What is the diagnosis and treatment for dyskinesia (involuntary movements)?

From the Guidelines

Dyskinesia, particularly paroxysmal kinesigenic dyskinesia (PKD), can be effectively managed with carbamazepine or oxcarbazepine, with more than 85% of patients achieving complete remission with low-dose therapy 1. The diagnosis of PKD is based mainly on clinical features, and necessary evaluations are needed to exclude secondary etiologies 1. Some key points to consider in the management of dyskinesia include:

• The initial dosage of carbamazepine for PKD treatment is recommended to be 50 mg and can be adjusted according to the practical effect 1.
• For patients who harbor HLA-B*15:02 or cannot tolerate the dizziness or drowsiness of carbamazepine, other voltage-gated sodium channel blockers, including lamotrigine, topiramate, and phenytoin sodium, are recommended as the second-line treatment 1.
• Personalized medical therapy and psychotherapy are recommended for patients with PKD 1.
• Drugs can be prescribed to patients with frequent and severe attacks, severe psychological impacts, and individuals who are willing to control the attacks 1.
• Approximately 97% of patients with primary PKD have a dramatic response to anticonvulsants, particularly the sodium channel blockers, of which carbamazepine/oxcarbazepine are preferred 1. It is essential to note that the management of dyskinesia should prioritize the individual patient's needs and response to treatment, and regular monitoring is necessary to adjust the treatment plan as needed 1.

From the FDA Drug Label

5.18 Tardive Dyskinesia Tardive dyskinesia (TD) has occurred in patients treated with antipsychotic drugs, including clozapine. The syndrome consists of potentially irreversible, involuntary, dyskinetic movements. The risk of TD and the likelihood that it will become irreversible are believed to increase with greater durations of treatment and higher total cumulative doses However, the syndrome can develop after relatively brief treatment periods at low doses. Prescribe clozapine in a manner that is most likely to minimize the risk of developing TD. Use the lowest effective dose and the shortest duration necessary to control symptoms. Periodically assess the need for continued treatment. Consider discontinuing treatment if TD occurs However, some patients may require treatment with clozapine despite the presence of the syndrome.

Tardive Dyskinesia is a potential side effect of clozapine, characterized by involuntary, dyskinetic movements. The risk of TD increases with longer treatment durations and higher cumulative doses. To minimize this risk, it is recommended to use the lowest effective dose and shortest duration necessary to control symptoms. If TD occurs, consider discontinuing treatment. However, some patients may still require treatment with clozapine despite the presence of TD 2.

From the Research

Definition and Types of Dyskinesia

• Dyskinesia refers to involuntary movements other than tremor, most commonly consisting of chorea, dystonia, or myoclonus 3, 4, 5.
• Levodopa-induced dyskinesia (LID) is a common dose-limiting adverse effect of levodopa therapy, occurring in patients with Parkinson's disease (PD) who have been treated with levodopa for a long time 6, 4, 5.
• LIDs are divided into "peak-dose dyskinesia," "diphasic dyskinesia," and "wearing off" or "off-period" dyskinesia, of which peak-dose dyskinesia is the most common, followed by off-period, and then diphasic dyskinesia 6, 5.

Epidemiology and Risk Factors

• The majority of patients will have developed dyskinesias after 10 years of treatment, and about 40-50% after 5 years 6.
• Occurrence of LID appears to be related to dose and duration of treatment with levodopa and severity and duration of disease 6.
• Patients with younger age of onset have been reported to have an earlier onset and higher rate of LID 6.

Treatment Strategies

• Treatment of LID includes adjustment of timing, type, and amount of dopaminergic medication, treatment with amantadine, and, in treatment-resistant cases, stereotactic surgery involving deep brain stimulation or lesioning procedures 3, 6, 4, 5.
• Peak-dose dyskinesia is treated mainly by reducing individual doses of levodopa and adding amantadine and dopamine agonists 3, 5.
• Off-period dystonia often responds to baclofen and botulinum toxin injections 5.
• Diphasic dyskinesias are the most difficult to treat, and many patients require deep brain stimulation to control their troublesome motor fluctuations and LIDs 5.

Assessment and Management

• New validated rating scales and home diaries can better help the health care provider assess the timing and severity of dyskinesia 4.
• Early recognition and assessment of TD, as well as how to best approach management of these often incapacitating symptoms, are crucial 7.
• A variety of emerging (experimental) drugs currently in development promise to provide better control of LIDs and other levodopa-related complications in the near future 5.