Control of fluid balance and osmolarity disorders in the cerebral pathology

Abstract

Neurologically injured patients are at risk for osmolarity disorders. This is due to the fact that the brain controls the complex mechanism of the overall fl uid balance and also possesses the capacity to locally minimize the plasma tonicity disturbances (cerebral osmoregulation). Perioperative fluid administration, mannitol use, syndrome of inappropriate antidiuretic hormone and cerebral salt-wasting syndrome are potential causes of hyponatremia. Enteral tube feeding, osmotic diuresis and insipid diabetes are potential causes of hypernatremia. Severe hyponatremia or severe hypernatremia have various neurological consequences. On the other hand, correction of these disorders must be done slowly, to avoid precipitating central pontine myelinolysis (for the case of correction of hyponatremia) or to avoid producing cerebral edema (for the case of correction of hypernatremia).

Keywords

• osmolarity
• tonicity
• hypersodemia
• hyposodemia
• mannitol
• insipid diabetes
• cerebral edema
• water balance