Common neurologic complications of hyponatremia and hypernatremia
What are the most common neurologic complications of hyponatremia and hypernatremia?
Alteration of mental status is the common neurologic alteration resulting from hyponatremia and may occur after acute reduction of serum sodium to below 130 mEq/L or with chronically depressed sodium concentrations of below 115 mEq/L. Seizures, seen in the presence of acute reduction of serum sodium to less than 125 mEq/L, are generalized in nature and signify a mortality risk of greater than 50%.
Therapy includes fluid restriction or sodium replacement in severe hyponatremia.
Rapid sodium replacement of sodium can result in myelinolysis (central pontine and/or extrapontine) throughout the brain due to rapid osmotic shifts.
Other patients at particular risk for this complication, despite slow and carefully monitored sodium replacement, include alcoholics and those with renal disease.
Hypernatremia (serum sodium >160 mEq/L) may lead to an altered mental state, progressing to coma or seizures.
Focal cerebral hemorrhage resulting from the tearing of parenchymal vessels or bridging veins (due to brain shrinkage) produces multiple neurologic symptoms, including hemiparesis, rigidity, tremor, myoclonus, cerebellar ataxia, and chorea, as well as signs of subarachnoid hemorrhage or subdural hematoma.
