Tetralogy of Fallot has which associated symptom?

• A. Cyanosis
• B. Syncope
• C. Hypertension
• D. Tachypnea

Answer: (A)

Cyanosis from a right-to-left shunt is the defining feature of Tetralogy of Fallot. The condition includes RV outflow tract obstruction, a large VSD, an overriding aorta, and right ventricular hypertrophy, which together cause deoxygenated blood to mix into the systemic circulation. This lowers arterial oxygen content, so the skin and mucous membranes appear blue, especially during spells when the obstruction worsens and more unoxygenated blood enters the circulation. This cyanosis is typically evident early in life and can become more pronounced with crying or agitation.

Syncope can occur during severe spells, but it is not the hallmark presentation. Hypertension is not a typical feature of Tetralogy of Fallot. Tachypnea can accompany poor oxygenation, yet it is not as characteristic as the presence of cyanosis.