[Recurrent hypertensive crises associated with severe orthostatic hypotension due to baroreflex failure syndrome].

The baroreflex mechanism is a central part of the regulation of the cardiovascular system, particularly in the control of vagal and sympathetic outflow to the heart and the peripheral circulation. Failure of the baroreflex is a rare cause of secondary hypertension. It is characterized by drastic changes in sympathetic activation and blood pressure following complete denervation of the baroreflex. Here, we report a case of baroreflex failure following bilateral carotid artery surgery and radiation. Moreover, postoperative orthostatic hypotension with recurrent syncope suggests a rare subform, the selective baroreflex failure, where efferent parasympathetic activity is preserved. Both high blood pressure and orthostatically induced syncope improved substantially after treatment with clonidine.