Familial hyperkalemia, hypertension, and hyporeninemia with normal aldosterone levels. A tubular defect in potassium handling.

A 52-year-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 sodium with increased endogenous aldosterone levels, and the inability to increase potassium excretion while exogenous mineralocorticoid (fludrocortisone acetate) was administered, indicated a distal tubular defect in potassium 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.