Teaching Video NeuroImages: phenytoin-induced orofacial dyskinesias.

Brendan P. Lucey, MD A 55-year-old right-handed man started phenytoin after 2 seizures. Four weeks later, he complained of involuntary facial movements. Examination revealed orofacial dyskinesias: eyebrow elevation and lip pursing (video on the Neurology Web site at www. neurology.org). No ataxia, slurred speech, or nystagmus was seen. His phenytoin level was 29.5 mg/L when examined, increased from 14.6 mg/L 15 days earlier. Phenytoin discontinued and dyskinesias resolved within 2 weeks. Dyskinesias, rare but well-documented complications of phenytoin, occur during initial or chronic treatment.1 Elevation of phenytoin level is not necessary for dyskinesias to develop; dyskinesias usually resolve with drug cessation.1,2 Recognition of this phenytoin side effect may preempt an extensive workup.