[Primary hyperaldosteronism: differentiation between aldosterone-producing adenoma and idiopathic adrenocortical...

The regulation of aldosterone secretion by sodium restricted and enriched diet was assessed in 21 patients with primary aldosteronism for differentiation between unilateral aldosterone-producing adenoma and adrenocortical hyperplasia causing autonomous aldosterone hypersecretion. Compared to 10 patients with idiopathic adrenocortical hyperplasia, urinary aldosterone excretion after 4 days of sodium restricted diet was significantly higher in 11 patients with established adenoma (41.3 +/- 16.3 micrograms/24 h vs 19.8 +/- 8.5 micrograms/24 h; P less than 0.005). After six days of sodium loading these differences became even more obvious (35.3 +/- 14.0 micrograms/24 h vs 12.7 +/- 3.7 micrograms/24 h; P less than 0.0005). Sodium excretion did not influence aldosterone secretion in the adenoma group. In patients with hyperplasia both parameters showed a negative correlation (r = -0.522; P less than 0.001). Differentiation without overlap between both patient groups was achieved by comparison of the quotient of aldosterone excretion and serum potassium level during sodium enriched diet.