Super-Refractory Status Epilepticus: Prognosis and Recent Advances in Management

Surgical management of status epilepticus: A systematic review

Status Epilepticus (SE), unresponsive to medical management, is associated with high morbidity and mortality. Surgical management is typically considered in these refractory cases. The best surgical approach for affected patients remains unclear; however, given the lack of controlled trials exploring the role of surgery. We performed a systematic review according to PRIMSA guidelines, including case reports and series describing surgical interventions for patients in SE. Cases (157 patients, median age 12.9 years) were followed for a median of 12 months. Patients were in SE for a median of 21 days before undergoing procedures including: focal resection (36.9%), functional hemispherectomy (21%), lobar resection (12.7%), vagus nerve stimulation (VNS) (12.7%), deep brain stimulation (DBS) (6.4%), multiple subpial transection (MST) (3.8%), responsive neurostimulation (RNS) (1.9%), and cortical stimulator placement (1.27%), with 24 patients undergoing multiple procedures. Multiple SE semiologies were identified. 47.8% of patients had focal seizures, and 65% of patients had focal structural abnormalities on MRI. SE persisted for 36.8 ± 47.7 days prior to surgical intervention. SE terminated following surgery in 81.5%, terminated with additional adjuncts in 10.2%, continued in 1.9%, and was not specified in 6.4% of patients. Long-term seizure outcomes were favorable, with the majority improved and 51% seizure-free. Eight patients passed away in follow-up, of which three were in SE. Seizures emerging from one hemisphere were both more likely to immediately terminate (OR 4.7) and lead to long-term seizure-free status (OR 3.9) compared to nonunilateral seizures. No other predictors, including seizure focality, SE duration, or choice of surgical procedure, were predictors of SE termination. Surgical treatment of SE can be effective in terminating SE and leading to sustained seizure freedom, with many different procedures showing efficacy if matched appropriately with SE semiology and etiology. PLAIN LANGUAGE SUMMARY: Patients with persistent seizures (Status Epilepticus) that do not stop following medications can be treated effectively with surgery. Here, we systematically review the entirety of existing literature on surgery for treating status epilepticus to better identify how and when surgery is used and what patients do after surgery.

ACVIM Consensus Statement on the management of status epilepticus and cluster seizures in dogs and cats

BACKGROUND

Seizure emergencies (ie, status epilepticus [SE] and cluster seizures [CS]), are common challenging disorders with complex pathophysiology, rapidly progressive drug-resistant and self-sustaining character, and high morbidity and mortality. Current treatment approaches are characterized by considerable variations, but official guidelines are lacking.

OBJECTIVES

To establish evidence-based guidelines and an agreement among board-certified specialists for the appropriate management of SE and CS in dogs and cats.

ANIMALS

None.

MATERIALS AND METHODS

A panel of 5 specialists was formed to assess and summarize evidence in the peer-reviewed literature with the aim to establish consensus clinical recommendations. Evidence from veterinary pharmacokinetic studies, basic research, and human medicine also was used to support the panel's recommendations, especially for the interventions where veterinary clinical evidence was lacking.

RESULTS

The majority of the evidence was on the first-line management (ie, benzodiazepines and their various administration routes) in both species. Overall, there was less evidence available on the management of emergency seizure disorders in cats in contrast to dogs. Most recommendations made by the panel were supported by a combination of a moderate level of veterinary clinical evidence and pharmacokinetic data as well as studies in humans and basic research studies.

CONCLUSIONS AND CLINICAL RELEVANCE

Successful management of seizure emergencies should include an early, rapid, and stage-based treatment approach consisting of interventions with moderate to preferably high ACVIM recommendations; management of complications and underlying causes related to seizure emergencies should accompany antiseizure medications.

Risk factors for super-refractory and mortality in generalized convulsive status epilepticus: a 10-year retrospective cohort study

Background

Generalized convulsive status epilepticus (GCSE) is one of the most challenging life-threatening neurological emergencies. If GCSE becomes super-refractory, it is associated with significant mortality. Although aggressive management of prolonged status epilepticus was conducted, the mortality has not decreased since the late 1990s.

Objectives

The present study aimed to explore the risk factors for progression to super-refractory in patients with generalized convulsive status epilepticus (GCSE). Moreover, we illustrated the risk factors for mortality in GCSE patients.

