Hyponatremia and Central Pontine Myelinolysis

What is hyponatremia? Information regarding CPM and EPM.

Hyponatremia: More treatment information.

Ok, so I’ve been researching like crazy. I have a friend who has CPM. He was recovering in the hospital from alcoholism. He possibly developed acute hyponatremia, and I have been doing research to find out as much possible about the differences between acute hyponatremia and chronic hyponatremia.

Hyponatremia is really an ugly beast when you try to break it down. It’s complex.

So there are different types of hyponatremia based on how it is induced. There are five different types (classifications) for hyponatremia. (who knew):

1.) Hypovalemic hyponatremia: body water, body sodium and extracellular fluid volume decrease.

2.) Euvolemic hyponatremia: Body water increases but sodium levels remain normal; to put it simply, dilution.  There is no edema but extracellular fluid increases slightly.

3.) Hypervolemic hyponatremia: Blood sodium increases, but body water increases more. There is a great increase in extracellular fluid. There is a presence of edema.

4.) Redistributive hyponatremia: This is related to the administration of mannitol, as well as with hyperglycemia. There is no change in body water or blood sodium, but there is a shift from intracellular fluid to extracellular. (Water moves from inside the cell to outside the cell.)

5.) Pseudohyponatremia: The blood sodium and body water are unchanged, but there is an abundance of lipids and proteins in the blood. Two conditions that cause this are hypertriglyceridemia and multiple myeloma.

This information was found from the following website:


I found the above website very informative in drugs that can cause hyponatremia. It also had a lot of important regarding how it should be treated.

For instance, there is chronic hyponatremia in which a person has below normal sodium levels for more than 48 hours. Then, there is acute hyponatremia in which a person has sodium levels lower than normal for less than 24 to 48 hours.

Now the key with acute hyponatremia is the rate at which it decreases over 24 to 48 hours. For instance, a person may be diagnosed with hyponatremia on day 1 with a level of 130, but by day 2 have a level of 118, and by day 3 have a level of 110. Would this be considered chronic or acute? If sodium levels continue to fall over a period of time, a few days to a few weeks, it is considered chronic, despite where it started or how quickly it initially dropped.  It is the overall period of time it has continued to drop.

This goes back to one of my earlier posts. It is actually believed that the longer it stays low the safer it is medically for the person. What I mean by that, it is less likely for a person to go into a coma or for a person to have their brain stem herniate due to swelling directly caused by a rapid drop in sodium.

There is a fine line between low and too low and how long it should stay that low. There is a large number of studies that say if you can stabilize the hyponatremic state, it is safer long term for the person. However, at that point, it becomes critical that the person’s sodium levels be raised to normal at an extremely slow rate (.5mmol/hr or less and no more than 8 mmol/24 hours)!!!

If a person develops acute hyponatremia, their sodium levels drop extremely low the first 24 to 48 hours. This is most common in persons who drink an excessive amount of water. This is also common in infants when parents water down their formula.

What do I mean by extremely low? The levels go from 135 to 110 or lower in the first 24 to 48 hours.

In persons who have their sodium levels drop this significantly, in this short of a period, they have an extremely high risk of developing brainstem herniation and/or cerebral swelling, and/or coma. Their functions are extremely impaired very quickly.

In persons who develop chronic hyponatremia, their initial physical symptoms are far less significant than those who develop acute hyponatremia. If a person, is conscious and can talk coherently, chances are they have chronic hyponatremia. If the person is unconscious, having seizures, thinks they’re a monkey, they probably have acute hyponatremia.

The difference of how to treat these patients vary greatly based on which type of hyponatremia they have. The chronic hyponatremic patient must have their sodium levels raised slowly.  The acute hyponatremic patient must have their levels raised rapidly, at least initially.

*****The acute hyponatremic patient has a greater risk for developing brainsterm herniation, coma, and cerebral swelling, so they must have their levels raised quickly to control this swelling. As I mentioned previously, raising the sodium levels, decrease the swelling in the brain. That said, the levels can’t be raised too quickly!

It is recommended that sodium levels be increased by 4-6 mmol/L during the first 1 to 2 hours. (http://emedicine.medscape.com/article/767624-treatment#a1126). ONCE SYMPTOMS BEGIN TO IMPROVE THIS THERAPY SHOULD BE SLOWED OR CEASE!!! In other words, once a person has stabilized there should be a reduction to this high dose treatment to prevent CNS abnormalities. It is further recommended that a person should not have their levels increased more than 12 to 15 mmol during that first 24 hours. Once it has reached that point, it should not be increased further for a total of 48 hours.*****

It is extremely difficult for a medical professional to determine which type of hyponatremia you or your loved one might have. You can help them determine this by letting them know if there were any issues the day or so before you were brought to the hospital. Were you feeling sick or experiencing headaches, fatigue or cramps in the 24 to 48 hours before you made it to the hospital?

Most people experience unexplained cramps in their hands or feet as the one of the first symptoms of hyponatremia; however, they don’t realize it, so they delay seeking treatment until the symptoms progress.

IF your doctor is unable to determine what type of hyponatremia you have by your symptoms or time frame alone, then they should perform an MRI or CT scan to check for swelling in the brain or brainstem!!! Please, be aware of this crucial step. If a person shows brainstem or brain swelling, then they should be treated for acute hyponatremia. This type of injury is less common in persons who have the chronic form!

There is so much to this puzzle, and it becomes more complex the more I research. It also leaves questions. For instance, it is known that alcoholics are more likely to develop CPM; however, I have not been able to determine what type of hyponatremia alcoholics develop most often, chronic or acute. If the develop chronic, then that is in accord with the research I have found thus far because those with chronic hyponatremia have the highest risk for developing CPM. If alcoholics develop acute hyponatremia, this would go against research that says those with acute hyponatremia rarely develop CPM.

So, the more I research, the more questions I have.

Please be patient as I learn more and pass the information to you. Please leave any questions or point out any inconsistencies you might find in my posts.  No matter what, please continue to pass the information forward. It will be nearly impossible to protect people from this threat without your help.


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