Abstracts

Rationale: Frontal lobe epilepsy is challenging to diagnose given the broad range of seizure semiologies and interictal epileptiform patterns. Frontal lobe seizures can be misdiagnosed as nonepileptic seizures. One of the clinical features that favor the diagnosis of non epileptic event is asynchronous extremity jerking and preserved sensorium despite bilateral ictal phenomena like shaking. We describe a case of a patient with independent bi frontal origin seizures presenting as asynchronous bilateral leg shaking with intact sensorium, initially thought to be non-epileptic events Methods: We searched PubMed for reports published from 1950-2014 using the following terms: frontal seizure asynchronous movements. Clinical data including continuous video electroencephalography (VEEG) recordings were extracted from the patient's file Results: This is a 16 year old young man with one year history of academic underachievement who initially presented with nausea and emesis followed by jerking of his lower extremities that prevented him from walking. He progressed to have continuous asynchronous twitching of his lower extremities without alteration of sensorium. The semiology at this point was suspicious for a non epileptic process. However, the twitching soon became continuous, persisting in sleep and a VEEG showed time locked periodic 1 hertz sharps in bi-frontal and central channels without further evolution and diffuse slowing. He then developed generalized tonic-clonic seizures clinically and electrographic seizures were captured from the right frontemporal region. This was followed by refractory status epilepticus and required numerous anti-seizure medications (Valproate, Fosphenytoin, Levetiracetam, Clobazam) and Pentobarbital induced burst suppression. CSF and serum studies for metabolic, toxic, infectious and autoimmune etiologies including paraneoplastic panel and NMDA receptor antibodies were negative. Brain magnetic resonance imaging (MRI) showed cortical areas of abnormal signal intensity most notably involving the mesial bi frontal regions with associated diffusion restriction. An extensive search for systemic malignancy was negative. He received high dose intravenous steroids, full course of plasmapheresis and intravenous immunoglobulin for the presumed autoimmune encephalitis. Eventually he became seizure free with one brief recurrence and made good recovery with extensive cognitive rehabilitation with some new neuropsychiatric deficits. He continues to have rare generalized frontally predominant spikes present mostly during drowsiness and sleep, but is clinically doing well on one antiepileptic medication. Conclusions: We describe a young man who presented with asynchronous bilateral lower extremity shaking with intact sensorium which was initially thought to be non-epileptic events. His further clinical and EEG evolution suggested immune mediated encephalitis though no antibody was isolated and he responded to early and aggressive immunotherapy. This case underscores the range of bizarre and atypical semiologies of frontal lobe seizures.