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Phenytoin-induced choreoathetosis in patients with severe myoclonic epilepsy in infancy

Y Saito1, H Oguni, Y Awaya

  • 1Department of Pediatrics, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan. saitoyo@tmin.ac.jp

Neuropediatrics
|December 19, 2001
PubMed

Insights

Phenytoin can cause choreoathetosis, a movement disorder, in patients with severe myoclonic epilepsy in infancy (SME). Reducing phenytoin dosage resolves this adverse effect, highlighting its importance in differential diagnosis.

Area of Science:

  • Neurology
  • Epileptology
  • Pharmacology

Background:

  • Severe myoclonic epilepsy in infancy (SME) is a severe form of epilepsy.
  • Phenytoin is a commonly used antiepileptic drug.

Observation:

  • Three patients with SME developed choreoathetosis after phenytoin dosage increases.
  • Movement disorder onset ranged from 2 days to 6 months post-dosage adjustment.
  • Choreoathetosis resolved upon reduction of phenytoin dosage.

Findings:

  • Phenytoin-induced choreoathetosis is a potential adverse effect in SME patients.
  • The episodic and paroxysmal nature of choreoathetosis can mimic degenerative disorders.
  • Ictal SPECT in one patient showed basal ganglia hypoperfusion contralateral to choreoathetosis.
  • Polypharmacy may increase the risk of developing this side effect.

Implications:

  • Phenytoin-induced choreoathetosis should be considered in SME patients with involuntary movements.
  • Early recognition and management are crucial to prevent misdiagnosis and ensure effective treatment.
  • SME patients may have increased susceptibility to phenytoin-induced movement disorders, suggesting basal ganglia involvement in SME pathophysiology.

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