Dyskinesia: Symptoms, Causes, and Treatment
Parkinson’s disease (PD) often referred to as simply Parkinson’s is a progressive disorder of the nervous system. This neurodegenerative disorder causes gradual breakdown and death of dopamine-producing neurons in a particular area of the brain, which is called substantial Ingra. This fall in dopamine level causes abnormal brain activity, impaired movement, and other symptoms.
There is no cure for Parkinson’s disease, at least as of now. However, there are medications that can control the symptoms, and in some critical cases, doctors recommend surgery. Here you can read about the most common medication for Parkinson’s disease.
What Is Levodopa?
Though Levodopa helps increases the dopamine level and is a good substitute for dopamine, in some cases, the use of levodopa has been found to have some side effects, like Nausea, Vomiting, loss of appetite, and fall in blood pressure. However, the most significant side-effect of levodopa is Dyskinesia.
What Is Dyskinesia?
One of the side-effects of levodopa is writhing movements of the face, limbs, or trunk. These movements are involuntary and erratic. Most of the time these movements are slow, almost dance-like, but in some cases, the movements are rapid, like a sudden jerk or extended muscle spasms. The important thing to note is that Dyskinesia is not a symptom of Parkinson’s, but a side effect of the medication.
Causes of Dyskinesia:
Patients, who are being treated with levodopa often show symptoms of Dyskinesia. However, these effects can be minimized by adjusting the medication and adding dopaminergic drugs like Carbidopa. Younger people affected with PD, who are given levodopa, develop motor fluctuations and dyskinesia earlier than others.
When a patient takes a dose of levodopa, it takes some time, before the drug starts its effect. Once that stage comes, the patient is able to perform all his/her work. This stage of mobility is called the ‘on’ phase.
After a few hours, the drug starts losing its effect and the patient starts having problems with mobility. This is called the ‘off’ phase. The mobility improves 15–45 minutes after taking the next dose of levodopa. This phenomenon is called ‘wearing off’ (also known as ‘early wearing off).
The terms ‘on’ and ‘off’ with regards to Parkinson’s refer to the switch between mobility and immobility in patients being treated with levodopa. The ‘on’ phase refers to the period, where the patient responds to levodopa, while the ‘off’ phase refers to the period where the patient responds poorly to levodopa. In most cases, Dyskinesia is very mild and does not affect routine work too much.
That is why people prefer to ‘accept’ this condition and be in an ‘on’ mode and be able to work, rather than get into ‘off’ mode and not be able to work or move. But in some cases, Dyskinesia can be quite severe and may interfere with the routine work of the patient.
Types of Dyskinesia:
Different people show different responses to the disease. Basis this, there are various types of Dyskinesia:
- Peak-Dose Dyskinesia: This is the most common type of Dyskinesia. It occurs usually after 1 to 2 years of taking a dose of levodopa when its proportion in the blood is at its peak. At this stage, the medication is most effective in controlling the symptoms. In the initial stage of Parkinson’s these symptoms are so mild that they may go unnoticed.
- Diphasic Dyskinesia: Sometimes Dyskinesia can occur just before the start of the ‘on’ phase or when the effect of medication star weaning and the patient comes closer to the ‘off’ phase. This is called diphasic dyskinesia. This is also called D-I-D syndrome, with the acronym meaning Dyskinesia-Improvement-Dyskinesia. This kind of Dyskinesia tends to improve when the dosage of levodopa is increased.
Treatment for Dyskinesia
The treatment therapy for controlling Dyskinesia involves finding the time period when the medication is effective. The best “therapeutic window” is the stage, where the level of levodopa is optimum — neither too high nor too low. Having a lower concentration of levodopa would result in motor fluctuations, while having a higher concentration of it may result in Dyskinesia.
Though levodopa is known as the main cause of Dyskinesia, there are drugs like dopamine agonists, COMT (catechol-o-methyl transferase) inhibitors, and MAO-B inhibitors that can make the condition critical.
Hence, to control Dyskinesia, one school of thought is to lower the levodopa dosage or by avoiding other dopaminergic medications. However, with the passage of time, as Parkinson’s progresses, reducing the levodopa dose is not a good idea, as it may not control the symptoms properly. As of now, there are two medications available to treat Dyskinesia, and a few more are in the development stage.
These two medications are:
- Doctor my recommend adding ‘amantadine’ to the medication regimen of a patient to reduce Dyskinesia without worsening “off” periods.
- Recently, an extended-release formulation of amantadine has been approved by the U.S. Food and Drug Administration. Being sold under the brand name ‘Gocovri’, the formulation has been made specifically for treating levodopa-induced Dyskinesia in people suffering from Parkinson’s disease. In addition to these two, there are some other Amantadine formulations, which are used sometimes as off-label for dyskinesia.
Conclusion:
The fall in the dopamine level in the blood is the main cause of Parkinson’s disease. Though not a cure, the symptoms can be controlled by using levodopa, which acts as a substitute for dopamine. However, a higher concentration of levodopa in the blood has its own side effects, the most troublesome being Dyskinesia, where the movements of the patient are affected.
Hence, it is critical to control the dopamine level in the blood. There are some medications, which are being used and some are in the development phase, which should be out soon.
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