ABSTRACT
Hypernatremia is a physiologic disturbance defined by a concentration of sodium in serum of 150 mEq/l or greater. The blood vessel changes in the central nervous system (CNS) will not occur if hypernatremia develops slowly. The discussion to follow will define the necessary concepts, give some clinical historical background, touch on etiologic factors, and describe clinical presentations, before moving to a more detailed discussion of pathophysiology and pathology. Inappropriate mixing resulted in very high solute intakes and a virtual epidemic of hypernatremia. Because the pathophysiology of hypernatremia has distinct features separating this form of dehydration from other more common varieties, a consideration of principles of therapy may help in understanding the disturbance. The experimental animal manifests dramatic CNS symptoms without hemorrhage but only after idiogenic osmols are present. The various disturbances of hypernatremia are mostly related to this property of sodium regardless of why the property exists. Water moves freely across virtually all the membrane interfaces of the body.
