Review Question - QID 107178

The differential between the upper extremity and lower extremity pulses and blood pressures is suggestive of coarctation of the aorta.

Hypertension is rare in children. However, when it occurs in young children, the majority of cases are not due to benign hypertension but rather are due to an underlying disorder. In children and adolescents, renal parenchymal disease and aortic coarctation are common causes of secondary hypertension. In coarctation, stenosis of the aorta distal to the origin of the left subclavian artery results in hypertension in arteries proximal to the lesion (including those primary arteries supplying the upper extremities), with relative hypotension to the lower extremities.

Viera et al. discuss the physical exam findings suggestive of coarctation of the aorta. A difference of >20 mmHg between the systolic blood pressures of the upper and lower extremities is suggestive of coarctation. Additionally, the finding of delayed or absent lower extremity pulses further supports the diagnosis. In addition, a systolic murmur may be heard in the patient's back.

Holloway et al. discuss imaging for coarctation. Echocardiography is a preferred diagnostic modality in young children with thin habitus. In larger individuals, MRI has proven to be the modality of choice. Gadolinium-enhanced MRA is currently the most useful diagnostic tool and can even provide quantitative information about collateral flow and the degree of stenosis. In cases where MRI cannot be used, CT-angiography may have some utility.

Illustration A shows notching of the ribs, which can be seen in coarctation of the aorta. Illustration B is a slice of an MRA showing coarctation and extensive collateral circulation.

Incorrect Answers:
Answer 1: Peripheral arterial disease is a common cause of exercise-induced claudication in adults and may cause decrease of perfusion pressure in the lower extremities in severe cases. However, this is very rare in children.
Answer 2: Raynaud's phenomenon can cause cold extremities via vasospams, but this does not fit with the hypertension seen in this vignette.
Answer 4: Tetralogy of Fallot can present with "Tet spells" in older children, but this patient's O2 saturation would be decreased.
Answer 5: Aortic stenosis can present with pulsus parvus et tardus, small and delayed pulses relative to the expected pulse. However, aortic stenosis is very unusual in a child, and the discordant hypertension is not characteristic.