Diarrhea

Definition

To most individuals, diarrhea means an increased frequency or decreased consistency of bowel movements; however, the medical definition is more exact than this. Diarrhea best correlates with an increase in stool weight; this increase is mainly due to excess water, which normally makes up 60 to 85 percent of fecal matter. In this way, true diarrhea is distinguished from diseases that cause only an increase in the number of bowel movements (hyperdefecation) or incontinence (involuntary loss of bowel contents).

Diarrhea is also classified by physicians as acute, which lasts one to two weeks, and as chronic, which continues for longer than two or three weeks. Viral and bacterial infections are the most common causes of acute diarrhea.

Description

In many cases, acute infectious diarrhea is a mild, limited annoyance common to adults and children. Chronic diarrhea, though, can have considerable effect on health and on social and economic well-being. People with celiac disease , inflammatory bowel disease, and other prolonged diarrheal illnesses develop nutritional deficiencies that diminish growth and immunity. They affect social interaction and result in the loss of many working hours. Rapid diagnosis and proper treatment can prevent much of the suffering associated with these illnesses.

Demographics

Worldwide, acute infectious diarrhea has a huge impact, causing over 5 million deaths per year. While most deaths are among children under five years of age in developing nations, the impact, even in developed countries, is considerable. For example, over 250,000 individuals are admitted to hospitals in the United States each year because of one of these episodes.

Causes and symptoms

Diarrhea occurs because more fluid passes through the large intestine (colon) than that organ can absorb. As a rule, the colon can absorb several times more fluid than is required on a daily basis. However, when this reserve capacity is overwhelmed, diarrhea occurs.

Diarrhea is caused by infections or illnesses that either lead to excess production of fluids or prevent absorption of fluids. Also, certain substances in the colon, such as fats and bile acids, can interfere with water absorption and cause diarrhea. Rapid passage of material through the colon can also do the same.

Symptoms related to any diarrheal illness are often those associated with any injury to the gastrointestinal tract, such as fever , nausea , vomiting , and abdominal pain . All or none of these may be present depending on the disease causing the diarrhea. The number of bowel movements can vary—up to 20 or more per day. In some persons, blood or pus is present in the stool. Bowel movements may be difficult to flush (float) or contain undigested food material.

The most common causes of acute diarrhea are infections (the cause of traveler's diarrhea), food poisoning , and medications. Medications are a frequent and often over-looked cause, especially antibiotics and antacids. Less often, various sugar-free foods, which sometimes contain poorly absorbable materials, cause diarrhea.

Chronic diarrhea is frequently due to many of the same things that cause the shorter episodes (infections, medications, etc.); however, symptoms last longer. Some infections can become chronic. This occurs mainly with parasitic infections (such as Giardia ) or when people have altered immunity (such as AIDS ). In children, more common causes of chronic diarrhea are food allergy and lactose intolerance . Toddlers who drink too much juice can have frequent, loose stools.

When to call the doctor

A physician or other healthcare provider should be contacted when the number of bowel movements exceeds three per day for 2 days or more or when fecal material contains blood. A doctor should be called if a person becomes dehydrated. Signs of dehydration include decreased urination, lethargy, poor skin tone, and generalized weakness. In very young children, the parents should call a doctor if they observe these symptoms of dehydration:

• dry mouth or tongue
• few or no tears when crying
• no wet diapers for three hours or more
• sunken eyes, cheeks, and fontanel (soft spot on the head of infants)
• irritability and listlessness
• skin that flattens slowly when pinched

Parents should also call the doctor if a child is vomiting so often that he or she cannot keep fluids down, has a high fever, complains of severe abdominal pain, or shows no improvement in symptoms after 24 hours.

Diagnosis

Most cases of acute diarrhea never need diagnosis or treatment, as many are mild and produce few problems. But persons of any age with fever over 102°F (38.9°C), signs of dehydration, bloody bowel movements, severe abdominal pain, known immune disease, or prior use of antibiotics need prompt medical evaluation.

When diagnostic studies are needed, the most useful are stool culture and examination for parasites; however, these are often negative, and a cause cannot be found in a large number of people. The earlier cultures are performed, the greater the chance of obtaining a positive result. For those with a history of antibiotic use in the preceding two months, stool samples need to be examined for the toxins that cause antibiotic-associated colitis. Tests are also available to check stool samples for microscopic amounts of blood and for cells that indicate severe inflammation of the colon. Examination with an endoscope is sometimes helpful in determining severity and extent of inflammation. Tests to check changes in blood chemistry (potassium, magnesium, etc.) and a complete blood count (CBC) are also often performed.

Chronic diarrhea is quite different, and most persons with this condition receive some degree of testing. Many exams are the same as for an acute episode, as some infections and parasites cause both types of diarrhea. A careful history to evaluate medication use, dietary changes, family history of illnesses, and other symptoms is necessary. Key points in determining the seriousness of symptoms are weight loss of over 10 lbs (4.5 kg), blood in the stool, and nocturnal diarrhea (symptoms that awaken an individual from sleep ).

Both prescription and over-the-counter medications can contain additives, such as lactose and sorbitol, that will produce diarrhea in sensitive individuals. Review of allergies or skin changes may also point to a cause. Social history may indicate that stress is playing a role or may identify activities which can be associated with diarrhea (for example, diarrhea that occurs in runners).

A combination of stool, blood, and urine tests may be needed in the evaluation of chronic diarrhea; in addition, a number of endoscopic and x-ray studies are frequently required.

Treatment

Treatment is ideally directed toward correcting the cause; however, the first aim should be to prevent or treat dehydration and nutritional deficiencies. The type of fluid and nutrient replacement depends on whether oral feedings can be taken and on the severity of fluid losses. Oral rehydration solution (ORS) or intravenous fluids are the choices; ORS is preferred if possible.

A physician should be notified if a person is dehydrated. If oral replacement is suggested then commercial (Pedialyte and others) or homemade preparations can be used. The World Health Organization (WHO) has provided this easy recipe for home preparation, which can be taken in small frequent sips:

• table salt, 3/4 tsp
• baking powder, 1 tsp
• orange juice, 1 c
• water, 1 qt

When feasible, food intake should be continued even in those people with acute diarrhea. A physician should be consulted regarding what type and how much food is permitted.

Anti-motility agents (loperamide, diphenoxylate) are useful for those with chronic symptoms; their use is limited or even contraindicated in most individuals with acute diarrhea, especially in those with high fever or bloody bowel movements. They should not be taken without the advice of a physician, and should not be used in children.

Other treatments are available, depending on the cause of symptoms. For example, the bulk agent psyllium helps some people by absorbing excess fluid and solidifying stools; cholestyramine, which binds bile acids, is effective in treating bile-salt-induced diarrhea. Low fat diets or more easily digestible fat is useful in some people. Antidiarrheal drugs that decrease excessive secretion of fluid by the intestinal tract is another approach for some diseases. Avoidance of medications or other products that are known to cause diarrhea (such as lactose) is curative in some people but should be discussed with a physician.

Alternative treatment

It is especially important to find the cause of diarrhea, since stopping diarrhea when it is the body's way of eliminating something foreign is not helpful and can be harmful in the long run.

One effective alternative approach to preventing and treating diarrhea involves oral supplementation of aspects of the normal flora in the colon with the yeasts Lactobacillus acidophilus, L. bifidus, or Saccharomyces boulardii. In clinical settings, these "biotherapeutic" agents have repeatedly been helpful in the resolution of diarrhea, especially antibiotic-associated diarrhea.

Nutrient replacement also plays a role in preventing and treating episodes of diarrhea. Zinc especially appears to have an effect on the immune system, and deficiency of this mineral can lead to chronic diarrhea. Also, zinc replacement improves growth in young persons. To prevent dehydration, individuals suffering from diarrhea should take plenty of fluids, especially water. The BRAT diet also can be useful in helping to resolve diarrhea. This diet limits food intake to bananas, rice, applesauce, and toast. These foods provide soluble and insoluble fiber without irritation. If the toast is slightly burnt, the charcoal can help sequester toxins and pull them from the body.

Acute homeopathic remedies can be very effective for treating diarrhea especially in infants and young children.

Prognosis

Prognosis is related to the cause of the diarrhea; for most individuals in developed countries, a bout of acute, infectious diarrhea is at best uncomfortable. However, in both industrialized and developing areas, serious complications and death can occur.

For those with chronic symptoms, an extensive number of tests are usually necessary to make a proper diagnosis and begin treatment; a specific diagnosis is found in 90 percent of people. In some, however, no specific cause is found and only treatment with bulk agents or anti-motility agents is indicated.

Prevention

Proper hygiene and food handling techniques can prevent many cases. Traveler's diarrhea can be avoided by people using products containing bismuth, such as Pepto-Bismol and/or antibiotics. The most important action is to prevent the complications of dehydration.

