I am going to do something unorthodox----combine pediatric research with adult research. I get to do that, because my specialty is family practice.
First, the pediatric research. Consider PANDAS, the syndrome of tics, OCD, ADD, depression, hair pulling and other neurological disorders triggered by strep infection and Sydenham’s Chorea (aka St Vitus Dance) the more dramatic movement disorder that can occur after rheumatic fever and which can occasionally look just like adult Parkinson’s. In these two diseases, antibodies to dopamine receptors are produced and cause inflammation (encephalitis since it is in the brain) of the basal ganglia. One of the characteristics of children suffering from these post strep immune neurological disorders is that during REM or dream sleep, they are not paralyzed. In other words, they act out their dreams, something that humans are not supposed to do. Normal human sleep involves paralysis so we do not punch our bed partner or try to fly out the window.
Another disease is characterized by loss of REM paralysis. For up to a decade before Parkinson’s symptoms develop, patients will experience loss of REM paralysis. Among (older adult) people who act out their dreams, 30% will go on to develop Parkinson’s within 3 years in one study and 60% within 7 years. Now, obviously, Parkinson’s is not the only cause of this REM movement disorder---30% will never develop Parkinson’s. But here is the part that should make people with Parkinson’s pay attention. People with allergic rhinitis are 2.9 times more likely to develop Parkinson’s in later life. And it is not their heightened immunity that puts them at risk. People with lupus, rheumatoid arthritis and other autoimmune disease do not have this elevated risk. The only autoimmune disease associated with an increased risk of Parkinson’s is psoriasis—and a common trigger of psoriasis is strep infection, plus psoriasis, by its nature, makes strep infections of the skin more common.
What do people with allergic rhinitis get? Lots of upper respiratory infections, i.e. ear and sinus infections. What is among one of the most common bacteria present in these infections? Strep.
Ok, if strep is a factor in Parkinson’s, then folks who get a lot of strep as an adult should be at risk. Which adults are most likely to go to Urgent Care with strep? Parents of young kids (duh). And teachers and health care workers. Guess who gets more Parkinson’s. Teachers and health care workers.
So, here is my hypothesis. Most adults no longer realize when they get strep. They have developed natural immunity that kicks in and clears the infection—but at a cost. Those immune factors trigger a cascade of events that can cause 1) rash (scarlet fever) 2) arthritis and carditis (rheumatic fever—way more common than folks realize) 3) kidney inflammation (glomerulonephritis) 4) guttate psoriasis. So, why can’t these same immune factors continue to cause a PANDAS type syndrome into adulthood? Damaging the basal ganglia over and over again with dopamine receptor antibodies until the substantia nigra is shot---and Parkinson’s develops?
Yes, I know that PANDAS is considered a disease of childhood. ADD was considered a disease of childhood when I started practice a gazillion years ago. Until we realized that adults have ADD too, they just learn to cope. Maybe adults with PANDAS learn to cope.
So, here is my proposed study. Take folks whose sleep studies show that they have REM movement disorders and give some of them prophylactic penicillin. Why prophylactic penicillin? Because if you take daily antibiotics to suppress strep, the body’s natural anti-strep immune system quiets down and sufferers stop getting things like rheumatic fever. One pediatric study showed that the anti-dopamine receptors that are part of PANDAS and SC cleared more quickly in kids given antibiotics for their strep infections than in those whose infections were not treated.
Why penicillin and not some stronger antibiotic? Because strep is about the only thing that is still sensitive to penicillin and likely to stay that way due to the antibiotic’s mechanism of action. Other bacteria will not be affected. No change in antibiotic resistance patterns will occur. Lots of kids take daily penicillin already to prevent rheumatic fever without problems.
Given the high rate at which people with REM movement disorder develop Parkinson’s, within two years, it should be clear if penicillin prophylaxis does any good. And if it does, it is cheap and easy. And Parkinson’s is a miserable disease.