Design

An observational retrospective cohort study.

Methods

We conducted a retrospective study of patients with GCSE admitted to our neurocritical unit, in Guangzhou, China, from October 2010 to February 2021. The data of sociodemographic information, etiology, laboratory results, treatment, and prognosis were collected and analyzed.

Results

A total of 106 patients were enrolled; 51 (48%) of them developed super-refractory status epilepticus (SRSE). Multivariate logistic regression analysis demonstrated that patients with autoimmune encephalitis (p = 0.015) and intracranial infection (p = 0.019) are likely to progress to SRSE. The in-hospital mortality was 11.8% and 9.1% for patients in the SRSE and non-SRSE groups, respectively (p = 0.652). Multivariate logistic regression analysis showed that neutrophil-to-lymphocyte ratios (NLR) at admission were independently associated with in-hospital mortality. Up to 31.4% of SRSE patients and 29.1% of non-SRSE patients died within 6 months after discharge (p = 0.798). Multivariate logistic regression analysis showed that plasma exchange (PE) was a protective factor for 6-month mortality. A high NLR at discharge was a risk factor for 6-month mortality.

Conclusion

In the current study, about 48% of GCSE patients progressed to SRSE. Regarding etiology, autoimmune encephalitis or intracranial infection was prone to SRSE. No significant differences were observed in the in-hospital and 6-month mortality between SRSE and non-SRSE groups. Multivariate logistic regression analysis showed that NLR at admission and discharge was an independent predictor of in-hospital and 6-month mortality, respectively. Moreover, PE significantly reduced the 6-month mortality.

Lennox-Gastaut syndrome characterized by super-refractory status epilepticus treated with high-dose anesthetics: A case report

RATIONALE

Super-refractory status epilepticus is a serious illness with high morbidity and mortality, which is defined as an SE that continues or recurs 24 hours or more after the onset of anesthesia. Anesthetic agents can be either pro-convulsant or anticonvulsant or both.

PATIENT CONCERNS

Epilepsy occurred at the age of 3 years. At the age of 4 years, generalized tonic-clonic seizure occurred for the first time. The patient was hospitalized at the age of 27 and 28 years for treating status epilepticus. At the age of 33 years, antiepileptic drugs were stopped due to poor appetite. In an early morning, the patient was found delirious with reduced speech.

DIAGNOSIS

Occasionally, the patient blinked his eyelids, or deflected his eyeballs to 1 side. When propofol was lowered to 10 mL/H, the epileptic wave reduced obviously. Afterwards, the patient opened his eyes autonomously and his consciousness gradually recovered. The patient could answer questions, and the limbs had voluntary movements. The patient breathing also gradually recovered, and his urine gradually returned to pale yellow from green. After anesthetic was stopped for 10 days, the patient lost his consciousness again. The patient eyes turned upward frequently, which was relieved in 1 to 2 seconds with an attack once every 2 to 5 minutes.

INTERVENTIONS

Clonazepam was gradually reduced to 2 mg qn, and the patient gradually woke up during this process. The patient was also treated with levetiracetam 1.5 g bid, oxcarbazepine 0.6 g bid, topiramate 50 mg bid and valproate 0.4 g tid.

OUTCOMES

After 1 month follow-up, status epilepticus did not appear again.

LESSONS

Propofol aggravated the tonic seizures. As tonic seizures occur during natural sleep and after sleep induced by various narcotic drugs, the decrease of consciousness level induced by excessive sedation of narcotic drugs has been suggested as the reason for poor seizure control.

Long-term outcomes in refractory status epilepticus

INTRODUCTION

Refractory status epilepticus (RSE) is a diagnosis that can be made when tonic-clonic status epilepticus (SE) and focal SE cannot be stopped by at least two anti-seizure medications after 30 and 60 minutes, respectively, from the time of commencement. It could result in mortality, loss of functionality, neurological deficiency, and other serious short- and long-term effects.

AREAS COVERED

This narrative review covers original clinical studies of any design and case series investigating long-term outcomes of RSE recorded after at least a year from the SE onset.

