Abstracts

Rationale: We present a case of a 34-year-old Male suffering from Epilepsia Partialis Continua (EPC) who underwent rapid epilepsy surgical evaluation, resulting in Responsive Neurostimulator (RNS) implantation within a period of 8 days. Prior history of HIV complicated by Immune Reconstitution Inflammatory Syndrome (IRIS) led to multifocal CNS injury and symptomatic onset focal seizures 3 years prior to seeking our second opinion. Seizures involved waxing and waning clonic twitching of the right lower face and left leg throughout the day with preserved awareness and were refractory to 6 antiseizure medications. Case escalated with dysphagia, gait instability, falls, severe nutritional deficiency, weight loss and wheelchair confinement. This poster explores the medical and surgical options taken into consideration, balanced with the level of urgency and lessons learned undertaking this endeavor.

Methods: Patient underwent urgent Epilepsy Monitoring Unit (EMU) investigation. Scalp video EEG monitoring facilitated Ictal SPECT scan. Pre-surgical MRI brain also acquired for co-registration with SPECT. Intracranial EEG involved left craniotomy for grid placement over left lateral frontal cortex and depth electrodes targeting right medial frontal cortex. Cortical stimulation mapped eloquent motor function. Findings resulted in implantation of RNS via 4-contact strip to left lateral frontal cortex and depth electrode to right medial frontal cortex. RNS treatment activated immediately post-op.

Results: Scalp EEG did not capture ictal patterns, however, numerous seizures were characterized on video. Right lower facial and left lower leg clonic activity indicated left lateral and right medial frontal involvement respectively. Hypothesis supported by co-registered Ictal SPECT with MRI showing left lateral frontal hypermetabolism following right lower facial seizures. Intracranial grid EEG confirmed a 1cm x 1cm ictal onset in left lateral frontal cortex and independent ictal activity in the right medial frontal cortex. Neurostimulation mapping confirmed cortices were eloquent for primary motor function. Resection deferred and pivoted to RNS implantation. Bandpass detectors readily captured seizures and standard monopolar responsive neurostimulation quickly escalated over 4 months to charge density of 3uC/cm^2, resulting in complete control of clinical seizures. Patient has since been able to participate in physical therapy, improved oral and G-tube nutrition and gradually regained independent walking.


Conclusions: EPC is notoriously refractory to antiseizure medications. Though consciousness may be preserved, clinical implications of seemingly minor ictal events with small cortical involvement can result in devastating complications and impact to daily living. Surgical epilepsy teams should have a low threshold to rapidly investigate and coordinate definitive surgery. Fine localization of EPC onset zones is feasible via intracranial EEG. Neurostimulation of EPC involving eloquent motor cortex via RNS is feasible and appears to be readily responsive.


Funding: None