Gastroenteritis

Definition

Gastroenteritis is an inflammation of the digestive tract, particularly the stomach, and large and small intestines. Viral and bacterial gastroenteritis are intestinal infections associated with symptoms of diarrhea , abdominal cramps, nausea , and vomiting .

Description

Gastroenteritis is an uncomfortable and inconvenient ailment, but is rarely life-threatening in the United States and other developed nations. Viral gastroenteritis is frequently referred to as the stomach or intestinal flu, although the influenza virus is not associated with this illness.

Demographics

Viral gastroenteritis is one of the most common acute (sudden-onset) illnesses in the United States, with millions of cases reported annually. Each year, an estimated 220,000 children younger than age five are hospitalized with gastroenteritis symptoms. Of these children, 300 die as a result of severe diarrhea and dehydration . In developing nations, diarrheal illnesses are a major source of mortality.

Causes and symptoms

Causes

Gastroenteritis is caused by the ingestion of viruses, certain bacteria, or parasites. Food that has spoiled may also cause illness. Young children may develop signs and symptoms of gastroenteritis as a reaction to a new food.

VIRAL INFECTION Viral infection is the most common cause of gastroenteritis. Viral gastroenteritis is highly contagious and can be spread through close contact with an infected person. Exposure also can occur through the fecal-oral route, such as by consuming foods or beverages contaminated by fecal material related to poor sanitation or poor hygiene, or by touching contaminated surfaces and then touching the mouth and ingesting the germs. The four types of viruses that cause most viral gastroenteritis include rotavirus, adenovirus, calicivirus, and astrovirus.

Typically, children ages three to 15 months are more vulnerable to rotaviruses, the most significant cause of acute watery diarrhea. Outbreaks of diarrhea caused by rotaviruses are common during the winter and early spring months, especially in child care centers. Symptoms in children last for three to eight days, and occur one to two days after exposure to the virus. Worldwide, rotaviruses are estimated to cause 800,000 deaths annually in children under five years of age. For this reason, much research has gone into developing a vaccine to protect children from this virus. Adults can be infected with rotaviruses, but these infections typically have minimal or no symptoms.

Children under age two are more susceptible to adenovirus serotypes 40 and 41. Vomiting and diarrhea symptoms occur about one week after exposure to the virus.

Calciviruses cause infection in people of all ages. This family of viruses includes the noroviruses (such as the Norwalk virus) and the sapoviruses (such as the sapporo virus). Calciviruses are transmitted from person-to-person contact, as well as through contaminated water or food. These viruses are the most likely to produce vomiting as a major symptom. Muscle aches also are common symptoms. The symptoms usually appear within one to three days after exposure to the virus.

Astrovirus primarily infects infants, young children, and the elderly. This virus is most active during the winter months. Symptoms of vomiting and diarrhea appear within one to three days after exposure to the virus.

BACTERIAL AND PARASITIC INFECTIONS Bacterial gastroenteritis is frequently a result of poor sanitation, the lack of safe drinking water, or contaminated food (conditions common in developing nations). Natural or man-made disasters can worsen underlying problems in sanitation and food safety.

In developed nations, including the United States, bacterial gastroenteritis may result from contaminated water supplies, improperly processed or preserved foods, or person-to-person contact in places such as child-care centers. The modern food production system potentially exposes millions of people to disease-causing bacteria through its intensive production and distribution methods. Common types of bacterial gastroenteritis can be linked to Salmonella and Campylobacter bacteria. However, Escherichia coli (E. coli) 0157:H7 and Listeria monocytogenes, bacterial causes of food borne illnesses, have caused increased concern in developed nations.

Cholera and Shigella remain two diseases of great concern in developing countries, and research to develop long-term vaccines against them is underway. Shigella bacteria are dangerous because they attack the intestinal wall and cause bleeding ulcers.

Parasitic infections that cause gastroenteritis are most commonly caused by Giardia, which is easily spread through contaminated water and human contact. Cryptosporidium is another common parasitic organism that causes the symptoms of gastroenteritis.

Symptoms

Gastroenteritis symptoms include nausea and vomiting , watery diarrhea, and abdominal pain and cramps. These symptoms are sometimes accompanied by bloating, low fever , chills, headache , and overall tiredness or weakness. Gastroenteritis symptoms typically last two to three days, but some viruses may last up to a week.

Infants, young children, the elderly, and anyone with an underlying disease are more vulnerable to complications of gastroenteritis. The greatest danger presented by gastroenteritis is dehydration. The loss of fluids through diarrhea and vomiting can upset the body's electrolyte balance, leading to potentially life-threatening problems such as heart beat abnormalities (arrhythmia). The risk of dehydration increases as symptoms become prolonged. Untreated, severe dehydration can be life threatening. Dehydration should be suspected if symptoms of a dry mouth, increased or excessive thirst, or decreased urination are experienced.

When to call the doctor

If symptoms do not resolve within one week, an infection or disorder more serious than gastroenteritis may be involved. Prompt medical attention is required if the child has any of these symptoms:

• a high fever of 102°F (38.9°C) or above
• blood or mucus in the diarrhea
• blood in the vomit
• bloody stools or black stools
• confusion
• severe abdominal pain or swelling
• inability to keep liquids down

If a child has the following symptoms, the parent should contact the child's pediatrician:

• diarrhea or vomiting that wakes the child during the night
• persistent or severe diarrhea or vomiting
• dehydration symptoms, including dry mouth, increased or excessive thirst, few or no tears when crying, decreased urination, dark yellow urine, irritability, low energy, lightheadedness or fainting, severe weakness, and sunken abdomen, eyes, and cheeks
• no improvement in symptoms after 36 hours

Diagnosis

A usual bout of gastroenteritis should not require a visit to the doctor. However, medical treatment is essential if symptoms worsen or if the child has any symptoms of dehydration.

