Hippocampal sclerosis after febrile status epilepticus: The FEBSTAT study

Abstract

Objective Whether febrile status epilepticus (FSE) produces hippocampal sclerosis (HS) and temporal lobe epilepsy (TLE) has long been debated. Our objective is to determine if FSE produces acute hippocampal injury that evolves to HS. Methods FEBSTAT and two affiliated studies prospectively recruited 226 children aged 1 month to 6 years with FSE and controls with simple febrile seizures. All had acute MRIs and follow-up MRIs were obtained at approximately 1 year later in the majority. Visual interpretation by two neuroradiologists informed only of subject age was augmented by hippocampal volumetrics, analysis of the intra-hippocampal distribution of T2 signal, and apparent diffusion coefficients. Results Hippocampal T2 hyperintensity, maximum in Sommer's sector, occurred acutely after FSE in 22 of 226 children in association with increased volume. Follow-up MRIs obtained on 14 of the 22 with acute T2 hyperintensity showed HS in 10 and reduced hippocampal volume in 12. In contrast, follow-up of 116 children without acute hyperintensity showed abnormal T2 signal in only 1 (following another episode of FSE). Furthermore, compared to controls with simple febrile seizures, FSE subjects with normal acute MRIs had abnormally low right to left hippocampal volume ratios, smaller hippocampi initially and reduced hippocampal growth. Interpretation Hippocampal T2 hyperintensity after FSE represents acute injury often evolving to a radiological appearance of HS after one year. Furthermore, impaired growth of normal appearing hippocampi after FSE suggests subtle injury even in the absence of T2 hyperintensity. Longer follow-up is needed to determine the relationship of these findings to TLE.

Historical Risk Factors Associated with Seizure Outcome After Surgery for Drug-Resistant Mesial Temporal Lobe Epilepsy

“…It loses its predictive value when the subgroup of patients with MTS is examined 13 . Febrile seizures are clearly related to MTS at times 14 . MRI findings of a markedly hyperintense hippocampus in children with febrile status epilepticus was highly 10 associated with later development of mesial temporal sclerosis 14,15 .…”

“…Febrile seizures are clearly related to MTS at times 14 . MRI findings of a markedly hyperintense hippocampus in children with febrile status epilepticus was highly 10 associated with later development of mesial temporal sclerosis 14,15 . It appears that it is critical to distinguish among different types and etiologies of TLE when predicting outcome after surgery.…”

It Goes Downhill from Here but Do Not Despair: Mesial Temporal Lobe Epilepsy is a Progressive Disease, but it Can be Benign

“…Whether this will be associated with epilepsy, mild or refractory remains to be awaited. The FEBSTAT study only includes patients with febrile status epilepticus, defined as seizures for more than 30 minutes, as compared with just a history of febrile seizure as reported in the Labate et al study (10). A small but not insignificant difference.…”

Hippocampal sclerosis: pathogenesis, clinical features, diagnosis, and treatment

“…Из этих 22 больных повторное МРТ в различные сроки выполнялось у 14, при этом в 10 случаях были выявлены признаки склероза гиппокампа. Тем не менее из 226 детей эпилепсия была диагностирована толь-ко у 16 пациентов и в большинстве случаев была не височ-ной [12]. Таким образом, фебрильный статус не всегда приводит к эпилепсии со склерозом гиппокампа, хотя временной интервал между преципитирующей травмой мозга и появлением височной эпилепсии может быть больше 10 лет, а катамнез такой длительности пока не ис-следовался.…”