Dr. Sarah Livelo 12 Oct 2021

What is Acute Gastroenteritis?

Acute gastroenteritis is an infectious condition characterized by diarrhea, which may be accompanied by fever, vomiting, or abdominal pain. It is the fourth most common cause of child deaths worldwide; about 68% of people with diarrheal disease are young children.

The most common cause of gastroenteritis is infection with rotavirus. Well-known etiologies include viruses, bacteria, and parasites. These infectious agents may be acquired from contaminated food or water, and unclean hands.

By definition, patients with acute gastroenteritis have at least 3 loose or watery stools per day. Children may present with fever, nausea, vomiting, abdominal pain, and signs of dehydration. Although most cases are mild to moderate, symptoms may become severe if not identified promptly and treated appropriately.

Risk Factors for Acute Gastroenteritis

Certain situations may place a child at higher risk for this illness. This includes living in areas with insufficient or inadequate sanitation, including unsanitary drinking water. Improper cooking or storage of food can become a haven for certain bacteria and parasites, especially in large catering events. Places that have potential problems with hygiene and sanitary measures, such as daycare, nursing homes and recreational swimming facilities, provide opportunities for unwanted transmission of infectious agents.

Younger children are more prone to infection with viral causes of gastroenteritis. Lack of breastfeeding or proper nutrition, infection with measles, and the presence of immunodeficiencies are other risk factors.

Types of Acute Gastroenteritis

Gastroenteritis may be caused by a variety of infectious (and noninfectious) agents. The following paragraphs give a small overview of each major group.

Viral Gastroenteritis

Viruses, such as rotavirus and calicivirus, can cause gastroenteritis. Symptoms may appear from 12 hours up to 4 days from exposure to the virus. Viral gastroenteritis can last between 1-8 days, and usually involves vomiting, followed by diarrhea, fever and abdominal pain.

Bacterial Gastroenteritis

A significant number of bacteria can cause gastroenteritis. Specific examples are non-typhoidal Salmonella, Shigella, Campylobacter, Yersinia, Escherichia coli, Vibrio cholerae and Clostridium difficile. It can take up to 7 days from exposure before symptoms show up. The duration of symptoms can run up to 10 days, even with treatment. Common symptoms include very frequent bloody or watery diarrhea (as much as 10 episodes a day), nausea, vomiting, abdominal pain, and high-grade fever of at least 40°C (104°F).

Parasitic Gastroenteritis

A handful of unintentionally ingested parasites can cause gastroenteritis, typically Giardia, Cryptosporidium, Cyclospora, and Entamoeba. Unlike viruses and bacteria, parasitic infections may take longer before symptoms become apparent. Affected individuals may acquire the parasite a few weeks before symptoms start.

Parasitic gastroenteritis is characterized by either watery or greasy and foul-smelling stools, with bloating, flatulence, and abdominal cramps. Some children are hit with fatigue, weight loss, and other signs of malabsorption of nutrients from the gut. Those who are immunocompromised may experience more severe symptoms.

Foodborne, Noninfectious Gastroenteritis

Acute gastroenteritis may develop from exposure to noninfectious agents. Some examples are chemicals or elements such as antimony, arsenic, cadmium, copper, mercury, thallium, and tin. Toxins from plants and animals may cause gastroenteritis as well, namely, shellfish toxins, mushroom toxins and tetrodotoxin (from puffer fish). Pesticides and nitrite poisoning are uncommon causes.

For some agents, only a few minutes are needed before symptoms appear, while others can take a few days. Frequently encountered signs and symptoms include nausea, vomiting, abdominal pain, muscle aches, body weakness, problems with vision and balance, and a metallic taste in the mouth. A few can cause neurological symptoms like confusion and convulsions.

The Overall Picture

The most common symptoms in children with gastroenteritis are diarrhea and vomiting. Stools may be loose or liquid, and some may have mucus or blood. Children may have fever and complain of abdominal pain. The degree of dehydration often determines how severe the infection is. Healthcare providers estimate the degree of dehydration by observing a child’s activity level, thirst for water or fluids, hydration of the skin and mucous membranes, the ease in breathing, and the quality of the skin when pinched.