A physician makes the diagnosis of gastroenteritis based on the presence of symptoms and after performing a medical examination. Unless there is an outbreak affecting several people or complications are encountered in a particular case, identifying the specific cause of the illness is not a priority. However, if identification of the infectious agent is required, a stool sample will be collected and analyzed for the presence of rotavirus, disease-causing (pathogenic) bacteria, or parasites.

When symptoms continue even after treatment or to rule out the presence of other illnesses with similar symptoms, the diagnostic evaluation may include blood tests, a hydrogen breath test, or an x ray of the bowel, called a barium enema. Endoscopic tests such as a colonoscopy or sigmoidoscopy may be performed. An endoscopic test is an internal examination of the colon using a flexible instrument (sigmoidoscope or colonoscope) inserted through the anus. When symptoms persist, a nutritional assessment , performed by a registered dietitian, may be included in the child's diagnostic evaluation.

Treatment

Gastroenteritis is a self-limiting illness that will resolve by itself. Acetaminophen (such as Tylenol) or ibuprofen (such as Advil or Motrin) should be used sparingly for relief of discomfort. Parents should ask the child's doctor for specific guidelines. Should pathogenic bacteria or parasites be identified in the patient's stool sample, medications such as antibiotics will be prescribed. Over-the-counter antidiarrheal medications such as Imodium should not be given to the child unless advised by the child's doctor, as these drugs may make it more difficult for the child's body to eliminate the virus.

An adequate intake of liquids and oral rehydrating solutions may be enough to treat mild dehydration. More severe dehydration requires medical treatment with intravenous (IV) fluids and may require hospitalization . IV therapy can be followed with oral rehydration as the patient's condition improves. Once normal hydration is achieved and symptoms have cleared, the patient can resume a regular diet.

Nutritional concerns

It is important for the child to stay hydrated and nourished during a bout of gastroenteritis. Formula feeding and breastfeeding should continue as normal. If dehydration is absent, drinking generous amounts of fluids, such as water or juice, is adequate. Caffeine should be avoided since it increases urine output and can contribute to or worsen dehydration. Dairy products, sugary beverages and foods, highly seasoned foods, and fatty or fried foods should be avoided until symptoms have cleared.

When diarrhea and vomiting symptoms have subsided, plain foods can be given. The traditional BRAT diet—bananas, rice, applesauce, and toast—is tolerated by the tender gastrointestinal system. Other foods can be gradually reintroduced into the diet once the child is symptom-free.

Minimal to moderate dehydration can be treated by giving the child generous amounts of fluids, including water, clear liquids, and oral rehydrating solutions containing glucose and electrolytes. Oral rehydrating solutions—including brands such as Pedialyte, Infalyte, Ceralyte, and Oralyte—are available at most grocery and drug stores. They are essential for replacing fluids, minerals , and salts lost from diarrhea or vomiting, and should be given when diarrhea or vomiting first occur.

Small sips of water, clear liquids, or ice chips are usually tolerated better than a large glass of liquid given all at once.

If the water supply is thought to be contaminated because of a recent storm or other reason, the water should be boiled or bottled water should be given.

The Centers for Disease Control and Prevention (CDC) recommends that families with infants and young children keep a supply of oral rehydration solution (two bottles or packages) at home at all times. However, it is important to make sure that the product has not expired before giving it to the child. Parents and caregivers should follow usage directions on the package.

Oral rehydrating solutions are formulated based on physiological properties. Fluids that are not based on these properties—such as cola, apple juice, broth, and sports beverages—are not recommended to treat dehydration.

Alternative treatment

Alternative and complementary therapies include approaches that are considered to be outside the mainstream of traditional health care. Symptoms of uncomplicated gastroenteritis can be relieved with adjustments in diet and homeopathy.

Probiotics, bacteria that are beneficial to a person's health, are recommended during the recovery phase of gastroenteritis. Specifically, live cultures of Lactobacillus acidophilus are said to be effective in soothing the digestive tract and returning the intestinal flora to normal. L. acidophilus is found in live-culture yogurt, as well as in capsule or powder form at health food stores. The use of probiotics has some support in the medical literature. Castor oil packs applied to the abdomen can reduce inflammation and also lessen spasms or discomfort.

Before using any alternative remedy, it is important for the parent/caregiver and child to learn about the therapy, its safety and effectiveness, and potential side effects. Although some remedies are beneficial, others may be harmful to certain patients. Dietary supplements should not be used as a substitute for medical therapies prescribed by a doctor. Parents should discuss these alternative treatments with the child's doctor to determine the techniques and remedies that may be beneficial for the child.

Prognosis

For most people, gastroenteritis is not a serious illness. It typically resolves within two to three days and there are usually no long-term effects. If dehydration occurs, recovery is extended by a few days. Gastroenteritis is not an anatomical or structural defect, nor is it an identifiable physical or chemical disorder.

