum into the vagina), enterocele (hernia of the small intestine into the rectum), rectal ulcer, and rectal prolapse.
Treatment with laxatives is generally unsatisfactory. Currently, relaxation exercises and biofeedback are being tested for pelvic floor dyssynergia and show much promise. Surgery may be needed to repair an enterocele or a large rectocele. Constipation can become so severe that stool must be removed by a doctor or nurse using a gloved finger or probe.
Foods and Drugs That Can Cause Diarrhea
|Food and Drugs||Ingredient Causing Diarrhea|
|Apple juice, pear juice, sugar-free gums, mints||Hexitols, sorbitol, mannitol|
|Apple juice, pear juice, grapes, honey, dates, nuts, figs, soft drinks (especially fruit flavors)||Fructose|
|Milk, ice cream, frozen yogurt, yogurt, soft cheese, chocolate||Lactose|
|Antacids containing magnesium||Magnesium|
|Coffee, tea, cola drinks, over-the-counter headache remedies||Caffeine|
Diarrhea is an increase in the volume, wateriness, or frequency of bowel movements.
A person with diarrhea caused by a significant medical problem usually has excessive volumes of stool, typically more than a pound of stool a day. People who eat large amounts of vegetable fiber normally may produce more than a pound, but it’s well formed and not watery. Normally, stool is 60 to 90 percent water; diarrhea mainly results when the percentage exceeds 90.
Osmotic diarrhea occurs when certain substances that can’t be absorbed into the bloodstream remain in the intestine. These substances cause excessive amounts of water to remain in the stool, leading to diarrhea. Certain foods (such as some fruits and beans) and hexitols, sorbitol, and mannitol (used as sugar substitutes in dietetic foods, candy, and chewing gum) can cause osmotic diarrhea. Also, lactase deficiency can lead to osmotic diarrhea. Lactase is an enzyme normally found in the small intestine that converts milk sugar (lactose) to glucose and galactose, so that it can be absorbed into the bloodstream. When people with a lactase deficiency drink milk or eat dairy products, lactose isn’t converted. As it accumulates in the intestine, it causes osmotic diarrhea. The severity of osmotic diarrhea depends on how much of the osmotic substance is consumed. Diarrhea stops soon after the person stops eating or drinking the substance.
Secretory diarrhea occurs when the small and large intestines secrete salts (especially sodium chloride) and water into the stool. Certain toxins-such as the toxin produced in a cholera infection and those produced in other infectious diarrheas-can cause these secretions. The diarrhea can be massive-more than a quart an hour in cholera. Other substances that cause salt and water secretion include certain laxatives, such as castor oil, and bile acids (which may build up after surgery to remove part of the small intestine). Certain rare tumors-such as carcinoid, gastrinoma, and vipoma-also can cause secretory diarrhea.
Malabsorption syndromes can also lead to diarrhea. People with these syndromes can’t digest foods normally. In generalized malabsorption, fats left in the large intestine because of malabsorption can cause secretory diarrhea, and carbohydrates may cause osmotic diarrhea. Malabsorption may be caused by such conditions as nontropical sprue, pancreatic insufficiency, surgical removal of part of the intestine, inadequate blood supply to the large intestine, a lack of certain enzymes in the small intestine, and liver disease.
Exudative diarrhea occurs when the lining of the large intestine becomes inflamed, ulcerated, or engorged, and it releases proteins, blood, mucus, and other fluids, which increase the bulk and fluid content of the stool. This type of diarrhea can be caused by many diseases, including ulcerative colitis, Crohn’s disease (regional enteritis), tuberculosis, lymphoma, and cancer. When the lining of the rectum is affected, the person often feels an urgent need to defecate and has frequent bowel movements because the inflamed rectum is more sensitive to distention by stools.
Altered intestinal transit can cause diarrhea. For stool to have normal consistency, it must remain in the large intestine for a certain amount of time. Stool that leaves the large intestine too quickly is watery; stool that stays too long is hard and dry. Many conditions and treatments can decrease the amount of time that stool stays in the large intestine, including an overactive thyroid (hyperthyroidism); surgical removal of part of the small intestine, large intestine, or stomach; treatment for ulcers in which the vagus nerve is cut; surgical bypass of part of the intestine; and drugs such as antacids and laxatives containing magnesium, prostaglandins, serotonin, and even caffeine.
Bacterial overgrowth (the growth of normal intestinal bacteria in abnormally large numbers or the growth of bacteria normally not found in the intestines) can lead to diarrhea. Normal intestinal bacteria play an important role in digestion. Thus, any disruption of the intestinal bacteria can cause diarrhea.
