An 8-week-old male presents with bilious vomiting since day 1 of life, failure to thrive, and abdominal distention. X-ray shows a 'double bubble' sign without distal gas. What is the most likely diagnosis and the pathological basis?

• A Hypertrophic pyloric stenosis; hypertrophy of the pyloric circular muscle
• B Jejunal atresia; vascular accident in utero causing intestinal ischemia
• C Malrotation with volvulus; abnormal intestinal rotation
• D Duodenal atresia; failure of recanalization of the duodenal lumen between weeks 8–10 of gestation ✓

Explanation

The double bubble sign on X-ray (two air-filled structures — the stomach and proximal duodenum — with no distal gas) is pathognomonic of duodenal atresia. The pathological basis is failure of recanalization of the duodenal lumen, which is normally solid during weeks 5–8 of development and must recanalize by week 10. It is associated with Down syndrome (30% of cases) and polyhydramnios. Bilious vomiting from birth (not from week 3–6 as in pyloric stenosis) and absence of distal bowel gas distinguish it from other causes.

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.