Prevention

A few steps can be taken to avoid gastroenteritis. Thorough hand washing is the most effective way to prevent the fecal-oral transmission of certain viruses, especially rotaviruses. People should wash their hands frequently, especially after using the bathroom and before eating. Child-care providers and caregivers should wash their hands after diapering a child and before preparing, serving, or eating, food. The child's hands also should be washed after every diaper change. Separate towels or disposable paper towels should be used to dry hands. Clean bathroom surfaces, disinfected toys , and prompt washing of soiled clothes in hot water also help prevent the spread of infectious germs.

Ensuring that food is prepared safely well-cooked and unspoiled can prevent bacterial gastroenteritis, but may not be effective against viral gastroenteritis. All kitchen utensils, counters, or cutting boards that come in contact with raw meat, especially poultry, should be washed with hot water and a chlorine bleach-based cleaner to prevent the spread of harmful bacteria. Meats should be refrigerated as soon as possible after bringing them home from the grocery store, and cooked leftovers should be refrigerated as soon as possible after a meal to prevent spoilage.

Consuming contaminated food or water can cause gastroenteritis when traveling to other countries. To reduce the risk, travelers should use bottled water for drinking and brushing teeth, and avoid ice (it may be made with contaminated water) and raw foods, including peeled fruit, raw vegetables, and salads.

KEY TERMS

Barium enema —An x ray of the bowel using a liquid called barium to enhance the image of the bowel. This test is also called a lower GI (gastrointestinal) series.

Colonoscopy —An examination of the lining of the colon performed with a colonoscope.

Constipation —Difficult bowel movements caused by the infrequent production of hard stools.

Defecation —The act of having a bowel movement or the passage of feces through the anus.

Dehydration —An excessive loss of water from the body. It may follow vomiting, prolonged diarrhea, or excessive sweating.

Diarrhea —A loose, watery stool.

Electrolytes —Salts and minerals that produce electrically charged particles (ions) in body fluids. Common human electrolytes are sodium chloride, potassium, calcium, and sodium bicarbonate. Electrolytes control the fluid balance of the body and are important in muscle contraction, energy generation, and almost all major biochemical reactions in the body.

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.

Feces —The solid waste, also called stool, that is left after food is digested. Feces form in the intestines and pass out of the body through the anus.

Gastroenterologist —A physician who specializes in diseases of the digestive system.

Glucose —A simple sugar that serves as the body's main source of energy.

Hydrogen breath test —A test used to determine if a person is lactose intolerant or if abnormal bacteria are present in the colon.

Influenza —An infectious disease caused by a virus that affects the respiratory system, causing fever, congestion, muscle aches, and headaches.

Intravenous (IV) therapy —Administration of fluids or medications through a vein, usually in the hand or arm.

Lactose —A sugar found in milk and milk products.

Microflora —The bacterial population in the intestine.

Pathogenic bacteria —Bacteria that produce illness.

Probiotics —Bacteria that are beneficial to a person's health, either through protecting the body against pathogenic bacteria or assisting in recovery from an illness.

Sigmoidoscopy —A procedure in which a thin, flexible, lighted instrument, called a sigmoidoscope, is used to visually examine the lower part of the large intestine. Colonoscopy examines the entire large intestine using the same techniques.

Research is underway involving vaccines that will decrease the risk of rotavirus infection, especially among infants and young children.

Parental concerns

Parents should reinforce with the child that gastroenteritis is not a serious condition and that symptoms usually subside in a few days. It is most important to prevent dehydration by following the recommendations listed previously. Parents should assure that the child gets adequate rest; the child should be kept home from school or day care until the symptoms have cleared. The child may be contagious before the onset of diarrhea and a few days after the diarrhea has ended. To prevent the spread of infection among family members, soiled clothing or bedding should be washed in hot water immediately, hands must be washed frequently, there should be no sharing of utensils or cups used by the child, and toys and bathroom surfaces should be cleaned with a chlorine-based cleaner.

See also Food poisoning.

Resources

PERIODICALS

DeWit, Matty A.S., et. al. "Risk Factors for Nororvirus, Sappporo-like Virus, and Group A Rotavirus Gastroenteritis." Emerging Infectious Diseases 9, no. 12 (December, 2003): 1563–70. Available online at: <www.cdc.gov/eid>.

ORGANIZATIONS

American College of Gastroenterology (ACG). P.O. Box 3099, Alexandria, VA 22302. (703) 820-7400. Web site: <www.acg.gi.org/patientinfo>.

American Gastroenterological Association. 4930 Del Ray Ave., Bethesda, MD 20814. (301) 654-2055. Patient Information Resources. Web site: <www.gastro.org/generalPublic.html>.

Centers for Disease Control and Prevention. 1600 Clifton Rd., Atlanta, GA 30333. (800) 311-3435 or (404) 639-3534. Web site: <www.cdc.gov>.

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). 2 Information Way, Bethesda, MD 20892-3570. (800) 891-5389. Web site: <www.niddk.nih.gov>.

WEB SITES

"Gastroenteritis." September 24, 2003. Mayo Clinic. Available online at: <www.mayoclinic.com/invoke.cfm?id=DS00085>.

"Gastrointestinal Infections and Diarrhea." KidsHealth. Nemours Foundation, February 2002. Available online at: <www.kidshealth.org/PageManager.jsp?dn=KidsHealth&lic=1&os=107&cat_id=137&article_id=22887>.

