What is the most appropriate next step for a newborn with abdominal distention, tenderness upon palpation, absent bowel sounds, and no meconium passage for 48 hours?

Most Appropriate Next Step for Newborn with Suspected Intestinal Obstruction

This newborn requires immediate pediatric surgical consultation (Option B) as the clinical presentation—abdominal distention, tenderness, absent bowel sounds, and failure to pass meconium for 48 hours—indicates a surgical emergency that may include life-threatening conditions such as intestinal atresia, malrotation with midgut volvulus, or Hirschsprung disease. 1

Clinical Reasoning

Why Immediate Surgical Referral Takes Priority

• This presentation represents a potential surgical emergency where 20% of neonates with bilious vomiting in the first 72 hours have midgut volvulus requiring urgent surgery, and 11% have lower GI causes requiring intervention 1

• The combination of absent bowel sounds with abdominal tenderness suggests peritonitis or bowel compromise, which mandates immediate surgical evaluation before any diagnostic imaging 1

• Delayed meconium passage beyond 48 hours with abdominal distention is typical for distal bowel obstruction, which may require urgent surgical intervention 1, 2

The Diagnostic Algorithm After Surgical Consultation

Once the surgical team is involved, they will direct the diagnostic workup:

Step 1: Plain Abdominal Radiographs (Initial Imaging)

• The American College of Radiology recommends plain abdominal radiographs as the first imaging study for suspected bowel obstruction 3
• These can demonstrate dilated bowel loops, air-fluid levels, and presence or absence of distal gas 3
• Classic findings include "double bubble" for duodenal atresia or "triple bubble" for jejunal atresia 1, 3

Step 2: Contrast Enema (If Distal Obstruction Suspected)

• For suspected distal obstruction, contrast enema is the diagnostic imaging procedure of choice 3
• Can demonstrate microcolon in cases of distal atresia or meconium plug syndrome 1, 2
• May be both diagnostic and therapeutic in meconium plug syndrome 4

Step 3: Rectal Suction Biopsy (If Hirschsprung Disease Suspected)

• Rectal suction biopsy detects hypertrophic nerve trunks and absence of ganglion cells, confirming Hirschsprung disease 5
• This is performed after initial stabilization and imaging, not as the first step 5, 6
• Hirschsprung disease presents with delayed meconium passage beyond 24 hours, abdominal distension, and vomiting 6

Why Other Options Are Incorrect as First Steps

Option A (Barium Enema Study): While contrast enema has a role in diagnosis, there is no literature supporting its use as the initial step prior to plain radiographs and surgical consultation 1. The clinical presentation suggests a surgical emergency requiring immediate surgical evaluation.

Option C (Ultrasound): The American College of Radiology notes limited literature supporting ultrasound in evaluating neonates with suspected bowel obstruction 3. Plain radiographs are the recommended initial imaging 3.

Option D (Rectal Suction Biopsy): While this confirms Hirschsprung disease, it is not the immediate next step in an unstable neonate with peritoneal signs 5, 6. Surgical consultation and stabilization take priority.

Critical Pitfalls to Avoid

• Never delay surgical consultation for imaging studies in a neonate with peritoneal signs (tenderness, absent bowel sounds) 1
• Do not assume this is simple meconium plug syndrome given the severity of presentation with tenderness and absent bowel sounds 1, 4
• Monitor closely for enterocolitis, which occurs in up to one-third of Hirschsprung patients and is a significant cause of mortality 5, 6
• Recognize that midgut volvulus requires urgent surgery and can present identically to this case 1