EXPERT OPINION

The future of a patient with RSE rests mostly on the long-term effects of this severe pathological condition, which may be accompanied with systemic complications like hyperthermia, hyperkalemia, acidosis, and/or stress cardiomyopathy. Younger patients with less severe RSE of shorter duration, particularly of the convulsive kind, are reported to have better long-term outcomes. Previous studies on the factors influencing the long-term outcomes of RSE, however, did not link the outcomes to treatment options for the condition. Such circumstances currently prevent making any definitive recommendations on the treatment of RSE until future research with adequate statistical power is completed.

Hippocampal glucocorticoid receptors modulate status epilepticus severity

Status epilepticus (SE) is a life-threatening medical emergency with significant morbidity and mortality. SE is associated with a robust and sustained increase in serum glucocorticoids, reaching concentrations sufficient to activate the dense population of glucocorticoid receptors (GRs) expressed among hippocampal excitatory neurons. Glucocorticoid exposure can increase hippocampal neuron excitability; however, whether activation of hippocampal GRs during SE exacerbates seizure severity remains unknown. To test this, a viral strategy was used to delete GRs from a subset of hippocampal excitatory neurons in adult male and female mice, producing hippocampal GR knockdown mice. Two weeks after GR knockdown, mice were challenged with the convulsant drug pilocarpine to induce SE. GR knockdown had opposing effects on early vs late seizure behaviors, with sex influencing responses. For both male and female mice, the onset of mild behavioral seizures was accelerated by GR knockdown. In contrast, GR knockdown delayed the onset of more severe convulsive seizures and death in male mice. Concordantly, GR knockdown also blunted the SE-induced rise in serum corticosterone in male mice. GR knockdown did not alter survival times or serum corticosterone in females. To assess whether loss of GR affected susceptibility to SE-induced cell death, within-animal analyses were conducted comparing local GR knockdown rates to local cell loss. GR knockdown did not affect the degree of localized neuronal loss, suggesting cell-intrinsic GR signaling neither protects nor sensitizes neurons to acute SE-induced death. Overall, the findings reveal that hippocampal GRs exert an anti-convulsant role in both males and females in the early stages of SE, followed by a switch to a pro-convulsive role for males only. Findings reveal an unexpected complexity in the interaction between hippocampal GR activation and the progression of SE.

Large-scale transient peri-ictal perfusion magnetic resonance imaging abnormalities detected by quantitative image analysis

Epileptic seizures require a rapid and safe diagnosis to minimize the time from onset to adequate treatment. Some epileptic seizures can be diagnosed clinically with the respective expertise. For more subtle seizures, imaging is mandatory to rule out treatable structural lesions and potentially life-threatening conditions. MRI perfusion abnormalities associated with epileptic seizures have been reported in CT and MRI studies. However, the interpretation of transient peri-ictal MRI abnormalities is routinely based on qualitative visual analysis and therefore reader dependent. In this retrospective study, we investigated the diagnostic yield of visual analysis of perfusion MRI during ictal and postictal states based on comparative expert ratings in 51 patients. We further propose an automated semi-quantitative method for perfusion analysis to determine perfusion abnormalities observed during ictal and postictal MRI using dynamic susceptibility contrast MRI, which we validated on a subcohort of 27 patients. The semi-quantitative method provides a parcellation of 3D T₁-weighted images into 32 standardized cortical regions of interests and subcortical grey matter structures based on a recently proposed method, direct cortical thickness estimation using deep learning-based anatomy segmentation and cortex parcellation for brain anatomy segmentation. Standard perfusion maps from a Food and Drug Administration-approved image analysis tool (Olea Sphere 3.0) were co-registered and investigated for region-wise differences between ictal and postictal states. These results were compared against the visual analysis of two readers experienced in functional image analysis in epilepsy. In the ictal group, cortical hyperperfusion was present in 17/18 patients (94% sensitivity), whereas in the postictal cohort, cortical hypoperfusion was present only in 9/33 (27%) patients while 24/33 (73%) showed normal perfusion. The (semi-)quantitative dynamic susceptibility contrast MRI perfusion analysis indicated increased thalamic perfusion in the ictal cohort and hypoperfusion in the postictal cohort. Visual ratings between expert readers performed well on the patient level, but visual rating agreement was low for analysis of subregions of the brain. The asymmetry of the automated image analysis correlated significantly with the visual consensus ratings of both readers. We conclude that expert analysis of dynamic susceptibility contrast MRI effectively discriminates ictal versus postictal perfusion patterns. Automated perfusion evaluation revealed favourable interpretability and correlated well with the classification of the visual ratings. It may therefore be employed for high-throughput, large-scale perfusion analysis in extended cohorts, especially for research questions with limited expert rater capacity.