"Viral Gastroenteritis." [cited August 20, 2001]. Centers for Disease Control. Available online at: <www.cdc.gov/ncidod/dvrd/revb/gastro/faq.htm>.

Julia Barrett Angela M. Costello

Gastroenteritis

Definition

Gastroenteritis is a general term for infection or irritation of the digestive tract, particularly the stomach and intestine. It is frequently referred to as stomach or intestinal flu, although the influenza virus does not cause this illness. Major symptoms include nausea, vomiting, diarrhea , and abdominal cramps. Fever and overall weakness sometimes accompany these symptoms. Gastroenteritis typically lasts about three days. Adults usually recover without problem, but children, the elderly, and persons with an underlying disease are more vulnerable to complications such as dehydration.

Description

Gastroenteritis is an uncomfortable and inconvenient ailment, but it is rarely life-threatening in the United States and other developed nations. However, in the United States an estimated 220,000 children younger than age five are hospitalized annually with gastroenteritis symptoms. Of these children, 300 die as a result of severe diarrhea and dehydration. In developing nations, diarrhea-related illnesses are a major source of mortality. In 1990, approximately three million deaths occurred worldwide as a result of diarrheal illness.

Viral gastroenteritis

Gastroenteritis is usually caused by infection with one of these viruses: rotavirus, adenovirus, astrovirus, calicivirus, and small round-structured viruses (SRSVs). These viruses are found all over the world and are particularly problematic where sanitation is poor. Typical exposure to these viruses occurs through the fecal-to-oral route, by ingesting food that is contaminated with fecal material or by coming in contact with an infected person's vomit or diarrhea and then inadvertently bringing the contaminant to the mouth. Other routes of transmission are quite likely, because exposure to as few as 100 virus particles can cause an infection.

Typically, children are more vulnerable to rotaviruses—the most common cause of acute watery diarrhea. It is estimated that each year rotaviruses cause 800,000 deaths worldwide in children younger than age five. For this reason, much research has gone into developing a vaccine to protect children from this virus. Adults can be infected with rotaviruses, but these infections typically have minimal or no symptoms.

Adenoviruses and astroviruses are minor causes of childhood gastroenteritis, and children may become infected with caliciviruses and SRSVs. Adults experience illness from astroviruses as well, but the major causes of adult viral gastroenteritis are the caliciviruses and SRSVs. The SRSVs are a type of calicivirus and include the Norwalk, Southhampton, and Lonsdale viruses. SRSVs are the most likely to produce vomiting as a major symptom.

Bacterial gastroenteritis

Bacterial gastroenteritis is frequently a result of poor sanitation, the lack of safe drinking water, or contaminated food—conditions that are common in developing nations. Natural or man-made disasters can worsen underlying sanitation and food-safety problems. In developed nations, modern food production, handling, and distribution systems and methods may expose millions of people to disease-causing bacteria. Common types of bacterial gastroenteritis can be linked to Salmonella and Campylobacter bacteria; however, Escherichia coli 0157 and Listeria monocytogenes are creating increased concern in developed nations. Cholera and shigella remain two diseases of great concern in developing countries, and research to develop long-term vaccines against them is underway.

Causes & symptoms

Gastroenteritis arises from ingestion of viruses, certain bacteria, or parasites. Spoiled food may also cause illness. Certain medications and excessive alcohol can irritate the digestive tract to the point of inducing gastroenteritis. Regardless of the cause, the symptoms of gastroenteritis include diarrhea, nausea, vomiting, abdominal pain , and cramps. Sufferers may also experience bloating, low fever, and overall tiredness. Typically, the symptoms last only two to three days, but some viruses may last up to a week.

A typical bout of gastroenteritis should not require a visit to the doctor. However, medical treatment is essential if symptoms worsen or if there are complications. Infants, young children, the elderly, and persons with underlying disease require special attention in this regard.

Dehydration is the greatest danger presented by gastroenteritis. The loss of fluids through diarrhea and vomiting can upset the body's electrolyte balance, leading to potentially life-threatening problems, such as heart beat abnormalities (arrhythmia). The risk of dehydration increases the longer that symptoms are present. Signs of dehydration include a dry mouth , increased or excessive thirst, or scanty urination.

Symptoms that do not clear up within a week may point to an infection or disorder more serious than gastroenteritis. Symptoms of great concern include a fever of 102°F (38.9°C) or above, blood or mucus in the diarrhea, blood in the vomit, and severe abdominal pain or swelling. Persons experiencing these symptoms should seek prompt medical attention.

Diagnosis

The symptoms of gastroenteritis are usually sufficient for identifying the illness. Unless there are complications or there is an outbreak that affects several people, identifying the specific cause of the illness is not a priority. However, if it is necessary to identify the infectious agent, a stool sample will be collected and analyzed for the presence of viruses, disease-causing (pathogenic) bacteria, or parasites.

Treatment

Gastroenteritis is a self-limiting illness that will resolve by itself. Symptoms of uncomplicated gastroenteritis can be relieved with adjustments in diet, herbal remedies, and homeopathy . An infusion of meadowsweet (Filipendula ulmaria ) may be effective in reducing nausea and stomach acidity. Once the worst symptoms are relieved, slippery elm (Ulmus fulva ) can be used to calm the digestive tract.

The homeopathic remedies Arsenicum album, ipecac , and Nux vomica are also believed to relieve the symptoms of gastroenteritis. In Chinese herbal medicine, the patent remedies Po Chai and Pill Curing can be effective for relieving nausea and diarrhea.

