Diagnosis: Hirschsprung Disease
The diagnosis is A. Hirschsprung disease, based on the classic triad of delayed meconium passage beyond 48 hours, abdominal distention, and the pathognomonic "squirt sign" (explosive release of stool and gas upon rectal examination with temporary symptom relief). 1, 2, 3
Clinical Reasoning
Pathognomonic Features Present
The "squirt sign" or explosive release of meconium with rectal examination is highly characteristic of Hirschsprung disease, occurring because the examining finger relieves the functional obstruction caused by the aganglionic segment 1, 3
Delayed meconium passage beyond 48 hours is a cardinal feature of Hirschsprung disease, occurring in the vast majority of affected neonates, with most patients presenting during the neonatal period with this finding 2, 3
The temporary relief of symptoms after rectal examination distinguishes this from other causes of neonatal obstruction, as the digital stimulation temporarily decompresses the dilated proximal bowel 1
Why Not Functional Constipation
Functional constipation does NOT occur in newborns - it typically develops after 2-3 years of age when toilet training begins and dietary patterns change 4
Functional constipation would not present with failure to pass meconium in the first 48 hours of life, as this represents a structural/neurological problem rather than a functional disorder 3, 4
The explosive decompression with rectal examination indicates a mechanical/functional obstruction at the level of the aganglionic segment, not a behavioral or dietary issue 1, 2
Diagnostic Confirmation Required
Plain abdominal radiographs should be obtained first to demonstrate dilated bowel loops and assess for complications like perforation 1, 5
Contrast enema is the diagnostic imaging procedure of choice for suspected distal obstruction, which can demonstrate the transition zone between dilated proximal bowel and narrow aganglionic distal segment, with sensitivity of 90% and specificity of 80% for the transition zone finding 1, 6
Rectal suction biopsy remains the gold standard for definitive diagnosis, demonstrating absence of ganglion cells in the myenteric and submucosal plexuses 2, 3
Critical Management Points
Immediate pediatric surgical consultation is mandatory, as this represents a surgical emergency requiring definitive operative management 1
The American College of Radiology emphasizes that delayed meconium passage beyond 48 hours with abdominal distention is typical for distal bowel obstruction requiring urgent surgical intervention 1
Watch for Hirschsprung-associated enterocolitis, which can develop rapidly and represents a life-threatening complication 2
Common Pitfall to Avoid
Never dismiss delayed meconium passage as "normal variation" - while some patients with Hirschsprung disease may eventually pass meconium (58% in delayed diagnosis cases had "normal" passage), the combination with abdominal distention and the squirt sign makes the diagnosis clear 4
Do not delay surgical consultation while waiting for imaging studies if peritoneal signs develop, as bowel perforation can occur 1, 7