A Case of Juvenile Onset Lennox-Gastaut Syndrome Presenting as Atypical Absence

Ha, Byoung Lip; Cheon, Sang Myeong; Kim, Sang Ho

Abstract

Atypical absence is less understood than typical absence. Several conditions that produce atypical absence are known including Lennox-Gastaut syndrome, myoclonic astatic epilpsy and epileptic encephalopathy with continuous spike and waves in slow wave sleep. A 17-year-old girl with mental retardation had developed frequent loss of consciousness and occasional falling attack with traumatic facial injury for 2 years. The interictal EEG showed 2 Hz slow spike-and-wave complex with maximum over right frontotemporal area and the brain MRI was normal. Carbamazepin was prescribed initially but the drug seemed to worsen the seizures. Long term video-EEG monitoring showed very frequent atypical absence seizures consisting of sudden hypotonia of head and oral automatism with or without secondary generalization. Generalized 2 to 2.5 Hz slow spike-and-wave complexes with duration of 10 to 40 seconds were seen during ictal period. About 10% to 20% of the non REM sleep was occupied with generalized slow spike-and-wave complex and/or polyspikes or polyspikes-and-wave complex with duration of within 1 second. Valprorate monotherapy had failed, then lamotrigin was added. In spite of polytherapy, the seizure was intractable. We think this intractable atypical absence might be associated with juvenile onset Lennox-Gastaut syndrome.