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 .
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.
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
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.
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
- 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
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.
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.
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 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.
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.
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.
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.
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 .
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American College of Gastroenterology (ACG). P.O. Box 3099, Alexandria, VA 22302. (703) 820-7400. Web site: http://www.acg.gi.org/patientinfo.
American Gastroenterological Association. 4930 Del Ray Ave., Bethesda, MD 20814. (301) 654-2055. Patient Information Resources. Web site: http://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: http://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: http://www.niddk.nih.gov.
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Julia Barrett Angela M. Costello