Treatment of Super-Refractory Status Epilepticus: A Review

Diagnostics and Non-pharmacological interventions for refractory and super refractory status epilepticus in Germany: A comprehensive analysis of 4 years of billing data

BACKGROUND

Status epilepticus (SE) is a critical neurological emergency, with its most severe form, refractory status epilepticus (RSE) and super-refractory status epilepticus (SRSE), posing significant treatment challenges and high mortality rates. Despite robust early-phase treatment evidence, effective management of RSE and SRSE remains less defined.

OBJECTIVE

This study aimed to assess the incidence of potential RSE and SRSE in Germany from 2019 to 2022, evaluate diagnostic and non-pharmacological interventions, and analyze associated healthcare costs.

METHODS

A cross-sectional retrospective analysis was conducted using data from the Institute for the Hospital Remuneration System (InEK). Cases were identified using ICD-10 code G41 and included patients who underwent mechanical ventilation for at least one hour. Data on demographics, diagnostic procedures, therapeutic interventions, discharge outcomes, and healthcare costs were extracted and analyzed.

RESULTS

Between 2019 and 2022, 89,921 SE cases were identified, with 21,729 (24.2 %) progressing to potential RSE or SRSE. Male patients comprised 56 % of these cases. The majority of cases occurred in patients aged 65-74 years. The overall mortality or hospice transfer rate for potential RSE/SRSE cases was 33.7 %. Common diagnostic procedures included EEG (80 %) and CT scans (113 %), while non-pharmacological interventions such as hypothermia therapy were used in 10 % of cases, and plasmapheresis was employed in 1 %. Electroconvulsive therapy, vagus nerve stimulation, deep brain stimulation, transcranial magnetic stimulation, ketogenic diet, resection of foreign tissue from the brain, and epilepsy surgery were not performed at all. 4 % of the patients who died in the hospital or were discharged to a hospice received interventions in a palliative care setting. The total estimated cost for potential RSE/SRSE cases in 2022 was approximately €44.24 million, highlighting the economic burden on the healthcare system.

CONCLUSION

The study underscores the need for improved diagnostic and therapeutic strategies in managing RSE and SRSE. It also calls for exploration of non-pharmacological treatments to reduce the high mortality and economic costs associated with these conditions. Further research is essential to establish evidence-based protocols for RSE and SRSE management.

Enteral topiramate treatment in refractory status epilepticus

OBJECTIVE

Refractory status epilepticus (RSE) is defined as persistent seizure activity despite first- and second-line antiepileptic medications (ASMs). Although benzodiazepines and a range of iv ASMs are available, mortality is 3-4 times higher than in those without RSE. Topiramate (TPM), a broad-spectrum ASM, may have neuroprotective, anti-inflammatory, and mitigating effects on neuronal injury. We aimed to investigate the efficacy of TPM and mortality in RSE.

METHODS

This retrospective, multicentre study was conducted on RSE ≥ 18 years of age in six different universities and state hospitals in Ankara and Istanbul, Turkey. Demographic data, seizure classification and etiology were analyzed. TPM was loaded and a maintenance dose was scheduled. The outcomes, prognoses, comorbidities were analysed. The effectiveness of TPM and mortality rates of the patients were also analyzed.

RESULTS

The study includes 60 patients with a mean age of 51.6 (±20, 20-84) years, 46.7 % were women. The patients were classified as having convulsive SE or nonconvulsive SE. TPM was performed as median third order ASM. The loading dose varied between 200 and 500 mg bid. The dose was subsequently reduced and maintained at 100-200 mg/day. There were 6 patients in whom TPM could not be continued due to adverse effects. TPM was considered successful in 22 patients, possibly successful in 23 patients and unsuccessful in 15 patients. Thirty-three patients were discharged from hospital, 8 were transferred to a rehabilitation center, 4 were transferred to a palliative care center and 13 died. There was no effect of age, gender, whether intubation was performed or not, etiologic classification, SE type (convulsive or nonconvulsive), duration of TPM administration, TPM loading dose on TPM success. Patients with RSE who were successfully treated with TPM had shorter hospital stays. The mortality predicting variables were determined as older age, not having epilepsy, failure to terminate RSE and acute symptomatic etiology.

