A case of acute functional hemispherotomy in a young woman with hemimegalencephaly and super-refractory status epilepticus

Abstract

Status epilepticus (SE) is a critical medical emergency that demands immediate and effective intervention. We report a unique case involving a 21-year-old woman with left hemimegalencephaly who was hospitalized for super-refractory status epilepticus (SRSE) that persisted for 8 weeks. Despite extensive treatment efforts including multiple anti-seizure medications, anesthetics, high-dose methylprednisolone, anakinra, magnesium infusion, and a ketogenic diet, her condition remained unchanged. Ultimately, a left functional hemispherotomy was performed, informed by MRI findings and EEG results showing predominantly left-sided epileptic activity. This decision was made collaboratively when all other therapeutic options had been exhausted. Postoperatively, the patient recovered with manageable neurological deficits and a satisfactory quality of life. To our knowledge, this is the first reported case of acute functional hemispherotomy in an adult with hemimegalencephaly and SRSE.

Keywords: Epilepsy; Epilepsy surgery; Functional hemispherotomy; Hemimegalencephaly; Status epilepticus; Super-refractory status epilepticus.

Fig. 1

Cerebral MRI at 4 different time points during the disease course. A) Age 9: MRI supposed to be normal, however retrospectively one can see signs of hemispheric asymmetry suggesting left-sided hemimegalencephaly. B) Age 21: three weeks after SRSE onset: MRI with clear left-sided hemimegaloencephaly. with diffuse confluent T2/Flair hyperintensity in white matter in left fronto-parietal region representing white matter demyelination and gliosis. C) MRI 3 weeks after surgery: Status after left-sided functional hemispherotomy. Pronounced edema in the left hemisphere with a midline shift of 11 mm to the right. Mainly signs of vasogenic edema in the basal ganglia on the left side. D) MRI 3 months after surgery: Status post left-sided functional hemispherotomy with encephalomalacia and resection defects in the left cerebral hemisphere. Resorption of blood, now with remaining blood products/hemosiderin in the form of scattered small low-signal foci in the resection cavity and linearly along the edge of the resection frontoparietally and temporally. Thickened dura under the craniotomy on the left side and a narrow (2–3 mm) extra-axial residual rim that may contain blood-mixed fluid. Reduction of postoperative parenchymal edema in the left cerebral hemisphere and regression of mass effect.

Fig. 2

Excerpts from EEG monitoring during the SRSE episodes and 4 months after functional hemispherotomy. A) EEG 2 weeks after SRSE onset under deep sedation. Longitudinal montage, vertical lines indicate 1-second intervals. Top panel showing the corresponding amplitude-integrated EEGs (F3-P3/F4-P4) and spectrograms (F3-O1/F4-O2) over a 4 h period. ASM: Valproate, Zonisamide, Sultinam. Sedatives/anesthetics: Propofol, Thiopental. The EEG shows a burst-suppression pattern with short bursts from 1 to 3 s alternating with suppression periods of 1–3 s. The majority of the bursts may be characterized as highly epileptiform, containing multiple left hemispheric epileptiform discharges. B) EEG 3.5 weeks after SRSE onset under the second attempt to wake up the patient. Longitudinal montage, vertical lines indicate 1-second intervals. Top panel showing the corresponding amplitude-integrated EEGs (F3-P3/F4-P4) and spectrograms (F3-O1/F4-O2) over a 4 h period. ASM: Sultinam, Valproate, Brivaracetam, Clobazam. Sedatives/anesthetics: Dexmedetomidine. Other: Meropenem (pneumonia). The EEG shows the end of an electroencephalographic seizure from the left frontocentral area with spreading to the midline and right frontal area. The amplitude-integrated EEGs and spectrograms show repeated seizures (>35) almost without free interval in the first 2 h period (seizures are seen as abrupt increases in amplitude and high frequencies). C) EEG 5 weeks after SRSE onset under the third weaning attempt. Longitudinal montage, vertical lines indicate 1-second intervals. Top panel showing the corresponding amplitude-integrated EEGs (F3-P3/F4-P4) and spectrograms (F3-O1/F4-O2) over a 4 h period. ASM: Brivaracetam, Clonazepam, Perampanel, Clobazam. Sedatives/anesthetics: Propofol. Other: The EEG shows the beginning of an electroencephalographic seizure from the left frontocentral area spreading to the entire left hemisphere as well as the midline. The amplitude-integrated EEGs and spectrograms show repeated left hemispheric seizures visible as abrupt increases in amplitude and high frequencies over a 4 h period of time. D) EEG 4 months after the acute functional hemispherotomy. Longitudinal montage, vertical lines indicate 1-second intervals. Top panel showing the corresponding spectrograms (F3-O1/F4-O2) over a 20 min period. ASM: Brivaracetam, Clobazam, Perampanel. The EEG shows sporadic spikes and polyspikes in the left frontal area combined with left hemispheric slowing. Normal activity in the right hemisphere with an 8 Hz posterior dominant rhythm upon eyes closure. No ictal activity.