Extreme blood pressure fluctuations in a patient with intact autonomic reflexes and intact sodium conservation.

A patient who had episodes of profound hypotension alternating with severe hypertension without an obvious precipitating cause is reported. The hypotensive episodes were accompanied by tiredness, syncope, bradycardia, and a low norepinephrine concentration while supine or standing. In contrast, the hypertensive episodes were associated with marked tachycardia, sweating, anxiety, abdominal pain, and very high levels of plasma norepinephrine concentration. Extensive investigations failed to support a diagnosis of pheochromocytoma. The testing of baroreceptor function and autonomic reflexes was normal. Blood pressure was not salt sensitive. It was concluded that this patient has a unique clinical syndrome of extreme fluctuation of blood pressure and sympathetic nervous activity yet intact cardiovascular reflexes and normal sodium conservation. The abnormal blood pressure regulation most likely has a central origin.