What is the recommended initial screening for a 2-day-old newborn with Down syndrome?

Recommended Screening for 2-Day-Old Newborn with Down Syndrome

The correct answer is C: Observe meconium passage within 24-48 hours, as gastrointestinal anomalies occur in 5% of infants with Down syndrome, including duodenal atresia and Hirschsprung disease, which require urgent identification and surgical intervention. 1, 2

Immediate Gastrointestinal Monitoring

• Failure to pass meconium within 24-48 hours is a critical red flag for Hirschsprung disease or other gastrointestinal malformations that are significantly more common in Down syndrome patients 1
• Duodenal atresia typically presents with bilious vomiting in the first 24-48 hours of life and may have been visible on prenatal ultrasound as the "double bubble" sign 3
• While duodenal atresia is the most recognized GI anomaly in Down syndrome, Hirschsprung disease is equally important and manifests as delayed meconium passage 2

Why the Other Options Are Incorrect

Serial abdominal x-rays (Option A) are not routinely indicated unless there are clinical signs of obstruction such as bilious vomiting, abdominal distension, or failure to pass meconium 1

Serial ultrasound for pyloric stenosis (Option B) is inappropriate because:

• Pyloric stenosis typically presents at 3-6 weeks of age, not in the first 2 days of life
• There is no established increased risk of pyloric stenosis in Down syndrome 4
• This would be premature and not evidence-based screening

Fecal calprotectin for necrotizing fasciitis (Option D) is completely incorrect:

• Necrotizing fasciitis is a soft tissue infection, not a gastrointestinal condition
• Fecal calprotectin is used for inflammatory bowel disease, not necrotizing fasciitis
• This option appears to confuse necrotizing enterocolitis (NEC) with necrotizing fasciitis, but NEC is primarily a disease of premature infants, not term infants with Down syndrome 4

Critical Additional Screening Beyond the Question

While observing meconium passage is the correct answer to this specific question, the most critical immediate evaluation for any newborn with Down syndrome is cardiac screening, as 40% have congenital heart disease 1, 2

• Echocardiography should be performed urgently regardless of the presence or absence of murmur or symptoms 1
• Complete blood count should be obtained to screen for transient myelodysplasia, which is common in trisomy 21 1
• Hematologic monitoring is essential given the 20-fold increased risk of childhood leukemia 1, 2

Clinical Approach Algorithm

1. First 24-48 hours: Monitor for meconium passage and feeding tolerance
2. If no meconium by 48 hours: Obtain abdominal x-ray and surgical consultation for possible Hirschsprung disease
3. If bilious vomiting occurs: Immediate abdominal x-ray to evaluate for duodenal atresia or other obstruction
4. Concurrent with GI monitoring: Arrange echocardiography and obtain CBC 1

Common Pitfall

The major pitfall is assuming that the absence of symptoms means no gastrointestinal pathology exists. Hirschsprung disease may present subtly with only delayed meconium passage before progressing to complete obstruction or enterocolitis 2. Active observation and documentation of meconium passage is essential, not passive waiting.