Nocturnal headache-hypertension syndrome: a chronobiologic disorder

The study of blood pressure (BP) monitoring in essential hypertensive patients recurrently suffering from nocturnal headache revealed a rhythmic elevation of sphygmomanometric values during the night. Such a finding was not detected in essential hypertensive patients suffering from occasional headache. The nocturnal elevation of BP was seen to be paralleled by the circadian peak of heart rate, suggesting that the disorder is a systemic phenomenon. Importantly, the headache episodes were seen to disappear after antihypertensive therapy that was adjusted to lower the nocturnal increase of BP. The therapeutic results suggested that the nocturnal headache was dependent on the phasic elevation of BP. The beneficial effects further suggested that the nocturnal headache and the nocturnal elevation of BP may represent a particular syndrome with a cause-effect relationship. The term "nocturnal headache-hypertension syndrome" is proposed.