Episodic dopamine discharge in paroxysmal hypertension. Page's syndrome revisited.

Dopamine concentration, a marker of the sympathetic discharge additional to norepinephrine and epinephrine levels, was determined in 31 patients. These patients, mostly women, had essential hypertension and hypertensive episodes that mimicked pheochromocytoma, except that the patients were rather plethoric (instead of pale) and often had associated nausea, epigastric discomfort, and polyuria. During and after hypertensive paroxysms, plasma free norepinephrine and epinephrine levels did not increase, but we found a mean eightfold and 16-fold increase of free and sulfated plasma dopamine levels, respectively, and similar although less marked dopamine level increases in the urine collected following the paroxysm. The hypertensive paroxysms, spontaneous or precipitated by stimulation of the autonomic nervous system, were similar to those described by Page as simulating diencephalic stimulation. Dopamine level may be a marker of the sympathetic discharge, undetected by measurements of free norepinephrine level, and may explain some clinical features of Page's syndrome.