SIGNIFICANCE

This observational, multicenter study indicates that enteral TPM therapy is well tolerated, has a favorable safety profile, and is effective in patients with RSE. This is the first study in the literature to end SE with both high and low dose oral TPM treatment.

Cerebrospinal fluid and serum cytokine profiles in severe viral encephalitis with implications for refractory status epilepticus: a retrospective observational study

Background

To identify new intervention targets, we explored the correlation between cytokines and the development of refractory status epilepticus (RSE) in patients with severe viral encephalitis (SVE).

Methods

We examined the characteristics of 14 cytokines in the cerebrospinal fluid (CSF) and serum, analyzing their correlation with acute symptomatic seizures and prognosis. Furthermore, we conducted a dynamic analysis of differences and correlations in the expression of cytokines among patients with SVE without seizures, those with controlled seizures, and those with RSE.

Results

We included 161 patients with SVE; the incidence of seizures was 55.2%, and the mortality rate was 5.5%. Notably, 18.9% of these patients developed RSE, with a mortality rate of 20%. During the early stage of SVE, CSF interleukin (IL)-6 and IL-8 levels were significantly higher, declining over time and affecting the prognosis. CSF IL-6 and IL-8 levels were significantly elevated in the RSE group compared to patients without seizures and with controlled seizures, decreasing gradually and independently of serum cytokine levels. CSF IL-8 and age were independent risk factors for RSE, with clinical utility.

Conclusions

Patients with SVE exhibit intrathecal cytokine storms, primarily characterized by elevated levels of IL-6 and IL-8, which influence prognosis. The strong and persistent hyperinflammation underscored by CSF IL-6 and IL-8 is associated with the occurrence and development of RSE; thus, CSF IL-8 and age are independent risk factors for SVE with RSE, indicating potential anti-inflammatory intervention targets.

First Seizures, Acute Repetitive Seizures, and Status Epilepticus

OBJECTIVE

This article provides current evidence on how and when to treat unprovoked first seizures in children and adults, guides intervention with appropriate doses and types of modern and effective therapies for acute repetitive (cluster) seizures, and reviews evidence for the diagnosis and management of established, refractory and super-refractory status epilepticus.

LATEST DEVELOPMENTS

Artificial intelligence shows promise as a clinical assistant in decision making after a first seizure. For nonanoxic convulsive refractory status epilepticus third-phase treatment, equipoise exists regarding whether it is better to add a second IV nonsedating antiseizure medication given via loading dose (eg, brivaracetam, lacosamide, levetiracetam, fosphenytoin or valproic acid) or to start an anesthetizing continuous IV infusion antiseizure medication such as ketamine, midazolam, propofol or pentobarbital.

ESSENTIAL POINTS

After a first seizure, the risk of a second seizure is about 36% at 2 years and 46% after 5 years. The risk is doubled in the presence of EEG epileptiform discharges, a brain imaging abnormality, a nocturnal first seizure, or prior brain trauma. For acute repetitive seizures, providers should give a proper dose of benzodiazepines based on the patient's weight and needs. First-phase treatment for convulsive established status epilepticus is the immediate administration of full doses of benzodiazepines. Second-phase treatment for convulsive established status epilepticus is a full loading dose of IV fosphenytoin, levetiracetam, valproic acid, or if necessary, phenobarbital.

Japanese guidelines for treatment of pediatric status epilepticus - 2023

The updated definition of status epilepticus (SE) by the International League Against Epilepsy in 2015 included two critical time points (t1: at which the seizure should be regarded as an "abnormally prolonged seizure"; and t2: beyond which the ongoing seizure activity can pose risk of long-term consequences) to aid in diagnosis and management and highlights the importance of early treatment of SE more clearly than ever before. Although Japan has witnessed an increasing number of pre-hospital drug treatment as well as first- and second-line treatments, clinical issues have emerged regarding which drugs are appropriate. To address these clinical concerns, a revised version of the "Japanese Guidelines for the Treatment of Pediatric Status Epilepticus 2023" (GL2023) was published. For pre-hospital treatment, buccal midazolam is recommended. For in-hospital treatment, if an intravenous route is unobtainable, buccal midazolam is also recommended. If an intravenous route can be obtained, intravenous benzodiazepines such as midazolam, lorazepam, and diazepam are recommended. However, the rates of seizure cessation were reported to be the same among the three drugs, but respiratory depression was less frequent with lorazepam than with diazepam. For established SE, phenytoin/fosphenytoin and phenobarbital can be used for pediatric SE, and levetiracetam can be used in only adults in Japan. Coma therapy is recommended for refractory SE, with no recommended treatment for super-refractory SE. GL2023 lacks adequate recommendations for the treatment of nonconvulsive status epilepticus (NCSE). Although electrographic seizure and electrographic SE may lead to brain damages, it remains unclear whether treatment of NCSE improves outcomes in children. We plan to address this issue in an upcoming edition of the guideline.