Supplementing the bacteria that are beneficial to a person's health (probiotics ) is recommended during the recovery phase of gastroenteritis. Specifically, live cultures of Lactobacillus acidophilus are said to be effective in soothing the digestive tract and returning the intestinal flora to normal. In fact, in 2002, a new study found it was reasonably effective in treating children with acute infectious diarrhea. L. acidophilus is found in live-culture yogurt and in capsule or powder form at health food stores. Castor oil packs applied to the abdomen can reduce inflammation, spasms, and discomfort.

It is important to stay hydrated and nourished during a bout of gastroenteritis. In the absence of dehydration, it should be sufficient to drink generous amounts of nonalcoholic fluids, such as water or juice. Caffeine should be avoided, since it increases urine output.

The traditional BRAT diet—bananas, rice, apple-sauce, and toast—is tolerated by the tender gastrointestinal system, but it is not particularly nutritious. Many, but not all, medical researchers recommend a diet that includes complex carbohydrates (rice, wheat, potatoes, bread, and cereal, for example), lean meats, yogurt, fruit, and vegetables. Milk and other dairy products shouldn't create problems if they are part of the normal diet. Fatty foods or foods with a lot of sugar should be avoided. These recommendations are based on clinical experience and controlled trials, but are not universally accepted.

Allopathic treatment

Over-the-counter medications such as Pepto Bismol are useful in relieving the symptoms of gastroenteritis. These medications work by altering the intestine's ability to move or secrete spontaneously, by absorbing toxins and water, or by altering intestinal microflora. Some over-the-counter medicines use more than one element to treat symptoms, and this information should be included on the label.

If over-the-counter medications are ineffective, a doctor may prescribe a more powerful anti-diarrheal drug, such as motofen or lomotil. If pathogenic bacteria or parasites are found in the patient's stool sample, medications such as antibiotics will be prescribed.

Minimal to moderate dehydration is treated with oral rehydrating solutions that contain glucose and electrolytes. These solutions are commercially available under names such as Naturalyte, Pedialyte, Infalyte, and Rehydralyte. If vomiting prevents the patient from taking a full dose of solution, he or she may better tolerate fluid taken in small, frequent amounts. Should oral rehydration fail or severe dehydration occur, medical treatment in the form of intravenous (IV) therapy is required. IV therapy can be followed with oral rehydration as the patient's condition improves. Once normal hydration is achieved, the patient can return to a regular diet.

Sometimes, a child's dehydration is so severe that it requires hospitalization with IV therapy. However, a study published in 2002 informed pediatricians that often, rapid intravenous rehydration and rapid nasogastric hydration in the emergency department are safe and effective alternatives to hospitalization for many children with viral gastroenteritis. Not only does this save money, it also saves a child the more frightening experience of being in a hospital overnight and the routine laboratory testing he or she would endure in the hospital setting.

Expected results

Gastroenteritis usually clears up within two to three days and there are no long-term effects. If dehydration occurs, recovery is extended by a few days.

Prevention

Gastroenteritis can be avoided by practicing good hygiene, which includes washing hands thoroughly after using the bathroom or coming in contact with an infected person, using disinfectants to clean areas the infected person has come in contact with, and washing infected linens in hot water. Making sure that food is well-cooked and unspoiled can prevent bacterial gastroenteritis, but may not be effective against viral gastroenteritis.

Resources

BOOKS

Hoffman, David. The Complete Illustrated Herbal. New York: Barnes & Noble, 1999.

Midthun, Karen, and Albert Z. Kapikian. "Viral Gastroenteritis." In Gastrointestinal and Hepatic Infections, edited by Christina Surawicz and Robert L. Owen. Philadelphia: W.B. Saunders, 1995.

PERIODICALS

Burke, Michael G."For Gastroenteritis, Rehydration But no Hospitalization." Contemporary Pediatrics (June 2002): 125.

Gorbach, Sherwood L. "Efficacy of Lactobacillus in Treatment of Acute Diarrhea." Nutrition Today 31, no. 6 (December 1996): 195.

Hart, C. Anthony, and Nigel A. Cunliffe. "Viral Gastroenteritis." Current Opinion in Infectious Diseases 10 (1997): 408.

Moss, Peter J., and Michael W. McKendrick. "Bacterial Gastroenteritis." Current Opinion in Infectious Diseases 10 (1997): 402.

Van Niel, Cornelius W., and others. "Lactobacillus Therapy for Acute Infectious Diarrhea in Children: A Meta-analysis." Pediatrics (April 2002): 678.

Paula Ford-Martin

Teresa G. Odle

Gastroenteritis

Definition

Gastroenteritis is a catchall term for infection or irritation of the digestive tract, particularly the stomach and intestine. It is frequently referred to as the stomach or intestinal flu, although the influenza virus is not associated with this illness. Major symptoms include nausea and vomiting, diarrhea, and abdominal cramps. These symptoms are sometimes also accompanied by fever and overall weakness. Gastroenteritis typically lasts about three days. Adults usually recover without problem, but children, the elderly, and anyone with an underlying disease are more vulnerable to complications such as dehydration.

