Neurologic Effects of Water and Sodium Disturbances

Abstract

Hyponatremia is caused by extracellular sodium depletion or water excess. The former may occur with salt-losing nephritis, excessive use of diuretics, Addison's disease, profuse sweating (especially with continuous water intake), burns, etc. Surgery, trauma, chronic debilitating illnesses, etc., predispose to water intoxication by sustained ADH release. Although water load during normal renal function is rare, it can produce water intoxication in unusual situations, e.g., in psychotic patients who consume large amounts of water, sodium-depleted patients whose extracellular fluid is already hypotonic and patients having excessive urethral irrigation with water during prostatic surgery and large water enemas. The neurologic symptoms arise from cerebral cellular swelling and also from reduced circulating blood volume in the case of sodium loss.