A two-day-old baby is pale and fussy. He was born to a 22-year-old primigravida who had had only occasional prenatal care. The delivery went smoothly, with Apgar values of 7 and 8 at 1 and 5 minutes, respectively. His temperature is 36.7 degrees Celsius (98 degrees Fahrenheit), his blood pressure is 70/30 mm Hg, his pulse rate is 148 beats per minute, and his respiratory rate is 68 beats per minute. A cyanotic and irritable infant with mild-to-moderate respiratory distress is seen on physical examination. Auscultation indicates a constant, machine-like murmur heard between the scapulae. Serum lactate levels are high. The aorta is shown on an echocardiogram to be anterior, inferior, and to the right of the pulmonary artery. Which of the following embryologic processes is most likely to be at fault for this patient's condition?

Question

Quizplus · Accepted Answer

Eductional Objective: An echocardiography that shows the aorta lying anterior to the pulmonary artery is indicative of great artery transposition (TGA). The inability of the embryonic aorticopulmonary septum to spiral properly during truncus arteriosus septation causes this potentially fatal cyanotic syndrome.

A Two-Day-Old Baby Is Pale and Fussy