Home Health A-Z Progressive Multifocal Leukoencephalopathy (PML) : Causes, Symptoms, Treatment

Progressive Multifocal Leukoencephalopathy (PML) : Causes, Symptoms, Treatment

Verified By Apollo Doctors February 10, 2023 1729 0
Progressive Multifocal Leukoencephalopathy
Progressive Multifocal Leukoencephalopathy


Progressive multifocal leukoencephalopathy (PML) is a rare brain infection due to a virus. It is known to destroy our brain’s white matter, myelin. Myelin is a fatty substance that covers and protects our brain’s nerve cells that send signals to different body parts. As the virus progresses, causing a gradual decrease of myelin, we may be at a higher risk of developing neurological disorders. The progress of the disease can slow down when we receive timely treatment from the doctor. 

Read about progressive multifocal leukoencephalopathy, its causes, symptoms, diagnosis, and various treatment options. 

What Is Progressive Multifocal Leukoencephalopathy?

Progressive multifocal leukoencephalopathy is a rare viral infection that affects our central nervous system. The virus attacks the fatty substance that covers and protects our brain’s nerve cells, making it challenging to move, think, and feel sensations. These nerve cells are responsible for sending and receiving messages to and from different body parts. 

The JC virus causes PML. Typically, this virus is present inside most of us. But it develops into a disease when our immune system is compromised, and it cannot fight the virus as it is intended to function. As the virus progresses, it can affect any part of our body. However, we can receive timely treatment to slow the progression of the disease. It is a serious condition that can be life-threatening. Experts have received nearly 4,000 reported cases in the United States and Europe combined. 

What Are The Symptoms Of Progressive Multifocal Leukoencephalopathy?

So long as the virus is inactive, we may not be aware of its presence within us. However, if we are immunocompromised, the chances of the virus being active are higher. And when it happens, the symptoms are based on the affected part of the brain. The initial symptoms are similar to those of other health conditions. However, the following are the signs of progressive multifocal leukoencephalopathy:

  • Lack of coordination 
  • Weakness in the legs and arms that progressively worsen
  • Speaking and walking issues
  • Loss of memory
  • Changes in personality
  • Facial drooping
  • A decline in mental ability

As the disease continues to damage the white cells of our brain, the symptoms start to become severe. We may experience:

PML is fatal. But timely treatment and our response to it significantly affect our prognosis.

What Causes Progressive Multifocal Leukoencephalopathy?

Experts first identified the virus affecting our central nervous system in John Cunnigham. That’s how the virus got its name. Close to 85% of most adults have the JC virus present in them. However, experts aren’t clear on how individuals ingest the virus. But there is certain evidence that suggests that children may get JCV through food and water. Typically, the virus in our brain is inactive and causes no symptoms. But it may develop into PML if we have a compromised or weak immune system. The virus is present in our lymph nodes, bone marrow, or kidneys. 

When Do You Seek Medical Advice For Progressive Multifocal Leukoencephalopathy?

If your immune system is compromised or you are showing symptoms of PML consulting a doctor may slow the progress of progressive multifocal leukoencephalopathy.


Who Is At Risk Of Developing Progressive Multifocal Leukoencephalopathy?

As mentioned earlier, people with weakened immune systems are at a higher risk of PML. The disease that reduces your immune system are:

  • Blood and bone marrow cancer
  • Lymph node cancer
  • An organ donor recipient taking immunosuppressant medication 

What Are The Ways A Doctor Diagnoses Progressive Multifocal Leukoencephalopathy?

When you visit the doctor for PML, the doctor may conduct a physical examination and ask about your symptoms. If the doctor suspects PML, you may have to undergo the following tests:

  • Blood test: Your blood sample can show if you have JC virus antibodies. If the test results show high antibodies, it can indicate PML.
  • Lumbar puncture: It is also known as a spinal tap. In this process, a needle is inserted into your spine to collect the spinal fluid. Your spinal fluid may show JC virus antibodies that help correctly diagnose the condition. 
  • Imaging tests: MRI and CT scans help detect anomalies in your brain’s white matter. If you suffer from PML, your brain will have multiple active lesions or abnormalities. MRI uses powerful magnets and radio waves to get a clear and detailed brain image. But when MRI images are unclear or do not give a clear picture, the step is a brain biopsy.
  • Brain biopsy: Your doctor surgically removes a piece of brain tissue to examine under a microscope. You will be anesthetized throughout the surgery.

What Are The Various Treatment Options For Progressive Multifocal Leukoencephalopathy?

There is no particular treatment for PML. Your doctor works on strengthening your weak immune system. For example, if you have HIV, you will be prescribed antiretroviral therapy, reducing the HIV in your system. Thus, restoring some of your immune system. Others can take advantage of plasma exchange. This treatment involves removing a certain amount of immunosuppressant drugs from your blood that helps strengthen the immune system to fight the virus effectively. Your doctor may also suggest including supportive and investigational therapies. 

There are no other effective treatment options for PML. However, various medications are still under research and are not approved by the authorities. 

It is important to know that the white matter damaged by the virus cannot regenerate. Therefore, some of your symptoms are permanent. 


Progressive multifocal leukoencephalopathy is a rare brain infection. It primarily affects people with a decreased immune system. With timely medical intervention and treatment, the progress of the disease. If you are diagnosed with PML, there is no need to be disheartened, as treatment and therapies help in your independence and help you continue leading your life.

Frequently Asked Questions (FAQs)

Is PML a common disease?

Progressive multifocal leukoencephalopathy is a rare brain disease that affects people with a weak immune system. It affects one in every 2,00,000 people. 

Can I prevent PML from developing?

Unfortunately, you cannot prevent from developing PML. However, you cannot eliminate the possibility of developing the disease in the future. 

Verified By Apollo Doctors
At Apollo, we believe that easily accessible, reliable health information can make managing health conditions an empowering experience. AskApollo Online Health Library team consists of medical experts who create curated peer-reviewed medical content that is regularly updated and is easy-to-understand.

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