CNS-MANIFESTATIONS OF DISORDERED SALT AND WATER-BALANCE

Although the blood-brain barrier protects the CNS against excesses or deficits of sodium and water in isotonic proportions, this mechanism may fail, at least temporarily, if disordered renal function produces a major shift in the osmolality of body fluids. The processes by which significant osmolality changes give rise to either edema or dehydration of the brain are described, as are their dire clinical consequences.