Rasmussen syndrome: absence seizures may be induced by oxcarbazepine

A female patient with electroclinical and neuroradiological features compatible with Rasmussen syndrome developed a particular clinical and EEG pattern. As the seizures were refractory to valproate at 750 mg/kg/day, oxcarbazepine (OXC) at 30 mg/kg/day was added. Seizures became more frequent and on neurological examination, no hemiparesis was detected. The interictal EEG showed focal spikes and diffuse paroxysms in the right fronto-temporal regions. Brain MRI revealed right hemiatrophy, mainly at the Sylvian fissure. After initiating OXC daily, brief absence seizures, lasting less than 20 seconds and associated with bilateral and synchronous 2.5-3-Hz spike-and-waves compatible with typical absences, were observed. OXC was discontinued and the typical absences disappeared. Treatment with intravenous gammaglobulin was started. At the last control visit, at nine years of age, no absence seizures were observed either by the parents or on the EEG recording. Our patient who met the diagnostic criteria for Rasmussen syndrome presented with absence seizures that may have been induced by OXC. The absence seizures disappeared after OXC was discontinued.