The most common cause of hypertension in this age group is primary, despite the absence of documented family history. Examples of secondary causes of hypertension include vascular abnormalities, the next most common cause, for example, coarctation of the aorta or renal artery stenosis; chronic renal disease, uncommon in an asymptomatic patient; and an adrenal tumor, such as pheochromocytoma, a rare event.