Nutritional concerns

Replacement of fluids and electrolytes is important for people experiencing diarrhea. These individuals should take in foods that contain salt, potassium, phosphates, and sugar. Most sodas, sport drinks and non-cream soups are good sources of electrolytes.

Parental concerns

Parents should be sure that their children who experience diarrhea drink plenty of fluids and replace electrolytes with an oral rehydration solution. A doctor should be called if the parent suspects a child is becoming dehydrated. Severe dehydration requires intravenous fluid administration in a medical setting. Antidiarrheal medications should be be given only on the advise of a physician.

KEY TERMS

Antimotility drug —A medication, such as loperamide (Imodium), dephenoxylate (Lomotil), or medications containing codeine or narcotics that decrease the ability of the intestine to contract.

Colitis —Inflammation of the colon (large intestine).

Endoscope —A medical instrument that can be passed into an area of the body (the bladder or intestine, for example) to allow visual examination of that area. The endoscope usually has a fiberoptic camera that allows a greatly magnified image to be shown on a television screen viewed by the operator. Many endoscopes also allow the operator to retrieve a small sample (biopsy) of the area being examined, to more closely view the tissue under a microscope.

Endoscopy —Visual examination of an organ or body cavity using an endoscope, a thin, tubular instrument containing a camera and light source. Many endoscopes also allow the retrieval of a small sample (biopsy) of the area being examined, in order to more closely view the tissue under a microscope.

Lactose intolerance —An inability to properly digest the lactose found in milk and dairy products.

Oral rehydration solution (ORS) —A liquid preparation of electrolytes and glucose developed by the World Health Organization that can decrease fluid loss in persons with diarrhea. Originally developed to be prepared with materials available in the home, commercial preparations have recently come into use.

Steatorrhea —An excessive amount of fat in the feces due to poor fat absorption in the gastrointestinal tract.

Resources

BOOKS

Ahlquist, David A., and Michael Camilleri. "Diarrhea and Constipation." In Harrison's Principles of Internal Medicine, 15th ed. Edited by Eugene Braunwald et al. New York: McGraw-Hill, 2001, pp. 241–9.

Ghishan, Fayez K. "Chronic Diarrhea." In Nelson Textbook of Pediatrics, 17th ed. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2003, pp. 1276–80.

Greenbaum, Larry A. "Acute Diarrhea and Oral Rehydration." In Nelson Textbook of Pediatrics, 17th ed. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2003, pp. 249–50.

——. "Diarrhea in Chronically Malnourished Children." In Nelson Textbook of Pediatrics, 17th ed. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2003, pp. 2250–1.

Sack, R. Bradley. "The Diarrhea of Travelers." In Cecil Textbook of Medicine, 22nd ed. Edited by Lee Goldman et al. Philadelphia: Saunders, 2003, pp. 1864–5.

Semrad, Carol E. and Don W. Powell. "Approach to the Patient with Diarrhea and Malabsorption." In Cecil Textbook of Medicine, 22nd ed. Edited by Lee Goldman et al. Philadelphia: Saunders, 2003, pp. 842–60.

ORGANIZATIONS

American Academy of Pediatrics. 141 Northwest Point Blvd., Elk Grove Village, IL 60007–1098. Web site: <www.aap.org>.

American College of Gastroenterology. 4900 B South 31st Street, Arlington VA 22206. Web site: <www.acg.gi.org/>.

WEB SITES

"Diarrhea." Centers for Disease Control and Prevention. Available online at <www.cdc.gov/ncidod/dpd/parasiticpathways/diarrhea.htm> (accessed January 5, 2005).

"Diarrhea." Merck Manual. Available online at <www.merck.com/mrkshared/mmanual/section3/chapter27/27b.jsp> (accessed January 5, 2005).

"Diarrhea." National Digestive Diseases Information Clearinghouse. Available online at <http://digestive.niddk.nih.gov/ddiseases/pubs/diarrhea/> (accessed January 5, 2005).

"Diarrhea." MedlinePlus. Available online at <www.nlm.nih.gov/medlineplus/diarrhea.html> (accessed January 5, 2005).

"Traveler's Diarrhea." American Academy of Family Practice. Available online at <http://familydoctor.org/182.xml> (accessed January 5, 2005).

L. Fleming Fallon, Jr., MD, DrPH

Diarrhea

Definition

To most individuals, diarrhea means an increased frequency or decreased consistency of bowel movements; however, the medical definition is more exact than this. In many developed countries, the average number of bowel movements is three per day. However, researchers have found that diarrhea best correlates with an increase in stool weight; stool weights above 10oz (300 gs) per day generally indicates diarrhea. This is mainly due to excess water, which normally makes up 60-85% of fecal matter. In this way, true diarrhea is distinguished from diseases that cause only an increase in the number of bowel movements (hyperdefecation) or incontinence (involuntary loss of bowel contents).

Diarrhea is also classified by physicians into acute, which lasts one or two weeks, and chronic, which continues for longer than 2 or 3 weeks. Viral and bacterial infections are the most common causes of acute diarrhea.

Description

In many cases, acute infectious diarrhea is a mild, limited annoyance. However, worldwide acute infectious diarrhea has a huge impact, causing over five million deaths per year. While most deaths are among children under five years of age in developing nations, the impact, even in developed countries, is considerable. For example, over 250,000 individuals are admitted to hospitals in the United States each year because of one of these episodes. Rapid diagnosis and proper treatment can prevent much of the suffering associated with these devastating illnesses.

Chronic diarrhea also has a considerable effect on health, as well as on social and economic well being. Patients with celiac disease, inflammatory bowel disease, and other prolonged diarrheal illnesses develop nutritional deficiencies that diminish growth and immunity. They affect social interaction and result in the loss of many working hours.

Causes and symptoms

Diarrhea occurs because more fluid passes through the large intestine (colon) than that organ can absorb. As a rule, the colon can absorb several times more fluid than is required on a daily basis. However, when this reserve capacity is overwhelmed, diarrhea occurs.

Diarrhea is caused by infections or illnesses that either lead to excess production of fluids or prevent absorption of fluids. Also, certain substances in the colon, such as fats and bile acids, can interfere with water absorption and cause diarrhea. In addition, rapid passage of material through the colon can also do the same.

Symptoms related to any diarrheal illness are often those associated with any injury to the gastrointestinal tract, such as fever, nausea, vomiting, and abdominal pain. All or none of these may be present depending on the disease causing the diarrhea. The number of bowel movements can vary—up to 20 or more per day. In some patients, blood or pus is present in the stool. Bowel movements may be difficult to flush (float) or contain undigested food material.

The most common causes of acute diarrhea are infections (the cause of traveler's diarrhea), food poisoning, and medications. Medications are a frequent and often over-looked cause, especially antibiotics and antacids. Less often, various sugar free foods, which sometimes contain poorly absorbable materials, cause diarrhea.

Chronic diarrhea is frequently due to many of the same things that cause the shorter episodes (infections, medications, etc.); symptoms just last longer. Some infections can become chronic. This occurs mainly with parasitic infections (such as Giardia ) or when patients have altered immunity (AIDS ).

The following are the more usual causes of chronic diarrhea:

• AIDS
• colon cancer and other bowel tumors
• endocrine or hormonal abnormalities (thyroid, diabetes mellitus, etc.)
• food allergy
• inflammatory bowel disease (Crohn's disease and ulcerative colitis)
• lactose intolerance
• malabsorption syndromes (celiac and Whipple's disease)
• other (alcohol, microscopic colitis, radiation, surgery)

Complications

The major effects of diarrhea are dehydration, malnutrition, and weight loss. Signs of dehydration can be hard to notice, but increasing thirst, dry mouth, weakness or lightheadedness (particularly if worsening on standing), or a darkening/decrease in urination are suggestive. Severe dehydration leads to changes in the body's chemistry and could become life-threatening. Dehydration from diarrhea can result in kidney failure, neurological symptoms, arthritis, and skin problems.

Diagnosis

Most cases of acute diarrhea never need diagnosis or treatment, as many are mild and produce few problems. But patients with fever over 102 °F (38.9 °C), signs of dehydration, bloody bowel movements, severe abdominal pain, known immune disease, or prior use of antibiotics need prompt medical evaluation.

When diagnostic studies are needed, the most useful are stool culture and examination for parasites; however these are often negative and a cause cannot be found in a large number of patients. The earlier cultures are performed, the greater the chance of obtaining a positive result. For those with a history of antibiotic use in the preceding two months, stool samples need to be examined for the toxins that cause antibiotic-associated colitis. Tests are also available to check stool samples for microscopic amounts of blood and for cells that indicate severe inflammation of the colon. Examination with an endoscope is sometimes helpful in determining severity and extent of inflammation. Tests to check changes in blood chemistry (potassium, magnesium, etc.) and a complete blood count (CBC) are also often performed.

