Recommended Hydration Regimen for Children with Viral Illness
For children with viral illness and mild to moderate dehydration, oral rehydration solution (ORS) is the first-line treatment, administered at 50-100 mL/kg over 3-4 hours, followed by replacement of ongoing losses with 60-120 mL ORS for each diarrheal stool or vomiting episode. 1
Assessment of Hydration Status
Determine dehydration severity through physical examination:
- Mild to moderate dehydration: Use the Clinical Dehydration Scale based on appearance, eyes, mucous membranes, and tears 2
- Severe dehydration (≥10% fluid deficit): Look for altered mental status, abnormal pulse with poor perfusion, shock or near-shock state 3
- Key pitfall: Signs of dehydration may be masked in hypernatremic children 3
Treatment Algorithm by Dehydration Severity
Mild to Moderate Dehydration (Most Common)
Initial rehydration phase:
- Administer ORS at 50-100 mL/kg over 3-4 hours 1
- Continue breastfeeding throughout the illness 1
- Resume age-appropriate normal diet immediately after rehydration is complete 1
Maintenance and ongoing loss replacement:
- For children <10 kg: Give 60-120 mL ORS for each diarrheal stool or vomiting episode, up to ~500 mL/day 1
- For children >10 kg: Give 120-240 mL ORS for each diarrheal stool or vomiting episode, up to ~1 L/day 1
Commercially available ORS products in the United States:
- Pedialyte (45 mEq/L sodium) and Ricelyte (50 mEq/L sodium) are appropriate for maintenance 1
- Solutions with 40-60 mEq/L sodium are recommended for viral diarrhea prevention and maintenance 1
- Avoid apple juice, Gatorade, and commercial soft drinks—these lack appropriate electrolyte composition 3
Alternative Route if Oral Intake Fails
Nasogastric ORS administration:
- Consider for children with moderate dehydration who cannot tolerate oral intake or are too weak to drink 1
- Administer at the same rate as oral therapy: 50 mL/kg over 3 hours 4
- This approach is as efficacious as intravenous therapy and more cost-effective 4
Severe Dehydration (Medical Emergency)
Immediate resuscitation:
- Administer intravenous isotonic crystalloid boluses of 20 mL/kg using lactated Ringer's or normal saline 1, 3
- For malnourished infants: Use smaller-volume frequent boluses of 10 mL/kg due to reduced cardiac capacity 3
- Continue boluses until pulse, perfusion, and mental status normalize 1, 3
Transition to oral therapy:
- Once the child awakens with normal mental status and can tolerate oral intake, transition to ORS to replace remaining deficit 3
- Continue replacing ongoing losses with ORS as described above 3
Adjunctive Therapy
Ondansetron for vomiting:
- May be given to children >4 years to facilitate tolerance of oral rehydration 1
- Increases success rate of oral rehydration and minimizes need for IV therapy 5
Avoid antimotility drugs:
- Loperamide and similar agents should not be given to children <18 years with acute diarrhea 1
Critical Clinical Pitfalls
Do not:
- Dilute infant formula—this provides no benefit 1
- Restrict feeding or practice "therapeutic starvation"—early feeding reduces severity and duration 1
- Use physiologically inappropriate fluids like sports drinks or juice for rehydration 3
- Administer IV fluids when oral or nasogastric rehydration is feasible 6
Laboratory testing:
- Routine electrolyte testing is unnecessary for mild to moderate dehydration 2, 4
- Reserve testing for severe dehydration requiring hospitalization 5
Special Considerations for Influenza
For children hospitalized with influenza: