Normotensive Primary Aldosteronism: A Case Report

We report the case of 35 year-old woman referred to endocrine department for hypokaliemia revealed by cardiac and neuromuscular symptoms. Clinical and ambulatory blood pressure measurements were normal (respectively: 120 / 80 mmHg and 122 ± 13.5 / 79 ± 13.4 mmHg). Biological findings: Hypokaliemia (2.1 to 2.5 mmol/l), metabolic alkalosis, inappropriate kaliuresis (42 mmol/24h), high plasma aldosterone (523 ng/l) and suppressed renin activity (<2.5 ng/l). Computered tomodensitometry showed a well-circumscribed homogenous mass, 12 mm in diameter, in the inner arm of the left adrenal gland. After surgical removal of the adenoma, blood pressure level decreased by about 20 mmHg, and biological and hormonal status were normalized. Spontaneous low baseline blood pressure level may explain lack of hypertension in this patient. In hypokaliemic patients, lack of hypertension should not exclude primary aldosteronism. Protective mechanisms against hypertension in such patients should be more studied and used in hypertension treatment research.