Chronic diarrhea is quite different, and most patients with this condition will receive some degree of testing. Many exams are the same as for an acute episode, as some infections and parasites cause both types of diarrhea. A careful history to evaluate medication use, dietary changes, family history of illnesses, and other symptoms is necessary. Key points in determining the seriousness of symptoms are weight loss of over 10 lb (4.5 kg), blood in the stool, and nocturnal diarrhea (symptoms that awaken the patient from sleep).

Both prescription and over-the-counter medications can contain additives, such as lactose and sorbitol, that will produce diarrhea in sensitive individuals. Review of allergies or skin changes may also point to a cause. Social history may indicate if stress is playing a role or identify activities which can be associated with diarrhea (for example, diarrhea that occurs in runners).

A combination of stool, blood, and urine tests may be needed in the evaluation of chronic diarrhea; in addition a number of endoscopic and x-ray studies are frequently required.

Treatment

Treatment is ideally directed toward correcting the cause; however, the first aim should be to prevent or treat dehydration and nutritional deficiencies. The type of fluid and nutrient replacement will depend on whether oral feedings can be taken and the severity of fluid losses. Oral rehydration solution (ORS) or intravenous fluids are the choices; ORS is preferred if possible.

A physician should be notified if the patient is dehydrated, and if oral replacement is suggested then commercial (Pedialyte and others) or homemade preparations can be used. The World Health Organization (WHO) has provided this easy recipe for home preparation, which can be taken in small frequent sips:

• Table salt—3/4 tsp
• Baking powder—1 tsp
• Orange juice—1 c
• Water—1 qt (1l)

When feasible, food intake should be continued even in those with acute diarrhea. A physician should be consulted as to what type and how much food is permitted.

Anti-motility agents (loperamide, diphenoxylate) are useful for those with chronic symptoms; their use is limited or even contraindicated in most individuals with acute diarrhea, especially in those with high fever or bloody bowel movements. They should not be taken without the advice of a physician.

Other treatments are available, depending on the cause of symptoms. For example, the bulk agent psyllium helps some patients by absorbing excess fluid and solidifying stools; cholestyramine, which binds bile acids, is effective in treating bile salt induced diarrhea. Low fat diets or more easily digestible fat is useful in some patients. New antidiarrheal drugs that decrease excessive secretion of fluid by the intestinal tract is another approach for some diseases. Avoidance of medications or other products that are known to cause diarrhea (such as lactose) is curative in some, but should be discussed with a physician.

Alternative treatment

It is especially important to find the cause of diarrhea, since stopping diarrhea when it is the body's way of eliminating something foreign is not helpful and can be harmful in the long run.

One effective alternative approach to preventing and treating diarrhea involves oral supplementation of aspects of the normal flora in the colon with the yeasts Lactobacillus acidophilus, L. bifidus, or Saccharomyces boulardii. In clinical settings, these "biotherapeutic" agents have repeatedly been helpful in the resolution of diarrhea, especially antibiotic-associated diarrhea. Their effectiveness is also supported by the results of a research study published in the Journal of the American Medical Association in 1996.

Nutrient replacement also plays a role in preventing and treating episodes of diarrhea. Zinc especially appears to have an effect on the immune system, and deficiency of this mineral can lead to chronic diarrhea. Also, zinc replacement improves growth in young patients. Plenty of fluids, especially water, should be taken by individuals suffering from diarrhea to prevent dehydration. The BRAT diet also can be useful in helping to resolve diarrhea. This diet limits food intake to bananas, rice, applesauce, and toast. These foods provide soluble and insoluble fiber without irritation. If the toast is slightly burnt, the charcoal can help sequester toxins and pull them from the body.

Acute homeopathic remedies can be very effective for treating diarrhea especially in infants and young children.

Prognosis

Prognosis is related to the cause of the diarrhea; for most individuals in developed countries, a bout of acute, infectious diarrhea is at best uncomfortable. However, in both industrialized and developing areas, serious complications and death can occur.

For those with chronic symptoms, an extensive number of tests are usually necessary to make a proper diagnosis and begin treatment; a specific diagnosis is found in 90% of patients. In some, however, no specific cause is found and only treatment with bulk agents or anti-motility agents is indicated.

Prevention

Proper hygiene and food handling techniques will prevent many cases. Traveler's diarrhea can be avoided by use of Pepto-Bismol and/or antibiotics, if necessary. The most important action is to prevent the complications of dehydration.

Resources

ORGANIZATIONS

World Health Organization, Division of Emerging and Other Communicable Diseases Surveillance and Control. Avenue Appia 20, 1211 Geneva 27, Switzerland. (+00 41 22) 791 21 11. 〈http://www.who.int〉.

OTHER

"Directory of Digestive Diseases Organizations for Patients." National Institute of Diabetes and Digestive and Kidney Disease. 〈http://www.niddk.nih.gov〉.

"A Neglected Modality for the Treatment and Prevention of Selected Intestinal and Vaginal Infections." JAMA. 〈http://pubs.ama-assn.org〉.

Selected publications and documents on diarrhoeal diseases (including cholera). World Health Organization (WHO). 〈http://www.who.ch/chd/pub/cdd/cddpub.htm〉.

KEY TERMS

Anti-motiltiy medications— Medications such as loperamide (Imodium), diphenoxylate (Lomotil), or medications containing codeine or narcotics that decrease the ability of the intestine to contract. These can worsen the condition of a patient with dysentery or colitis.

Colitis— Inflammation of the colon.

Endoscope— An endoscope, as used in the field of gastroenterology, is a thin flexible tube that uses a lens or miniature camera to view various areas of the gastrointestinal tract. Both diagnosis, through biopsies or other means, and therapeutic procedures can be done with this instrument.

Endoscopy— The performance of an exam using an endoscope is known generally as endoscopy.

Lactose intolerance— An inability to properly digest milk and dairy products.

Oral rehydration solution (ORS)— A liquid preparation developed by the World Health Organization that can decrease fluid loss in persons with diarrhea. Originally developed to be prepared with materials available in the home, commercial preparations have recently come into use.

Steatorrhea— Excessive amounts of fat in the feces.

Diarrhea

Definition

To most persons, diarrhea means an increased frequency or softer consistency of bowel movements; however, the medical definition is more exact than this. Diarrhea best correlates with an increase in stool weight; stool weights above 300 g per day generally indicates diarrhea. This is mainly due to excess water, which normally makes up 60-85% of fecal matter. In this way, true diarrhea is distinguished from diseases that cause only an increase in the number of bowel movements (hyperdefecation), or incontinence (involuntary loss of bowel contents).

Diarrhea is also classified by physicians into acute, which lasts one to two weeks, and chronic, which continues for longer than 23 weeks. Viral and bacterial infections are the most common causes of acute diarrhea.

Description

In many cases, acute infectious diarrhea is a mild, limited annoyance. However, acute infectious diarrhea has a huge impact worldwide, causing over five million deaths per year. While most deaths are among children under five years of age in developing nations, the impact, even in developed countries, is considerable. For example, over 250,000 persons are admitted to hospitals in the United States each year because of diarrhea. Rapid diagnosis and proper treatment can prevent much of the suffering associated with this illness.

Chronic diarrhea also has a considerable effect on health, as well as on social and economic well being. Patients with celiac disease, inflammatory bowel disease , and other prolonged diarrheal illnesses develop nutritional deficiencies, which diminish growth and immunity. They affect social interaction and result in the loss of many working hours.

Causes & symptoms

Diarrhea occurs because more fluid passes through the large intestine (colon) than can be absorbed. As a rule, the colon can absorb several times more fluid than is required on a daily basis. However, when this reserve capacity is overwhelmed, diarrhea occurs.

Diarrhea is caused by infections or illnesses that either lead to excess production of fluids or prevent absorption of fluids. Also, certain substances in the colon, such as fats and bile acids, can interfere with water absorption and cause diarrhea. In addition, rapid passage of material through the colon can cause diarrhea.

Symptoms related to diarrheal illness are often those associated with any injury to the gastrointestinal tract, such as fever, nausea, vomiting , and abdominal pain . All or none of these may be present depending on the cause of diarrhea. The number of bowel movements can vary with up to 20 or more per day. In some patients, blood or pus is present in the stool. Bowel movements may contain undigested food material.

The most common causes of acute diarrhea are infections (the cause of traveler's diarrhea), food poisoning , and medications. Medications are a frequent and often overlooked cause, especially antibiotics and antacids. Both prescription and over-the-counter medications can contain additives, such as lactose and sorbitol, that will produce diarrhea in sensitive persons. Less often, various sugar-free foods, which sometimes contain poorly absorbable materials, cause diarrhea. Review of allergies or skin changes may also point to a cause.

Chronic diarrhea is frequently due to many of the same things that cause the shorter episodes (infections, medications, etc.); symptoms just last longer. Some infections can become chronic. This occurs mainly with parasitic infections (such as Giardia ), or when patients have altered immunity (such as AIDS ).

