Viral gastroenteritis (stomach flu)

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Definition

Viral gastroenteritis is present when a virus causes an infection of the stomach and intestine. The infection can lead to diarrhea and vomiting. It is sometimes called the "stomach flu."

Alternative Names

Rotavirus infection - gastroenteritis; Norwalk virus; Gastroenteritis - viral; Stomach flu; Diarrhea - viral; Loose stools - viral; Upset stomach - viral

Causes

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 your system in many ways:

  • Directly from food or water
  • By way of objects such as plates and eating utensils
  • Passed from person to person by way of close contact

Many types of viruses can cause gastroenteritis. The most common viruses are:

  • Norovirus (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 in children. It can also infect adults who are exposed to children with the virus, and people living in nursing homes.
  • Astrovirus.
  • Enteric adenovirus.

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

Symptoms

Symptoms most often appear within 4 to 48 hours after contact with the virus. Common symptoms include:

Other symptoms may include:

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

Exams 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
  • Sunken soft spots (fontanelles) on the top of an infant's head
  • No tears
  • Sunken eyes

Tests of stool samples may be used to identify the virus that is causing the sickness. Most of the time, this test is not needed. A stool culture may be done to find out if the problem is being caused by bacteria.

Treatment

The goal of treatment is to make 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. These liquids do not replace lost minerals and can make diarrhea worse.
  • Drink small amounts of fluid (2 to 4 oz.) every 30 to 60 minutes. Do not try to force down large amounts of fluid at one time, which can cause vomiting. Use a teaspoon or syringe for an infant or small child.
  • Babies can continue to drink breast milk or formula along with extra fluids. You do NOT need to switch to a soy formula.

Try eating small amounts of food frequently. Foods to try include:

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

If you have diarrhea and are unable to drink or keep down fluids because of nausea or vomiting, you may need fluids through a vein (IV). Infants and young children are more likely to need IV fluids.

Parents should closely monitor the number of wet diapers an infant or young child has. Fewer wet diapers is a sign that the infant needs more fluids.

People taking water pills (diuretics) who develop diarrhea may be told by their provider to stop taking them until symptoms improve. However, DO NOT stop taking any prescription medicine without first talking to your provider.

Antibiotics do not work for viruses.

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

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

Outlook (Prognosis)

For most people, the illness goes away in a few days without treatment.

Possible Complications

Severe dehydration can occur in infants and young children.

When to Contact a Medical Professional

Call your provider if diarrhea lasts for more than several days or if dehydration occurs. You should also contact your 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 stomach flu is to handle food properly and wash your hands thoroughly after using the toilet.

A vaccine to prevent rotavirus infection is recommended for infants starting at age 2 months.

References

Bass DM. Rotaviruses, caliciviruses, and astroviruses. In: Kliegman RM, Stanton BF, St Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 265.

Bhutta ZA. Acute gastroenteritis in children. In: Kliegman RM, Stanton BF, St Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 340.

Dupont HL. Acute infectious diarrhea in immunocompetent adults. N Engl J Med. 2014; 370:(16)1532-1540. PMID: 24738670 www.ncbi.nlm.nih.gov/pubmed/24738670.

DuPont HL. Approach to the patient with suspected enteric infection. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 283.

Hanes CF, Sears CL. Infectious enteritis and proctocolitis. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 10th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 110.

Semrad CE. Approach to the patient with diarrhea and malabsorption. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 140.

Version Info

  • Last reviewed on 5/11/2016
  • Subodh K. Lal, MD, gastroenterologist with Gastrointestinal Specialists of Georgia, Austell, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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