Clinical Scenario:
A 10-year-old boy is brought to the emergency department after a generalized tonic–clonic seizure. He has had recurrent morning headaches and easy fatigability for several weeks. On examination, his blood pressure in the right arm is 170/105 mmHg. Fundoscopy shows hypertensive retinal changes.
Cardiovascular examination reveals strong radial pulses but markedly weak and delayed femoral pulses. The blood pressure measured in the lower limb is substantially lower than that in the upper limb. A systolic murmur is best heard over the left interscapular region.
Which of the following is the most likely diagnosis?
A. Essential hypertension
B. Coarctation of the aorta
C. Pheochromocytoma
D. Renal artery stenosis
E. Takayasu arteritis
Correct answer & Explanation:
Correct answer: B. Coarctation of the aorta
Explanation
This child has severe hypertension with hypertensive encephalopathy, manifested by seizure, headache, and hypertensive retinal changes. The crucial clue to the underlying cause is the discrepancy between upper- and lower-extremity circulation.
The combination of:
- Marked upper-limb hypertension
- Lower blood pressure
- Weak and delayed femoral pulses
- Radiofemoral delay
- Systolic murmur over the interscapular region
is highly characteristic of coarctation of the aorta.
In older children, coarctation may remain undiagnosed until they present with hypertension, headache, epistaxis, or exercise-related leg symptoms.
The obstruction increases the pressure proximal to the coarctation, producing upper-extremity hypertension and increased left-ventricular afterload. Blood flow to the lower body is reduced, producing diminished femoral pulses and a lower arm–leg blood-pressure gradient. Over time, collateral vessels may develop around the obstruction.
Why the other options are less likely
A. Essential hypertension — Incorrect
Although essential hypertension can occur in older children, it would not explain the marked radiofemoral delay and lower-limb hypotension. These findings should immediately prompt evaluation for coarctation.
B. Coarctation of the aorta — Correct
The classic combination of upper-extremity hypertension + diminished/delayed femoral pulses + arm–leg BP difference makes this the best diagnosis.
C. Pheochromocytoma — Incorrect
Pheochromocytoma can cause severe hypertension and headache, but typically produces episodic symptoms such as palpitations and diaphoresis and does not cause a radiofemoral delay.
D. Renal artery stenosis — Incorrect
Renovascular hypertension is an important differential diagnosis in a hypertensive child, but the pulse and blood-pressure discrepancy between the upper and lower limbs strongly favors coarctation. An abdominal/renal bruit would be a more suggestive clue for renovascular disease.
E. Takayasu arteritis — Incorrect
Takayasu arteritis can cause hypertension and pulse discrepancies, but one would expect features such as absent/asymmetric pulses, arterial bruits, systemic inflammation, or involvement of multiple large vessels. The classic radiofemoral delay with an interscapular systolic murmur is much more characteristic of coarctation.
High-yield Exam/MCQ clue
Child with severe hypertension ± headache/seizure → always examine femoral pulses and measure BP in all four limbs.
Upper-limb hypertension + weak/delayed femoral pulses + lower leg BP → Coarctation of the aorta.
