Desmopressin at 2 mcg q6 hrs IV/SC
6 mL/kg of 5% dextrose in water, repeated until serum sodium rise back below 9 mEq in 24 hrs
If concerns for iatrogenic rapid increase in serum Na concentration (IV crystalloid bolus before Na lab comes back):
Stop IV fluids, send urine osmolality, repeat serum Na
If uOsm is < 100 mOsm/L, this suggests free water diuresis
Or if sodium appears to be on a trajectory to increase >8mEq/L in 24hrs
Administer DDAVP 1 mcg x1
Stop IV fluids, send urine osmolality, repeat serum Na
If uOsm is < 100 mOsm/L, this suggests free water diuresis
Or if sodium appears to be on a trajectory to increase >8mEq/L in 24hrs
Administer DDAVP 1 mcg x1
Osmotic demyelination syndrome
Hypoxic encephalopathy
Limbic encephalitis
Acute toxic-metabolic encephalopathy 
Neoplastic meningitis
Hypoglycemia
Posterior reversible encephalopathy syndrome
Hyperosmolar state 