Diagnostic considerations in pheochromocytoma and chronic hemodialysis: case report and review of the literature.

We present a patient on long-term hemodialysis (LTH) discovered to have a pheochromocytoma. A thorough workup pertaining his catecholamine status was performed, and intraoperative catecholamine changes were monitored. This condition poses some analytical difficulties as both interpretation of plasma catecholamine measurements and determination of their metabolic products are impaired. The literature about catecholamines with respect to hemodialysis is reviewed, and the known cases of pheochromocytoma in LTH patients are discussed. Predialysis norepinephrine concentrations were almost consistently elevated though less than 3-fold when compared to normal controls. Epinephrine is not significantly different in both groups. At least a 3.3-fold increase of epinephrine or norepinephrine in LTH patients with adrenal pheochromocytomas is observed. We conclude that plasma epinephrine elevations can be evaluated in the conventional manner, and norepinephrine concentrations beyond a 3-fold elevation should raise the suspicion of a pathological catechol excess syndrome. The interpretation of plasma homovanillic acid and vanillylmandelic acid in this condition is complicated by the lack of data in LTH patients without pheochromocytoma. Markedly elevated baseline concentrations for these parameters are assumed.