*%^*?@#+!!! Dammit, JIM!!! AOL (or AOHELL) just lost the blog I spent 2 1/2 hours writing this morning about PML...it WAS a good one, too!
I decided I should take some time and do a bit of research about PML since I so casually mentioned it in the article yesterday about the FDA returning TYSABRI to the market. In the blog you will never read now and I can NEVER recreate (thank you, AOL), I talked about what exactly PML is and why the FDA has their panties in a wad when it comes to TYSABRI and the possible development of Progressive Multifocal Leukoencephalopathy.
I DO know a bit about the disease because of past required study in HIV/AIDS progression. It's certainly not a newly known disorder...People with AIDS (about 5-6%) have developed PML in the course of their disease. Researchers have known about PML for a decade or so. Doctors know the virus that causes PML...they also know it is due to a severely suppressed immune system. They also know it is generally fatal.
I can't recreate the blog I already wrote...I have MS after all! My memory isn't great and I'm a bit fatigued already from earlier writing. Fortunately, I DID cut and paste some basic information into Microsoft Word and saved it with some links to web articles about PML...I did this just before AOHELL decided to have a server problem and lose everything I had already typed in my blog and HADN'T saved just yet!
This is the best I can do for now...you'll have to do a bit of your own research today for more information and if I become so moved to "try" to write about this topic again, you can KNOW I will definitely create it in a word processing program first! Do you suppose the powers that be from AOL will now report me to Homeland Security for my online negativity???
PML is a rare and usually fatal viral infection of the brain. Caused by the JC virus (the initials of the first patient from whom the virus was isolated), PML destroys the brain cells (oligondendrocytes) that produce the surrounding protective coating (myelin) of nerve cells.
The JC virus is common; by middle age approximately 80% of adults have been exposed to it. This virus doesn't cause disease in people with healthy immune systems. However, it remains dormant in the kidneys, bone marrow, or lymph nodes for may years. Researchers believe that once it is reactivated, the JC virus is carried to the brain by circulating B cells. As the words "progressive" and "multifocal" indicate, PML can progress very quickly and it is not confined to only one part of the brain.
PML causes lesions on the white matter of the brain. The symptoms experienced are directly related to the location and size of the lesions. Lack of coordination of an arm or leg, partial paralysis of one side, partial loss of vision, impairment of thought and speech patterns, memory problems, walking or standing difficulties and dementia are reported in most cases. Not all individuals with PML will necessarily experience the same symptoms or with the same intensity.
PML is similar to another demyelinating disease, multiple sclerosis, but since it destroys the cells that produce myelin (unlike MS, in which myelin itself is attacked but can be replaced), it progresses much more quickly. Most patients die within four months of onset.
Symptoms of PML include mental deterioration, vision loss, speech disturbances, ataxia (inability to coordinate movements), paralysis, and, ultimately, coma. In rare cases, seizures may occur.
There is no cure for PML, nor is there currently an effective treatment for the disorder. Treatment is symptomatic and supportive.
The course of PML is relentlessly progressive. Death usually occurs between 1 and 4 months after onset.