Pediatric Gastroenteritis

Updated: Jan 17, 2023
  • Author: Randy P Prescilla, MD; Chief Editor: Russell W Steele, MD  more...
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Practice Essentials

Although often considered a benign disease, acute gastroenteritis remains a major cause of morbidity and mortality in children around the world, accounting for 1.34 million deaths annually in children younger than 5 years, or roughly 15% of all child deaths. [1] As the disease severity depends on the degree of fluid loss, accurately assessing dehydration status remains a crucial step in preventing mortality. Luckily, most cases of dehydration in children can be accurately diagnosed by a careful clinical examination and treated with simple, cost-effective measures. Although dehydration technically refers to pure water loss and can be associated with euvolemic or even hypervolemic states in certain pediatric disorders, the term is used throughout this article in its more general sense to mean overall fluid or volume loss due to diarrhea.



Adequate fluid balance in humans depends on the secretion and reabsorption of fluid and electrolytes in the intestinal tract; diarrhea occurs when intestinal fluid output overwhelms the absorptive capacity of the gastrointestinal tract. The 2 primary mechanisms responsible for acute gastroenteritis are (1) damage to the villous brush border of the intestine, causing malabsorption of intestinal contents and leading to an osmotic diarrhea, and (2) the release of toxins that bind to specific enterocyte receptors and cause the release of chloride ions into the intestinal lumen, leading to secretory diarrhea. [2]

Even in severe diarrhea, however, various sodium-coupled solute co-transport mechanisms remain intact, allowing for the efficient reabsorption of salt and water. By providing a 1:1 proportion of sodium to glucose, classic oral rehydration solution (ORS) takes advantage of a specific sodium-glucose transporter (SGLT-1) to increase the reabsorption of sodium, which leads to the passive reabsorption of water. Rice and cereal-based ORS may also take advantage of sodium-amino acid transporters to increase reabsorption of fluid and electrolytes. [2]



Identifying the specific etiologic agent responsible for the acute gastroenteritis rarely changes management. However, it may be helpful to differentiate between viral, bacterial, parasitic, and noninfectious causes of diarrhea.

By far, viruses remain the most common cause of acute gastroenteritis in children, both in the developed and developing world. Rotavirus represents the most important viral pathogen worldwide, responsible for 37% of diarrhea-related deaths in children younger than 5 years. [3]  Rotavirus infection follows seasonal variation, with an increased incidence in winter and decreased incidence in summer months.

In the United States, routine rotavirus vaccination has led to a 60-75% reduction in pediatric rotavirus hospitalization since 2006. [4, 5]  A 2014 retrospective analysis reported that implementation of rotavirus vaccines has reduced the diarrhea-related healthcare use in US children by as much as 94% in 2009–2010. [6, 7]  With the continued decline of rotavirus-associated gastroenteritis, noroviruses (Norwalk-like viruses) have become the leading cause of medically attended acute gastroenteritis in children younger than 5 years in the United States, accounting for 14,000 hospitalizations, 281,000 emergency department visits, 627,000 outpatient visits, and more than $273 million in treatment costs each year. [8]  Caliciviruses, astroviruses, and enteric adenoviruses make up the remainder of cases of viral gastroenteritis. Viral gastroenteritis typically presents with low-grade fever and vomiting followed by copious watery diarrhea(upto10-20bowelmovementsper day),with symptomspersisting for 3-8 days. [9]

In developed countries, bacterial pathogens account for a small portion, perhaps 2-10%, of all cases of pediatric gastroenteritis. In the United States, the most important pathogens, in order of prevalence, are CampylobacterSalmonellaShigella, and Enterohemorrhagic Escherichia coli (EHEC) species. [9]  Relative to viral gastroenteritis, bacterial disease is more likely to be associated with high fevers, shaking chills, bloody bowel movements (dysentery), abdominal cramping, and fecal leukocytes.

In developing countries, Enterotoxigenic E coli (ETEC) remains the most important bacterial cause of acute gastroenteritis in children, followed by CampylobacterSalmonella, and Shigella, while also causing the majority of traveler’s diarrhea in all age groups. [10]  Unlike other bacterial causes of gastroenteritis, ETEC is unlikely to cause dysentery.

C difficile has emerged as an important cause of antibiotic-associated diarrhea in children. Any antibiotic can trigger infection with C difficile, although penicillins, cephalosporins, and clindamycin are the most likely causes. [9]  Since 50% of neonates and young infants are colonized with C difficile, symptomatic disease is unlikely in children younger than 12 months. [9]

Parasites remain yet another source of gastroenteritis in young children, with Giardia and Cryptosporidium the most common causes in the United States. Parasitic gastroenteritis generally presents with watery stools but can be differentiated from viral gastroenteritis by a protracted course or history of travel to endemic areas. [9]



United States statistics

Children in the United States experience, on average, 1.3-2.3 episodes of diarrhea each year. Overall, acute gastroenteritis accounts for than 1.5 million outpatient visits, 220,000 hospitalizations, and direct costs of more than $2 billion each year in the United States alone. [9]

The Community Acute Gastroenteritis (CAGE) Study found that the prevalence of acute gastroenteritis with diarrhea or vomiting was highest among patients aged 0-4 years (13.5%). In the acute diarrhea analysis, the prevalence of illness among those aged 5-17 years was 3.3%. Overall, the 30-day prevalence of acute gastroenteritis was 10.4%, a rate of 1.27 cases per person per year; of these, 23% reported both diarrhea and vomiting, 50% reported only diarrhea, and 27% reported only vomiting. [11, 12]

A study by Hullegie et al investigated the effects of first-year daycare attendance on acute gastroenteritis incidence and primary care contact rate up to age 6 years. The study found that first-year daycare attendance advances the timing of acute gastroenteritis infections, resulting in increased acute gastroenteritis disease burden in the first year and relative protection thereafter. The study also added that protection against acute gastroenteritis infection persists at least up to age 6 years. [13]

International statistics

Worldwide, children younger than 5 years have an estimated 1.7 billion episodes of diarrhea each year, leading to 124 million clinic visits, 9 million hospitalizations, and 1.34 million deaths, with more than 98% of these deaths occurring in the developing world. [1, 14, 15, 16]

Although the prevalence of acute gastroenteritis in children has changed little over the past 4 decades, mortality has declined sharply, from 4.6 million in the 1970s to 3 million in the 1980s and 2.5 million in the 1990s. [17] One of the most important reasons for this decline has been the increasing international support for the use of oral rehydration solution (ORS) as the treatment of choice for acute diarrhea, with the proportion of diarrheal episodes treated with ORS rising from 15% in 1984 to 40% in 1993. [17]