Accelerated hypertension with encephalopathy due to an isolated dissection of a renal artery branch vessel.

Typical causes of renovascular hypertension include intramural atherosclerotic lesions of the main renal arteries or their branches and fibromuscular dysplasia of the renal arterial wall with luminal narrowing. We report a patient with new-onset, accelerated hypertension (blood pressure 220/140 mm Hg, status epilepticus, retinal hemorrhages) secondary to a dissection of the anterior division of the right renal artery that was accompanied by hyperreninemia, hyperaldosteronism, and hypokalemia. At presentation in the untreated state, unstimulated plasma renin activity and the serum aldosterone level were markedly elevated. Following right nephrectomy, blood pressure levels normalized without antihypertensive therapy, and plasma renin activity, serum aldosterone and potassium levels normalized. Histologic study of the right renal artery showed an isolated dissection of the anterior branch of the vessel between the muscularis and adventitia that created marked reduction in luminal diameter and renal ischemia. There was no evidence of any other vascular abnormalities, atherosclerosis, or fibromuscular dysplasia. These findings demonstrate that an isolated dissection of a branch of the renal artery may induce profound hyperreninemia and represents a rare, reversible etiology for accelerated hypertension associated with acute encephalopathy.