The Clinical and Physiologic Significance of the Serum Sodium Concentration

Abstract

(Concluded)* Hyponatremia with circulatory insufficiency and contracted extracellular-fluid volume. The pathophysiology of this second type of hyponatremia is not nearly so clearly understood as in the type just considered. The existence of this type of hyponatremia seems to contradict the normal regulation of the serum sodium and total solute concentrations as hitherto considered. Figure 3 demonstrates from studies of McCance⁵³ the development of this state experimentally in a normal subject during forced sodium depletion. The subject was maintained on a diet containing very little sodium, with water as desired. On the occasions indicated by the small vertical arrows he was made . . .