Osmotic demyelination syndrome


  • Formerly called "central pontine myelinolysis"
  • A neurologic condition caused by rapid correction of hyponatremia, with starting serum sodium normally 120 meq/L or less
  • Caused by rapid correction of hyponatremia (>12 mEq/L/24 h), as water moves from cells to extracellular fluid, yielding intracellular dehydration.
  • Symptoms are often irreversible or only partially reversible

Risk Factors

Risk Factors for Over-correction[1]

Clinical Features

Symptoms can be present 2-6 days after rapid correction of serum sodium

Differential Diagnosis

Altered mental status

Diffuse brain dysfunction

Primary CNS disease or trauma



  • Evaluate for alternative/reversible causes of AMS or exacerbating factors
  • MRI can be used to visualize the pontine lesion, with a characteristic "batwing" lesion of the pons appearing in typical cases


  • 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


  • Admit


See hyponatremia for safe correction rate

See Also


  1. George, J. C., Zafar, W., Bucaloiu, I. D., & Chang, A. R. (2018). Risk Factors and Outcomes of Rapid Correction of Severe Hyponatremia. Clinical Journal of the American Society of Nephrology: CJASN, 13(7), 984–992.
  2. Sterns RH and Hix JK. Overcorrection of hyponatremia is a medical emergency. Kidney International. Volume 76, Issue 6, 2 September 2009, Pages 587-589.