[Paroxysmal automatic movements mimicking neonatal seizures induced by midazolam]

We have observed paroxysmal automatic movements including drum-beating and pedaling motions in three full-term neonates following intravenous bolus injections (0.1-0.3 mg/kg/dose) or drip infusions (0.2 mg/kg/h) of midazolam used for sedation. In one patient, abnormal movements were also induced by a bolus injection of midazolam during the EEG recording, and no change was revealed in the EEG during the episode. In another patient, abnormal movements were further worsened by an injection of diazepam. Interictal EEGs of all patients were normal. The clinical manifestations of these paroxysmal automatic movements and the mode of their appearance were quite similar in all patients. It is quite likely that abnormal movements in the patient without ictal EEG change do not have epileptic origin but brainstem release phenomenon induced by midazolam. Because the abnormal movements in the other two cases had similar clinical manifestations and mode of appearance, we suspected that these movements were also non-epileptic though ictal EEGs were not recorded in theses cases. When we encounter paroxysmal automatic movements mimicking neonatal seizures following intravenous midazolam administration, ictal EEG recordings are recommended. If there are no ictal changes, we should avoid treatment with anticonvulsant drugs for these movements. Since midazolam is frequently used in neonates for sedation during various examinations, future investigations on the selection of appropriate drugs and dosage for sedation in neonates, including the usage of midazolam, are necessary.