A 3-day-old neonate presents with bilious vomiting and X-ray shows the 'double bubble' sign without distal bowel gas. The MOST likely diagnosis is:
- A Jejunal atresia
- B Hirschsprung's disease
- C Duodenal atresia ✓
- D Meconium ileus
Correct answer: C. Duodenal atresia
Explanation
The 'double bubble' sign on abdominal X-ray — two air-filled structures representing the stomach and dilated proximal duodenum with absence of distal bowel gas — is pathognomonic of duodenal atresia. This is the most common atresia at a single site and has a strong association with trisomy 21 (Down syndrome) in ~30% of cases. Jejunal atresia shows multiple dilated loops. Hirschsprung's shows colonic distension. Meconium ileus shows ground-glass appearance in the right iliac fossa.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.