What is the management approach for intractable vomiting in a 3-month-old baby?

Management of Intractable Vomiting in a 3-Month-Old Baby

Intractable vomiting in a 3-month-old requires immediate assessment for bilious emesis and signs of surgical obstruction, followed by oral rehydration with small frequent volumes (5 mL every minute) if no red flags are present. 1

Immediate Red Flag Assessment

The first priority is determining whether this represents a surgical emergency:

• Bilious (green) vomiting indicates obstruction distal to the ampulla of Vater and requires urgent surgical evaluation for malrotation with volvulus, which can occur at any age including 3 months 1, 2
• Projectile vomiting suggests pyloric stenosis, though this typically presents between 2-8 weeks of age; at 3 months, it's less likely but still warrants ultrasound evaluation if forceful vomiting is present 2, 3
• Abdominal distension or tenderness requires emergency evaluation for intestinal obstruction 1, 3
• Bloody vomitus, altered mental status, or signs of severe dehydration (>10% body weight loss) necessitate immediate IV access and emergency care 3

Hydration Management (Primary Treatment)

If no red flags are present, the cornerstone of management is oral rehydration:

• Administer oral rehydration solution (ORS) in small, frequent volumes starting at 5 mL every minute using a spoon or syringe with close supervision 4, 1
• Simultaneous correction of dehydration often lessens the frequency of vomiting, so aggressive oral rehydration should be attempted before considering antiemetics 4
• Replace each vomiting episode with 10 mL/kg of ORS to account for ongoing losses 2
• If oral rehydration fails despite proper technique, consider rapid IV rehydration with 20-30 mL/kg isotonic crystalloid over 1-2 hours 5

Nutritional Management

Feeding should continue alongside rehydration:

• Breastfed infants should continue nursing on demand without interruption 4, 1, 2
• Formula-fed infants should receive full-strength formula immediately in amounts sufficient to satisfy energy requirements 2
• Consider lactose-free or lactose-reduced formula only if formula intolerance is suspected (though this is less common at 3 months) 1

Antiemetic Considerations

The use of antiemetics in infants this young is controversial:

• Antiemetics are generally NOT indicated for routine viral gastroenteritis in young infants 2
• Ondansetron (0.2 mg/kg oral, maximum 4 mg) may be considered ONLY if persistent vomiting prevents oral intake entirely and is preventing successful oral rehydration 2, 3, 6
• The evidence shows ondansetron reduces vomiting frequency and improves oral rehydration success, but this must be weighed against using it in very young infants 6

Differential Diagnosis to Consider

At 3 months of age, the most likely causes are:

• Gastroesophageal reflux (GER) is the most common cause of non-bilious vomiting in the first months of life, often related to overfeeding 1
• Acute viral gastroenteritis is common and typically self-limited 2, 3
• Formula intolerance should be considered if vomiting persists despite adequate hydration 1
• Late-presenting pyloric stenosis is possible though uncommon at 3 months 2
• Malrotation with volvulus can present at any age, not just in newborns, so maintain vigilance 2

When to Escalate Care

Parents should return immediately or call if:

• Vomiting becomes bilious (green) or bloody 2, 3
• Decreased urine output (fewer than 4 wet diapers in 24 hours) 2
• Lethargy, inconsolable crying, or altered mental status 3
• Inability to tolerate any oral fluids after proper oral rehydration technique 4, 2
• Poor weight gain or weight loss on follow-up, which would elevate concern for GERD disease rather than benign reflux 2

Critical Pitfall to Avoid

Do not assume all vomiting in infants is benign reflux or viral gastroenteritis. The distinction between bilious and non-bilious vomiting changes the urgency and approach entirely 2. A serum bicarbonate level ≤13 mEq/L predicts failure of oral rehydration and need for hospitalization 5, though routine laboratory testing is not required in well-appearing infants with non-bilious vomiting who can maintain hydration 3.