Central pontine myelinolysis is a neurological disorder. It results from damage to the myelin sheath of your brain cells in certain regions — usually the central pontine region — of your brain.
The myelin sheath insulates your brain cells — or neurons — and allows electrical signals to travel around your body. The damage can lead to symptoms in many different parts of your body.
In 10% of cases, there’s damage to areas of your brain other than the central pontine region. To account for this, the disorder is also called osmotic demyelination syndrome (ODS).
The disorder is underdiagnosed, but approximately 2.5% of all people admitted to the intensive care unit develop ODS.
What Are the Causes of Central Pontine Myelinolysis?
Central pontine myelinolysis occurs when your body’s salt levels are increased too quickly after being low. It’s most likely to happen if your sodium levels were depleted for two days or more before you got treatment.
This condition isn’t caused by eating or drinking; instead, it happens when you are given sodium intravenously in a medical setting.
If you have certain risk factors that your medical team doesn’t know about, they may try to increase your sodium levels too fast. The high levels of salt cause water and small electrolytes to leave your brain cells very quickly, which damages some myelin sheaths.
The disorder was originally described in 1949 among a population of people with alcoholism. People with alcoholism are at a higher risk for developing the disorder.
But it wasn’t until the 1970s that doctors realized that other populations were also at risk for this condition, including:
- Transplant recipients — particularly recipients of liver transplants
- People with hyperemesis during pregnancy — when you are constantly nauseous and vomiting
- People with chronically debilitating conditions
Many people outside of these risk categories won’t develop this disorder even when their sodium levels are rapidly increased.
What Are the Symptoms of Central Pontine Myelinolysis?
The symptoms from central pontine myelinolysis typically set in around two to three days after your sodium levels are corrected. These initial symptoms include:
- Muscle weakness in your limbs
- Palsies — tremors and paralysis
- Difficulty speaking
- Difficulty swallowing
- Changes in consciousness
Originally, researchers greatly overestimated the mortality rate of this disorder because their data was coming from autopsied patients. Around 94% of people who develop central pontine myelinolysis will survive and 25% to 40% of these people will make full recoveries, but 25% to 30% of people with the disorder develop permanent symptoms.
You can even develop some symptoms weeks to months after the disorder begins. These include:
- Paralysis in your arms or legs
- Difficulty coordinating
- Impaired sensation
- Mental impairment
How Is Central Pontine Myelinolysis Diagnosed?
The best way to diagnose central pontine myelinolysis is with magnetic resonance imaging (MRI). Your doctor will look for particular changes in the images of your brain that indicate damage to your myelin sheaths.
The damage may not immediately show up in the MRI, so if your doctor may want you to repeat the MRI in one to two weeks.
Central pontine myelinolysis might look like a number of other conditions in your brain images. It’s important that your doctor does not confuse this condition with these others, including:
Imaging may not be enough to see the damage to your neurons. In this case, your doctor will need to do a very thorough neurological exam that could include many other techniques.
One example is electroencephalography, where your doctor analyses electrical signals in certain parts of your brain.
What Is the Treatment for Central Pontine Myelinolysis?
The main treatment for central pontine myelinolysis is to prevent it from happening in the first place. Your medical team needs to be aware of any risk factors that you have so they can increase your sodium levels at a safe rate.
If the disorder does set in, the main treatment will depend on the particular symptoms that you develop. In most cases, you will need months of physical therapy and other forms of rehabilitation.
If you develop tremors or symptoms that resemble Parkinson’s disease, then your doctor might prescribe dopaminergic drugs. These are usually used to treat Parkinson's disease.
Another key aspect of treatment while you are still in a medical setting is to prevent any secondary complications from developing. Your team should carefully monitor your symptoms to be sure that none of these complications occur:
There are also clinical trials for this disorder that could help you. Your doctor may recommend trying one of these if you develop central pontine myelinolysis.