An easy diagnostic approach to primary aldosteronism

The infusion of 40 mEq potassium (aspartate) in 250 mi isotonic l-fructose at a rate of 20 mEq/h into 5 patients (34-56 years old) with aldosteronoma and 2 patients with bilateral primary aldosteronism consistently raised the ir mean arterial pressure by 15-20 mmHg. Their pressure values returned to the baseline levels 4-5 h after the infusion. In contrast, in controls (10 patients with idiopathic arterial hypertension, matched for age, sex, and m agnitude of the untreated hypertension, and 7 patients with inactive adrena l nodules as incidental findings on upper abdomen ultrasound or computerize d tomography) the same procedure caused negligible arterial pressure change s. The cause of the rise in blood pressure observed uniquely in patients wi th primary aldosteronism after infusion of potassium (aspartate) cannot be accounted for by an increase in plasma aldosterone, blood volume, or plasma angiotensin II. The cause of this response thus remains obscure; nonethele ss, this simple procedure may prove useful in differentiating primary aldos teronism from idiopathic hypertension, in excluding the adrenal disorder, a nd in revealing even its mildest forms. (C) 1999 Elsevier Science Inc. All rights reserved.