Abstract

ABSTRACT: A 66-year-old hypertensive diabetic patient with latent hypoaldosteronism and mild renal failure was treated by adding enalapril, an angiotensin converting enzyme inhibitor, to the furosemide and nifedipine regimen because of an insufficient antihypertensive response for 1 month. Seven days after enalapril addition, the blood pressure was significantly reduced, but frank hyperkalemia occurred with a marked rise in BUN and a slight increase in serum creatinine. Plasma renin activity (PRA) and plasma aldosterone (PA) values remained low before and during enalapril therapy. Transient treatment with sodium polystyrene sulfate after enalapril withdrawal improved the hyperkalemia and renal function, but PRA and PA levels were low. PA and its precursor steroids also responded poorly to graded angiotensin II infusion and rapid ACTH injection. Latent hypoaldosteronism probably predisposed this patient to frank hyperkalemia with progressive dehydration and slightly reduced renal function during antihypertensive therapy.