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Truncus arteriosus — RACP Paediatrics MCQ

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HardCardiologyTruncus arteriosusRACP Paediatrics

A newborn has severe cyanosis with SpO2 55%. Echocardiogram shows a large single arterial trunk overriding the ventricular septum with a large VSD. There is no separate pulmonary artery arising from the heart; pulmonary arteries arise from the single trunk. What is the most likely diagnosis?

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Correct answer: C — Truncus arteriosus

A single arterial trunk arising from both ventricles with a VSD and pulmonary arteries arising from the trunk is truncus arteriosus (common arterial trunk). It is associated with DiGeorge syndrome (22q11 deletion) and requires early surgical repair (usually in the neonatal period). The VSD is closed and the pulmonary arteries are separated from the trunk with a conduit placed.

Reference: RCH Melbourne – 2023 – Cyanotic Heart Disease CPG; RACP Paediatric Curriculum – Cardiology