Acute gastroenteritis is a common infection in childhood. The majority of cases are caused by viruses, while ∼20% are bacterial, and a small number are parasitic. Most children have a mild presentation where nausea, vomiting, and diarrhea are not severe enough to prevent adequate oral intake or participation in normal activities. Severe disease is characterized by signs of significant dehydration, end-organ damage, fevers ≥ 40°C, signs of sepsis, bloody or bilious emesis, and toxic appearance. Children with mild-to-moderate gastroenteritis can be diagnosed clinically. Children with severe illness, atypical presentations, or signs of significant dehydration should undergo laboratory studies. Treatment is usually supportive with fluid replacement, antiemetics, and antipyretics. Antimicrobial therapy (empiric or tailored) may be utilized for children with suspected or confirmed bacterial or parasitic infections. Prevention of infectious gastroenteritis involves vaccination of infants against rotavirus, travel vaccines where appropriate, and patient/caregiver education on hand hygiene and food and water hygiene.
- Common illness in children, causing each year: 
- > 1.5 million outpatient visits
- ∼ 200,000 hospitalizations
- Severe illness is more common in children < 5 years of age. 
Epidemiological data refers to the US, unless otherwise specified.
- Most cases of gastroenteritis in children are viral gastroenteritis. 
- ∼ 20% of cases are bacterial gastroenteritis. 
- Parasites (e.g., Giardia lamblia) should be considered in children with persistent diarrhea.
Symptoms of infectious gastroenteritis in children are similar to adults and typically include:
- Nausea and vomiting
- Abdominal pain
- In children, additional clinical features that raise concern for severe illness include: 
- Fever ≥ 40°C or tachypnea
- Signs of poor peripheral perfusion
- Bloody or bilious emesis
- Altered mental status or excessive crying/fussiness
- Diagnosis is usually clinical.
Consider diagnostic studies for infectious gastroenteritis in children with: 
- Severe gastroenteritis
- Recent international travel or local outbreak
- Symptoms lasting > 1 week
- Assess for signs of significant dehydration; if present, order diagnostic studies for dehydration. 
|Clinical dehydration scale for acute gastroenteritis in children ≤ 5 years of age |
|Thirsty, restless, and/or lethargic but irritable with stimuli||1|
|Cold, sweaty, drowsy, limp, or unarousable||2|
|Tacky or sticky||1|
Diagnosis of viral gastroenteritis in children is usually clinical; diagnostic studies for infectious gastroenteritis are not routinely indicated. 
Gastrointestinal causes 
- Gastrointestinal causes of acute abdomen
- Inflammatory bowel disease
- Congenital disorders with diarrhea 
- Functional diarrhea 
- Antibiotic-associated diarrhea
Extra-intestinal causes 
- Meningitis in children
- Otitis media
- UTI in children and adolescents
- Toxic shock syndrome
The differential diagnoses listed here are not exhaustive.
Treatment of infectious gastroenteritis in children is generally supportive.
All patients 
- Determine the need for admission, e.g., patients with:
- Admission criteria for dehydration
- Severe gastroenteritis
- Inability to manage symptoms at home
- Barriers to follow up
- Provide symptomatic treatment.
- Give antipyretics and antiemetics as needed.
- Antidiarrheal medications are not routinely used. 
- Probiotics are not routinely recommended but may reduce the duration of diarrhea for immunocompetent patients. 
- Consider antimicrobial therapy for select patients. 
- Optimize nutrition.
- Maintain adequate oral intake through breastfeeding or age-appropriate foods. 
- Zinc supplementation is recommended for patients with malnutrition or in low-income regions. 
- Educate patients and/or caregivers on preventing onward transmission of gastroenteritis.
Mild to moderate gastroenteritis 
- Encourage fluid intake.
- Breastfed infants: Continue giving breastmilk.
- All other children: Consider apple juice diluted with water in a 50:50 mix followed by preferred fluids. 
- Give oral rehydration solution (ORS) if signs of moderate dehydration are present. 
- Advise caregivers to seek medical assistance if signs of significant dehydration develop.
Breastmilk should not be withheld in order to give ORS. 
Severe gastroenteritis or children with admission criteria for dehydration 
- Admit to hospital and initiate contact precautions.
- Identify patients in shock and start IV fluid resuscitation.
- Initiate treatment of dehydration and electrolyte repletion with either IV fluids or ORS.
When feasible, ORS is preferred over IV fluids; children unable to tolerate oral fluids can receive ORS via a nasogastric tube. 
We list the most important complications. The selection is not exhaustive.
- See “Prevention of infectious gastroenteritis.”
- Breastfeeding is associated with a reduced incidence of acute gastroenteritis in infants.