A 3-year-old girl presents with cyanosis that worsens with crying and exertion. Physical examination reveals a systolic ejection murmur at the left upper sternal border and a right ventricular heave. Chest X-ray shows a boot-shaped heart with decreased pulmonary vascular markings. Which of the following is the pathophysiologic basis for her cyanosis?
- A)Pulmonary vascular obstruction from increased blood flow
- B)Decreased systemic vascular resistance
- C)Complete mixing of systemic and pulmonary circulations
- D)Right-to-left shunt due to right ventricular outflow obstructionGABARITO
- E)Left-to-right shunt with pulmonary edema
Explicação
Tetralogy of Fallot (TOF) consists of four features: VSD, RV outflow obstruction (pulmonary stenosis), RV hypertrophy, and overriding aorta. Cyanosis results from right-to-left shunting through the VSD due to elevated RV pressure from outflow obstruction, allo... Ver explicação completa e trilha adaptativa →