Tetralogy of Fallot

Tetralogy of Fallot is a congenital heart defect with four parts: a ventricular septal defect, pulmonary stenosis, an overriding aorta, and right ventricular hypertrophy. The tighter the pulmonary stenosis, the more blood shunts right to left through the defect and the bluer the infant, while mild stenosis may cause no cyanosis at rest. Listen for a harsh systolic ejection murmur at the left sternal border; the chest x-ray shows a boot-shaped heart. The emergency is the tet spell: sudden deeper cyanosis, fast deep breathing, irritability and prolonged crying, often triggered by crying, feeding or straining to stool. The first action is to place the infant knee-to-chest and calm them, then give 100% oxygen, with an IV fluid bolus and morphine as prescribed. Toddlers squat to rest for the same reason, so let them. Chronic low oxygen causes clubbing and polycythemia, so keep the child well hydrated. Complete repair usually happens in the first year, followed by continuous cardiac monitoring for dysrhythmias, and antibiotics before dental work are needed while the defect is unrepaired.