Description

Gastroenteritis is an uncomfortable and inconvenient ailment, but it is rarely life-threatening in the United States and other developed nations. However, an estimated 220,000 children younger than age five are hospitalized with gastroenteritis symptoms in the United States annually. Of these children, 300 die as a result of severe diarrhea and dehydration. In developing nations, diarrheal illnesses are a major source of mortality. In 1990, approximately three million deaths occurred worldwide as a result of diarrheal illness.

The most common cause of gastroenteritis is viral infection. Viruses such as rotavirus, adenovirus, astrovirus, and calicivirus and small round-structured viruses (SRSVs) are found all over the world. Exposure typically occurs through the fecal-oral route, such as by consuming foods contaminated by fecal material related to poor sanitation. However, the infective dose can be very low (approximately 100 virus particles), so other routes of transmission are quite probable.

Typically, children are more vulnerable to rotaviruses, the most significant cause of acute watery diarrhea. Annually, worldwide, rotaviruses are estimated to cause 800,000 deaths in children below age five. For this reason, much research has gone into developing a vaccine to protect children from this virus. Adults can be infected with rotaviruses, but these infections typically have minimal or no symptoms.

Children are also susceptible to adenoviruses and astroviruses, which are minor causes of childhood gastroenteritis. Adults experience illness from astroviruses as well, but the major causes of adult viral gastroenteritis are the caliciviruses and SRSVs. These viruses also cause illness in children. The SRSVs are a type of calicivirus and include the Norwalk, Southhampton, and Lonsdale viruses. These viruses are the most likely to produce vomiting as a major symptom.

Bacterial gastroenteritis is frequently a result of poor sanitation, the lack of safe drinking water, or contaminated food-conditions common in developing nations. Natural or man-made disasters can make underlying problems in sanitation and food safety worse. In developed nations, the modern food production system potentially exposes millions of people to disease-causing bacteria through its intensive production and distribution methods. Common types of bacterial gastroenteritis can be linked to Salmonella and Campylobacter bacteria; however, Escherichia coli 0157 and Listeria monocytogenes are creating increased concern in developed nations. Cholera and Shigella remain two diseases of great concern in developing countries, and research to develop long-term vaccines against them is underway.

Causes and symptoms

Gastroenteritis arises from ingestion of viruses, certain bacteria, or parasites. Food that has spoiled may also cause illness. Certain medications and excessive alcohol can irritate the digestive tract to the point of inducing gastroenteritis. Regardless of the cause, the symptoms of gastroenteritis include diarrhea, nausea and vomiting, and abdominal pain and cramps. Sufferers may also experience bloating, low fever, and overall tiredness. Typically, the symptoms last only two to three days, but some viruses may last up to a week.

A usual bout of gastroenteritis shouldn't require a visit to the doctor. However, medical treatment is essential if symptoms worsen or if there are complications. Infants, young children, the elderly, and persons with underlying disease require special attention in this regard.

The greatest danger presented by gastroenteritis is dehydration. The loss of fluids through diarrhea and vomiting can upset the body's electrolyte balance, leading to potentially life-threatening problems such as heart beat abnormalities (arrhythmia). The risk of dehydration increases as symptoms are prolonged. Dehydration should be suspected if a dry mouth, increased or excessive thirst, or scanty urination is experienced.

If symptoms do not resolve within a week, an infection or disorder more serious than gastroenteritis may be involved. Symptoms of great concern include a high fever (102 ° F [38.9 °C] or above), blood or mucus in the diarrhea, blood in the vomit, and severe abdominal pain or swelling. These symptoms require prompt medical attention.

Diagnosis

The symptoms of gastroenteritis are usually enough to identify the illness. Unless there is an outbreak affecting several people or complications are encountered in a particular case, identifying the specific cause of the illness is not a priority. However, if identification of the infectious agent is required, a stool sample will be collected and analyzed for the presence of viruses, disease-causing (pathogenic) bacteria, or parasites.

Treatment

Gastroenteritis is a self-limiting illness which will resolve by itself. However, for comfort and convenience, a person may use over-the-counter medications such as Pepto Bismol to relieve the symptoms. These medications work by altering the ability of the intestine to move or secrete spontaneously, absorbing toxins and water, or altering intestinal microflora. Some over-the-counter medicines use more than one element to treat symptoms.

If over-the-counter medications are ineffective and medical treatment is sought, a doctor may prescribe a more powerful anti-diarrheal drug, such as motofen or lomotil. Should pathogenic bacteria or parasites be identified in the patient's stool sample, medications such as antibiotics will be prescribed.

It is important to stay hydrated and nourished during a bout of gastroenteritis. If dehydration is absent, the drinking of generous amounts of nonalcoholic fluids, such as water or juice, is adequate. Caffeine, since it increases urine output, should be avoided. The traditional BRAT diet-bananas, rice, applesauce, and toast-is tolerated by the tender gastrointestinal system, but it is not particularly nutritious. Many, but not all, medical researchers recommend a diet that includes complex carbohydrates (e.g., rice, wheat, potatoes, bread, and cereal), lean meats, yogurt, fruit, and vegetables. Milk and other dairy products shouldn't create problems if they are part of the normal diet. Fatty foods or foods with a lot of sugar should be avoided. These recommendations are based on clinical experience and controlled trials, but are not universally accepted.

