What is the best treatment for diarrhea in an infant?

Treatment of Diarrhea in Infants

Oral rehydration solution (ORS) containing 50-90 mEq/L sodium is the first-line treatment for all infants with diarrhea, combined with immediate continuation of breastfeeding or full-strength formula feeding without any interruption. 1

Immediate Rehydration Strategy

Assessment of Dehydration Severity

• Examine skin turgor, mucous membranes, mental status, pulse, and capillary refill time to categorize severity: mild (3-5% fluid deficit), moderate (6-9% deficit), or severe (≥10% with shock) 1
• Weigh the infant immediately to establish baseline and monitor treatment effectiveness 1
• Thirst, delayed capillary filling, absence of tears, mucosal dryness, and "sickly" appearance are early dehydration signs 2

ORS Administration Protocol

• Mild dehydration: Administer 50 mL/kg ORS over 2-4 hours 1
• Moderate dehydration: Administer 100 mL/kg ORS over 2-4 hours 1
• Severe dehydration: Give 20 mL/kg boluses of Ringer's lactate or normal saline IV until pulse, perfusion, and mental status normalize 1
• For vomiting infants, give small frequent volumes (5 mL every minute) using a spoon or syringe—never bottles 1

Ongoing Loss Replacement

• Replace each liquid stool with 10 mL/kg ORS 1
• Replace each vomiting episode with 2 mL/kg ORS 1

Feeding Management During Diarrhea

Breastfed Infants

Continue breastfeeding on demand without any interruption throughout the entire diarrheal episode. 1 Breast milk reduces stool output compared to ORS alone and provides a 25-fold reduction in mortality risk from diarrhea 3. Breastfeeding maintains hydration status even when infants refuse other foods 3.

Formula-Fed Infants

• Immediately resume full-strength, lactose-free or lactose-reduced formula after rehydration 1
• Full-strength lactose-free formula reduces both stool output and duration of diarrhea by approximately 50% compared to gradual reintroduction 4, 1
• When lactose-free formulas are unavailable, full-strength lactose-containing formulas can be used under supervision 4
• Never dilute formula or delay full-strength feeding—this worsens nutritional outcomes and prolongs diarrhea 1

Older Infants on Solid Foods

• Continue usual diet including starches, cereals, yogurt, fruits, and vegetables 4
• Avoid foods high in simple sugars and fats 4

Critical Medication Contraindications

Antidiarrheal agents including loperamide are absolutely contraindicated in all infants and children under 2 years of age due to risks of respiratory depression, cardiac arrest, and death. 1, 5 Postmarketing cases of cardiac arrest, syncope, and respiratory depression have been reported in pediatric patients less than 2 years of age 5.

• Antibiotics are not indicated unless dysentery, high fever, or watery diarrhea lasting >5 days is present 4, 1

Lactose Intolerance Considerations

• Do not diagnose lactose intolerance based solely on stool pH (<6.0) or reducing substances (>0.5%) without clinical symptoms 4, 6
• True lactose intolerance is diagnosed by exacerbation of diarrhea upon introduction of lactose-containing formula 4, 6
• Only 5-10% of infants with acute diarrhea have true lactose intolerance 7
• If lactose intolerance occurs, temporarily reduce or remove lactose from diet 4

Red Flags Requiring Immediate Medical Attention

Return immediately or call if the infant develops:

• Irritability or lethargy 1
• Decreased urine output 1
• Intractable vomiting 1
• Persistent diarrhea beyond expected course 1
• Sunken eyes, very poor skin turgor, or altered mental status 1

Common Pitfalls to Avoid

• Never use homemade ORS, plain water, or fizzy drinks for rehydration 2
• Never use bottles for ORS administration—this interferes with suckling and gives implicit credibility to bottle feeding 3
• Never stop breastfeeding or formula for more than 4 hours 7
• Never gradually reintroduce formula—immediate full-strength feeding is superior 4, 1
• Dehydration can occur very rapidly in infants, particularly those under 6 years of age 5