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Tetralogy of Fallot – tet spell — RACP Paediatrics MCQ

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ModerateCardiologyTetralogy of Fallot – tet spellRACP Paediatrics

A 3-month-old infant becomes deeply cyanotic and inconsolable during crying. The mother notes the child turns blue and draws up the knees to the chest. Between episodes SpO2 is 85%. There is a harsh ejection systolic murmur at the left upper sternal edge. CXR shows a boot-shaped heart. What is the most likely diagnosis?

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Correct answer: D — Tetralogy of Fallot

Cyanotic spells (tet spells/hypercyanotic episodes) triggered by crying or agitation with knee-to-chest positioning (which increases SVR), a boot-shaped heart on CXR, and an ejection systolic murmur from RVOT obstruction are classic for Tetralogy of Fallot. Acute management of a tet spell includes knee-chest positioning, oxygen, morphine, and IV fluid bolus. Propranolol can be used for prophylaxis.

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