A 12-year-old boy presents to the office with pain in his legs with activity gradually becoming worse over the past month. He is unable to ride a bicycle with his friends due to the pain in his legs. Examination of the heart reveals an ejection click and accentuation of the second heart sound. Femoral pulses are weak and delayed compared to the brachial pulses. Blood pressure obtained in both arms is elevated. Chest x-ray reveals rib notching. Which of the following is the most likely diagnosis?

• A. Abdominal aortic aneurysm
• B. Pheochromocytoma
• C. Coarctation of the aorta
• D. Thoracic outlet syndrome

Answer: (C)

Focusing on this case, the pattern fits coarctation of the aorta. The child’s leg pain with activity signals reduced blood flow to the lower body, while the upper-extremity hypertension with weak, delayed femoral pulses (radio-femoral delay) shows a pressure gradient across a narrowed aorta. Rib notching on chest X-ray comes from enlarged collateral intercostal arteries developing to bypass the obstruction. The heart findings of an ejection click and a loud S2 can be seen with a bicuspid aortic valve, which often accompanies coarctation. Altogether, these signs point to a congenital narrowing of the aorta just after the left subclavian artery.

Other options don’t fit the pattern: an abdominal aortic aneurysm is uncommon in a 12-year-old and would present differently; pheochromocytoma would cause episodic hypertension and other systemic symptoms without the characteristic rib notching and leg claudication; thoracic outlet syndrome affects upper-extremity symptoms related to arm position, not lower-extremity perfusion or rib notching.