Differential Diagnosis and Management of Vomiting in Infants

Immediate Assessment and Management

The American Academy of Pediatrics recommends that breastfed infants with vomiting should continue breastfeeding on demand, as breast milk should never be interrupted in breastfed infants with vomiting 1
The American Academy of Pediatrics suggests that for mild dehydration (3-5% deficit), oral rehydration solution (ORS) should be administered 60-120 mL for each vomiting episode, and given in small, frequent volumes (5 mL every minute initially) using spoon or syringe 2, 1
The American Academy of Pediatrics recommends that breastfed infants should continue nursing throughout, supplemented with ORS if needed, and that each vomiting episode should be replaced with approximately 10 mL/kg ORS 2, 1

The presence of bilious (green) vomiting indicates obstruction distal to ampulla of Vater and requires immediate surgical evaluation, according to the American College of Surgeons 1, 3
Projectile vomiting raises concern for pyloric stenosis, typically presenting 2-8 weeks of age, as noted by the American Academy of Pediatrics 1
Blood in vomit or stool suggests mucosal injury or more serious pathology, according to the American Academy of Family Physicians 4, 1

Gastroesophageal reflux (GER) is common in infants, peaks at 4 months of age, and is characterized by a "happy spitter" - vomiting without other concerning symptoms, as described by the American Academy of Pediatrics 4, 5
Acute viral gastroenteritis is usually self-limiting, often accompanied by diarrhea, and typically peaks early and improves within 24-48 hours, according to the Infectious Diseases Society of America 2

The American Academy of Pediatrics recommends that ondansetron (0.2 mg/kg oral, max 4 mg) may be considered ONLY if persistent vomiting completely prevents oral intake, and that antiemetics should not be used routinely in infants this young with presumed viral gastroenteritis 1
The American Academy of Pediatrics suggests that antidiarrheal or antimotility agents should not be used, as they can cause serious side effects and are ineffective, and that maternal elimination diet (restrict milk and eggs for 2-4 weeks) may be considered in breastfeeding mothers if vomiting persists beyond 48-72 hours 1, 4, 5

Parental reassurance and education are usually sufficient for infants with non‑bilious vomiting, as most are “happy spitters” who vomit without other concerning symptoms. 6

Upper gastrointestinal (UGI) series is not indicated in otherwise healthy infants with non‑bilious vomiting and normal growth because it demonstrates low diagnostic performance for gastro‑esophageal reflux (sensitivity 31‑86 %, specificity 21‑83 %). 6
UGI series should be reserved only to exclude anatomic abnormalities (e.g., malrotation, esophageal stricture) when the clinical picture is severe or atypical. 6