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 hav e a pheochromocytoma. A thorough workup pertaining his catecholamine s tatus was performed, and intraoperative catecholamine changes were mon itored. This condition poses some analytical difficulties as both inte rpretation of plasma catecholamine measurements and determination of t heir metabolic products are impaired, The literature about catecholami nes with respect to hemodialysis is reviewed, and the known cases of p heochromocytoma in LTH patients are discussed. Predialysis norepinephr ine concentrations were almost consistently elevated though less than 3-fold when compared to normal controls, Epinephrine is not significan tly different in both groups, At least a 3.3-fold increase of epinephr ine or norepinephrine in LTH patients with adrenal pheochromocytomas i s observed. We conclude that plasma epinephrine elevations can be eval uated in the conventional manner, and norepinephrine concentrations be yond a 3-fold elevation should raise the suspicion of a pathological c atechol excess syndrome. The interpretation of plasma homovanillic aci d and vanillylmandelic acid in this condition is complicated by the la ck of data in LTH patients without pheochromocytoma. Markedly elevated baseline concentrations for these parameters are assumed.