Gastroenteritis is inflammation of the digestive tract that results in vomiting, diarrhea, or both and is sometimes accompanied by fever or abdominal cramps.
For gastroenteritis in adults, see Gastroenteritis.
Gastroenteritis, sometimes incorrectly called “stomach flu,” is the most common digestive disorder among children (see Gastroenteritis: Overview of Gastroenteritis). Severe gastroenteritis causes dehydration and an imbalance of blood chemicals (electrolytes) because of a loss of body fluids in the vomit and stool.
About 5 billion episodes occur worldwide each year, most commonly in developing countries among children under 5 years of age. In developing countries where children are more vulnerable and care is often not easy to access, about 1.5 million children die each year from diarrhea caused by gastroenteritis. In developed countries where children are well nourished and have access to excellent medical care (most importantly, hydrating fluids given by vein [intravenously] when needed), gastroenteritis can cause discomfort and incapacitation but does not last long and only very rarely has serious consequences. About 2% of children in developed countries will require hospitalization at some time because of severe gastroenteritis and dehydration. In the United States, severe gastroenteritis causes about 200,000 hospitalizations and 3 to 5 million outpatient visits. Of the 25 to 35 million episodes that occur each year in the United States, 300 to 400 result in death.
Viruses (such as rotavirus) are the most common cause of gastroenteritis in the United States. Children usually contract viral gastroenteritis from other children who have had it or who have been exposed to it, such as those in child care centers, schools, and other crowded settings. Viral gastroenteritis is generally spread from hand to mouth but can also be spread by sneezing and spitting. It spreads particularly easily because of the way children play—putting hands and fingers in and near their mouth and then touching toys and each other.
Bacteria (such as Escherichia coli [E. coli], Salmonella, or Shigella) and parasites (such as Giardia) can also cause gastroenteritis. Children can contract bacterial gastroenteritis from touching or eating contaminated foods, particularly raw or inadequately cooked meats or eggs, drinking unpasteurized milk or juice, and touching animals that carry certain bacteria. For example, children can contract Salmonella by touching reptiles (turtles or lizards), birds, or amphibians (frogs or salamanders) and rarely can contract E. coli by touching animals at petting zoos. Bacteria may grow in many types of foods that have been left out and not refrigerated (potential problem situations include buffets and picnics). If Staphylococcus bacteria contaminate food, it may secrete a toxin that causes sudden vomiting and diarrhea. Gastroenteritis contracted from food containing microorganisms or bacterial toxins is sometimes called food poisoning (see Poisoning: Chemical Food Poisoning). Occasionally, some bacteria are transmitted by dogs or cats with diarrhea. Children can contract bacterial or parasitic gastroenteritis from eating shellfish; swallowing contaminated water, such as from wells, streams, and swimming pools; and while traveling in developing countries.
Occasionally, gastroenteritis results when children eat things they are not supposed to, such as plants and drugs. Rarely, gastroenteritis results because of an allergic condition (eosinophilic gastroenteritis).
Symptoms and Diagnosis
Symptoms are usually a combination of vomiting, diarrhea, abdominal cramps, fever, and poor appetite. Usually, vomiting predominates early in the illness, particularly when the cause is viral. Diarrhea becomes more prominent later, but some children have both at the same time. With viral causes, watery diarrhea may be the main symptom. The stools may be bloody if certain bacteria are the cause. These symptoms eventually lessen in children who drink enough fluids. The most common complication of severe gastroenteritis is dehydration (see Miscellaneous Disorders in Infants and Young Children: Dehydration in Children), which occurs when fluid is lost in vomit and stool. Children who are slightly dehydrated are thirsty, but seriously dehydrated children become listless, irritable, or sluggish (lethargic). Infants are much more likely than older children to become dehydrated and develop serious side effects. Dehydrated infants produce no tears when they cry and produce less urine. However, it can be hard to assess urine output in diapered children who are having frequent watery stools. It is easier to identify decreased urine output and excessive thirst in older children.
A doctor bases the diagnosis of gastroenteritis on the child's symptoms and on the parents' responses to questions about what the child has been exposed to. Diagnostic tests are not usually needed because most forms of gastroenteritis last a short time. However, general laboratory tests can help doctors pinpoint a cause of the gastroenteritis and identify any imbalance of blood chemicals.
