REVERSIBLE HYPERKALEMIA DURING ANTIHYPERTENSIVE THERAPY IN A HYPERTENSIVE DIABETIC PATIENT WITH LATENT HYPOALDOSTERONISM AND MILD RENAL-FAILURE

A 66-year-old hypertensive diabetic patient with latent hypoaldosteron ism and mild renal failure was treated by adding enalapril, an angiote nsin converting enzyme inhibitor, to the furosemide and nifedipine reg imen because of an insufficient antihypertensive response for 1 month. Seven days after enalapril addition, the blood pressure was significa ntly reduced, but frank hyperkalemia occurred with a marked rise in BU N and a slight increase in serum creatinine. Plasma renin activity (PR A) and plasma aldosterone (PA) values remained low before and during e nalapril therapy. Transient treatment with sodium polystyrene sulfate after enalapril withdrawal improved the hyperkalemia and renal functio n, but PRA and PA levels were low. PA and its precursor steroids also responded poorly to graded angiotensin II infusion and rapid ACTH inje ction. Latent hypoaldosteronism probably predisposed this patient to f rank hyperkalemia with progressive dehydration and slightly reduced re nal function during antihypertensive therapy.