Phenytoin-induced Dyskinesia

A Case Report

Kashvi C. Shah; Nishi S. Patel; Paritosh Vasani; Avinash Khadela; Vivek P. Chavda; Lalitkumar Vora

Disclosures

J Med Case Reports. 2023;17(313) 

In This Article

Abstract and Introduction

Abstract

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.

Introduction

Phenytoin (also known as 5,5-diphenylhydantoin) is an aromatic hydantoin derivative used to treat prophylactic seizures and posttraumatic seizures. It aids in the regulation of seizures by blocking voltage-gated sodium channels and inhibiting neuronal firing.[1] Despite having complicated and unpredictably varying pharmacokinetic features, phenytoin is often safe, effective, affordable, and relatively easy to use. Ataxia, diplopia, nystagmus, vertigo, mental confusion, hallucinations, blurred vision, mydriasis, cerebral atrophy, cerebral malfunction, migraines, and sleeplessness are common adverse effects involving the central nervous system.[2] Phenytoin-induced dyskinesia is uncommon, although it is prevalent with other antiepileptic drugs. Various involuntary movement abnormalities, such as orofacial and limb dyskinesia, shaking, asterixis, hemiballismus, dystonia, and myoclonias, can be brought on by phenytoin intoxication.[3]

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