Treatment of PD
Currently, there is no real cure for Parkinson’s. There are medications that fight the symptoms, but not the disease itself. Simply put, there is no way to restore the cells that died within the substantia nigra (see the neuroscience post).
Most patients with PD are prescribed Levadopa (L-DOPA). Other drugs are used in PD treatment as well, but L-DOPA is the most widely used one. This medication is converted into dopamine in dopaminergic neurons, which causes relief from many of the motor symptoms (it barely helps with the psychiatric symptoms though). However, only 5-10% of the L-DOPA passes the blood-brain barrier (a sort of filter for our brain). Because of that, most of the medicine is processed elsewhere, which causes many side-effects.
It’s pretty much an endless list of side-effects, among which nausea, increased anxiety, hair loss, vivid dreams and/or insomnia, gastrointestinal bleeding are prominent. Chronic users of L-DOPA, basically all PD patients, show more and more serious side-effects of the L-DOPA. They can even become resistant to the drug at one point.
The use of L-DOPA and hallucinations
One of the side-effects I didn’t mention yet is hallucination. In the previous blog post (on neuroscience) I mentioned that schizophrenia and PD are in a way closely related. L-DOPA becomes dopamine in the brain, but when those levels are elevated too much, PD patients become psychotic. Schizophrenia is caused by elevated dopamine levels according to the dopamine theory. PD patients can experience visual and auditory hallucinations.
These hallucinations can be as dangerous to a PD patient as to a schizophrenic. For instance, I remember very well when my grandmother started to have hallucinations for the first time. She wanted to wash her hands, but instead of turning on the cold water, she was washing her hands with boiling hot water. She didn’t feel it during the hallucination, but later on she did. (She also loved to cook and she often saw flying chicken breasts. Luckily this hallucination wasn’t as harmful as the other one).
To remedy these hallucinations, they get anti-psychotics. And you guessed it – these lower the dopamine levels again. Which causes the motor symptoms to show up again. And so they get more L-DOPA again. It’s pretty much a vicious circle at that. And don’t forget all the horrible side-effects of the anti-psychotics.
Interestingly, schizophrenics often show something called “Parkinsonism” – in this case drug-induced Parkinson’s, due to the use of anti-psychotics.
Deep Brain Stimulation (DBS)
Brain surgery such as DBS was once much more common. Ever since the invention of L-DOPA, surgery to treat PD came to a standstill. Recently, however, it has become more common again. As I mentioned, many chronic users of L-DOPA become resistant to it, and DBS has proven to be a very successful treatment. DBS mostly resolves the motor symptoms of the disease, much like L-DOPA.
Basically, DBS is the implantation of a “brain pacemaker”. This tiny device sends electrical impulses to specific parts of the brain. It changes brain activity in a very controlled way, and it’s reversible, unlike lesioning techniques that surgeons used to perform.
Note, though, that this isn’t a cure for Parkinson’s. It is a symptom fighter like L-DOPA but a more successful one at that.
It has proven to be helpful for people with chronic pain, Tourettes Syndrome and major depression, as well.
Currently, researchers are asking themselves the questions “what causes the cells in the substantia nigra to die, and how can this be prevented?” and “how can we replace the dead cells?”.
There are ongoing gene trials, where they try to prevent the disease from coming into being by using non-infectious virus cells. Successful results have been announced, read more about it here.
Stem cell research has been a target as well, but it is highly controversial and has not yet shown any real results in humans. There has been some success in animals, as they survived more often and showed less behavioral abnormalities.
As you can tell, we’re still far away from finding a real cure for Parkinson’s Disease. I sincerely hope that our brilliant brain researchers will find a cure some time soon.
Thanks for reading and I hope I have been able to shed some light on this illness.
Friday, I’ll continue where we left – sanity vs. insanity!