Abstracts

Rationale: Mesial temporal sclerosis (MTS) is defined by hippocampal gliosis, atrophy, and neuronal loss. Clinical features associated with development of MTS in children have not been well described. We present 3 children with prolonged or recurrent seizures and frequent spikes on EEG. All 3 developed MTS on serial MRIs. Through these cases we attempt to identify factors associated with progression of MTS. Methods: We retrospectively reviewed medical records of 3 children whose MRI studies reflected development of hippocampal atrophy. The Institutional Review Board at Children's Hospital Boston approved the study. Results: Case 1: A previously healthy 9 year-old girl presented with a prolonged complex partial seizure and subsequent simple partial seizures. She initially had T2 signal hyperintensity in the right hippocampus. A year later, the signal abnormality resolved but new right hippocampal volume loss was found. EEG showed frequent sleep-potentiated right posterior quadrant spike and wave discharges, occupying 86% of slow-wave sleep. Clinically, she has remained seizure-free on oxcarbazepine, without cognitive deficits or behavioral changes for almost 2 years. Case 2: A 14 year-old boy with developmental delay presented with recurrent prolonged seizures lasting 10 minutes to 2 hours since 15 months of age. Initial MRI at presentation showed normal hippocampi; 2 years later, right hippocampal volume was less. EEG showed frequent right frontotemporal spikes, potentiated during slow-wave sleep, and independent left and right frontal spikes. After initial seizure control with phenytoin, he began experiencing yearly breakthrough seizures, which increased to monthly at puberty. Currently, he is managed on phenytoin, lamotrigine, and clobazam with improved seizure control on increased clobazam. Case 3: An 11 year-old boy with a history of prematurity, intraventricular hemorrhage, post-hemorrhagic hydrocephalus, ventriculoperitoneal shunt placement, and perioperative thalamic hemorrhage presented on day of life 1 with seizures. Initial MRI at 4 years of age showed normal hippocampi. Four years later, follow-up MRI showed T2 signal hyperintensity and atrophy consistent with MTS. Seizure frequency varied throughout the years, up to 1-2 times per day. EEG showed sleep potentiated generalized spikes, with a spike wave index at approximately 100%, while awake he also had frequent runs of generalized spike and wave complexes. Clinically he continues on phenobarbital, zonisamide and diazepam, with occasional breakthrough seizures. Conclusions: All 3 children had serial MRIs showing MTS, 2 with clear development of MTS after initially showing normal hippocampi. Common features consist of status epilepticus and abundant interictal spikes on EEG, which may be associated with development of MTS in children. Although prospective studies are needed, early medical intervention guided towards prevention of status epilepticus and decreasing abundant interictal discharges may help prevent development of MTS in children.