Progressive multifocal leukoencephalopathy (PML) is a disorder that harms the myelin that covers and protects nerves in the brain's white matter. Myelin is an insulating tissue layer that forms around nerves in the brain and spinal cord, as well as in other places. It is meant to enable fast, efficient impulse transmission along the nerve cells.
When myelin is damaged, nerve cells in the brain that lack this protection cannot transmit messages to nerves in the rest of the body. The damage can also cause the impulses to slow down, which can lead to diseases like PML and multiple sclerosis. PML is a life-threatening condition that is usually fatal.
PML is caused by the JC virus (JCV), named in 1971after a patient, John Cunningham, who had PML. The virus was isolated from John Cunningham's brain. JCV is very common, affecting 70 to 90 percent of humans, but is harmful only in cases of immunodeficiency, as in people with AIDS or whose immune systems have been compromised by certain conditions or by drugs such as Raptiva®, Tysabri® and Rituxan™.
Symptoms and Complications of PML
Patients with PML will usually experience the following symptoms:
- Headaches
- Clumsiness and loss of coordination
- Aphasia (loss of language ability)
- Memory loss
- Problems with seeing
- Progressive weakness of the arms and legs
Symptoms depend upon which area of the brain is affected. They progress over a period of days to weeks, and sometimes months, but eventually lead to death unless the immune system can be reconstituted.
The only effective treatment of PML is in AIDS patients who have the disease. Strengthening the immune system in these patients can help alleviate the symptoms of PML.
For non-AIDS patients with PML, the disease may last for months, with 80 percent of patients dying in the first six months. Spontaneous improvement has been reported. People who survive PML often must deal with severe neurological disabilities.
If you've developed PML, you may be entitled to compensation. Our PML lawyers help people with cases of drug-related PML. To find out if you qualify, contact us for more information.