Osmotic demyelination syndrome (ODS)

What is ODS ?

  • ODS is a brain cell dysfunction.
  • It is induced by the injury of the layer (myelin sheath) covering nerve cells in the middle of the brainstem (pons).


  • When the myelin sheath that encloses nerve cells is demolished, signals from one nerve to another aren’t appropriately transmitted. 
  • Although the brainstem is mainly affected, other areas of the brain can also be affected.
  • The most widespread cause of ODS is a quick change in the body’s sodium levels.
  • This most frequently occurs when someone is being treated for low blood sodium (hyponatremia) and the sodium is replaced too quickly. 
  • Occasionally, it occurs when a high level of sodium in the body (hypernatremia) is improved too quickly.
  • ODS does not usually happen on its own.
  • Most repeatedly, it’s a complication of treatment for other problems, or from the additional problems themselves.

Risks include:

  • Alcohol usage
  • Liver ailment
  • Malnutrition from severe illnesses
  • Severe nausea and vomiting during pregnancy 
  • Radiation treatment of the brain


Symptoms may comprise any of the following:

  • Confusion
  • Delirium
  • hallucinations
  • Balance issues
  • tremor
  • Difficulty swallowing
  • Reduced alertness
  • tiredness or sleepiness, lethargy, poor responses
  • Slurred speech
  • Weakness in the face, arms, or legs, generally affecting both sides of the body

Exams and Tests

The health care provider will conduct a physical exam and interrogate about the symptoms.

  • A head MRI scan may disclose a problem in the brainstem (pons) or other portions of the brain. 
  • This is the primary diagnostic test.

Additional tests may include:

  • Blood sodium level and further blood tests
  • Brainstem auditory evoked response (BAER).


  • ODS is an emergency disorder that requires to be treated in the hospital though maximum people with this condition are already in the hospital for another problem.
  • There is no known treatment for central pontine myelinolysis. 
  • Treatment is directed on lessening symptoms.
  • Physical therapy may benefit maintain muscle strength, mobility, and function in weakened arms and legs.

Outlook (Prognosis)

The nerve damage resulted by central pontine myelinolysis is frequently long-lasting. 

The disorder can result in serious long-term (chronic) disability.

Possible Complications

Complications may comprise:

  • Reduced capacity to interact with others
  • Decreased power to work or care for self
  • Incapability to move, other than to blink eyes (“locked in” syndrome)
  • Lasting nervous system damage


In the hospital, slow, regulated treatment of a low sodium level may decrease the risk for nerve damage in the pons. 

Being conscious of how some medicines can alter sodium levels can prevent the level from changing too quickly.

Alternative Names

  • ODS
  • Central pontine demyelination


Q. Is osmotic demyelination syndrome reversible?

  • The clinical indications of ODS are known to develop for 2-6 days after a rapid elevation of the serum sodium level.
  • The symptoms are frequently irreversible or only somewhat reversible, and they include dysarthria, dysphagia, tetraparesis, behavioral disturbances, lethargy, confusion, disorientation, and coma.

Q. Is osmotic demyelination syndrome fatal?

  • The disorder can resolve totally or result in permanent disability or death. 

Q. Can you recover from ODS?

  • Although ODS may result in permanent disability or death, many patients can have a full or reasonable spontaneous functional recovery . 
  • Yet, recovery with the aid of supportive care is unpredictable i.e. unrelated to the severity of the initial presentation.


Back to Top