A 6-hour-old neonate has bilious vomiting and an abdominal X-ray showing the 'double bubble' sign with no distal gas. The most likely diagnosis and embryological basis is:

• A Jejunal atresia due to vascular accident in utero
• B Malrotation with midgut volvulus due to non-rotation of the midgut loop
• C Pyloric stenosis due to pyloric muscle hypertrophy
• D Duodenal atresia due to failure of recanalization of the solid cord stage of duodenal development ✓

Explanation

The double bubble sign (gas in stomach and duodenum only, no distal gas) is pathognomonic of duodenal atresia. The embryological basis is failure of recanalization during the solid cord stage of duodenal development (5th–8th week). Duodenal atresia is associated with Down syndrome in 30% of cases and requires duodenoduodenostomy. Malrotation also shows a double bubble but with some distal gas; pyloric stenosis presents after 2–4 weeks with non-bilious vomiting.

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.