The severity depends on when PML is detected. If it’s detected before it causes physical symptoms the effects are less severe.
PML can be detected early, before it causes symptoms, with regular 3-4 monthly MRI scans.
With there is risk of
physical disability with a
1 in 30
chance of death
Late detection is when PML is allowed to develop and presents with neurological symptoms.
With there is risk of
physical disability with a
1 in 3
chance of death
The symptoms of PML depend on where the infection is in the brain but the most common are personality changes, cognitive problems, similar symptoms to a MS relapse and epileptic attacks.
The most effective treatment of PML is to get Tysabri out of the body and let the immune system back in the brain to identify the infection and clear it. This means stopping the drug and washing it out using a treatment called plasma exchange.