Normokalemic Primary Aldosteronism

In the recent past, one of us1has marshaled circumstantial evidence to support his conviction that about 20% of patients with "essential" hypertension harbor a small, aldosterone-secreting adrenal cortical tumor as its cause. Careful retrospective study, during the past 11 years, of our cases of proved primary aldosteronism had convinced us that many of these patients had not had hypokalemia until shortly (one to two years) before we saw them. Yet hypertension had been present for 10 to 15 years and was cured by removal of the adrenal adenoma. This meant that such patients would have had to be classified as having "essential" hypertension during those preceding years, and that hypokalemia and severe potassium depletion are late manifestations of an underlying process which has been active for many years. It became increasingly clear to us that our own insistence on the demonstration of persistent hypokalemia as a major diagnostic