A full-term newborn boy presents with severe cyanosis and respiratory distress within 6 hours of birth. Vital signs show HR 165/min, RR 58/min, BP 55/35 mmHg, SpO2 72% on room air, and temperature 37.2°C. Chest radiograph demonstrates an "egg on string" appearance with decreased pulmonary vascularity. Echocardiography reveals the aorta arising from the right ventricle and pulmonary artery from the left ventricle. Patent ductus arteriosus is present. No associated chromosomal abnormalities are noted. Which embryologic error accounts for this defect?
- A)Failure of truncal cushions to fuse completely resulting in a single outflow tract
- B)Failure of endocardial cushion fusion
- C)Excess apoptosis of the interventricular septum
- D)Abnormal neural crest migration causing failure of aorticopulmonary septum spiralingGABARITO
- E)Abnormal left to right shunting through the ductus arteriosus
Explicação
Transposition of the great arteries results from failure of the aorticopulmonary septum to spiral, producing parallel rather than serial circulations. Neural crest cell abnormalities underlie this defect. Severe cyanosis appears early, and survival requires mi... Ver explicação completa e trilha adaptativa →