Treatment of Dehydrated Children

Assessment and Rehydration

The Centers for Disease Control and Prevention recommends initiating oral rehydration therapy immediately with 50-100 mL/kg of oral rehydration solution (ORS) containing 50-90 mEq/L sodium over 2-4 hours, based on the degree of dehydration, and beginning age-appropriate feeding as soon as rehydration is achieved 1
For mild dehydration (3-5% fluid deficit), administer 50 mL/kg ORS over 2-4 hours 1
For moderate dehydration (6-9% fluid deficit), administer 100 mL/kg ORS over 2-4 hours 1
For severe dehydration (≥10% fluid deficit, shock), this is a medical emergency requiring immediate IV rehydration with 20 mL/kg boluses of Ringer's lactate or normal saline until pulse, perfusion, and mental status normalize 1

Administer ORS using small, frequent volumes initially, starting with one teaspoon (5 mL) and gradually increasing the amount as tolerated 1
Reassess hydration status after 2-4 hours of oral rehydration therapy 1
If still dehydrated, reestimate the fluid deficit and restart rehydration therapy 1

Replace ongoing fluid losses during both rehydration and maintenance phases, administering 10 mL/kg ORS for each watery or loose stool, 2 mL/kg ORS for each episode of vomiting, and 1 mL of ORS for each gram of diarrheal stool 1

Resume normal feeding immediately upon achieving rehydration, with breast-fed infants continuing to nurse on demand, formula-fed infants offered full-strength, lactose-free or lactose-reduced formula, and older children resuming their normal age-appropriate diet 1

Do not delay rehydration while searching for fever source, begin oral rehydration immediately based on clinical assessment of dehydration 1
Do not withhold feeding, resume normal diet as soon as rehydration is achieved 1
Do not rely solely on fever height, the degree of dehydration, not fever severity, determines the rehydration approach 1