Aside from discomfort, embarrassment, and the disruption of daily activities, severe diarrhea can lead to a loss of water (dehydration) and electrolytes such as sodium, potassium, magnesium, and chloride. If large amounts of fluid and electrolytes are lost, blood pressure can drop enough to cause fainting (syncope), heart rhythm abnormalities (arrhythmias), and other serious disorders. At particular risk are the very young, the elderly, the debilitated, and people with very severe diarrhea. Bicarbonate may be lost in the stool as well, leading to metabolic acidosis, a type of acid-base imbalance in the blood.
A doctor first tries to establish whether the diarrhea appeared suddenly and for a short time or whether it’s persistent. A doctor tries to determine whether changes in diet may be the cause; whether the person has other symptoms, such as a fever, pain, and rash; and whether the person has been exposed to others who have a similar condition. Based on the person’s description and an examination of stool samples, the doctor and laboratory personnel determine if the stool is formed or watery, if it has an unusual odor, and if it contains fat, blood, or undigested materials. The volume of stool over a 24-hour period is also determined.
When diarrhea persists, often a sample of the stool must be examined microscopically for cells, mucus, fat, and other substances. The stool also can be tested for blood and substances that might produce osmotic diarrhea. Samples can be tested for infectious organisms, including certain bacteria, amebas, and Giardia organisms. If the person is surreptitiously taking a laxative, it also can be identified in the stool sample. A sigmoidoscopy (an examination of the sigmoid colon using a fiber-optic viewing tube) may be performed, so that a doctor can examine the lining of the anus and rectum. Sometimes a biopsy (removal of a specimen of the rectal lining for microscopic examination) is performed.
Diarrhea is a symptom, and its treatment depends on the cause. Most people with diarrhea only have to remove the cause, such as dietetic chewing gum or a certain drug, to suppress the diarrhea until the body heals itself. Sometimes chronic diarrhea is cured when the person stops drinking coffee or cola drinks containing caffeine. To help alleviate diarrhea, a doctor may prescribe a drug such as diphenoxylate, codeine, paregoric (tincture of opium), or loperamide. Sometimes even a bulking agent used for chronic constipation, such as psyllium or methylcellulose, helps relieve diarrhea. Kaolin, pectin, and activated attapulgite can help firm up the stool.
When severe diarrhea causes dehydration, hospitalization and fluid replacement with intravenous water and salts may be necessary. As long as the person isn’t vomiting and doesn’t feel nauseated, drinking liquids containing a balance of water, sugars, and salts can be very effective.
Fecal incontinence is the loss of control over bowel movements.
Fecal incontinence can occur briefly during bouts of diarrhea or when hard stool becomes lodged in the rectum (fecal impaction). People with injuries to the anus or spinal cord, rectal prolapse (protrusion of the rectal lining through the anus), dementia, neurologic injury from diabetes, tumors of the anus, or injuries to the pelvis during childbirth can develop persistent fecal incontinence.
A doctor examines the person for any structural or neurologic abnormality that may be causing fecal incontinence. This involves examining the anus and rectum, checking the extent of sensation around the anus, and usually performing a sigmoidoscopy (an examination of the sigmoid colon using a flexible viewing tube). Other tests, including an examination of the function of nerves and muscles lining the pelvis, may be needed.
The first step in correcting fecal incontinence is to try to establish a regular pattern of bowel movements that produce well-formed stool. Dietary changes, including the addition of a small amount of fiber, often help. If such changes don’t help, a drug that slows bowel movements, such as loperamide, may succeed.
Exercising the anal muscles (sphincters) increases their tone and strength and helps prevent fecal incontinence from recurring. Using biofeedback, a person can retrain the sphincters and increase the sensitivity of the rectum to the presence of stools. About 70 percent of well-motivated people benefit from biofeedback.
If fecal incontinence persists, surgery may help in a small number of cases-for instance, when the cause is an injury to the anus or an anatomic defect in the anus. As a last resort, a colostomy (the surgical creation of an opening between the large intestine and the abdominal wall) may be performed. The anus is sewn shut, and the person defecates into a removable plastic bag attached to the opening in the abdominal wall.
Irritable Bowel Syndrome
Irritable bowel syndrome is a disorder of motility of the entire gastrointestinal tract that produces abdominal pain, constipation, or diarrhea.
Irritable bowel syndrome affects women three times more often than men. In this syndrome, the gastrointestinal tract is especially sensitive to many stimuli. Stress, diet, drugs, hormones, or minor irritants may cause the gastrointestinal tract to contract abnormally.
Periods of stress and emotional conflict that cause depression or anxiety frequently exacerbate episodes of irritable bowel syndrome. Some people with the syndrome appear to be much more aware of their symptoms, evaluate them more seriously, and experience greater disability than others. Other people with irritable bowel syndrome who experience similar stress and emotional conflicts either develop less severe gastrointestinal symptoms or react to them with less concern and disability.
