Tetralogy of Fallot may present with episodic spells characterized by which finding?

Tetralogy of Fallot may present with episodic spells characterized by which finding?

• A. Hypercyanotic spells
• B. Hypertension
• C. Hyperglycemia
• D. Jaundice

Answer: (A)

In Tetralogy of Fallot, episodic spells—often called Tet spells—occur when the right-to-left shunt across the ventricular septal defect worsens due to infundibular (RVOT) obstruction. This sudden increase in shunting markedly reduces pulmonary blood flow, leading to acute hypoxemia and deepening cyanosis. These spells are commonly triggered by crying, feeding, or agitation and are often relieved by positioning that raises systemic vascular resistance, such as the knee-chest position or squatting, which helps decrease the right-to-left shunt and improve pulmonary blood flow. Thus, the episodic finding is profound hypercyanosis during these spells. Hypertension, hyperglycemia, and jaundice do not describe these sudden cyanotic episodes seen in TOF.

In Tetralogy of Fallot, episodic spells—often called Tet spells—occur when the right-to-left shunt across the ventricular septal defect worsens due to infundibular (RVOT) obstruction. This sudden increase in shunting markedly reduces pulmonary blood flow, leading to acute hypoxemia and deepening cyanosis. These spells are commonly triggered by crying, feeding, or agitation and are often relieved by positioning that raises systemic vascular resistance, such as the knee-chest position or squatting, which helps decrease the right-to-left shunt and improve pulmonary blood flow. Thus, the episodic finding is profound hypercyanosis during these spells. Hypertension, hyperglycemia, and jaundice do not describe these sudden cyanotic episodes seen in TOF.