Viral gastroenteritis

Definition

Viral gastroenteritis is sometimes called the "stomach flu." It refers to swelling or inflammation of the stomach and intestines from a virus. The infection can lead to diarrhea and vomiting.

Alternative Names

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

Causes, incidence, and risk factors

Gastroenteritis can affect one person or a group of people who all ate the same food or drank the same water. The germs may get into the food you eat (called contamination) in different ways.

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:

• Norovirus (or Norwalk-like virus) is common among school-age children. It may also cause outbreaks in hospitals and on cruise ships.
• Rotavirus is the leading cause of severe gastroenteritis in children. It can also infect adults who are exposed to children with the virus, and people living in nursing homes.
• Astrovirus
• Enteric adenovirus

Symptoms

Symptoms most often appear within 4 to 48 hours after contact with the contaminated food or water, and include:

• Abdominal pain
• Diarrhea
• Nausea and vomiting

Other symptoms may include:

• Chills, clammy skin, or sweating
• Fever
• Joint stiffness or muscle pain    
• Poor feeding
• Weight loss

Signs and tests

The health care provider will look for signs of dehydration, including:

• Dry or sticky mouth
• Lethargy or coma (severe dehydration)
• Low blood pressure
• Low or no urine output; concentrated urine that looks 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 which virus is causing the sickness. This is usually not needed for viral gastroenteritis. A stool culture may be done to find out whether diarrhea are causing the problem.

Treatment

The goal of treatment is to prevent dehydration by making sure the body has enough water and fluids. Fluids and electrolytes (salt and minerals) that are 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 younger 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. Do not try to force large amounts of fluid 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 often 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. 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 health care provider.

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.

You can buy medicines at the drugstore that can help stop or slow diarrhea.

• Do not use these medicines without talking to your health care provider if you have bloody diarrhea, a fever, or if the diarrhea is severe.
• Do not give these medicines to children.

Support Groups

Expectations (prognosis)

The illness usually runs its course in a few days without treatment.

Children may become severely ill from dehydration caused by diarrhea.

People with the highest risk for severe gastroenteritis include young children, the elderly, and people who have a suppressed immune system.

Complications

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

Calling your health care provider

Call your health care provider if diarrhea lasts for more than several days or if dehydration occurs. You should also contact your health care provider 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 viruses and bacteria are passed from person to person by unwashed hands. The best way to prevent viral gastroenteritis is to handle food properly and wash your hands thoroughly after using the toilet.

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

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References

DuPontHL. Approach to the patient with suspected enteric infection. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 291.

Semrad CE. Approach to the patient with diarrhea and malabsorption. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 142.

Giannella RA. Infectious enteritis and proctocolitis and bacterial food poisoning. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger & Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier;2010:chap 107.

Zulfigar AB. Acute gastroenteritis in children. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier;2011:chap 332.

Bass DM. Rotaviruses, caliciviruses, and astroviruses. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier;2011:chap 257.