A 4-year-old boy presents with progressive dyspnoea on exertion and cyanosis that is MORE pronounced in the lower extremities than the upper extremities. There is clubbing of the toes but not the fingers. Which defect BEST explains this presentation?

• A Tetralogy of Fallot
• B Transposition of great arteries with VSD
• C Patent ductus arteriosus with Eisenmenger syndrome ✓
• D Total anomalous pulmonary venous connection (TAPVC) supracardiac type

Explanation

Differential cyanosis (cyanosis and clubbing MORE prominent in lower limbs than upper) is pathognomonic of PDA with Eisenmenger syndrome. When pulmonary resistance exceeds systemic resistance, the shunt reverses (right-to-left) through the PDA; desaturated blood flows preferentially to the lower body via the aorta distal to the PDA, sparing the upper limbs supplied by the aorta proximal to the ductus. In TGA, reverse differential cyanosis (upper worse than lower) can occur. TOF causes generalized cyanosis.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.