A newborn presents with intestinal atresia — the duodenum shows a 'double bubble' sign on abdominal X-ray. The second and third parts of the duodenum temporarily occlude during embryological development. Which process is responsible for re-canalization of the duodenal lumen?

• A Apoptosis of mesodermal cells surrounding the gut tube
• B Peristaltic stretching of the duodenal wall by amniotic fluid swallowing
• C Vacuolization within the solid epithelial core followed by coalescence of vacuoles ✓
• D Migration of mesodermal cells into the gut lumen displacing the epithelial plug

Explanation

During the 5th-6th week of embryonic development, rapid epithelial proliferation transiently obliterates the duodenal lumen (the solid stage). Re-canalization occurs from the 8th-10th week through vacuolization — vacuoles form within the solid epithelial core and coalesce, restoring the lumen. Failure of complete vacuolization causes duodenal atresia (complete obstruction with double bubble sign) or stenosis. This process is unique to the duodenum; other segments of the gut obliterate by simple elongation. Down syndrome (trisomy 21) is associated in 30% of duodenal atresia cases.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.