Lamotrigine-induced tic disorder: report of five pediatric cases
To describe the clinical spectrum of lamotrigine (LTG)-induced tics (an uncommon side effect) in children. Retrospective analysis of patients from our hospital-based practice who developed tics while on LTG. Data obtained from medical records, interviews with parents, video-EEGs, and homemade videotapes. Three males and two females (range, 2.5-12 years; mean, 6.9 years) developed a movement disorder within the first 10 months of therapy (maintenance doses, 4-17 mg/kg/day). Four patients exhibited simple motor tics; one patient experienced mostly vocal (i.e., gasping sounds) tics. Laryngoscopic evaluation of one 2.5-year-old with repetitive gasping sounds was normal. In three cases, tics resolved completely within 1 month of drug cessation; tics recurred in two of these patients after reintroduction of LTG. A fourth patient experienced gradual improvement after stopping LTG over 4 months; the fifth patient's simple motor tics improved spontaneously with a reduction in medication. None of the patients had clinical features of a neurodegenerative disorder, and none met diagnostic criteria for Tourette syndrome. Two patients, however, had a diagnosis of acquired epileptic aphasia syndrome, and one patient had nonprogressive expressive and receptive language dysfunction. A fourth patient had global static encephalopathy, and the fifth patient had only attentional problems. In all patients, tics were not associated with ictal EEG changes. LTG may infrequently induce simple motor tics, vocal tics, or both. Patients with severe language dysfunction may be particularly susceptible to this uncommon side effect. Further studies are necessary to clarify the population at risk.