Hepatobiliary Disease USMLE Step 1 Practice Question
A term newborn presents with bilious vomiting 6 hours after birth. Vital signs show HR 145/min, RR 48/min, and mild dehydration. Abdominal examination reveals distension without hepatosplenomegaly. Abdominal radiograph demonstrates the "double bubble" sign. Upper endoscopy confirms narrowing of the second duodenum by an annular pancreatic tissue. Laboratory studies show normal liver function tests. Which embryologic error most likely produced this abnormality?
Answer choices
- AFailure of neural crest cells to migrate to the colon
- BAbnormal migration of the ventral pancreatic budCorrect answer
- CPersistence of the vitelline duct
- DFailure of foregut recanalization
- EIncomplete rotation of the cecal bud
- FFailure of the dorsal pancreatic bud to fuse with the ventral pancreatic bud
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