Sympathoadrenal function in patients with paroxysmal hypertension: pseudopheochromocytoma.
OBJECTIVE
The causes of paroxysmal hypertension in patients in whom pheochromocytoma has been excluded ('pseudopheochromocytoma') usually remain unclear. Blood pressure disturbances and symptoms of catecholamine excess in these patients may reflect activation of the sympathetic nervous and adrenal medullary systems. We therefore examined sympathoadrenal function in patients with pseudopheochromocytoma compared with age-matched control subjects in whom there was no suspicion of pheochromocytoma.


METHODS
Plasma catecholamines and hemodynamics were examined in response to intravenous glucagon, yohimbine, and trimethaphan in 11 patients with pseudopheochromocytoma and a comparison group of nine normotensive and five hypertensive volunteers. Adrenomedullary function was also assessed by abdominal F-fluorodopamine positron emission tomography and measurements of plasma metanephrine, the O-methylated metabolite of epinephrine.


RESULTS
Compared with controls, patients with pseudopheochromocytoma had normal plasma concentrations of norepinephrine, but 120% higher (P < 0.05) baseline plasma concentrations of epinephrine, 80% higher (P < 0.01) baseline plasma concentrations of metanephrine, and sixfold larger (P < 0.05) increases in plasma epinephrine after glucagon. Adrenal 18F-fluorodopamine-derived radioactivity did not differ between groups. Compared with changes in plasma norepinephrine, falls in blood pressure after trimethaphan were 13-fold larger (P < 0.005) and increases in blood pressure after yohimbine were threefold larger (P < 0.01) in pseudopheochromocytoma patients than in controls.


CONCLUSIONS
Patients with pseudopheochromocytoma exhibit a pattern of normal sympathetic noradrenergic outflow, adrenomedullary activation, and augmented blood pressure responses to changes in the sympathoneural release of norepinephrine.
Sharabi
Yehonatan
Y
National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA.
Goldstein
David S
DS
Bentho
Oladi
O
Saleem
Ahmed
A
Pechnik
Sandra
S
Geraci
Marilla F
MF
Holmes
Courtney
C
Pacak
Karel
K
Eisenhofer
Graeme
G
D000311:Adrenal Glands / Q000503:physiopathology*; D000328:Adult; D017704:Baroreflex; D018660:Blood Pressure Monitoring, Ambulatory; D004837:Epinephrine / Q000097:blood; D005260:Female; D005934:Glucagon / Q000494:pharmacology; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D016584:Panic Disorder / Q000209:etiology; D010673:Pheochromocytoma / Q000503:physiopathology*; D049268:Positron-Emission Tomography; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D014294:Trimethaphan / Q000494:pharmacology; D015016:Yohimbine / Q000494:pharmacology
D015016:Yohimbine; D014294:Trimethaphan; D005934:Glucagon; D007545:Isoproterenol; D009638:Norepinephrine; D004837:Epinephrine