Fosphenytoin-induced dyskinesias in an infant with Sturge-Weber syndrome

Phenytoin-induced dyskinesias are uncommon and underrecognized.1 An 11-month-old girl with Sturge-Weber syndrome (figure 1) and left hemiparesis had prolonged pharmacoresistant seizures. After IV fosphenytoin (peak level = 17.9 μg/mL, free level not obtained), she developed right hemi-dyskinesias with nystagmoid eye movements that stopped during sleep (video on the Neurology ® Web site at [Neurology.org][1]). Video-EEG showed no ictal change (figure 2). Concurrent medications included oxcarbazepine, levetiracetam, and valproic acid. The movements resolved 8 hours after discontinuing fosphenytoin. Right cerebral infarction was the presumed underlying cause of phenytoin-induced hemi-dyskinesia. Diagnosis of phenytoin-induced dyskinesias requires a high index of suspicion and typically resolves upon medication discontinuation. [1]: http://neurology.org/lookup/doi/10.1212/WNL.0000000000002595