The following are the more usual causes of chronic diarrhea:

• AIDS
• colon cancer and other bowel tumors
• endocrine or hormonal abnormalities (thyroid, diabetes mellitus , etc.)
• food allergy
• inflammatory bowel disease (Crohn's disease and ulcerative colitis)
• lactose intolerance
• malabsorption syndromes (celiac and Whipple's disease)
• other (alcohol, microscopic colitis, radiation, surgery)

Complications

The major effects of diarrhea are dehydration, malnutrition, and weight loss. Signs of dehydration can be hard to notice but include thirst, dry mouth , weakness or lightheadedness (particularly if worsening on standing), urine darkening, or a decrease in urination. Severe dehydration leads to changes in the body's chemistry and could become life-threatening. Dehydration from diarrhea can result in kidney failure, neurological symptoms, arthritis, and skin problems.

Diagnosis

Most cases of acute diarrhea never need diagnosis or treatment, as many are mild and produce few problems. But patients with fever over 102°F (38.9°C), signs of dehydration, bloody bowel movements, severe abdominal pain, known immune disease, or recent use of antibiotics need prompt medical evaluation.

When diagnostic studies are needed, the most useful are stool culture and examination for parasites; however these are often negative and a cause cannot be found in a large number of patients. The earlier cultures are performed, the greater the chance of obtaining a positive result. Stool samples of patients who had used antibiotics in the preceding two months need to be examined for the toxins that cause antibiotic-associated colitis. Tests are also available to check stool samples for microscopic amounts of blood and for cells that indicate severe inflammation of the colon. Examination with an endoscope is sometimes helpful in determining severity and extent of inflammation. Tests to check changes in blood chemistry (potassium, magnesium , etc.) and a complete blood count (CBC) may be performed.

Chronic diarrhea is quite different, and most patients with this condition will receive some degree of testing. Many exams are the same as for an acute episode, as some infections and parasites cause both types of diarrhea. A careful history to evaluate medication use, dietary changes, family history of illnesses, and other symptoms is necessary. Key points in determining the seriousness of symptoms are weight loss of over 10 lb (4.5 kg), blood in the stool, and nocturnal diarrhea (symptoms that awaken the patient from sleep). A combination of stool, blood, and urine tests may be needed in the evaluation of chronic diarrhea; in addition a number of endoscopic and x-ray studies are frequently required.

Treatment

Diet

Treatment is ideally directed toward correcting the cause; however, the first aim is to prevent or treat dehydration and nutritional deficiencies. When possible, food intake should be continued even in patients with acute diarrhea. A physician should be consulted as to what type and how much food is permitted. Low-fat diets or more easily digestible fat is useful in some patients. The BRAT diet, which limits food intake to bananas, rice, applesauce, and toast, can help to resolve diarrhea. These foods provide soluble and insoluble fiber without irritation. If the toast is slightly burnt, the charcoal can help sequester toxins and pull them from the body.

The patient should drink plenty of fluids, however, in severe cases hospitalization to provide intravenous fluids may be necessary. A physician should be notified if the patient is dehydrated, and if oral replacement is suggested then commercial (Pedialyte and others) or homemade preparations can be used. The World Health Organization (WHO) has provided this easy recipe for home preparation, which can be taken in frequent small sips:

• table salt: 3/4 teaspoon
• baking powder: 1 teaspoon
• orange juice: 1 cup
• water: 1 quart or liter

Supplements

Nutrient replacement also plays a role in preventing and treating diarrhea. Zinc especially appears to have an effect on the immune system, and deficiency of this mineral can lead to chronic diarrhea. Also, zinc replacement improves growth in young patients.

Dietary supplements that are generally beneficial in the treatment of digestive disorders include:

• vitamin C: 50-500 mg daily
• vitamin B₆: 50-150 mg daily
• magnesium aspartate: 400 mg daily
• vitamin E: 400 IU daily
• glutamine: 3,000 mg daily
• garlic, deodorized: 2,000 mg daily
• deghycirrhizinated licorice : chew as needed

Probiotics

Probiotics refers to treatment with beneficial microbes either by ingestion or through a suppository. Studies and the clinical use of probiotics have shown their utility in the resolution of diarrhea, especially antibiotic-associated diarrhea. Beneficial microbes include the bacteria Lacto-bacillus acidophilus and L. bifidus and the yeast Saccharomyces boulardii. To treat diarrhea, the patient can eat one cup of yogurt (containing active Lactobacillus acidophilus cultures) daily. Alternatively, one or two acidophilus capsules may be taken at each meal or at bedtime.

Acupuncture

Shallow acupuncture , when the needles are inserted superficially and rapidly removed, was more therapeutic than drugs in children with acute or chronic diarrhea. In another study, acupuncture eliminated symptoms and normalized stools in children with chronic diarrhea who had not responded to conventional or Chinese medicines.

Herbals and Chinese medicines

Herbal remedies for diarrhea include meadowsweet, goldenseal , and chamomile taken as an infusion throughout the day.

Chinese patent medicines used for treating diarrhea include:

• Xiang Sha Liu Jun Wan (Six-Gentlemen Pill with Aucklandia and Amomum)
• Fu Zi Li Zhong Wan (Prepared Aconite Pill to Regulate the Middle)
• Si Shen Wan (Four-Miracle Pill)
• Wu Mei Wan (Mume Pill)
• Jian Pi Wan (Strengthen the Spleen Pill)
• Shen Ling Bai Zhu Wan (Ginseng, Poria, and Atractylodes Macrocephala Pill)

Allopathic treatment

Anti-motility agents (loperamide, diphenoxylate) are useful for persons with chronic diarrhea; their use is limited or even contraindicated in patients with acute diarrhea, especially in those with high fever or bloody bowel movements. They should not be taken without the advice of a physician. Other treatments that are available, depending on the cause of diarrhea, include the bulk agent psyllium and the binder cholestyramine. Also, new antidiarrheal drugs that decrease excessive secretion of fluid by the intestinal tract are available.

Expected results

Prognosis is related to the cause of the diarrhea; for most individuals in developed countries, a bout of acute, infectious diarrhea is at best uncomfortable. However, in both industrialized and developing areas, serious complications and death can occur.

Prevention

Proper hygiene and food handling techniques will prevent many cases. Traveler's diarrhea can be avoided by use of Pepto-Bismol and/or antibiotics, if necessary. The most important action is to prevent dehydration, as outlined above.

Resources

BOOKS

Fine, Kenneth D. "Diarrhea." In Sleisenger & Fordtran's Gastrointestinal and Liver Disease. Edited by Mark Feldman, et al. Philadelphia: W. B. Saunders Company. 1997.

Friedman, Lawrence S., and Kurt J. Isselbacher. "Diarrhea." In Harrison's Principles of Internal Medicine. Edited by Anthony S. Fauci, et al. New York: McGraw Hill, 1998.

Thielman, Nathan M. and Richard L. Guerrant. "Food-Borne Illness." In Conn's Current Therapy, 1996. Edited by Robert E. Rakel. Philadelphia: W. B. Saunders Company, 1996.

Ying, Zhou Zhong and Jin Hui De. "Gastrointestinal Diseases." In Clinical Manual of Chinese Herbal Medicine and Acupuncture. New York: Churchill Livingston, 1997.

PERIODICALS

Donowitz, Mark, Freddy T. Kokke, and Roxan Saidi. "Evaluation of Patients with Chronic Diarrhea." New England Journal of Medicine 332 (March 16, 1995): 725-729.

Dupont, Herbert L. and The Practice Parameters Committee of the American College of Gastroenterology. "Guidelines on Acute Infectious Diarrhea in Adults." American Journal of Gastroenterology 92 (1977): 1962-1975.

Penny, Mary E. and Claudio F. Lanata. "Zinc in the Management of Diarrhea in Young Children." New England Journal of Medicine 333 (September 28, 1995): 873-874.

"Traveler's Diarrhea: Don't Let It Ruin Your Trip." Mayo Clinic Health Letter (January 1997).

"When Microbes Are on the Menu." Harvard Health Letter (December 1994): 4-5.

ORGANIZATIONS

World Health Organization (WHO). CH-1211 Geneva 27, Switzerland. +41 22 791 2111. Fax: +41 22 791 0746. Telex: 45 415416. postmaster@who.ch. http://www.who.ch.

OTHER

Directory of Digestive Diseases Organizations for Patients. http://www.niddk.nih.gov/DigDisOrgPat/DigDisOrgPat.html (January 17, 2001).

Selected publications and documents on diarrhoeal diseases (including cholera). World Health Organization (WHO). http://www.who.ch/chd/pub/cdd/cddpub.htm (January 17, 2001).

Belinda Rowland

Diarrhea

Diarrhea, a condition that has a major impact on global health, is highly correlated with nutritional status. It is an important area of focus due not only to its high worldwide prevalence and health costs, but also because it can be significantly reduced by appropriate interventions and treatment.

