Treatment of Acute Gastroenteritis in Children
Oral rehydration solution (ORS) is the first-line treatment for children with acute gastroenteritis and mild-to-moderate dehydration, administered at 50-100 mL/kg over 2-4 hours, with immediate resumption of age-appropriate diet after rehydration. 1, 2
Assessment of Dehydration Severity
Evaluate the child's hydration status through physical examination focusing on:
- Mild dehydration (3-5% deficit): Slightly dry mucous membranes, normal skin turgor 2
- Moderate dehydration (6-9% deficit): Loss of skin turgor, dry mucous membranes, decreased urine output, prolonged skin retraction time 1, 3
- Severe dehydration (≥10% deficit): Signs of shock, altered mental status, poor perfusion—this is a medical emergency requiring immediate IV therapy 1
Rehydration Protocol by Severity
Mild Dehydration (3-5% deficit)
- Administer 50 mL/kg of ORS over 3-4 hours 1, 2
- For vomiting children, give small frequent volumes: 5-10 mL every 1-2 minutes using a spoon or syringe, gradually increasing as tolerated 1, 2
- Replace ongoing losses with 10 mL/kg ORS for each diarrheal stool and 2 mL/kg for each vomiting episode 1, 3
Moderate Dehydration (6-9% deficit)
- Administer 100 mL/kg of ORS over 2-4 hours 1, 3
- Reassess hydration status after 2-4 hours; if still dehydrated, reestimate fluid deficit and restart rehydration 3
- Continue replacing ongoing losses as above 3
Severe Dehydration (≥10% deficit)
- Immediate IV rehydration with 20 mL/kg boluses of Ringer's lactate or normal saline until pulse, perfusion, and mental status normalize 1
- Once consciousness returns, transition to oral rehydration for remaining deficit 1
Managing Vomiting
A common pitfall is allowing thirsty children to drink large volumes rapidly, which worsens vomiting. 1
- Administer ORS in small volumes (5-10 mL) every 1-2 minutes via spoon, syringe, or cup 1, 2
- Ondansetron may be given to children >4 years to facilitate oral rehydration tolerance: 8 mg sublingual every 4-6 hours 1, 2
- Continuous nasogastric infusion of ORS can be used for persistent vomiting 1
- Greater than 90% of vomiting children can be successfully rehydrated orally with this approach 1
Dietary Management
Resume age-appropriate diet immediately after rehydration is complete—do not withhold food. 1, 2
- Breastfed infants: Continue nursing on demand throughout illness 1, 3, 4
- Bottle-fed infants: Give full-strength, lactose-free or lactose-reduced formula immediately upon rehydration 1, 3
- Older children: Continue usual diet including starches, cereals, yogurt, fruits, and vegetables 1
- Avoid foods high in simple sugars and fats 1, 2
Early feeding reduces illness duration by approximately 18 hours and decreases treatment failure by half compared to delayed feeding 1. The traditional BRAT diet has limited supporting evidence 1.
Medications to Avoid
Antimotility agents (loperamide) should NEVER be given to children <18 years due to risk of ileus, lethargy, and reported deaths 1, 4
- Antibiotics are not routinely indicated unless there is bloody diarrhea (dysentery), high fever, or diarrhea lasting >5 days 1
- Antidiarrheal agents are generally not indicated and may cause complications 1
When to Use IV Therapy
Switch to intravenous fluids if:
- Severe dehydration with shock or altered mental status 1
- Failure of oral rehydration therapy despite proper technique 3
- Intractable vomiting unresponsive to ondansetron 1
- Stool output >10 mL/kg/hour (though most can still be managed orally) 1
Red Flags Requiring Immediate Medical Attention
- Bloody diarrhea (may require antimicrobial therapy) 1, 4
- Signs of severe dehydration or shock 1
- Altered mental status or lethargy 2
- Inability to tolerate any oral fluids despite proper technique 2
- Decreased urine output despite adequate fluid administration 2
Follow-Up
Instruct parents to return immediately if the child becomes irritable or lethargic, has decreased urine output, or develops intractable vomiting 2. Follow up with primary care within 24-48 hours if symptoms persist 2.