Impaired Renal Tubular Potassium Secretion in Systemic Lupus Erythematosus

Abstract

Two patients with long-standing systemic lupus erythematosus had persistent hyperkalemia. The hyperkalemia could not be explained by renal insufficiency, oliguria, diminished distal Na delivery, acidemia or hemolysis. After Na depletion, urinary aldosterone excretion and plasma aldosterone concentration rose appropriately. No increase in urinary K excretion or decrease in serum K concentration was noted after fludrocortisone acetate, furosemide or acetazolamide plus NaHCO3 treatment. These patients have a primary defect in renal tubular K secretion that may be related to an immune complex interstitial nephritis.