A simplified screening test for differentiating primary aldosteronism from essential hypertension with low plasma renin activity.

: A simplified screening test for differentiating primary aldosteronism (PA) from low renin essential hypertension (LREH) is presented. Nine patients with LREH and 5 patients with PA due to adrenal adenoma were studied. In the patients with LREH, the levels of plasma renin activity (PRA) before and after treatment with furosemide (0.7 mg/kg, i.v.) and a 2-hour ambulation under treatment with dexamethasone (1.0 mg) (dexamethasone + furosemide test) increased briskly, compared to the levels of PRA before and after treatment with furosemide (0.7 mg/kg, i.v.) and a 2-hour ambulation (furosemide test). In patients with PA, there was no significant difference between the mean levels before the furosemide test and before the dexamethasone + furosemide test, or between the mean levels after the furosemide test and after the dexamethasone + furosemide test. These results suggest that the suppression of PRA in patients with LREH may be related to a factor controlled by dexamethasone. It is concluded that the dexamethasone + furosemide test is useful for differentiating PA due to adenoma from LREH.