Development of a nomogram model for early prediction of refractory convulsive status epilepticus

INTRODUCTION

We aim to identify risk factors that predict refractory convulsive status epilepticus (RCSE) and to develop a model for early recognition of patients at high risk for RCSE.

METHODS

This study involved 200 patients diagnosed with convulsive status epilepticus (CSE), of whom 73 were RCSE and 127 were non-RCSE. Variables included demographic information, lifestyle factors, medical history, comorbidities, clinical symptoms, neuroimaging characteristics, laboratory tests, and nutritional scores. A predictive model was developed through multivariable logistic regression analysis. The model's predictive performance and clinical utility were evaluated using various metrics, including the area under the receiver operating characteristic (AUROC) curve, GiViTI calibration belt, and decision curve analysis (DCA). Additionally, we performed internal five-fold cross-validation for this model.

RESULTS

We developed a nomogram model with six predictors: age ≤ 40 years, prior history of epilepsy, presence of epileptic foci, duration of CSE > 30 min, c-reactive protein > 6 mg/L, and nutritional risk screening ≥ 3 points. Our model has a high AUROC (0.838) and good consistency (P = 0.999). In DCA, the curve of our model exhibits a positive net benefit across the entire range of threshold probabilities. Moreover, our model achieved an accuracy of 0.778 and a Kappa value of 0.519 in the five-fold cross-validation.

CONCLUSION

We developed an objective, simple and accessible model to assess the risk of RCSE. This model shows promise as a valuable tool for evaluating the individual risk of RCSE.

Treatment of convulsive status epilepticus in Brazil: a review

Status epilepticus (SE) is the most severe presentation of epilepsy. Currently, SE is defined according to 2 sequential time frames: time 1, after which it is unlikely that the seizure will resolve spontaneously, therefore requiring the initiation of therapy; and time 2, when long-term consequences become more likely. For convulsive SE, these time frames are well defined: 5 minutes for time 1 and 30 minutes for time 2. "Time is brain" in the treatment of SE, as delays in diagnosis and treatment are associated with worse outcomes. After clinical stabilization, the first step is the administration of intravenous (IV) benzodiazepines. Rapid initiation of treatment and use of appropriate dosing are more important than the selection of a specific benzodiazepine. Following this, treatment continues with the use of an IV antiseizure medication (ASM). In Brazil, the recommended options available are phenytoin and levetiracetam. Status epilepticus is considered refractory to treatment if seizures persist after the administration of benzodiazepines and IV ASM. The cornerstone of this stage is the induction of therapeutic coma using IV anesthetic drugs (IVADs), although evidence is limited regarding the choice among midazolam, propofol, or barbiturates. Super-refractory SE is defined when seizures persist despite continuous infusion of IVADs or recur after these drugs are tapered. There is very limited data regarding the treatment of super-refractory SE. In the absence of randomized controlled trials, treatment should be guided by the physician's experience, clinical judgment, and established therapeutic options from previous reports.

Effectiveness of Highly Purified Cannabidiol in Refractory and Super-Refractory Status Epilepticus: A Case Series

INTRODUCTION

Refractory and super-refractory status epilepticus are medical emergencies that must be promptly treated in consideration of their high mortality and morbidity rate. Nevertheless, the available evidence of effective treatment for these conditions is scarce. Among novel antiseizure medications (ASMs), highly purified cannabidiol (hpCBD) has shown noteworthy efficacy in reducing seizures in Lennox-Gastaut syndrome, Dravet syndrome, and Tuberous Sclerosis Complex.

