A neonate presents with bilious vomiting and abdominal distension on day 2 of life. X-ray shows a 'double bubble' sign with absence of distal gas. The most likely diagnosis and embryological basis is:
- A Pyloric stenosis; failure of pyloric muscle to develop normally
- B Duodenal atresia; failure of recanalization of the duodenum during the 8th–10th week of gestation ✓
- C Malrotation with midgut volvulus; incomplete rotation of the midgut at 10 weeks
- D Jejunal atresia; segmental vascular accident in utero
Explanation
The 'double bubble' sign on plain X-ray (large gastric bubble + dilated duodenum with no distal gas) is pathognomonic of duodenal atresia. The embryological basis is failure of the solid-plug stage of duodenal development to recanalize between weeks 8–10 of gestation. It is associated with Down syndrome (trisomy 21) in ~30% of cases, cardiac anomalies (~30%), and annular pancreas. Bilious vomiting appears within 24–48 hours. Treatment is duodenoduodenostomy. Jejunal atresia also gives double bubble but with some distal gas; malrotation/volvulus shows spiral/corkscrew duodenum on UGI contrast.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.