Neonatal Vomiting – First-Week Quick Review

Physiologic: gastroesophageal reflux (regurgitation)
Infectious: gastroenteritis, neonatal sepsis
Obstructive:
- Proximal ⇒ TEF/EA, pyloric stenosis
- Mid/upper ⇒ duodenal atresia, malrotation ± volvulus
- Distal ⇒ intestinal atresia, Hirschsprung, meconium ileus, intussusception
Inflammatory / ischemic: necrotizing enterocolitis (NEC)
Metabolic / other: increased intracranial pressure, inborn errors, drug-related

Case $1$ (day $3$ , non-bilious, watery diarrhea, weight ↓ $15\%$ ) ⇒ gastroenteritis ± dehydration
Case $2$ (day $5$ , bilious emesis, wt ↓ $13\%$ ) ⇒ upper bowel obstruction (duodenal atresia/malrotation)
Case $3$ (day $7$ , bilious → fecaloid vomit + bloody stool, distension) ⇒ late bowel obstruction / intussusception
Case $4$ (immediate, drooling, choking, polyhydramnios) ⇒ tracheoesophageal fistula / esophageal atresia
Case $5$ (premature $27$ wks, feeds, distension, bilious ± blood, sepsis) ⇒ NEC (differentiate from sepsis, volvulus)

Age at onset:
- < $24$ h ⇒ TEF/EA, atresias, metabolic, CNS
- $2$ – $7$ d ⇒ feeding issues, infection, NEC, late obstruction
Character of vomit
- Bilious (green) → obstruction distal to ampulla of Vater
- Bloody → mucosal injury / stress ulcer / swallowed maternal blood
- Projectile clear → pyloric stenosis (classically after $2$ – $6$ wks but note)
Quantity / frequency / relation to feeds
Associated: stools (delay, diarrhea, blood), urine output, fever/hypothermia, respiratory signs, neurologic status
Prenatal & perinatal risks: polyhydramnios, maternal anticoagulants, PROM, chorioamnionitis, prematurity

Vital signs: HR $120$ – $160$ bpm, RR $30$ – $60$ /min, T $36.5$ – $37.5$ ℃
Hydration: fontanel, mucosa, CRT, skin turgor, weight loss (> $10\%$ significant)
Abdominal: shape, distension, visible peristalsis, bowel sounds, masses, tenderness, rectal exam (blood / explosive stool)
Respiratory: drooling, choking, aspiration
Cardiovascular: murmurs, pulses (coarctation)
Neuro: tone, primitive reflexes (Moro, ATNR, grasp)

Baseline: complete metabolic panel (electrolytes, glucose, BUN/Cr), CBC, CRP if infection suspected
Imaging:
- Abdominal US preferred first (no radiation) → gas pattern, pyloric “olive”, free fluid
- Plain radiograph / contrast studies when obstruction suspected (double bubble, air-fluid levels)
- CT/MRI head if raised ICP
Specific tests
- Apt test for bloody emesis (differentiate maternal vs fetal blood)
- Blood/urine/CSF cultures for sepsis
- Rectal biopsy for Hirschsprung
- Esophageal pH / upper GI contrast for reflux

Stabilize ABCs; prevent aspiration (position, suction)
Assess & correct dehydration/electrolytes
- Oral rehydration if mild; IV isotonic fluids if ≥ moderate
Withhold enteral feeds & NG decompression if obstruction/NEC suspected
Empiric broad-spectrum antibiotics for sepsis or NEC risk
Parental guidance: breastfeeding technique, formula preparation, feeding volume/frequency
Specific therapy
- NEC: bowel rest, antibiotics, surgical consult
- TEF/EA, atresias, malrotation, pyloric stenosis, imperforate anus: prompt surgical repair
- GER: thickened feeds, hydrolyzed formula if CMPA
- Iron supplementation for proven deficiency