Overview Snapshot A 2-week-old newborn is brought to the physician because his lips have turned blue on three occsions during feeding. His blood pressure is 75/45 mmHg, pulse is 170/min, and respirations are 44/min. A grade 3/6 harsh systolic ejection murmor is heard at the left upper sternal border. A CXR shows a small boot shaped heart and decreased pulmonary vacular markings. Introduction Most common cyanotic congenital cardiac anormality in children occurs in 7-10% of congenital heart lesions Consists of four distinct physical defects including pulmonary stenosis/atresia degree of stenosis can be responsible for varying severities of presentation right ventricular hypertrophy (RVH) overriding aorta vetricular septal defect (VSD) Risk factors include maternal rubella or viral illness Down syndrome DiGeorge syndrome Presentation Signs and symptoms presentations can range broadly during infancy and include "Tet spells" acute cyanosis most commonly occur at 2-6 months of age caused by increased right-to-left shunt at times of increased cardiac output commonly occur in the morning or after a nap when systemic vascular resistance (SVR) is low may be precipitated by feeding, crying, hot baths, or fever failure to thrive (if diagnosed late) mental status changes child adopts squatting posture squating increases SVR to decrease bloodflow across the VSD CNS infections direct venous blood flow to brain without filtering through pulmonary circulation Physical exam systolic ejection murmor found at left upper sternal border with right ventricular lift single second heart sound (S2) digital clubbing Evaluation CXR shows "boot-shaped heart" and decreased pulmonary vascular markings EKG shows right-axis deviation and RVH Echocardiography definitive diagnosis by echocardiography also helps guide surgical approach Differential Tricuspid or pulmonary atresia, transposition of the great vessels, hypoplastic left heart syndrome, PDA Treatment Treat cyanotic "tet" spells with O2, knee-to-chest position, IV fluids, morphine Oxygen leads to decreased pulmonary vascular resistence due to vasodilation Morphine decreases tachycardia, increasing filling time. Also decreases PVR IV fluids increases right ventricular preload in severe cases, administer propranolol and phenylephrine Prostaglandin E (PGE1) maintains a patent ductus arteriosus in cyanotic newborns with severe pulmonary stenosis/atresia Surgical correction indications indicated in children with severe hypoxemic spells technique temporary palliation prior to surgery can be achieved through creation of an artificial shunt Prognosis, Prevention, and Complications Prognosis depends on degree of pulmonary stenosis and blood flow across the VSD without repair of TOF, mortality is 50% by 3 years 90% by 20 years 95% by 30 years Possible complications include increased risk of CNS infections and abscesses Due to bypass of pulmonary circulation allowing for direct blood flow from periphery