How many lesions on the brain occur with progressive multifocal leukoencephalopathy?

Progressive multifocal leukoencephalopathy (PML) is a rare but serious brain infection that is caused by the JC virus (JCV). JCV is a type of polyomavirus, which is a group of viruses that also includes the BK virus and the simian virus 40 (SV40). PML typically occurs in people with weakened immune systems, such as those with AIDS, leukemia, or lymphoma.

PML is characterized by the development of multiple lesions in the brain. These lesions are typically located in the white matter of the brain, which is the tissue that connects the different parts of the brain. The lesions can vary in size, from a few millimeters to several centimeters.

The number of lesions that occur with PML can vary from person to person. Some people may only have a few lesions, while others may have dozens or even hundreds of lesions. The number of lesions does not necessarily correlate with the severity of the disease. Some people with a small number of lesions may experience severe symptoms, while others with a large number of lesions may have only mild symptoms.

The symptoms of PML can vary depending on the location and size of the lesions. Common symptoms include:

* Difficulty with thinking and memory

* Weakness or paralysis on one side of the body

* Vision problems

* Speech problems

* Seizures

PML is a progressive disease, which means that it gets worse over time. There is no cure for PML, but treatment can help to slow the progression of the disease and improve symptoms. Treatment options include antiviral medications, steroids, and plasmapheresis.

PML is a serious disease, but it is important to remember that it is rare. Most people with weakened immune systems do not develop PML. If you are concerned about your risk of PML, talk to your doctor.