Minimal to moderate dehydration is treated with oral rehydrating solutions that contain glucose and electrolytes. These solutions are commercially available under names such as Naturalyte, Pedialyte, Infalyte, and Rehydralyte. Oral rehydrating solutions are formulated based on physiological properties. Fluids that are not based on these properties-such as cola, apple juice, broth, and sports beverages-are not recommended to treat dehydration. If vomiting interferes with oral rehydration, small frequent fluid intake may be better tolerated. Should oral rehydration fail or severe dehydration occur, medical treatment in the form of intravenous (IV) therapy is required. IV therapy can be followed with oral rehydration as the patient's condition improves. Once normal hydration is achieved, the patient can return to a regular diet.

Alternative treatment

Symptoms of uncomplicated gastroenteritis can be relieved with adjustments in diet, herbal remedies, and homeopathy. An infusion of meadowsweet (Filipendula ulmaria ) may be effective in reducing nausea and stomach acidity. Once the worst symptoms are relieved, slippery elm (Ulmus fulva ) can help calm the digestive tract. Of the homeopathic remedies available, Arsenicum album, ipecac, or Nux vomica are three said to relieve the symptoms of gastroenteritis.

Probiotics, bacteria that are beneficial to a person's health, are recommended during the recovery phase of gastroenteritis. Specifically, live cultures of Lactobacillus acidophilus are said to be effective in soothing the digestive tract and returning the intestinal flora to normal. L. acidophilus is found in live-culture yogurt, as well as in capsule or powder form at health food stores. The use of probiotics is found in folk remedies and has some support in the medical literature. Castor oil packs to the abdomen can reduce inflammation and also reduce spasms or discomfort.

Prognosis

Gastroenteritis is usually resolved within two to three days and there are no long-term effects. If dehydration occurs, recovery is extended by a few days.

Prevention

There are few steps that can be taken to avoid gastroenteritis. Ensuring that food is well-cooked and unspoiled can prevent bacterial gastroenteritis, but may not be effective against viral gastroenteritis.

Resources

PERIODICALS

Hart, C. Anthony, and Nigel A. Cunliffe. "Viral Gastroenteritis." Current Opinion in Infectious Diseases 10 (1997): 408.

Moss, Peter J., and Michael W. McKendrick. "Bacterial Gastroenteritis." Current Opinion in Infectious Diseases 10 (1997): 402.

KEY TERMS

Dehydration— A condition in which the body lacks the normal level of fluids, potentially impairing normal body functions.

Electrolyte— An ion, or weakly charged element, that conducts reactions and signals in the body. Examples of electrolytes are sodium and potassium ions.

Glucose— A sugar that serves as the body's primary source of fuel.

Influenza— A virus that affects the respiratory system, causing fever, congestion, muscle aches, and headaches.

Intravenous (IV) therapy— Administration of intravenous fluids.

Microflora— The bacterial population in the intestine.

Pathogenic bacteria— Bacteria that produce illness.

Probiotics— Bacteria that are beneficial to a person's health, either through protecting the body against pathogenic bacteria or assisting in recovery from an illness.

Gastroenteritis

Gastroenteritis is an inflammation of the stomach and the intestines. More commonly, gastroenteritis is called the stomach flu.

The symptoms of gastroenteritis always include diarrhea. Fever, and vomiting can also be present. Typically the symptoms associated with a bout of gastroenteritis typically last only several days and are self-limiting. But sometimes the malady can be more extended.

The diarrhea in gastroenteritis is very loose, even watery. Also, bowel movements are frequent, occurring even several times an hour as the body attempts to expel the offending microorganism. This large loss of fluid creates the potential for dehydration. Usually dehydration is not an issue in an adult, unless the person is incapable of caring for themselves and has no other caregiver. Dehydration is an important issue in children. If a child is hospitalized because of diarrhea, it is usually because of complications arising from dehydration, rather than from the actual stomach and intestinal infection.

The other symptoms of gastroenteritis are especially complicating in children. Vomiting makes it difficult to administer drugs to combat a bacterial infection . Also, the loss of stomach contents can exacerbate dehydration.

Gastroenteritis-induced diarrhea is one of the major causes of death in infants around the world. In Asia, Africa, and Latin America millions of deaths in the newborn to four years age group occurs every year.

Gastroenteritis can be caused by viruses and bacteria . Viruses are the more common cause. Many There types of viruses can cause gastroenteritis. These include rotaviruses, enteroviruses, adenoviruses , caliciviruses, astroviruses, Norwalk virus and a group of Norwalk-like viruses. Of these, rotavirus infections are the most common.

Viral gastroenteritis tends to appear quickly, within three days of ingestion of the virus, and diminishes within a week. Those whose immune system is compromised may experience symptoms for a longer period of time.

Rotavirus is a virus that contains ribonucleic acid as the genetic material. The genetic material is enclosed within a double shell of protein. The virus is a member of the Reoviridae family of viruses. There are three main groups of rotavirus with respect to the antibodies that are produced against them. These types are called groups A, B, and C. Group A rotavirus is the cause of more than three million cases of gastroenteritis in the United States every year. The group B rotavirus causes diarrhea in adults, and has been the cause a several major outbreaks of severe diarrhea in China. Finally, the group C rotavirus can cause diarrhea in both children and adults, but is encountered much less frequently than groups A and B.

