Adjustment of the osmostat in primary aldosteronism.

Abstract

OBJECTIVE: To analyze osmoregulation in primary aldosteronism. DESIGN: The physiologic and pathologic factors involved in function of the osmostat and in hypernatremia were reviewed. RESULTS: Patients with primary aldosteronism commonly have mild hypernatremia, with serum sodium concentrations usually less than 150 meq/L. Hypernatremia has been detected in patients with aldosterone-producing adrenal adenomas and adrenal hyperplasia. The patients seem to ingest normal amounts of water. Adjustment of the osmosta (in the hypothalamus) to a higher than normal level of plasma osmolality seems to be the cause. Resetting of the osmostat to a higher level has rarely been noted in conditions other than primary aldosteronism. The hypernatremia can be corrected by either medical or surgical treatment of the primary aldosteronism. CONCLUSION: Mild hypernatremia in primary aldosteronism is attributable to shifting of the osmostat to the right.