Combined Responsive Neurostimulation and Focal Resection for Super Refractory Status Epilepticus: A Systematic Review and Illustrative Case Report

OBJECTIVE

Super-refractory status epilepticus (SRSE) is a neurologic emergency with high mortality and morbidity. Although medical algorithms typically are effective, when they do fail, options may be limited, and neurosurgical intervention should be considered.

METHODS

We report a case of SRSE treated acutely with responsive neurostimulation (RNS) and focal surgical resection after intracranial monitoring. We also conducted a systematic review of the literature for neurosurgical treatment of SRSE (e.g., neurostimulation). Only published manuscripts were considered.

RESULTS

Our patient's seizure semiology consisted of left facial twitching with frequent evolution to bilateral tonic-clonic convulsions. Stereoelectroencephalography and grid monitoring identified multiple seizure foci. The patient underwent right RNS placement with cortical strip leads over the lateral primary motor and premotor cortex as well as simultaneous right superior temporal and frontopolar resection. Status epilepticus resolved 21 days after surgical resection and placement of the RNS. The systematic review revealed 15 case reports describing 17 patients with SRSE who underwent acute neurosurgical intervention. There were 3 patients with SRSE with RNS placement as a single modality, all of whom experienced cessation of SE. Four patients with SRSE received vagus nerve stimulation (3 as a single modality and 1 with combined corpus callosotomy), of whom 1 had SE recurrence at 2weeks. Two patients with SRSE received deep brain stimulation, and the remaining 8 underwent surgical resection; none had recurrence of SE.

CONCLUSIONS

RNS System placement with or without resection can be a viable treatment option for select patients with SRSE. Early neurosurgical intervention may improve seizure outcomes and reduce complications.

Factors associated with mortality in patients with super-refractory status epilepticus

Super-refractory status epilepticus (SRSE) is a critical condition in which seizures persist despite anesthetic use for 24 h or longer. High mortality has been reported in patients with SRSE, but the cause of death remains unclear. We investigated the factors associated with mortality, including clinical characteristics, SE etiologies and severities, treatments, and responses in patients with SRSE in a 13-year tertiary hospital-based retrospective cohort study comparing these parameters between deceased and surviving patients. SRSE accounted for 14.2% of patients with status epilepticus, and 28.6% of SRSE patients died. Deceased patients were mostly young or middle-aged without known systemic diseases or epilepsy. All deceased patients experienced generalized convulsive status epilepticus and failure of anesthetic tapering-off, significantly higher than survivors. An increased number of second-line anesthetics besides midazolam was observed in the deceased (median, 3, interquartile range 2–3) compared to surviving (1, 1–1; p = 0.0006) patients with prolonged use durations (p = 0.047). For mortality, the cut-off number of second-line anesthetics was 1.5 (AUC = 0.906, p = 0.004). Deceased patients had significantly higher renal and cardiac complications and metabolic acidosis than survivors. In SRSE management, multi-anesthetic use should be carefully controlled to avoid systemic complications and mortality.

Ketamine in adult super-refractory status epilepticus: Efficacy analysis on a prospective registry

Background

Status epilepticus (SE) persisting despite two anti‐seizures medications (ASM) and anesthetics is labeled super refractory (SRSE), correlating with important morbidity and mortality. Its treatment relies on expert opinions. Due to its pharmacological properties, ketamine (KET) has received increasing attention, but data are essentially retrospective.

Aims

To describe an unselected cohort of adults receiving KET for SRSE.

Methods

Analysis of a prospective registry of consecutive SE episodes, identifying SRSE patients receiving ketamine (KET). Comparison with recent adult series including more than 10 patients.