Diarrhea has various causes and symptoms, resulting in a wide range of definitions for this illness. The U.S. National Institutes of Health (NIH) defines diarrhea as loose, watery stools occurring more than three times a day, which is the most common definition. The term acute diarrhea is used to describe an episode lasting less than three weeks. Persistent diarrhea is an episode that lasts more than fourteen days, and chronic diarrhea is the term for recurring episodes of diarrhea. Dysentery is diarrhea that contains blood. The severity of diarrhea ranges from asymptomatic to severe dehydration resulting in death.

Causes of Diarrhea

Diarrhea can present in many ways because it has many potential causes. Most cases of diarrhea are caused by some type of infection. For example, surveillance studies in rural Bangladesh have cited infection as the cause of 86 percent of the cases of diarrhea in that population. This is the case in much of the developing world. Regardless of the cause, diarrhea results from an alteration of the lining of the wall of the intestines . Normal digestion occurs when there is a balance of fluid and nutrients across the bowel wall. Disruption of this process can be caused directly by organisms, toxins , or immune reactions. Any imbalance alters the composition of the stool and the motility (motion) of the bowel wall, resulting in an increased loss of fluid and nutrients. Dehydration is the result of loss of body fluids and electrolytes . A loss of 5 percent of body weight can result in a rapid heart rate, dizziness, decreased urination, disorientation, and even coma. A 10 percent loss of body weight caused by severe diarrhea can lead to acidosis , shock , and death.

People in developing countries suffer most from infectious forms of diarrhea. Most infections pass through a fecal-oral route. This results from environmental causes such as poor sanitation, decreased access to clean water, and a poor understanding of transmission and treatment of disease. These are conditions that arise most frequently in the developing world, though they affect both rural and urban populations. Improvements in these areas result in a dramatic reduction of cases of infectious diarrhea, as shown in studies in numerous developing nations, such as India, Gambia, and elsewhere, where poor socioeconomic status affects a large percentage of the population. Traveler's diarrhea is the result of exposure to such infectious agents when visiting countries where sanitation is inadequate.

Diarrhea in Developing Nations

Diarrhea is a major cause of death in much of the world, particularly in developing nations, where the effect is greatest among the young. The World Health Organization (WHO) attributes 3.5 million deaths a year to diarrhea, with 80 percent of these deaths occurring in children under the age of five, and most occurring in children between six months and three years of age. Children are the most susceptible because a smaller amount of fluid

loss is necessary to result in significant dehydration, because they have fewer internal resources, and because their energy requirements are higher.

Children in developing nations suffer from an average of four cases of diarrhea a year. Most of these cases are infectious diarrhea. Infectious diarrhea also contributes to malnutrition due to a decreased nutritional intake and diminished absorption of vital nutrients during the acute episode and recovery period. Malnutrition, in turn, decreases the ability of the immune system to fight further infections, making diarrheal episodes more frequent.

Studies have shown that poor nutritional status can double the risk of contracting diarrhea when exposed to an infectious agent. In addition, the duration of the acute episode can be up to three times as long in malnourished children. In addition, reduced immunity and deficiencies of nutrients such as vitamin A and zinc , which are common in malnourished individuals, can increase the health risks from diarrhea. Diarrhea also causes decreased appetite and food intake, decreased absorption of nutrients from the food that is ingested, and increased catabolism of body proteins . The resulting undernutrition stunts future mental and physical development.

Eating patterns before and after diarrheal episodes play an important role in this cycle. In developing countries, environmental factors, such as pervasive bacterial contamination of water used for drinking, cooking, and cleaning, contribute to continued exposure to agents that cause diarrhea. Maternal practices related to feeding are also a factor. Reduced breastfeeding rates in developing nations mean that fewer children receive the protective and nutritional benefits of breast milk. Nursing allows for the delivery of milk high in fats, proteins, and calories in a sterile fashion. When illness causes mothers to wean their children too early, nutritious breast milk is replaced with cereals and gruels that are often low in calories and proteins and are made with contaminated water. Commercial formulas are also often diluted with contaminated water and put in bottles that are not sterile.

A lack of maternal education often leads to the common practice of withholding food during acute episodes of diarrhea out of fear that eating will exacerbate the symptoms. Because of the nutritional losses from diarrhea, children actually need up to a 30 percent increase in calories and a 100 percent increase in protein intake during the acute and recovery stages of diarrhea. Studies have shown that children who receive increased nourishment during this time suffer less from the acute and long-term effects of diarrhea. The WHO recommends the continuation of breastfeeding throughout an acute episode, as well as the use of mixed food cereals high in calories and protein. There is also evidence to support zinc supplementation, which can reduce the morbidity rates from diarrhea.

Treatment

The mainstay of treatment for diarrhea is rehydration to replace the fluid and electrolyte losses. This is the cornerstone of oral rehydration therapy (ORT), which has greatly reduced the morbidity and mortality from diarrheal illnesses throughout the world. Rehydration must be combined with the fulfillment of increased nutritional demands. Antibiotics have a very limited role in effectively reducing morbidity and mortality from diarrhea, and antimotility and absorbent agents have virtually no role.

It is evident that the morbidity and mortality from diarrhea results from a complex interplay of environmental hazards, risk factors, and treatment response. Interventions to reduce the global impact of diarrhea must therefore be multifactorial in their approach. This is an illness that imposes a large health burden on society, but has avenues for effective intervention.

see also Malnutrition; Oral Rehydration Therapy.

Seema Pania Kumar

Bibliography

Basch, Paul (1999). Textbook of International Health. New York: Oxford University Press.

Chen, Lincoln, and Scrimshaw, Nevin (1983). Diarrhea and Malnutrition: Interactions, Mechanisms, and Interventions. New York: Plenum Press.

Semba, Richard, and Bloem, Martin (2000). Nutrition and Health in Developing Countries. Totowa, NJ: Humana Press.

Internet Resources

National Institutes of Health. <http://www.nih.gov>

World Health Organization. <http://www.who.int>

diarrhoea is a world-wide health problem. It ranges from a trivial nuisance for travellers to a fatal illness, particularly among children in underdeveloped countries. Infection is the commonest but not the only cause of diarrhoea. The several causes will be reviewed, but first it is necessary to be clear about the meaning of the term itself.

Diarrhoea is commonly defined as a change in bowel habit resulting in an increase in stool frequency or fluidity or both. Since stool frequency and consistency varies widely in the normal population it is the change from what is usual that is important. Stool frequency alone is not a good indicator of ‘true diarrhoea’ since stool frequency can increase in ‘irritable bowel syndrome’, but the total amount of stool passed each day may be unchanged and within normal limits. It is for this reason that diarrhoea is best defined by stool weight, which for an individual in the Western world is usually less than 200 g/day. In the developing world, stool weight is higher in the normal population (250–400 g/day). Diarrhoea may be acute — an illness of abrupt onset lasting 3–7 days — or chronic (persistent), which is usually defined as lasting more than 14 days.

Mechanisms and causes of diarrhoea

Normally, during a 24-hour period, about 9 litres of fluid enter the small intestine. About 2 litres come from the diet, and the remaining 7 litres from secretions into the alimentary tract which carry the enzymes and other substances necessary for the digestion and absorption of food: saliva, gastric juice, biliary, and pancreatic secretions, and additional fluid secreted by the small intestine itself. Of these 9 litres only 1–2 litres pass on into the colon, so under normal circumstances the small intestine reabsorbs 7 litres of fluid into the bloodstream. The colon also retrieves the major part of the fluid with which it is presented, so that only about 100 ml finally leave the body in faeces. Diarrhoea results when these absorptive mechanisms fail to retrieve the large volume of fluid entering the small intestine, or when there is excessive secretion of fluid into either the small or large intestine. In some circumstances both decreased absorption and increased secretion are combined.

Acute or chronic diarrhoea may be due to a variety of pathophysiological mechanisms and is often categorized into four major groups as follows:

Osmotic diarrhoea

Failure of the intestine to absorb certain solutes results in an increase in the osmolality of intestinal contents which draws an excess of water into the gut from the body fluids down the osmotic gradient. This occurs in conditions that involve carbohydrate malabsorption (monosaccharide intolerance, lactase and sucrase deficiency) or ingestion of non-absorbed saccharides, such as sorbitol, which is used as a sweetener in sugar-free confectionery, and the laxative, lactulose. Magnesium sulphate (Epsom salts) is effective as a laxative because of its osmotic effects. Other conditions which produce malabsorption syndromes, such as coeliac disease, also produce diarrhoea because of the presence of non-absorbed solute in the intestine.

Secretory diarrhoea

Cholera toxin is an example of a bacterial product which produces high-volume watery diarrhoea by promoting massive secretion from the lining of the small intestine. The non-osmotic laxatives, phenolphthalein and senna, partly act by stimulating secretory mechanisms in the intestine. Bile salts, which aid in the process of digestion and absorption of nutrients, are normally absorbed in the last part of the small intestine (terminal ileum). Surgical removal or disease of this part of the bowel causes bile acids to move on into the colon where they interfere with water absorption, causing diarrhoea.

