Causes

Viral gastroenteritis is a leading cause of severe diarrhea in both adults and children. Many types of viruses can cause gastroenteritis. The most common ones are:

• Astrovirus
• Enteric adenovirus
• Norovirus (also called Norwalk-like virus). It is common among school-age children.
• Rotavirus, the leading cause of severe gastroenteritis in children. It can also infect adults exposed to children with the virus. Outbreaks may also occur in nursing homes.

These viruses are often found in contaminated food or drinking water. Symptoms of viral gastroenteritis usually appear within 4 - 48 hours after exposure to the contaminated food or water.

Those with the highest risk for severe gastroenteritis include the young, the elderly, and people who have suppressed immune systems.

Symptoms

• Abdominal pain
• Diarrhea
• Nausea
• Vomiting

Other symptoms may include:

• Chills
• Clammy skin
• Excessive sweating
• Fever
• Joint stiffness
• Leakage (incontinence) of stool
• Muscle pain
• Poor feeding
• Vomiting blood (very rare)
• Weight loss

Exams and Tests

Your health care provider will look for signs that the body does not have enough water (dehydration). These include:

• Dry or sticky mouth
• Lethargic or comatose (severe dehydration)
• Low blood pressure
• Low or no urine output; concentrated urine appears dark yellow
• Markedly sunken soft spots (fontanelles) on the top of an infant's head
• No tears
• Sunken eyes

Tests that examine stool samples may be used to identify the specific virus. This is usually not needed for viral gastroenteritis. A stool culture may be done to identify a bacterial cause for diarrhea.

Treatment

The goal of treatment is to prevent dehydration by making sure the body has as much water and fluids as it should. Fluids and electrolytes (salt and minerals) lost through diarrhea or vomiting must be replaced by drinking extra fluids. Even if you are able to eat, you should still drink extra fluids between meals.

• Older children and adults can drink sports beverages such as Gatorade, but these should not be used for children. Instead, use the electrolyte and fluid replacement solutions or freezer pops available in food and drug stores.
• Do NOT use fruit juice (including apple juice), sodas or cola (flat or bubbly), Jell-O, or broth. All of these have a lot of sugar, which makes diarrhea worse, and they don't replace lost minerals.
• Drink small amounts of fluid (2-4 oz.) every 30-60 minutes, rather than trying to force large amounts at one time, which can cause vomiting. Use a teaspoon or syringe for an infant or small child.
• Breast milk or formula can be continued along with extra fluids. You do NOT need to switch to a soy formula.

Food may be offered frequently in small amounts. Suggested foods include:

• Cereals, bread, potatoes, lean meats
• Plain yogurt, bananas, fresh apples
• Vegetables

People with diarrhea who are unable to drink fluids because of nausea may need intravenous (directly into a vein) fluids. This is especially true in small children.

Antibiotics do not work for viruses.

Drugs to slow down the amount of diarrhea (anti-diarrheal medications) should not be given without first talking with your health care provider. They may cause the infection to last longer. DO NOT give these anti-diarrheal medications to children unless directed to do so by a health care provider.

People taking water pills (diuretics) who develop diarrhea may be told by their health care provider to stop taking the diuretic during the acute episode. However, DO NOT stop taking any prescription medicine without first talking to your doctor.

The risk of dehydration is greatest in infants and young children, so parents should closely monitor the number of wet diapers changed per day when their child is sick.

Outlook (Prognosis)

Most infections will go away on their own. Children may become severely ill from dehydration caused by diarrhea.

Possible Complications

Rotavirus causes severe gastroenteritis in infants and young children. Severe dehydration and death can occur in this age group.

When to Contact a Medical Professional

Call your health care provider if diarrhea persists for more than several days or if dehydration occurs. You should also contact your doctor if you or your child has these symptoms:

• Blood in the stool
• Confusion
• Dizziness
• Dry mouth
• Feeling faint
• Nausea
• No tears when crying
• No urine for 8 hours or more
• Sunken appearance to the eyes
• Sunken soft spot on an infant's head (fontanelle)

Prevention

Most infectious organisms are transmitted by unwashed hands. The best way to prevent viral gastroenteritis is to handle food properly and wash hands thoroughly after using the toilet.

Vaccination to prevent severe rotavirus infection is recommended for infants starting at age 2 months.

Alternative Names

Rotavirus infection; Norwalk virus; Gastroenteritis - viral; Stomach flu

References

Craig SA, Zich DK. Gastroenteritis. In: Mark JA, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa: Mosby Elsevier;2009:chap 92.

Zulfigar AB. Acute gastroenteritis in children. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 337.

Cortese MM, Parashar UD. Prevention of rotavirus gastroenteritis among infants and children: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR. 2009;58:1-25.

Update Date: 4/12/2012

Reviewed by: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Divison of Physician Assistant STudies, University of Washington School of Medicine; and George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.