Periodic Fluctuation of Blood Pressure and Its Management in a Patient with Pheochromocytoma

The case of a 69 year old man with a right adrenal pheochromocytoma who manifested cyclic fluctuations of blood pressure with a cycle length of 9 to 13 min is reported. We collected and reviewed 14 similar cases previously reported in the literature. In these cases, right adrenal pheochromocytoma was most common, while 1 case involved the left adrenal and 2 cases were of extra-adrenal origin. The incidence in males was twice that in females and the median age was 45.3 years. Although a good correlation between the blood pressure and plasma norepinephrine concentrations was observed in our patient, the exact mechanism for the cyclic fluctuations of blood pressure is not known. In our patient, both YM-09538 and bunazosin were effective in controlling severe hypertension preoperatively. YM-09538 induced significant increases in urinary norepinephrine concentrations (1327±238μg/day), while bunazosin induced a significant decrement in urinary norepinephrine concentrations (475±188μg/day) compared with pretreatment levels (900±42μg/day) (p<0.01). These observations indicated that bunazosin as a postsynaptic α-adrenergic receptor blocker interfered with release of norepinephrine from the tumor and thus might be beneficial in the management of elevated blood pressure in patients with pheochromocytoma.