Rotavirus gastroenteritis is very contagious, spreading from person to person in a fecal to oral route. Not surprisingly, the virus is frequently encountered in day care facilities, where the care of the soiled diapers of infants occurs regularly. Improper hygiene , especially hand washing, contributes directly to the spread of the virus. Infected individuals can shed large numbers of virus in their diarrhea. Infection can also be spread by the contamination of eating utensils. Food can become contaminated if the food handler has not properly washed their hands after using the bathroom. Shellfish can also be a source of the virus. Because shellfish feed by filtering water through a special filter feeding apparatus, virus in the water can become trapped and concentrated inside the shellfish. Eating the shellfish, especially raw, spreads the virus.

Gastroenteritis due to the Norwalk virus tends to be more common in adults. However, more advanced immunological methods of detection have detected antibody to the virus in many children. Thus, children may be infected by the virus but show no symptoms. Infection in the adult years produces gastroenteritis, for reasons that are as yet unknown. Discovering the nature of the asymptomatic response of children could led to a therapeutic strategy for the adult infection.

Bacteria also cause gastroenteritis. The bacteria of concern include certain strains of Escherichia coli, Salmonella, Shigella , and Vibrio cholerae. In developed countries, where sanitary conditions and water treatment are established, bacterial gastroenteritis is infrequent. But the bacterial form remains problematic in the under-developed world, where water is more vulnerable to contamination. Bacterial gastroenteritis can also be caused by the ingestion of contaminated food. For example the presence of Salmonella in potato salad that has been improperly stored or of E.coli O157:H7 in undercooked meat can cause the malady.

The protozoan Cryptosporidium parvum also causes gastroenteritis following the ingestion of contaminated water.

The bacterial and protozoan cases of gastroenteritis account for well below half of the reported cases. The majority of cases are of viral origin.

In the treatment of gastroenteritis it is important to establish whether the source of the condition is bacterial, viral, protozoan or another and non-biological factor. Intolerance to the digestion of the lactose constituent of milk can also cause gastroenteritis, for example. The need to establish the origin of the malady is important, since bacterial infections will respond to the administration of antibiotics while viral infections will not. Furthermore, the use of antibiotics in a viral infection can actually exacerbate the diarrhea.

In August 1998, a vaccine for rotavirus gastroenteritis was licensed for sale in the United States. From September 1998 until July 1999, 15 cases of intussusception (a condition where a segment of bowel folds inside an adjacent segment, causing an obstruction) were reported among infants who received the vaccine. Subsequently, the vaccine was withdrawn from the market. No other vaccine has as yet been licensed for use.

See also Enterobacterial infections; Transmission of pathogens

Gastroenteritis

What Is Gastroenteritis?

What Causes Gastroenteritis?

How Is Gastroenteritis Treated?

How Can Gastroenteritis Be Prevented?

Resource

Gastroenteritis (gas-tro-en-ter-I-tis) is a disease in which the lining of the stomach and intestines becomes inflamed, resulting in what is sometimes referred to as an upset stomach or “stomach flu.”

KEYWORDS

for searching the Internet and other reference sources

Gastrointestinal system

Food poisoning

Infection

Inflammation

What Is Gastroenteritis?

Gastroenteritis is a general term for inflammation* of the gastrointestinal (gas-tro-in-TES-ti-nal) tract, the part of the digestive system consisting of the stomach, small intestine, and large intestine. Loss of appetite, vomiting, cramps, nausea*, and diarrhea* are the most common symptoms of gastroenteritis. In the United States, gastroenteritis usually is a mild disease. In countries where water supplies are dirty, sewage treatment is poor, or medical facilities are scarce, it sometimes leads to death.

* inflammation

(in-fla-MAY-shun) is the body’s reaction to irritation, infection, or injury that often involves swelling, pain, redness, and warmth.

* nausea

(NAW-zha) refers to a feeling of being sick to one’s stomach or needing to vomit.

* diarrhea

(di-ah-RE-a) refers to frequent, watery stools (bowel movements).

What Causes Gastroenteritis?

There are many different causes of gastroenteritis. Viral infections are the most common cause in the United States. Certain bacteria and parasites that can get into food or water supplies also can lead to the disease. In addition, gastroenteritis can result from food allergies or sensitivities, side effects of certain medications, and alcohol or toxic (poisonous) substances.

How Is Gastroenteritis Treated?

Mild gastroenteritis usually lasts just two or three days. Often, the only treatment needed is rest and drinking lots of clear fluids. However, gastroenteritis can be serious if vomiting and diarrhea cause dehydration (de-hy-DRAY-shun), a condition that results when a person loses fluid and body salts faster than they can be replaced by drinking. If a person becomes dehydrated, hospitalization may be needed to deliver intravenous (in-tra-VEE-nus) fluid replacement therapy. Intravenous (IV) therapy replaces lost fluid by dripping liquids and salts directly into the bloodstream through a small needle inserted into a vein.

How Can Gastroenteritis Be Prevented?

Washing the hands thoroughly after using the toilet, and before handling food, and before eating are important ways to prevent infectious gastroenteritis. Preparing and storing food properly also are important. For travelers who plan to visit developing countries, vaccines* are available against some of the diseases that cause gastroenteritis.

* vaccines

(vak-SEENZ) are preparations of a weakened or killed germ or of part of the germ’s structure. A vaccine stimulates the immune system to fight the germ but does not cause severe infection.

See also

Diarrhea

Food Poisoning

Viral Infections

Resource

U.S. Centers for Disease Control and Prevention (CDC), 1600 Clifton Road, Atlanta, GA 30333. This U.S. government agency posts a fact sheet about viral gastroenteritis at its website. Telephone 800-311-3435 http://www.cdc.gov