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Overview

Snapshot
  • A 2-week-old newborn is brought to the physician because his lips have turned blue on three occasions during feeding. His BP is 75/45, Pulse is 170, and RR is 44. A grade 3/6, harsh, systolic ejection murmur is heard at the left upper sternal border. A CXR shows a small boot-shaped heart and decreased pulmonary vascular markings.
Introduction
  • Most common cyanotic congenital cardiac abnormality
    • result of anterosuperior displacement of infundibular septum
    • caused by abnormal migration of neural crest cells 
  • Consists of four, distinct physical defects including 
    • VSD 
    • overriding aorta
      • overrides the VSD
    • pulmonary stenosis
      • most important determinant for prognosis 
        • cyanosis may or may not be present depending on degree of stenosis
    • RVH
      • result of increased afterload caused by pulmonary stenosis
  • Risk factors include
    • Down syndrome
    • cri-du-chat syndrome
    • trisomy 13/18
Presentation
  • Symptoms
    • presentations can range broadly during infancy with
      • "tet spells"
        • acute cyanosis and dyspnea that
          • develop over the first 6 months of life
          • caused by right to left shunt
            • a result of ↑ pressure caused by stenotic pulmonic valve
        • may occur during crying or when overheated or panicked
      • acyanotic "pink tet"
        • infant who has TOF but is not cyanotic is called a "pink tet"
        • degree of cyanosis depends upon 
          • severity of pulmonary stenosis
          • direction of blood flow across the VSD
      • failure to thrive
      • mental status changes
      • child adopting a squatting posture
        • increasing SVR via compression of the femoral arteries
        • improves bloodflow across the VSD
        • allows blood to enter pulmonary circulation
  • Physical Exam
    • long, harsh, systolic ejection murmur at mid-left sternal border
    • single second heart sound (S2)
    • digital clubbing
Evaluation
  • CXR shows "boot-shaped heart
Treatment
  • Prostaglandin E (PGE1)
    • keeps the ductus arteriosus patent in cyanotic newborns
      • allows collateral circulation to the lungs in spite of pulmonary stenosis
      • blood flows from the aorta through the ductus arteriosus to the pulmonary artery to the lungs
  • Surgical correction in children with a hypoxemic spells is necessary for repair
 

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