Results

Eleven patients received KET after a median of 4 days (range: 2–20); median dose was 5 mg/kg/h (range: 2.5–15). KET provided permanent SE control in three (27%). Previous series, using KET administration delays and doses similar to our cohort, report KET efficacy in 28–96% of cases.

Conclusions

We found a lower SE control rate than existing literature, whose data are, however, often retrospective, potentially selecting patients with less severe SE forms or responding to KET. This might explain outcome differences, as KET administration modalities were comparable with our cohort. Since randomized controlled studies are lacking on this subject, the analysis of this prospective, unselected cohort, if confirmed, suggests a current overestimation of KET efficacy in SRSE.

Good seizure outcome after focal resection surgery for super-refractory status epilepticus: Report of two cases

Background:

There is scarce evidence regarding focal resection surgery for super-refractory status epilepticus (SRSE), which is resistant to general anesthetic treatment over 24 h. We report two patients with SRSE, in whom good seizure outcomes were obtained following focal resection surgery.

Case Description:

Patient 1: A 58-year-old man who underwent left anterior temporal lobectomy with hippocampectomy at the age of 38 years after being diagnosed left medial temporal lobe epilepsy. After 19 years of surgery with no epileptic attacks, the patient developed SRSE. Electroencephalogram (EEG) demonstrated persistence of lateralized periodic discharges in the left frontotemporal region. On the 20^th day after SRSE onset, resection of the frontal lobe and temporal lobe posterior to the resection cavity was performed. Patient 2: A 62-year-old man underwent craniotomy for anaplastic astrocytoma in the left frontal lobe at the age of 34 years. Since the age of 60 years, he developed SRSE 3 times over 1 and 1/12 years. On EEG, repeated ictal discharges were observed at the medial part of the left frontal region during the three SRSEs. Corresponding to the ictal EEG findings, high signals on diffusion-weighted magnetic resonance images and focal hypermetabolism on fluorodeoxyglucose-positron emission tomography were observed around the supplementary motor area, medial to the resection cavity. Resection surgery of the area was performed during the interictal period.

Conclusion:

Good seizure outcome was obtained in the two cases which provide additional support for the recent concept of focal resection surgery as an indication for SRSE.

Chinese expert recommendations on ketogenic diet therapy for super-refractory status epilepticus

Super-refractory status epilepticus (SRSE) is a serious and life-threatening neurological condition. Ketogenic diet (KD) is a diet characterized by high fat, low carbohydrate, and moderate protein. As KD shows effectiveness in controlling seizures in more than half of SRSE patients, it can be a treatment option for SRSE. Currently, KD treatment for SRSE is based on personal experience and observational evidence has been published. In the context of a lack of a validated guideline, we convened a multicenter expert panel within the China Association Against Epilepsy (CAAE) Ketogenic Diet Commission to work out the Chinese expert recommendations on KD for SRSE. We summarize and discuss the latest clinical practice of KD for SRSE in critical care settings. Recommendations are given on patient selection, the timing of KD, diet implementation, and follow-up. More research data are needed in this area to support better clinical practice.

Animal Models of Epilepsy: A Phenotype-oriented Review

Epilepsy is a serious neurological disorder characterized by abnormal, recurrent, and synchronous discharges in the brain. Long-term recurrent seizure attacks can cause serious damage to brain function, which is usually observed in patients with temporal lobe epilepsy. Controlling seizure attacks is vital for the treatment and prognosis of epilepsy. Animal models, such as the kindling model, which was the most widely used model in the past, allow the understanding of the potential epileptogenic mechanisms and selection of antiepileptic drugs. In recent years, various animal models of epilepsy have been established to mimic different seizure types, without clear merits and demerits. Accordingly, this review provides a summary of the views mentioned above, aiming to provide a reference for animal model selection.

Neurological and Neurodegenerative Disorders: Novel Concepts and Treatment

The journal "Aging and Disease" has released a special issue focused on novel concepts in understanding the pathophysiology and treatment of neurological and neurodegenerative disorders. The special issue comprises review and original research articles discussing the various disease mechanisms and/or treatment updates on aging, mild cognitive impairment, dementia, acute stroke, pediatric stroke, super-refractory status epilepticus, reflex epilepsy, drug-resistant epilepsy, Parkinson's disease, and traumatic brain injury. This editorial discusses the highlights from these articles.