USMLE-Rx Step 1 Qmax Challenge #1690

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USMLE-Rx Step 1 Qmax Challenge #1690A 38-year-old diabetic woman gives birth to a term male infant. Immediately after birth, the infant is cyanotic and tachypneic. A murmur is not auscultated during the newborn screening examination. His hypoxemia quickly worsens over minutes, and a chest radiograph is obtained, which resembles the results shown here for an older child. He undergoes cardiac catheterization, in which a balloon is guided to perforate the atrial septum. He is also given an infusion of prostaglandin E1. An ECG after the procedure demonstrates right-axis deviation and right ventricular hypertrophy. The infant’s hypoxia stabilizes, and he later undergoes definitive, corrective surgery.

Which of the following is the underlying condition responsible for this infant’s hypoxemia?

A. Concomitant ventricular septal defect
B. Pulmonary atresia
C. Tetralogy of Fallot
D. Total anomalous pulmonary venous return
E. Transposition of the great vessels
F. Tricuspid atresia


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