Phenytoin-induced dyskinesia: a case report

Background: Dyskinesia is a movement disorder categorized by involuntary movement of muscle. Although dyskinesia can be brought on by taking medications, it can also be a symptom of a variety of diseases. Antiepileptic drug-induced involuntary movements have been well researched. Rare reports have been made for dyskinesia, a type of dystonia caused by phenytoin. The mechanism of its occurrence must be succinctly studied.

Case presentation: A 53-year-old Asian patient taking phenytoin (100 mg twice daily) experienced symptoms of perioral muscle involuntary movement, impaired speech, and generalized tremors and was admitted to the hospital. Brain magnetic resonance imaging showed significant development of encephalomalacia and porencephaly. The serum phenytoin levels were in the toxic range (33 g/ml). These were suggestive of phenytoin-induced dyskinesia. Levetiracetam and clonazepam were initiated, and the patient showed significant improvement in the symptoms.

Conclusion: This case presented a substantial reference value for the differential diagnosis and treatment prognosis of phenytoin-induced dyskinesia. The phenytoin-induced dyskinesia in this patient was successfully reversed with prompt identification and treatment. According to the case study's findings, such people may benefit from periodic therapeutic drug monitoring.