Phaeochromocytoma with nocturnal elevation of blood pressure.

A 47-year-old woman with phaeochromocytoma showed blood pressure changes characterized by the regular appearance of hypertension at night. The urinary excretion of catecholamines and their metabolites showed augmentation roughly parallel with the elevation of the blood pressure. During normotensive periods, the urinary excretion of catecholamines and their metabolites was elevated. The findings suggested that the pressor effect of catecholamine hypersecretion was compromised to a certain degree and that the regular nocturnal appearances of hypertensive paroxysm conceivably resulted from a spontaneous cyclic augmentation of the catecholamine secretion from the tumour.