| Abstrakt: |
Eight patients with aldosterone-producing adenoma (APA) (7 histologically proved) and 6 patients with idiopathic hyperaldosteronism (IHA) (2 histologically proved) were evaluated for differential diagnosis using clinical, radiographic, and biochemical parameters. Mean basal plasma aldosterone (445±146 (SD) pg/ml), 18-hydroxycorticosterone (975±394 pg/ml), and 18-hydroxydeoxycorticosterone levels (374±266 pg/ml) and mean diastolic blood pressure were significantly higher in patients with APA ( p<0.05 and p<0.01), whereas mean plasma potassium levels and stimulated plasma renin activity were lower in subjects with APA as compared to patients with IHA ( p<0.01 and p<0.01). Radiographic procedures predicted the correct diagnosis in 3 of 8 operated cases (37%) and selective adrenal vein sampling in 5 of 6 cases (83%). Urinary aldosterone excretion (30±10 µg/24 h) was suppressed in all patients with IHA after a 21 isotonic saline infusion in 2 h (13±6, p<0.01). In all patients with APA, however, aldosterone excretion was not suppressible (basal: 36±12). Plasma aldosterone levels of some patients with APA could be reduced by saline infusion and the response was not characteristically different between both groups. After 10 mg metoclopramide iv. the slopes of plasma aldosterone levels were similar for patients with APA and normal subjects. Patients with IHA showed a different secretion pattern with a delay of both the increase and the decline of aldosterone levels. Graded angiotensin II infusions (subpressor doses for normotensive individuals) did not increase plasma aldosterone levels in patients with APA. However, in patients with IHA, excessive increases of aldosterone levels were seen (basal: 268±54 pg/ml, after 4 ng A II/kg·min: 806±262). From these data, we conclude that patients with APA could be reliably identified before operation by determination of urinary aldosterone before and after a simple saline infusion test. Additionally, plasma aldosterone levels after metoclopramide iv. or angiotensin II infusions may be helpful diagnostic tools. [ABSTRACT FROM AUTHOR] |
