Hyponatremia and Central Pontine Myelinolysis

What is hyponatremia? Information regarding CPM and EPM.

To summarize:

Ok, I know I’ve covered a LOT of information over the past few weeks regarding hyponatremia.

There is so much information and it is very complex that it’s hard to not get confused and lost in reading it, so I’m going to try to summarize what I’ve discussed so far.

There at least five categories of hyponatremia: Hypovalemic, Euvolemic, Hypervolemic, Redistributive, and Pseudohyponatrmia.

The most commonly impacted people:

Infants due to diluted formula


athletes (especially marathon runners)

Those who have liver cancer, liver damage, chirossis of the liver.

The elderly (usually due to malnutrition and dehydration)

Brain injuries, brain tumors

Transplant patients

Burn patients

Person’s who are receiving chemotherapy

Person’s with kidney disease and those who receive dialysis

Person’s who take certain medications like diuretics and anti depressants.

AID’s patients

Person’s who have pneumonia or flu

Anorexics and bulemics.

I’m sure I’m leaving about a dozen other groups affected, but you get the picture. It’s pretty common. Approximately, 1.5 million people are treated for it each year, and that’s probably a low number because I do not believe it includes persons who develop it while being treated for other conditions and develop hyponatremia as a secondary illness. I’ll try to find more information on that in the future.

Hyponatremia is extremely dangerous.  If your blood sodium levels drop very quickly in a 24 to 48 hour period (acute hyponatremia), your brainstem can herniate and/or your brain swells. This can lead to seizures, comas, and of course death.

If you develop chronic hyponatremia, (when your sodium levels drop over a period of 2 days to several weeks) you are less likely to have brain swelling or brainstem herniation, but you become at extremely great risk for developing Central Pontine Myelinolysis or Extrapontine myelinolysis.

The proper treatment is an absolute must. General IV fluids should be avoided if hyponatremia is suspected. Instead, an IV of saline solution ranging from .9% to 3% saline should be used. In some cases, fluid restriction will correct hyponatremia.

A person should have their sodium levels checked a minimum of every 2 to 4 hours.

If they are uncertain of the type of hyponatremia you have, then an MRI should be used to determine if there is cerebral swelling (swelling of the brain) or brainstem swelling. If there’s swelling present on the MRI, then you most likely have an acute form of hyponatremia.

If you have an acute form of hyponatremia, you are at a high risk of dying from immediate brain injury. Because of the risk, it is necessary to raise your blood sodium levels quickly to a safe level. It should be raised 2 to 4 mmol/L in 1 to 2 hours. However, once symptoms improve, the treatment should be halted for at least 24 to 48 hours. No matter what, levels should not be raised more than 15 mmol in 24 hours, in regards to acute hyponatremia.

If a person has chronic hyponatremia, they do not usually display the same severe symptoms. They usually feel sick. They might experience fatigue, nausea, have a severe headache, dizziness, loss of consciousness, delirium, etc. They do not usually have seizures, coma, or death. They are usually more alert compared to a person with acute hyponatremia.

The treatment for someone with chronic hyponatremia is signficantly different from acute hyponatremia because their sodium level MUST be raised slowly. It should be raised no more than .5 to 1 mmol/ L per hour. It should not be raised more than 8 to 10 mmol in a 24 hour period. Some even caution that it should be raised no more than 6 to 8 mmol per 24 hours. If it is raised faster than this, a person can develop Central Pontine Myelinolysis or Extrapontine Myelinolysis.

Expect to be in the ICU for 4 to 5 days at the very least if the treatment is being done correctly.

A person should NOT be given oral prescription medications along with IV saline solutions. The treatment should be fluid restriction if the hyponatremia is not severe or if it is a chronic form. If the fluid restriction does not work (with the chronic form), than a .9% solution should be started. If they have the acute form, then the 3% solution should be used first. Again, if the sodium levels begin to rise to a point where the symptoms begin to subside, then the treatments should be discontinued to see how the body responds.

If a person’s body is not responding to fluid restriction or IV saline solutions, then a person should be given the oral prescription medications. THEY SHOULD NOT BE GIVEN AT THE SAME TIME AS IV SALINE SOLUTIONS. IT SHOULD BE ONE OR THE OTHER–NOT BOTH.

I really think these are the most important aspects to hyponatremia. Please feel free to contact me if you have any questions or want more information over any of the topics I’ve posted so far. If you find out any relevant information regarding hyponatremia that you think I should include, PLEASE contact me or leave a message here. I REALLY appreciate your help.

Thank you for your support!

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