Postprandial hypotension. Pathophysiological mechanisms and clinical implications in different disorders.

T he physiological effects of food have been appreciated for some time, but the relation between food and disordered blood pressure regulation has been recognized relatively recently.In 1953, Smirk 1 noted that hypertensive patients given the ganglionic blocker pentolinium had a marked fall in blood pressure after meals but this was not pursued further, presumably because it was not considered a clinical problem (Figure 1).In 1977, Seyer-Hansen 2 reported a patient with autonomic failure and parkinsonism who had severe dizziness, visual disturbances, and hypotension caused by food ingestion; similar symptoms were provoked by oral glucose.In 1981, Robertson et al 3 demonstrated in a group of patients with autonomic dysfunction a profound fall in both systolic and diastolic blood pressure after food ingestion while the patients were seated.These findings were later confirmed, with further data indicating substantial postprandial hypotension even in the supine position. 4t is now evident that postprandial hypotension is a definite entity that can contribute to morbidity in a number of disorders.Although it can be defined as a fall in blood pressure after the ingestion of food, the precise levels that cause clinical problems vary in different situations.The symptoms caused may range from feelings of apathy and lightheadedness to somnolence and syncope.These are probably dependent on the extent to which perfusion is impaired in different vascular regions.With carotid artery stenosis, for instance, even with a small fall in pressure, there may be a greater propensity to cerebral symp-