CASE PRESENTATION

Here, we present two cases of effective use of hpCBD in both refractory and super- refractory status epilepticus. The administration of the nasogastric tube permitted the resolution of status epilepticus without adverse events. At 6-month follow-up, both patients were on hpCBD treatment, which continued to be efficacious for treating seizures.

CONCLUSION

According to our experience, hpCBD should be taken into consideration as an add-on therapy of RSE and SRSE while also considering the possibility of maintaining this treatment during the follow-up of patients. However, more studies and real-world experiences are needed to better understand its effectiveness in this setting and the interaction with other ASMs.

Myelin oligodendrocyte glycoprotein antibody-associated cerebral cortical encephalitis with super-refractory status epilepticus

BACKGROUND

Seizures are commonly reported in patients with myelin oligodendrocyte glycoprotein antibody-associated cerebral cortical encephalitis (MOG-CCE). However, seizure management during the acute phase has not been established.

CASE REPORT

A 9-year-old previously healthy boy presented with fever persisting for approximately 6 days, along with headache and altered consciousness. Plain T2-weighted and fluid-attenuated inversion recovery imaging showed swelling and abnormal hyperintense lesions in the bilateral frontal, parietal, temporal, and insular cortices with left hemisphere predominance. Consciousness disturbance persisted, and focal myoclonic seizures clustered hourly. Seizures were arrested by titrating the thiopental dose but recurred with dose reduction, and the patient exhibited super refractory status epilepticus. Adverse effects due to long-term use of thiopental became apparent. Hence, continuous infusion of ketamine and intrathecal dexamethasone therapy (IT-DEX) was started. After administration of ketamine and IT-DEX, his seizure was arrested promptly. The cerebrospinal fluid and serum at the time of transfer were clear positive for ani-MOG antibody; therefore, the patient was diagnosed with MOG-CCE. The patient received three courses of intravenous methylprednisolone pulse therapy, followed by oral prednisolone gradually tapered over 6 months. He did not experience any relapse for 6 months.

CONCLUSION

In MOG-CCE, some cases may present with super-refractory status epilepticus (SRSE) in the acute phase and be refractory to anti-seizure medication, analogous to febrile infection-related epilepsy syndrome. IT-DEX and continuous infusion ketamine are useful for seizure control in MOG-CCE.

The Fundamentals of Antiseizure Medications: A Through Z

Since bromides were first used in 1857 to treat epilepsy, numerous antiseizure medications (ASM) have been developed. Many of these are available for the treatment of epilepsy and status epilepticus today. With so many ASM available, questions arise as to whether all of these medications are needed and when should they be used. As precision medicine begins to play a larger role in determining targeted treatments for specific types of epilepsy, a complete understanding of various medications is needed. Additionally, access to several of these medications can be limited in the United States and are especially limited globally. All these factors can make proper selection of ASM challenging and difficult for clinicians. This review highlights important aspects of older and newer medications, developments in precision medicine for epilepsy, increasing understanding of effective treatments for status epileptics, and a global perspective on ASM availability.

Super Refractory Status Epilepticus Improved After Emergency Use of Ganaxolone: Case Report

We present a case of a 34-year-old man with epilepsy who developed super refractory status epilepticus in the setting of COVID-19 pneumonia in whom aggressive therapy with multiple parenteral, enteral, and non-pharmacologic interventions were utilized without lasting improvement in clinical examination or electroencephalogram (EEG). The patient presented with multiple recurrences of electrographic status epilepticus throughout a prolonged hospital stay. Emergency use authorization was obtained for intravenous ganaxolone, a neuroactive steroid that is a potent modulator of both synaptic and extrasynaptic GABAA receptors. Following administration of intravenous ganaxolone according to a novel dosing paradigm, the patient showed sustained clinical and electrographic improvement.

Use of perampanel oral suspension for the treatment of refractory and super-refractory status epilepticus

INTRODUCTION

Status epilepticus (SE) is a medical emergency associated with a significant risk of disability and death. The treatment of SE follows a step-wise approach, with limited data on ideal antiseizure medications (ASMs) for refractory and super refractory SE (RSE/SRSE). Perampanel (PER), an AMPA receptor antagonist, has shown promise in animal models but still has limited data in humans. This study tried to evaluate optimal dosage and safety of PER in RSE and SRSE patients.

