THE LOW SALT SYNDROMES

Abstract

Hyponatremia is an ominous development, since one-third to one-half of the patients with Na levels of 132 meq/l or less die in the course of the hospitalization. At least 5 different types of low salt syndrome have been recognized to date. In 2 of these, true salt depletion and hyponatremia, in association with cell hypo-osmolarity seen in chronic illness, the extracellular Na stores are decreased. In 2 others, dilutional hyponatremia and hyperlipemic hyponatremia, the total Na of the body is intact. In the 5th type of low salt syndrome, i.e., the new steady states occurring in renal, hepatic or congestive heart failure, the total Na of the body is increased. Attempts to differentiate these various types of low salt syndrome in accordance with this scheme facilitate corrective therapy.