If you have Parkinson’s disease and pain or discomfort that interrupts your sleep, then I think I have some fresh insight, and for some, something to discuss with your doctor.
(I can’t believe I’m writing an article to explain another article that I wrote, but I’m still processing a lot of this myself.)
Restless Leg Syndrome (RLS) is a horribly misleading term for a condition that is estimated to affect 5% of the U.S. population. The branding, at least for my mind, connotes a playful condition, when it is actually a painful condition at worst and a sleep-depriving condition at best. Sleep is interrupted by pain or discomfort, usually in the legs, but can progress to the arms or torso.
You may not be aware that RLS is considered to be both a sleep disorder and a movement disorder. RLS is believed to be related to a dysfunction in one of the sections of the brain that control movement (the basal ganglia) that use the brain chemical dopamine. If that sounds familiar, that is because that is the exact same area of the brain, and the same chemical, that is the culprit behind the primary motor symptoms of Parkinson’s disease.
People with RLS do have a somewhat higher risk of developing PD (it can be an initial presenting symptom), but usually it is not a progressively worsening condition. EXCEPT for this…
Up until recently, the primary first-line treatment was dopamine replacement therapy, basically the same drugs we are prescribed for PD, but at lower doses. Dopamine agonists were generally used instead of carbidopa/levodopa for a variety of reasons, but one reason is that the standard immediate release doesn’t remain effective long enough to last through the night.
Now, here’s where it starts to get interesting for us…
Although dopamine-related medications are effective in managing RLS symptoms, long-term use can lead to worsening of the symptoms in many individuals. Fortunately, this apparent progression can be reversed by removing the person from all dopamine-related medications.
So, basically it works great for a number of years, then stops working and pain is more frequent. But people with RLS can stop the medication and reset to where they were before, because unlike PD, RLS is usually not a progressive condition. Stopping the medication is not an option for PD, because studies have been pretty conclusive that whether you take the meds or not, PD progressively gets worse. The meds only mask the symptoms.
To my mind, this raises MANY questions. But, the primary concern is that years of dopamine related medications can make RLS pain and interrupted sleep worse.
However, for people with RLS, something changed. 6 years ago, study results from a small study at Johns Hopkins led to major changes to how RLS is treated. (Interestingly enough, I remember my wife’s pain doctor giving her a note for me about this as he knew I had been diagnosed with PD, but at the time I had no idea of the relevance.)
In a nutshell, this study found that glutamate, a neurotransmitter involved in arousal (morning wood?), was abnormally high levels in people with RLS, and pointed out that there are already drugs on the market, such as the anticonvulsive gabapentin enacarbil, that can reduce glutamate levels in the brain. 6 years later, this drug is now the first-line treatment for RLS patients (once other conditions, such as iron deficiency or neuropathy are ruled out).
So, what’s my point?
There are multiple types of Parkinson’s pain. I am an expert in none of them, but experience some. With RLS having a similar link to dopamine dysfunction in the basal ganglia, it should not be surprising that some PD pain and sleep issues are very similar to RLS (neither condition is diagnosed via scientific biomarkers).
I have discussed my pain and sleep disruption issues with multiple movement disorder specialists over the last 5+ years. No one ever mentioned RLS to me, although I can clearly recognize it now that I better understand it. (See the main article for a discussion of RLS symptoms.)
RLS is considered a movement disorder, but maybe they never mentioned it because an RLS diagnosis would be irrelevant, especially with dopamine replacement therapy as the first line treatment for RLS.
Now that the first line therapy for RLS has changed, for PD with pain and sleep disruption similar to RLS, doesn’t it make sense to try a drug currently used as first line treatment for RLS to reduce glutamate, while continuing dopamine therapy for PD?
I plan to discuss this with my MDS, but I have to wait so long to get an appointment! Maybe I should track down my wife’s old pain doctor, because I think he understood this years ago. It’s not an urgent issue for me yet, so I’ll wait.