What type of fluid should be given to a 21-month-old child with dehydration?

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Last updated: October 26, 2025View editorial policy

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Fluid Management for a 21-Month-Old Child with Dehydration

For a 21-month-old child with dehydration, oral rehydration solution (ORS) such as Pedialyte should be the first-line fluid choice, administered at 60-120 mL for each diarrheal stool or vomiting episode. 1

Initial Assessment and Management

  • For mild to moderate dehydration, administer oral rehydration solution (ORS) at 50-100 mL/kg over 3-4 hours 2
  • For severe dehydration, begin with intravenous isotonic crystalloid boluses (up to 20 mL/kg) until pulse, perfusion, and mental status normalize, then transition to oral rehydration 1
  • Start with small volumes (5-10 mL) using a teaspoon, syringe, or medicine dropper if the child is vomiting, and gradually increase as tolerated 2

Type of Fluid to Use

  • Use commercially available, low-osmolarity ORS such as Pedialyte (45 mEq/L sodium) or Ricelyte (50 mEq/L sodium) 1
  • Do not use apple juice, Gatorade, or commercial soft drinks for rehydration as they have inappropriate electrolyte content and high osmolality 1, 2
  • For a child weighing less than 10 kg, administer 60-120 mL ORS for each diarrheal stool or vomiting episode 1
  • For a child weighing more than 10 kg, administer 120-240 mL ORS for each diarrheal stool or vomiting episode 1

Ongoing Fluid Management

  • Continue ORS administration as long as diarrhea or vomiting persists 1
  • If the child is breastfed, continue nursing throughout the illness 1
  • Resume age-appropriate diet within 3-4 hours after rehydration is complete 2, 3
  • For maintenance fluids after rehydration, continue with ORS and add other appropriate fluids like breast milk or formula 1

Monitoring Response

  • Reassess hydration status after 3-4 hours to determine if rehydration is adequate 3
  • Monitor for signs of worsening dehydration: increased thirst, sunken eyes, decreased urine output, lethargy 4
  • If the child cannot tolerate oral intake but is not in shock, consider nasogastric administration of ORS at 15 mL/kg/hour 3

Special Considerations

  • Studies show that children who successfully tolerate at least 20-25 mL/kg of ORS during initial rehydration are more likely to be successfully managed at home 5
  • Both glucose-based (Pedialyte) and rice-based (Ricelyte) ORS are effective for rehydration of infants with mild to moderate dehydration 6
  • For hypernatremic dehydration, slow administration of ORS containing either 75 or 90 mEq/L sodium has been shown to be safe and effective 7

Common Pitfalls to Avoid

  • Avoid anti-diarrheal medications in children with acute diarrhea 2
  • Do not restrict fluids, as adequate hydration is essential for recovery 3
  • Do not delay feeding until diarrhea stops; early feeding can reduce the severity, duration, and nutritional consequences of diarrhea 1
  • Do not use homemade salt-sugar solutions due to risk of incorrect preparation; use commercially available ORS when possible 8

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Pediatric Dehydration Management with Oral Rehydration Solutions

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Oral Rehydration Therapy for Children

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Management of a Mildly Dehydrated Child with Bilirubinuria

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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