Exudative diarrhoea

occurs usually as a result of damage to the lining of the gut, which leads to impaired absorption or increased losses of body fluids into the lumen. Common causes include intestinal infections, inflammatory bowel diseases (Crohn's disease and ulcerative colitis), other forms of colitis including those due to irradiation and ischaemia, and coeliac disease.

Increased motility

Rapid transit through the intestine can result in true diarrhoea due to the reduced time available for intestinal absorption. This mechanism is thought to be important in some forms of laxative abuse, diabetic diarrhoea, and thyrotoxicosis. Certain functional disorders, such as irritable bowel syndrome, are also associated with more rapid intestinal transit, although in these conditions the change in bowel habit is often regarded as ‘pseudodiarrhoea’ because the increase in bowel frequency is not accompanied by an increase in stool weight.

Acute diarrhoea

Patients with acute watery diarrhoea generally have an intestinal infection. In infants and young children this is most commonly due to a virus infection (rotavirus or adenovirus). There are reported to be no less than 130 million cases annually worldwide, of which about 1 in 150 are fatal.

In adult travellers a frequent cause is a type of E. coli bacterium, which thrives in hot countries and forms toxins that disturb the function of the gut lining. In the indigenous population of industrialized countries, the commonest organisms are bacteria of the Salmonella, Campylobacter, or Clostridium families. The last is particularly common in the elderly and in immunocompromised patients undergoing anti-cancer chemotherapy. Acute diarrhoea accompanied by blood (dysentery) usually indicates infection with an invasive enteropathogen (an organism that attacks the cells of the lining of the gut) such as a member of the genus Shigella (causing bacillary dysentery), an invasive strain of E. coli, or amoebiasis (amoebic dysentery).

Organisms cause acute diarrhoea either by multiplying in a food source, and surviving to be ingested if it is not fully cooked (e.g. Salmonella in chickens), or through living in the gut of people or animals, whose faeces contaminate food or water by reason of defective personal or social hygiene (e.g. E. coli and Shigella from humans; Campylobacter from farm animals, birds, or pets).

In many instances the presence of infection can be determined by microscopic examination of the stool for evidence of parasites and microbiological culture for bacteria.

When acute diarrhoea is due to infection it is usually self-limiting and will remit without specific therapy. When the illness is more severe, oral rehydration therapy with glucose–electrolyte solutions is the mainstay of therapy to correct dehydration and acidosis. There is no need to modify food intake during episodes of diarrhoea, although secondary deficiency of lactase absorption can occur and it sometimes wise to restrict milk and milk products. Breast feeding of infants should continue despite diarrhoea.

Anti-diarrhoeal agents, such as loperamide, are sometimes helpful to reduce bowel frequency but should be avoided in children. Antibiotics are not routinely used for the treatment of acute infective diarrhoea although it is well established that a short course can reduce the severity and duration of symptoms. Some infections, however, do require antibiotic therapy, particularly the invasive organisms that cause dysentery such as severe Shigella and Salmonella infections and amoebiasis.

Persistent diarrhoea

When diarrhoea is persistent, measurement of stool weight over a 3-day period may be needed to confirm whether this is true diarrhoea or ‘pseudo-diarrhoea’. Laxative abuse may be revealed by urine testing. Chronic parasitic infection can be sought and excluded by microscopic examination of the stools. Inflammatory bowel disease usually requires an examination of the colon by endoscopy and possibly a small bowel radiological examination using barium by mouth — a barium ‘follow-through’ examination. If a small bowel disorder such as coeliac disease is considered likely then a small intestinal mucosal biopsy may be required to confirm the diagnosis.

The treatment of chronic diarrhoea depends entirely on the causes. Chronic infections due to certain parasites such as Giardia lamblia and Entamoeba histolytica require anti-microbial chemotherapy. Chronic diarrhoea due to inflammatory bowel disease usually requires treatment with anti-inflammatory drugs such as corticosteroids or 5-aminosalicylic acid. Dietary therapy is sometimes required when the problem is a food sensitivity, such as coeliac disease when a gluten-free diet is appropriate.

Michael Farthing, and Anne Ballinger

Diarrhea

Description

Diarrhea is the abnormal increase of liquid in stool and increase in the frequency of passing stool (defecation). The person with diarrhea has watery or loose stool more than three times a day. Other symptoms include cramping, pain, feeling the urge to defecate, irritation of the skin around the anus (perianal), and inability to control defecation (fecal incontinence ). Approximately 10% of the patients with advanced cancer suffer from diarrhea. Diarrhea lasting fewer than two weeks is called "acute diarrhea, " and diarrhea lasting for longer than two months is called "chronic diarrhea."

Diarrhea is a debilitating condition that can significantly affect quality of life. Diarrhea can prevent patients from participating in social activities and going to work. Persons with diarrhea fear soiling their clothing or bed linens, a fear that prevents them from leaving home. Loss of sleep due to nighttime diarrhea can cause fatigue, which ultimately affects the patient's ability to function normally. Uncontrolled diarrhea can lead to chemical imbalances, loss of fluids (dehydration), and even death.

Causes

Although there are many causes of diarrhea, only those associated with cancer will be discussed. The most common cause of diarrhea in cancer patients is related to constipation or its treatment. Cancer patients may experience diarrhea as a result of their treatment, or it can be due to dietary changes, infections, hormone imbalances, digestion disorders, or inflammation. Treatment-related diarrhea can be caused by chemotherapy , hormone therapy, radiation therapy , biological response modifiers (drugs that improve the patient's immune system), or surgery. In addition, cancer patients may develop temporary lactose intolerance, which causes diarrhea.

Chemotherapy drugs kill the rapidly growing cancer cells. However, certain normal cells of the body are rapidly growing and they too are affected. Rapidly growing cells are found in the intestines, as well as other parts of the body. Diarrhea occurs as a result of injury to the cells of the intestine. These effects are temporary. Chemotherapy drugs, hormones, and biological response modifiers that frequently cause diarrhea include:

• Dactinomycin
• Daunorubicin
• Diethylstilbestrol diphosphate
• Doxorubicin
• Fluorouracil
• Flutamide
• Hydroxyurea
• Interferon
• Interleukin-2 (Aldesleukin )
• Irinotecan
• Methotrexate
• Nitrosoureas
• Thioguanine

Radiation therapy can cause diarrhea if the intestines are in the treatment field. Diarrhea results from the injury and destruction of the cells lining the intestines, which leads to a decrease in the uptake (absorption) of fluids and an increase in the speed with which stool moves through the intestines. Radiation therapy can cause diarrhea, and other intestinal problems, many months or years after treatment has been completed.

Diarrhea usually develops within one week following pretreatment (chemotherapy and irradiation) for bone marrow transplantation . This diarrhea usually disappears within two weeks. Also, bone marrow transplant patients with graft-versus-host disease develop severe diarrhea.

Treatments

Prevention

There are some measures that can prevent diarrhea. Patients who are receiving abdominal radiation therapy can be put into certain positions to minimize exposure of healthy intestines to radiation. Diarrhea caused by chemotherapy cannot be prevented; however, the administration of atropine during treatment with irinotecan may prevent diarrhea. Patients should stop taking dietary supplements, as these can cause diarrhea.

There are many dietary changes that can be made to prevent or reduce diarrhea. Foods to avoid include:

• whole grain breads and cereals
• fresh or frozen fruits (except banana)
• dried fruits
• fruit juices with pulp and prune juice
• raw vegetables
• canned onions, corn, olives, pickles, and Brussels sprouts
• fatty foods
• dried beans
• rich desserts
• milk and milk products
• alcohol and caffeinated coffee and tea
• spicy foods
• fried foods

Management

Of the utmost importance in the treatment of diarrhea is the replacement of fluids lost by frequent, watery stools. The patient should drink six to eight glasses of fluid daily, including clear broth, ginger ale (without the fizz), water, weak tea, and commercial formulas that contain sugars and minerals (electrolytes). Patients with severe diarrhea may need intravenous fluid replacement either at home or in the hospital.

Diarrhea can cause the perianal skin to become irritated and painful; therefore, it needs to be cleaned thoroughly after each bout of diarrhea. Baby wipes or a mild soap with water can be used to clean the irritated skin. The area should be patted dry and occasionally exposed to air. Taking a sitz bath (sitting in a bathtub of shallow water) with lukewarm water may relieve the discomfort. Petroleum jelly or other type of barrier cream may be used.

The patient should eat small, frequent meals. Foods and drinks should be taken at room temperature. Foods that can help control diarrhea include:

• bananas
• applesauce
• boiled white rice
• tapioca
• white bread
• plain pasta
• creamed cereals
• eggs
• potatoes (without skin; mashed or baked)
• fish
• chicken or turkey (without skin)

There are some medications that can slow down the movement of stool through the intestines and increase intestinal water absorption. The patient may need a combination of drugs and/or dose adjustments to achieve relief. A physician should be consulted before any over-the-counter antidiarrheal medications are taken. Antidiarrheal medications include:

• Atropine sulfate with diphenoxylate HCl (Lomotil)
• Codeine phosphate
• Loperimide HCl (Imodium-AD)
• Octreotide phosphate (Sandostatin)

These medications should not be used if infection as the cause of diarrhea has not been eliminated.

Patients who are experiencing diarrhea due to graft-versus-host disease will continue to take their immunosuppressant drugs. They may also be treated with corticosteroids and antidiarrheal medications.

Alternative and complementary therapies

Peppermint tea, chamomile tea, valerian capsules, or aloe vera juice may reduce cramping and intestinal spasms. An Ayurvedic physician may recommend taking equal parts of yogurt and water with fresh ginger, or a powder of beleric myrobalan fruit. Ginger capsules may relieve intestinal spasms and pain. Glutamine supplements may speed up the healing process and relieve irritated intestines.

Resources

BOOKS

Lenhard, Raymond E, Robert T. Osteen, and Ted Gansler. Clinical Oncology. American Cancer Society, 2000.

Maleskey, Gale. Nature's Medicines: from Asthma to Weight Gain, from Colds to High Cholesterol—The Most Powerful All-Natural Cures. Emmaus, PA: Rodale Press, Inc., 1999.

Somerville, Robert, ed. The Medical Advisor. Alexandria, VA:Time-Life Books, 1997.

Yarbro, Connie Henke, Michelle Goodman, Margaret Hansen Frogge, and Susan L. Groenwald, eds. Cancer Nursing, Principles and Practice, 5th ed. Sudbury, MA: Jones and Bartlett Publishers, 2000.

Yarbro, Connie Henke, Margaret Hansen Frogge, and Michelle Goodman, eds. Cancer Symptom Management, 2nd ed. Sudbury, MA: Jones and Bartlett Publishers, 1999.

PERIODICALS

Kornblau, Steven, Al B. Benson III, Robert Catalano, Richard E. Champlin, Constance Engelking, et al. "Management of Cancer Treatment—Related Diarrhea: Issues and therapeutic Strategies." Journal of Pain and Symptom Management 19, no. 2 (February 2000): 118-127.

Wadler, Scott, Al B. Benson III, Constance Engelking, Robert Catalano, Michael Field, et al. "Recommended Guidelihnes for the Treatment of Chemotherapy-Induced Diarrhea." Journal of Clinical Oncololgy 16, no. 9 (September 1998): 3169-3178.

OTHER

"What About Diarrhea?" American Cancer Society, Inc. 2000.1 July 2001 <http://www3.cancer.org/cancerinfo>

Belinda Rowland, Ph.D.

KEY TERMS

Defecation

—The passage of stool from the body.

Dehydration

—The condition caused by excessive loss of water from the body.

Electrolytes

—Molecules, such as sodium and potassium, that are necessary for normal body functioning. Diarrhea can cause electrolytes to become lost and/or unbalanced.

Perianal

—The skin surrounding the anal opening.

diarrhea , frequent discharge of watery feces from the intestines, sometimes containing blood and mucus. It can be caused by excessive indulgence in alcohol or other liquids or foods that prove irritating to the stomach or intestine, by allergy to certain food products, by poisoning with heavy metals, by chemicals such as are found in cathartics, by hyperactivity of the nervous system, and by infection with a virus (intestinal grippe) or with bacteria or their toxins. Diarrhea is a concomitant of many infectious diseases, especially typhoid fever , bacillary or amebic dysentery , and cholera . Persistent diarrhea may result in severe dehydration and shock. It is therefore necessary to replace the fluid lost by the body. Treatment is with a bland diet and drugs that will decrease the activity of the intestines, as well as with specific measures directed at the underlying cause. The elderly are at especially high risk for diarrheal deaths caused by viruses. Ulcerative colitis is an inflamatory and ulcerative disease of the colon, properly described as "irritable bowl," and characterized by bloody diarrhea. Crohn's disease affects the distal ileum and colon, but may occur in any part of the gastrointestinal tract, from the mouth to the anus and perianal area. The symptoms are chronic diarrhea associated with abdominal pain, fever, anorexia, weight loss, and a mass or fullness in the right lower quadrant (of the abdomen).

diarrhoea Frequent passage of loose watery stools, commonly the result of intestinal infection; rarely as a result of adverse reaction to foods or disaccharide intolerance. Severe diarrhoea in children can lead to dehydration and death; it is treated by feeding a solution of salt and sugar to replace fluid and electrolyte losses.

Osmotic diarrhoea is diarrhoea associated with retention of water in the bowel as a result of an accumulation of non‐absorbable water‐soluble compounds; especially associated with excessive intake of sorbitol and mannitol. Also occurs in disaccharide intolerance.

Diarrhea

What Is Diarrhea?

What Are the Symptoms of Diarrhea?

What Causes Diarrhea?

What If Diarrhea Lasts a Long Time?

Diarrhea in Infants

How Is Diarrhea Treated?

Can Diarrhea Be Avoided?

Resources

Diarrhea is a condition in which bowel movements are abnormally frequent and stools are abnormally liquidy. It is not itself a disease but is usually a symptom of some other underlying disorder. Diarrhea may be a result of food poisoning, diseases such as dysentery or cholera, emotional upsets, or many other conditions.

KEYWORD

for searching the Internet and other reference sources

Digestion

What Is Diarrhea?

Diarrhea is very common, a condition with which almost everyone is familiar. Usually, it is little more than an unpleasant nuisance that briefly interferes with work or play. Sometimes, however, severe attacks can seriously endanger a person’s health by causing dehydration*. Diarrhea can last different lengths of time: it may be either acute (coming and going quickly) or chronic (long-lasting).

* dehydration

(dee-hy-DRAY-shun) is loss of fluid from the body.

Diarrhea develops in the small or large intestines. The intestines may become irritated and inflamed by an infection or by certain foods. The inflamed intestine does not reabsorb as much water from the stool (bowel contents) as it normally would. In some infections, the intestines actually add more water to the stool. This extra water makes the stools very loose.

What Are the Symptoms of Diarrhea?

Although diarrhea may occur by itself, often it is accompanied by abdominal pain, gurgling bowel sounds, nausea, vomiting, and general weakness. The stools, or bowel movements, are loose or watery and may contain blood, pus, mucus, or droplets of fat. Sometimes attacks of diarrhea alternate with periods of constipation.

What Causes Diarrhea?

Bouts of diarrhea that range from mild to severe can be caused by several types of infectious microorganisms* (my-kro-OR-gan-iz-ims) in contaminated food or water. Diarrhea can also result from the body having trouble digesting dairy products or other foods. Mild cases of diarrhea can be caused by eating spicy food or by anxiety about something stressful, like having to give a speech in front of a lot of people.

* microorganisms

are living organisms that can only be seen using a microscope. Examples of microorganisms are bacteria and viruses.

Food poisoning

We all have heard of a party at which a lot of people got sick after eating the same food. Foods that are not cooked thoroughly or kept refrigerated until just before serving can cause food poisoning. Also, it is important to make sure that raw meat or poultry does not come in contact with cooked foods, that the hands are washed thoroughly before handling any foods, and that all dishes and utensils are thoroughly washed after they have been in contact with raw meat or poultry.

Bacteria such as staphylococcus (staf-i-lo-KOK-us) can cause digestive upsets of this kind. Certain strains of a common intestinal bacterium known as E. coli (EE KO-ly) can cause very serious illness with symptoms that include diarrhea. A group of bacteria called salmonella (sal-mo-NEL-la) also are often responsible for food poisoning. Salmonella causes gastroenteritis (gas-tro-en-ter-I-tis), or inflammation of the gastrointestinal tract. Salmonella infection can cause diarrhea for a week or longer.

Dysentery

Dysentery is an intestinal infection that causes severe diarrhea, often with blood, pus, and mucus in the stools. It is especially common in developing (poor) countries with poor sanitation facilities, causing the food and water supply to become contaminated. The most common causes of dysentery are bacteria and amebas*. Amebic dysentery can cause chronic diarrhea that comes and goes.

* amebas

(a-MEE-buz) are small, one-celled animals that live in fresh and salt water. Amebas can be seen only with a microscope.

Cholera

Outbreaks of cholera often accompany natural disasters such as earthquakes and great storms that disrupt sanitation and cause food and water to become contaminated. It also is widespread in refugee camps and other wartime situations in which people live in severely overcrowded conditions. Food and water contaminated by the cholera bacteria cause a watery form of diarrhea that can rapidly lead to death from severe dehydration.

Giardiasis

A mainly tropical disease that can give rise to severe diarrhea is giardiasis (jee-ar-DY-a-sis). Caused by a parasite*, it usually enters the body in contaminated drinking water.

In recent years, giardiasis has become increasingly prevalent in developed countries such as the United States, especially among preschool children. In settings such as households and day-care centers, where children are in close contact, giardiasis can be caught by touching stool-contaminated objects or from hand-to-hand contact.

