Viral Gastroenteritis

What is viral gastroenteritis?

Viral gastroenteritis is an inflammation, swelling, and irritation of the inside lining of your gastrointestinal tract. A virus causes this illness. It can infect your stomach, small intestine, and large intestine.

Viral gastroenteritis is very common. In most cases, it lasts only a few days and doesn’t need treatment. The biggest danger is dehydration from fluid loss due to diarrhea and vomiting.

What causes viral gastroenteritis?

Several viruses can cause gastroenteritis. Viruses can be found in the vomit and the diarrhea of infected people. It can live for a long time outside the body. People who are infected can spread the virus to objects they touch, especially if they don’t wash their hands after using the bathroom. Food workers with the infection can spread it to others through food and drinks. Sewage that gets into the water supply can also spread the illness. Viral gastroenteritis is sometimes called stomach flu. But the seasonal flu (influenza) virus does not cause it.

Some of the common viruses that cause gastroenteritis include:

  • Rotavirus. This virus most often infects infants age 3 to 15 months. The illness lasts for 3 to 7 days and is most common in fall and winter.

  • Norovirus. This virus is the most common cause of adult infections. It’s often responsible for outbreaks on cruise ships. Symptoms last from 1 to 3 days and can occur any time of the year.

  • Adenovirus. This virus occurs year-round and affects children age 2 and younger. Symptoms last from 5 to 12 days.

Many other viruses can also cause viral gastroenteritis.

What are the symptoms of viral gastroenteritis?

Symptoms of viral gastroenteritis often begin about 1 to 2 days after the virus gets into the body.

Common symptoms include:

  • Nausea

  • Vomiting

  • Watery diarrhea

 Other possible symptoms are:

  • Headache

  • Fever

  • Chills

  • Stomachache

Signs of dehydration:

  • Decreased urine output

  • Dark-colored urine

  • Dry skin

  • Thirst

  • Dizziness

Signs of dehydration in young children:

  • Dry diapers (from a lack of urination)

  • Lack of tears

  • Dry mouth

  • Drowsiness

  • Sunken fontanel (the soft spot on the top of an infant’s head)

How is viral gastroenteritis diagnosed?

Your healthcare provider will most likely diagnose your condition based on your history and symptoms. In rare cases you may need testing. If your symptoms don't go away, your healthcare provider may ask for a stool sample. This is done to look for viruses, bacteria, and parasites.

Can viral gastroenteritis be prevented?

Vaccines are available to protect children from rotavirus. Healthcare providers give shots to babies before age 6 months. You and your children can help prevent viral gastroenteritis by taking these steps:

  • Wash hands for 20 seconds with soap and clean, running water after going to the bathroom, after changing a diaper, and before touching any food.

  • Use alcohol-based sanitizers.

  • If someone in the house has gastroenteritis, wash all surfaces that might be contaminated with a bleach-based cleaner.

  • Don't eat or drink any food or water with warnings of contamination.

How is viral gastroenteritis treated?

Specific treatment is often not needed. In most cases, you simply need to drink plenty of fluids and rest at home until the virus leaves your system. In rare cases, you may need treatment for severe dehydration with IV (intravenous) fluids.

Helpful home care tips include:

  • Drink plenty of light fluids like water, ice chips, diluted fruit juice, and broth. Keep in mind that sports drinks are high in sugar. They are not appropriate if you are extremely dehydrated. In this case, you will need an oral rehydration solution.

  • Don't have drinks that contain milk, caffeine, or alcohol.

  • Once you feel hungry again, start with mild, easy-to-digest foods.

  • Rehydrate children with oral rehydration solutions.

  • You may take antidiarrheal medicines for a couple days. But don't take these if you have a fever or bloody stool. Don't take them if you are an older adult. Don't give these to a child.

When should I call my healthcare provider?

Viral gastroenteritis is common in children and adults. In most cases, the disease is not serious and will run its course in a few days. Call your healthcare provider if you or a family member has any of the following:

  • Vomiting or diarrhea that’s not getting better

  • Bloody or tar-like stool

  • Any signs of dehydration

Key points about viral gastroenteritis

  • Viral gastroenteritis is an inflammation of the inside lining of your gastrointestinal tract.

  • It can be caused by rotavirus, norovirus, adenovirus, and other viruses.

  • Babies can be vaccinated against rotavirus.

  • Symptoms of viral gastroenteritis are nausea, vomiting, and watery diarrhea.

  • Dehydration is the most serious complication of this illness.

  • This illness should run its course in a few days. But it may need medical care if diarrhea or vomiting persists or if there are signs of dehydration.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.

  • Before your visit, write down questions you want answered.

  • Bring someone with you to help you ask questions and remember what your provider tells you.

  • At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

  • Know why a new medicine or treatment is prescribed and how it will help you. Also know what the side effects are.

  • Ask if your condition can be treated in other ways.

  • Know why a test or procedure is recommended and what the results could mean.

  • Know what to expect if you do not take the medicine or have the test or procedure.

  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.

  • Know how you can contact your provider if you have questions, especially after office hours or on weekends.

Online Medical Reviewer: Jen Lehrer MD
Online Medical Reviewer: Jessica Gotwals RN BSN MPH
Online Medical Reviewer: Tennille Dozier RN BSN RDMS
Date Last Reviewed: 8/1/2023
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