How should dehydration in children be assessed and managed, including oral rehydration therapy and intravenous fluid replacement?

Assessment and Management of Dehydration in Children

Assess Dehydration Severity Using Clinical Signs

The most critical first step is to classify dehydration severity using a combination of physical examination findings, as this determines all subsequent management decisions. 1, 2

Mild Dehydration (3-5% Fluid Deficit)

• Increased thirst and slightly dry mucous membranes 1, 2
• Normal mental status and skin turgor 3

Moderate Dehydration (6-9% Fluid Deficit)

• Loss of skin turgor with skin tenting when pinched 1, 2
• Dry mucous membranes, sunken eyes, and reduced urine output 3

Severe Dehydration (≥10% Fluid Deficit)

• Severe lethargy or altered consciousness 1, 2
• Prolonged skin tenting >2 seconds 2
• Cool, poorly perfused extremities with delayed capillary refill 1, 2
• Rapid, deep breathing indicating acidosis 1, 2

Capillary refill time, prolonged skin retraction, and decreased perfusion are more reliable predictors than sunken fontanelle or absent tears. 1, 2

Obtain body weight immediately to calculate fluid deficit and monitor response 1, 3

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Rehydration Protocol Based on Severity

Mild Dehydration (3-5% Deficit)

Administer 50 mL/kg of oral rehydration solution (ORS) containing 50-90 mEq/L sodium over 2-4 hours. 1, 2

• Start with very small volumes (5 mL or one teaspoon) using a spoon, syringe, or medicine dropper 1, 2
• Gradually increase volume as tolerated 1
• Use commercially prepared ORS (e.g., Pedialyte) rather than homemade solutions or sports drinks 2, 4

Moderate Dehydration (6-9% Deficit)

Administer 100 mL/kg of ORS over 2-4 hours using the same small-volume technique. 1, 2

• If oral intake is not tolerated, consider nasogastric administration at 15 mL/kg/hour 1, 2

Severe Dehydration (≥10% Deficit)

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, 2

• Administer boluses without delay; may require two IV lines or alternate access sites (venous cutdown, femoral vein, intraosseous) 1
• Once circulation is restored and mental status normalizes, transition to ORS for remaining deficit 2, 4

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Reassess and Replace Ongoing Losses

Reassess hydration status after 2-4 hours of rehydration therapy. 1, 2

• If rehydrated, transition to maintenance phase 1, 2
• If still dehydrated, reestimate deficit and continue rehydration 1

Replace Ongoing Losses

• Administer 10 mL/kg of ORS for each watery stool 2, 3
• Administer 2 mL/kg of ORS for each vomiting episode 2, 3
• For children <2 years without dehydration: give 50-100 mL ORS after each stool 1
• For older children: give 100-200 mL ORS after each stool 1

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Nutritional Management During and After Rehydration

Resume age-appropriate diet immediately upon rehydration—there is no justification for "bowel rest" or delayed feeding. 1, 2

Infants

• Breastfed infants must continue nursing on demand without any interruption throughout the illness. 2, 4
• Bottle-fed infants should resume full-strength, lactose-free or lactose-reduced formula immediately after rehydration 2, 4

Children >4-6 Months

• Offer freshly prepared foods including cereals, starches, yogurt, fruits, and vegetables 2
• Add a few drops of vegetable oil to cereal and bean or cereal and meat mixtures 1
• Offer food every 3-4 hours 1
• Avoid foods high in simple sugars and fats during acute phase 2

Early feeding promotes intestinal cell renewal and prevents nutritional deterioration 3

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Critical Contraindications and Pitfalls

Absolutely Contraindicated

Antimotility agents (loperamide) are absolutely contraindicated in all children <18 years due to risks of respiratory depression and serious cardiac adverse reactions. 2

• Anti-diarrheal agents are contraindicated for treatment of diarrheal disease 1, 4
• Soft drinks and colas are not recommended due to high osmolality and inadequate sodium content 2, 4

Antibiotics

• Not indicated for routine watery diarrhea 1, 3
• Reserve for dysentery (bloody diarrhea), high fever, or diarrhea lasting >5 days 2
• Specific indications: cholera, Shigella dysentery, amoebic dysentery, acute giardiasis 1

Common Pitfalls to Avoid

• Do not rely solely on sunken fontanelle or absent tears for assessment 1, 2
• Do not use homemade salt-sugar solutions; commercial ORS ensures proper electrolyte composition 2
• Do not withhold food or impose "bowel rest"—this delays recovery 1, 2
• Do not routinely order laboratory tests for mild-moderate dehydration 2

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When to Seek Urgent Medical Evaluation

Instruct caregivers to return immediately if: 2

• Many watery stools continue or high stool output (>10 mL/kg/hour) persists
• Fever develops
• Increased thirst or sunken eyes appear
• Bloody diarrhea develops
• Intractable vomiting occurs preventing fluid intake
• Condition worsens or severe lethargy develops
• Decreased urine output (fewer than 3 wet diapers in 24 hours)