MATERIALS AND METHODS

We retrospectively analysed 17 adult patients with RSE (1) or SRSE (16) treated with PER. Demographic and clinical data, including EEG patterns, ASMs administered, PER dosages, and PER plasma concentrations, were collected. For patients receiving a 24 mg PER loading dose (full dose group), the following treatment regimen was applied: 24 mg per day for 48 h following by 16 mg per day. The response to PER was assessed based on electroencephalographic (EEG) improvement from high to low epileptiform activity or from low to the absence of epileptiform activities. Safety was evaluated monitoring hepatic and renal function.

RESULTS

A response rate of 58.82 % was observed, with significantly higher responses in the full dose group (81.82 %) compared to those receiving PER doses below 24 mg (low dose group) (16.67 %) (p-value = 0.004; OR 0.044, 95 % CI 0.003 to 0.621, p = 0.021). No other clinical factors significantly influenced treatment response. Hepatic enzymes become elevated in most patients (70.59 %) but spontaneously decreased.

DISCUSSION

Our findings suggest that a 24 mg PER dose administered for 48 h may be more effective in managing RSE and SRSE compared to doses below 24 mg, potentially due to pharmacokinetic factors.

CONCLUSION

More robust data on PER in RSE and SRSE, including standardized dosing procedures and plasma level monitoring are needed. PER's potential benefits should be explored further, particularly in patients with RSE and SRSE.

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.

Try, Try Again: Success Rates After Continued Treatment Attempts in Refractory Status Epilepticus

Staged Treatment Response in Status Epilepticus: Lessons From the SENSE Registry Beuchat I, Novy J, Rosenow F, Kellinghaus C, Rüegg S, Tilz C, Trinka E, Unterberger I, Uzelac Z, Strzelczyk A, Rossetti AO. Epilepsia . 2023. doi:10.1111/epi.17817 Objectives: Although in epilepsy patients the likelihood of becoming seizure-free decreases substantially with each unsuccessful treatment, to our knowledge this has been poorly investigated in status epilepticus (SE). We aimed to evaluate the proportion of SE cessation and functional outcome after successive treatment steps. Methods: We conducted a post-hoc analysis of a prospective, observational, multicenter cohort (SENSE), in which 1049 incident adult SE episodes were prospectively recorded at 9 European centers. We analyzed 996 SE episodes without coma-induction before the third treatment step. Rates of SE cessation, mortality (in ongoing SE or after SE control), and favorable functional outcome (assessed with modified Rankin Scale) were evaluated after each step. Results: SE was successfully treated in 838 (84.1%) patients, 147 (14.8%) had a fatal outcome (36% of them died while still in SE), and 11 patients were transferred to palliative care while still in SE. Patients were treated with a median of three treatment steps (range 1-13) with 540 (54.2%) receiving more than two steps (refractory SE, RSE) and 95 (9.5%) more than five. SE was controlled after the first two steps in 45%, with additional 21% treated after the third, and 14% after the fourth step. Likelihood of SE cessation (p < 0.001), survival (p = 0.003), and reaching good functional outcome (p < 0.001) significantly decreased between the first two treatment lines and the third, especially in patients not experiencing convulsive generalized SE, but remained relatively stable afterwards. Significance: The significant worsening of SE prognosis after the second step clinically supports the concept of RSE. However, and differing from findings in human epilepsy, RSE remains treatable in around one third of patients even after several failed treatment steps. Clinical judgement remains essential to determine the aggressiveness and duration of SE treatment and avoid premature treatment cessation in SE patients.

Ketamine in the treatment of refractory and super-refractory status epilepticus: Experience from two centres

PURPOSE

There is insufficient evidence on the management of refractory status epilepticus (RSE) and super-RSE (SRSE). Ketamine is a N-methyl-d-aspartate receptor antagonist in the treatment of these entities. Our objectives were to study the effectiveness and safety of ketamine in the treatment of adult patients with RSE and SRSE, to determine the factors that can influence the response to ketamine, and to explore its use in patients without mechanical ventilation.