Dehydration is most likely minimal if a child can drink or eat normally, has no vomiting episodes, and is able to pass the usual amount of urine.

Most cases of acute gastroenteritis typically do not last beyond a week. However, there are prolonged cases lasting 7-13 days, and persistent cases that last for more than 2 weeks.

Important Points to Share to Healthcare Providers

When seeking medical care, the following are important points that should be shared to healthcare providers. These can significantly contribute to a better assessment of a child:

  1. duration of symptoms: when did the symptoms start? which symptom developed first?
  2. descriptions of the stools and/or vomit, such as the estimated amount per episode, color, and consistency
  3. fever episodes: what was the highest recorded temperature?
  4. how much food and liquids can he or she take at the moment? are they thirsty or refusing to drink water?
  5. when was the last time the child urinated? for infants, compare how many wet diapers per day before and after symptoms started


The main goal in acute gastroenteritis is to prevent or limit dehydration. This includes providing an oral solution with the proper balance of electrolytes, to replenish any losses. This is called an oral rehydration solution (ORS) and is commonly given to children with mild to moderate cases of acute gastroenteritis. For infants and young children who breastfeed, breastmilk may also be given, initially in small amounts, as long as the child can tolerate it. Milk may also be continued for babies on formula.

If the child can successfully drink ORS, a slow reintroduction of fruits, vegetables, bread, potatoes, or cereals may be done. Foods and liquids high in fats or sugar, such as soda or juice, should not be given as these could worsen symptoms.

Children who are actively vomiting, refusing or are unable to drink, have decreased consciousness, or have an excessive amount of diarrhea may be rehydrated through intravenous means (inserting a line through the skin and into a vein). Certain surgical conditions, if present alongside diarrhea, may also be an indication for intravenous hydration.

Depending on the child’s overall condition and the likely cause of the symptoms, healthcare providers may include either antibiotics, probiotics, or zinc supplementation. There are instances where appropriate hydration is already sufficient for treatment.


Even infants and young children can get easily hit with acute gastroenteritis. Prevention can start right when a child is born.

Choosing to breastfeed a child, whether exclusively or as the major nutrition source in mixed feeding, promotes a stronger immune system to combat viral gastroenteritis, most especially in developing countries. Immunization with the rotavirus vaccine significantly decreases the risk of a severe rotavirus infection in the first few months of life. Studies also show the benefits of Vitamin A supplementation in a child’s diet, as a concomitant vitamin A deficiency can contribute to a severe outcome in gastrointestinal infections. Vitamin A supplementation is done through fortification of common foods, such as milk and dairy.

The most important risk factor involved in acute gastroenteritis is hygiene. Make sure that a child’s environment is regularly cleaned. Soiled sheets should be changed, and surfaces cleaned with warm or hot water and soap. If possible, use hot water and high heat for the laundry. When bringing your child to environments with possible hygiene concerns (such as daycare), choose areas that are well-kept and regularly sanitized.


Acute gastroenteritis is a common infectious disease with diarrhea as the predominant symptom. Nausea, vomiting, fever and abdominal pain may also occur. Most cases are mild and are frequently due to viral infections. Management of this illness centers on rehydration and proper hygiene measures.

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About the Author:
Dr. Sarah Livelo is a licensed physician with specialty training in Pediatrics. When she isn't seeing patients, she delves into healthcare and medical writing. She is also interested in advancements on nutrition and fitness. She graduated with a medical degree from the De La Salle Health Sciences Institute in Cavite, Philippines and had further medical training in Makati Medical Center for three years.


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  • Hartman, S., Brown, E., Loomis, E., & Russell, H.A. (2019). Gastroenteritis in Children. Am Fam Physician. 2019 Feb 1;99(3):159-165.
  • Thornton, K.A., Mora-Plazas, M., Marín, C., & Villamor, E. (2014). Vitamin A Deficiency Is Associated with Gastrointestinal and Respiratory Morbidity in School-Age Children. The Journal of Nutrition 144(4): 496-503.
  • Swanson, W.S. (2015). Surviving the Stomach Bug: Truths & Tips for Parents. Mama Doc Medicine: Finding Calm and Confidence in Parenting, Child Health, and Work-Life Balance. Taken from:

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