During an episode, the contractions of the gastrointestinal tract become stronger and more frequent, and the resulting rapid transit of food and feces through the small intestine often leads to diarrhea. Crampy pain seems to result from the strong contractions of the large intestine and increased sensitivity of the pain receptors in the large intestine. Episodes 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’s not clear that these foods are actually the cause.
There are two major types of irritable bowel syndrome. The spastic colon type, which is commonly triggered by eating, usually produces periodic constipation or diarrhea with pain. 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.
The second type mainly produces painless diarrhea or relatively painless constipation. The diarrhea may begin very suddenly and with extreme urgency. Typically, the diarrhea follows soon after a meal, although it can sometimes occur immediately upon awakening. Sometimes the urgency is so strong that the person loses control and can’t reach a bathroom in time. Diarrhea during the night is rare. Some people have bloating and constipation with relatively little pain.
Most people with irritable bowel syndrome appear to be healthy. A physical examination generally doesn’t reveal anything unusual except 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 inflammatory bowel disease (see page 527 in Chapter 108, Inflammatory Bowel Diseases) and the many other conditions that can cause abdominal pain and changes in bowel habits. These test results are usually normal, although the stool may be watery. A sigmoidoscopy (an examination of the sigmoid colon using a flexible viewing tube) may cause spasms and pain, but the test results are otherwise normal. Sometimes other tests-such as abdominal ultrasound, x-rays of the intestines, or a colonoscopy (an examination of the large intestine using a flexible viewing tube)-are used.
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 gastrointestinal tract functioning normally.
In general, a normal diet is best. People with abdominal 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, shouldn’t 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 shouldn’t eat dairy products.
Some people with irritable bowel syndrome can improve their condition by eating more fiber, especially if the main problem is constipation. They may 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. Increasing the dietary fiber may aggravate some symptoms, such as flatulence and bloating.
Drugs that slow the function of the gastrointestinal tract and are considered to be antispasmodics, such as propantheline, haven’t been proved effective, although they’re frequently prescribed. Antidiarrheal drugs, such as diphenoxylate and loperamide, help people with diarrhea. Antidepressant drugs, mild tranquilizers, psychotherapy, hypnosis, and behavior modification techniques may help some people with irritable bowel syndrome.
Flatulence is a feeling of an increased amount of gas in the gastrointestinal tract. Air is a gas that can be swallowed with food. Swallowing small amounts of air is normal, but some people unconsciously swallow large amounts, especially when they feel anxious. Most swallowed air is later belched up, so only some passes from the stomach into the rest of the gastrointestinal system. Swallowing large amounts of air may make a person feel full, and the person may belch excessively or pass the air through the anus.
Other gases are produced in the gastrointestinal system by several means. Hydrogen, methane, and carbon dioxide are produced by bacterial metabolism of food in the intestine, especially after a person eats certain foods such as beans and cabbage. People who have deficiencies of the enzymes that break down certain sugars also tend to produce large amounts of gas when they eat foods containing the sugars. Lactase deficiency, tropical sprue, and pancreatic insufficiency all may lead to the production of large amounts of gas.
The body eliminates gas through belching, absorbing gas through the walls of the gastrointestinal tract into the blood and then excreting it through the lungs, and passing gas through the anus. Bacteria in the gastrointestinal system also metabolize some gases.
Flatulence is commonly thought to cause abdominal pain, bloating, belching, and excessive passing of gas through the anus; however, the exact relationship between flatulence and any of these symptoms isn’t really known. Some people appear to be particularly sensitive to the effects of gas in the gastrointestinal system; others can tolerate large amounts without developing any symptoms.
Flatulence can produce repeated belching. People normally pass gas through the anus more than 10 times a day, but flatulence may cause a person to pass gas more often. Infants with crampy abdominal pain sometimes pass excessive amounts of gas. Whether these children actually produce more gas than others or are simply more sensitive to it isn’t clear.
Bloating and belching are difficult to relieve. If belching is the main problem, reducing the amount of air being swallowed can help. However, this can be difficult because people generally aren’t aware of swallowing air. Avoiding chewing gum and eating more slowly in a relaxed atmosphere may help.
People who belch or pass gas excessively may need to change their diet by avoiding foods that are difficult to digest. Discovering which foods are causing the problem may require eliminating one food or one group of foods at a time. A person can start by eliminating milk and dairy products, then fresh fruits, and then certain vegetables and other foods. Belching may also result from drinking carbonated beverages or taking antacids such as baking soda.
Taking drugs sometimes helps people reduce their production of gas, although drugs generally aren’t very effective. Simethicone, present in some antacids and also available separately, can provide a little relief. Sometimes other drugs-including other types of antacids, metoclopramide, and bethanechol-may help. Eating more fiber helps some people but worsens the symptoms in others.