Inappropriate Renal Sodium Loss Reverted by Vena Cava Obstruction

Abstract

Sodium balance is normally regulated by the interaction of the kidneys, the adrenal cortex, and one or several additional regulatory mechanisms, at present poorly defined (1-3). Excessive renal sodium loss, if not drug-induced, may occur in certain types of renal disease (salt-losing nephritis) (4-8) and in adrenal insufficiency. Renal sodium loss in the face of hyponatremia also occurs in a syndrome linked to overhydration secondary to inappropriate antidiuretic hormone release (9-14). Sodium loss is not correctable in renal disease but can be overcome by appropriate substitution therapy in adrenal insufficiency and by fluid restriction when it is associated with overhydration.