Effect of alterations of sodium intake in patients with hyporeninemic hypoaldosteronism.

The effect of changes of sodium intake on serum and urinary electrolytes, plasma renin activity (PRA) and plasma aldosterone concentration (PA) was studied in five hyperkalemic patients with the syndrome of hyporeninemic hypoaldosteronism (SHH). The patients were evaluated during 8 days on a 10-mEq sodium and 50-mEq potassium diet plus furosemide, followed by 8 days on a 150-mEq sodium and 50-mEq potassium diet. After sodium depletion, both PRA and PA were substantially higher than after a previous 4-day period of simple dietary sodium restriction and an increase in serum potassium concentration occurred in only one subject. Administration of a normal sodium intake induced small increases in serum chloride in all five subjects and a decrease in bicarbonate concentration in one patient. It is concluded that, at least in some patients with SHH, PRA and PA are volume-responsive and that considerable alterations of sodium intake have relatively little influence on serum electrolyte concentrations.