* parasites

are creatures that live in and feed on the bodies of other organisms. The animal or plant harboring the parasite is called its host. Two parasitic infections, cyclosporiasis and cryptosporidiosis (discussed elsewhere), are major causes of diarrhea worldwide.

Traveler’s Diarrhea

Traveling to foreign countries and drinking water or eating foods washed in the local water supply can also cause

digestive upsets that include diarrhea; these are sometimes called traveler’s diarrhea.

Often, the exact cause of traveler’s diarrhea cannot be determined. Likely suspects are certain viruses and strains of bacteria such as E. coli that are present in the local water supply. Other causes may include changes in diet, excessive alcohol intake, and salmonella or shigella bacteria.

Lactose Intolerance

Sometimes people get diarrhea from eating dairy products like milk, cheese, and ice cream. This is because there is a sugar in milk and milk products called lactose (LAK-tos). To be able to digest this sugar, there must be an enzyme* in the body called lactase (LAK-tays). Some people do not make enough of this enzyme, and when they eat milk or milk products they get diarrhea.

* enzymes

are natural substances that speed up specific chemical reactions in the body.

Malabsorption

Many diseases can interfere with the intestine’s ability to absorb or take up digested foods. This is called malabsorption (mal-ab-SORP-shun). When foods are not digested and absorbed properly, it can cause diarrhea.

Antibiotic-Induced Diarrhea

Antibiotics kill not only the bacteria that make us sick, but also kill the “good” bacteria that normally live in the intestines and help us digest food. This can allow the overgrowth of certain bacteria that cause diarrhea.

What If Diarrhea Lasts a Long Time?

Diarrhea caused by parasites, such as in amebic dysentery and giardiasis, can become chronic (long-lasting). Infestation with worms also can produce lasting diarrhea.

More often, the cause of chronic diarrhea is not an infection. Instead, it may be the result of inflammatory bowel disease, which includes ulcerative colitis (ko-LY-tis) and Crohn’s disease. A disorder known as diverticulitis (di-ver-tik-yoo-LY-tis), in which abnormal pouches in the walls of the intestines become inflamed, can also cause chronic diarrhea. Other causes include cancer of the intestine, a condition called irritable bowel syndrome, and inability to digest certain foods.

Diarrhea in Infants

Infants and young children commonly get diarrhea from viral infection or giardiasis. When a baby has diarrhea, usually the condition is more serious than in adults or older children. An infant with these symptoms can lose body fluids so rapidly that his life can be endangered, especially if he also is vomiting. Signs of dehydration in infants, such as a dry mouth, lack of urine production, or unresponsiveness, require immediate medical attention. Bacterial intestinal infections such as cholera cause many infant fatalities in developing countries.

How Is Diarrhea Treated?

Most cases of diarrhea are mild and do not require medical attention. For bouts that last more than a few days, recur, or show blood in the stool, a doctor should be consulted. For infants, medical advice should be sought if the diarrhea lasts more than 48 hours. Medical tests that may be used in diagnosis may include examination and culture of stool samples (for bacteria, viruses, or parasites), x-rays, or use of a colonoscope (ko-LON-o-skope), an instrument for viewing the lining of the colon.

Treatment of mild diarrhea consists mainly of drinking liquids to prevent dehydration. In some cases, doctors may prescribe medications that ease symptoms. Treatment of severe diarrhea depends largely upon the cause. For example, antibiotics may be prescribed for dysentery or certain kinds of food poisoning.

Did You Know?

More people died from unsanitary conditions during the U.S. Civil War than from bullets. Of the estimated 600,000 fatalities during the war, the majority were due to epidemics of diarrhea-inducing diseases such as dysentery and typhoid fever. These diseases were caused by contaminated food and water in the encampments. A voluntary organization called the U.S. Sanitary Commission was founded to combat the conditions and provide medical assistance, and they held “sanitary fairs” to raise money.

Can Diarrhea Be Avoided?

Washing one s hands thoroughly after using the toilet is always important, but especially so where contagious forms of diarrhea such as giardiasis can be spread. Travelers in foreign countries should use bottled (not tap) water, and avoid eating raw fruits and vegetables.

See also

Cancer

Cholera

Constipation

Cyclosporiasis and Cryptosporidiosis

Gastroenteritis

Inflammatory Bowel Disease

Irritable Bowel Syndrome

Worms

Resources

Rosenthal, M. Sara. The Gastrointestinal Sourcebook. Los Angeles: Lowell House, 1997. This book is easy to read and tells how to take care of the digestive system and its upsets.

Janowitz, Henry D. Your Gut Feelings. New York: Oxford University Press, 1994. This is a well-written, illustrated book that includes a chapter on diarrhea.

Peikin, Steven. Gastrointestinal Health. New York: HarperCollins, 1991.

diarrhoea (dy-ă-ree-ă) n. frequent bowel evacuation or the passage of abnormally soft or liquid faeces. Its causes include intestinal infections, other forms of intestinal inflammation, anxiety, and the irritable bowel syndrome. Severe or prolonged diarrhoea may lead to excess losses of fluid, salts, and nutrients in the faeces.

di·ar·rhe·a / ˌdīəˈrēə/ (Brit. di·ar·rhoe·a) • n. a condition in which feces are discharged from the bowels frequently and in a liquid form. DERIVATIVES: di·ar·rhe·al adj. di·ar·rhe·ic / -ˈrēik/ adj.

diarrhoea Frequent elimination of loose, watery stools, often accompanied by cramps and stomach pains. It arises from various causes, such as infection, intestinal irritants or food allergy. Mild attacks can be treated by replacement fluids.

diarrhoea XVI (also diaria, diarie XV). — late L. — Gr. diárrhoia, f. diarrheîn flow through, f. DIA- + rheîn flow.

diarrhea •adhere, Agadir, appear, arrear, auctioneer, austere, balladeer, bandolier, Bashkir, beer, besmear, bier, blear, bombardier, brigadier, buccaneer, cameleer, career, cashier, cavalier, chandelier, charioteer, cheer, chevalier, chiffonier, clavier, clear, Coetzee, cohere, commandeer, conventioneer, Cordelier, corsetière, Crimea, dear, deer, diarrhoea (US diarrhea), domineer, Dorothea, drear, ear, electioneer, emir, endear, engineer, fear, fleer, Freer, fusilier, gadgeteer, Galatea, gazetteer, gear, gondolier, gonorrhoea (US gonorrhea), Greer, grenadier, hear, here, Hosea, idea, interfere, Izmir, jeer, Judaea, Kashmir, Keir, kir, Korea, Lear, leer, Maria, marketeer, Medea, Meir, Melilla, mere, Mia, Mir, mishear, mountaineer, muleteer, musketeer, mutineer, near, orienteer, pamphleteer, panacea, paneer, peer, persevere, pier, Pierre, pioneer, pistoleer, privateer, profiteer, puppeteer, queer, racketeer, ratafia, rear, revere, rhea, rocketeer, Sapir, scrutineer, sear, seer, sere, severe, Shamir, shear, sheer, sincere, smear, sneer, sonneteer, souvenir, spear, sphere, steer, stere, summiteer, Tangier, tear, tier, Trier, Tyr, veer, veneer, Vere, Vermeer, vizier, volunteer, Wear, weir, we're, year, Zaïre

diarrhoea •adhere, Agadir, appear, arrear, auctioneer, austere, balladeer, bandolier, Bashkir, beer, besmear, bier, blear, bombardier, brigadier, buccaneer, cameleer, career, cashier, cavalier, chandelier, charioteer, cheer, chevalier, chiffonier, clavier, clear, Coetzee, cohere, commandeer, conventioneer, Cordelier, corsetière, Crimea, dear, deer, diarrhoea (US diarrhea), domineer, Dorothea, drear, ear, electioneer, emir, endear, engineer, fear, fleer, Freer, fusilier, gadgeteer, Galatea, gazetteer, gear, gondolier, gonorrhoea (US gonorrhea), Greer, grenadier, hear, here, Hosea, idea, interfere, Izmir, jeer, Judaea, Kashmir, Keir, kir, Korea, Lear, leer, Maria, marketeer, Medea, Meir, Melilla, mere, Mia, Mir, mishear, mountaineer, muleteer, musketeer, mutineer, near, orienteer, pamphleteer, panacea, paneer, peer, persevere, pier, Pierre, pioneer, pistoleer, privateer, profiteer, puppeteer, queer, racketeer, ratafia, rear, revere, rhea, rocketeer, Sapir, scrutineer, sear, seer, sere, severe, Shamir, shear, sheer, sincere, smear, sneer, sonneteer, souvenir, spear, sphere, steer, stere, summiteer, Tangier, tear, tier, Trier, Tyr, veer, veneer, Vere, Vermeer, vizier, volunteer, Wear, weir, we're, year, Zaïre