The best way to prevent gastroenteritis is to encourage children to wash their hands and to teach them to avoid improperly stored foods. A good general guideline is to keep cold foods cold and hot foods hot. Food placed out for consumption should be consumed within an hour. Diaper-changing areas should be disinfected with a freshly prepared solution of household bleach (¼ cup bleach diluted in 1 gallon of water).
Two vaccines to prevent rotavirus infection are available (see Immunization: Rotavirus). The current rotavirus vaccines are not associated with intussusception (the serious problem of the intestine telescoping in on itself), as was the case with the original vaccine. Once they become widely used, these vaccines should significantly reduce the number of hospitalizations and deaths due to gastroenteritis, particularly in the developing world.
Breastfeeding is another simple and effective way to help prevent gastroenteritis. Children with diarrhea should not return to child care centers until their symptoms are gone.
Parents can help prevent dehydration by encouraging their child to drink fluids even if just in small, frequent amounts.
Infants and children with a weakened immune system should not touch reptiles, birds, or amphibians.
Parents can prevent recreational water illnesses by not allowing their children to swim in public water if they have diarrhea. Children who wear diapers should be checked frequently for stool and changed in an area that is not near the water. Parents should teach their children to avoid swallowing water when they swim.
Once a child has gastroenteritis, parents should monitor their child's hydration status. Infants are dehydrated and need medical care right away if
Children should be encouraged to drink fluids even if just in small, frequent amounts. Infants should continue to breastfeed or drink formula in addition to an oral electrolyte solution (rehydration solution—available as powders and liquids in pharmacies and some grocery stores). Juice, soda, carbonated beverages, teas, sports drinks, and beverages containing caffeine should not be given to infants and young children. These drinks may contain too much sugar, which can worsen diarrhea, and have too few salts (electrolytes), which are needed to replace those the body has lost. For older children, however, sports drinks are preferable to juice and soda because of their lower sugar content, but they still have lower amounts of electrolytes than oral electrolyte solutions.
For a vomiting child, frequent small amounts of fluid help prevent dehydration. Parents should offer the child a few sips of a liquid. If the liquid is not vomited, the sips are repeated every 10 or 15 minutes, increasing the amount given to an ounce or two after an hour or so and increased as tolerated. These larger amounts can be given less often, about every hour. Liquids are absorbed very quickly, so if the child vomits more than 10 minutes after drinking, most of the liquid has been absorbed and the liquids should be continued. The amount of liquid to give a child within a 24-hour period depends on the child's age but generally should be about 1½ ounces of liquid for each pound the child weighs. If the child's vomiting or diarrhea lessens, parents may try resuming a more normal diet the next day. Electrolyte solutions should not be continued for longer than 24 hours because of potential problems associated with inadequate nutritional intake.
Children with diarrhea but little vomiting should get extra fluid to make up for the fluid lost in the diarrhea. But, unlike children with vomiting, they may be given larger amounts of fluid at a time. They are fed their normal diet, except that if there is significant diarrhea, the child's consumption of dairy products (which contain lactose) should probably be reduced. Severe gastroenteritis may decrease the child's ability to absorb lactose, resulting in even more diarrhea.
Children who cannot keep down even sips of liquid or who have signs of severe dehydration (such as lethargy, dry mouth, lack of tears, and no urine for 6 hours or more) are in danger and should see a doctor immediately. Children who do not have these signs should see a doctor if symptoms last more than 1 or 2 days. If the dehydration is severe, the doctor may give the child intravenous fluids.
Antidiarrheal drugs such as loperamide are not usually recommended for children. However, under the guidance of a doctor, certain drugs that prevent or relieve nausea or vomiting (such as ondansetron) can be given once the cause of vomiting has been determined. Antibiotics are of no value when a viral infection is the cause of gastroenteritis. Doctors give antibiotics only for certain bacteria that are known to respond to these drugs. Antiparasitic drugs may be given for a parasitic infection.
Probiotics, such as lactobacillus (typically present in yogurt), may slightly shorten the duration of diarrhea (perhaps by a day) if people begin taking them soon after the illness starts. However, probiotics probably do not prevent more serious consequences of gastroenteritis such as the need for intravenous fluids or for hospitalization.
Last full review/revision November 2012 by William J. Cochran, MD