Abstract
A 52 yr old man had hypertension, persistent hyperkalemia and hyperchloremic metabolic acidosis; renal and adrenal functions were normal. Four other members of the family have the same findings. The patient''s plasma aldosterone (PA) level was within normal range, though plasma renin activity (PRA) was undetectable. The ability to conserve Na with increased endogenous aldosterone levels, and the inability to increase K excretion while exogenous mineralocorticoid (fludrocortisone acetate) was administered, indicated a distal tubular defect in K handling. Effective reduction of the hyperkalemia by K+-Na+ exchange resin also corrected the acidosis and the hyperchloremia, suggesting that hyperkalemia may cause metabolic acidosis.