A 12-year-old girl complains of headaches and blurred vision. She has a history of high blood pressure but is not currently taking medication. Her blood pressure is 160/95 mm Hg and pulse is 95 per minute. Funduscopic examination reveals small retinal microaneurysms and cotton-like zones of retinal edema and necrosis. She is hospitalized for further evaluation. Renal arteriography shows segmental stenoses forming multiple ridges that project into the lumen. What is the most likely cause of secondary hypertension in this young patient?

The most frequent cause of renovascular hypertension in children is fibromuscular dysplasia. This disease is characterized by fibrous and muscular stenosis of the renal artery. Areas of medial thickening alternate with areas of atrophy producing a "string of beads" pattern in angiograms. Stenosis or total occlusion of a main renal artery produces hypertension that is potentially curable by reconstitution of the arterial lumen. Buerger disease (choice A) and Kawasaki disease (choice D) do not typically affect the renal arteries. Giant cell arteritis (choice C) and Takayasu arteritis (choice E) may cause secondary hypertension by producing sclerotic thickening of the renal arteries; however, these vascular diseases are distinctly uncommon in children.Diagnosis: Fibromuscular dysplasia