METHODS

Adult patients who had received intravenous ketamine for the treatment of RSE or SRSE at Hospital Universitario Clínico San Carlos (Madrid, Spain) or Hospital Universitari Vall d'Hebron (Barcelona, Spain) from 2017 to 2023 were retrospectively analysed.

RESULTS

This study included 58 adult patients, mean (standard deviation) age 60.2 (15.7) years, of whom 41 (70.7 %) were male; 33 (56.9 %) patients responded to ketamine without recurrence, with a low rate of adverse effects (8.6 %). The presence of SRSE at the time of ketamine initiation (OR 0.287, p = 0.028) and the time elapsed between status epilepticus onset and ketamine administration (OR 0.991, p = 0.034) were associated with worse response to ketamine. Patients treated without mechanical ventilation had similar rates of response without recurrence (62.5% vs 56.9 %) and lower mortality (37.5% vs 53.5 %) compared to the overall group.

CONCLUSION

Ketamine is an effective drug with few adverse effects. Prompt administration should be considered in patients with RSE requiring anaesthesia, in patients with SRSE, and in patients with RSE who do not respond to standard antiseizure drugs and in whom mechanical ventilation is not advised.

Hydrogen treatment reduces electroencephalographic activity and neuronal death in rats with refractory status epilepticus by inhibiting membrane NR2B phosphorylation and oxidative stress

OBJECTIVE

To investigate the effects of hydrogen therapy on epileptic seizures in rats with refractory status epilepticus and the underlying mechanisms.

METHODS

Status epilepticus was induced using pilocarpine. The effects of hydrogen treatment on epilepsy severity in model rats were then monitored using Racine scores and electroencephalography (EEG), followed by western blot of plasma membrane N-methyl-D-aspartate receptor subtype 2B (NR2B) and phosphorylated NR2B expression. We also generated a cellular epilepsy model using Mg2+-free medium and used polymerase chain reaction to investigate the neuroprotective effects of hydrogen.

RESULTS

There were no significant differences in Racine scores between the hydrogen and control groups. EEG amplitudes were lower in the hydrogen treatment group than in the control group. In epilepsy model rats, hippocampal cell membrane NR2B expression and phosphorylation increased gradually over time. Although hippocampal cell membrane NR2B expression was not significantly different between the two groups, NR2B phosphorylation levels were significantly lower in the hydrogen group. Hydrogen treatment also increased superoxide dismutase, mitochondrial (SOD2) expression.

CONCLUSIONS

Hydrogen treatment reduced EEG amplitudes and NR2B phosphorylation; it also decreased neuronal death by reducing oxidative stress. Hydrogen may thus be a potential treatment for refractory status epilepticus by inhibiting membrane NR2B phosphorylation and oxidative stress.

Role of Vagus Nerve Stimulation in Refractory and Super Refractory Status Epilepticus: A Pediatric Case Series

BACKGROUND

Status epilepticus is a life-threatening condition that is defined as refractory (RSE) when the seizure activity continues despite treatment with benzodiazepine and a second appropriate treatment. Super refractory status epilepticus (SRSE) is an RSE that persists or recurs for ≥24 h. Few papers have reported the outcomes of pediatric patients affected by RSE and SRSE and treated with neuromodulation therapies. Vagus nerve stimulation (VNS) is an approved treatment for drug-resistant epilepsy. We present our findings of pediatric patients treated with VNS for RSE/SRSE.

METHODS

We present a case series of seven consecutive pediatric patients treated with VNS for SRSE since 2012 by a single surgeon in Monza and Padua. A rapid titration was started soon after implantation. We considered electroclinical data before and after VNS implantation and at the last follow-up.

RESULTS

We achieved the resolution of SRSE in five out of seven patients in a mean time of two weeks. At the last follow-up, these patients had a significant reduction of seizure burden without any relapse of SE.

DISCUSSION AND CONCLUSIONS

Based on our limited findings, we discuss the potential role of VNS therapy in similar but distinct clinical contexts. For patients with drug-resistant epilepsy and RSE/SRSE, prompt VNS consideration is suggested, offering rapid responses and potentially reducing pharmacological load. Meanwhile, in NORSE/FIRES, we suggest early neuromodulation during the acute phase if standard treatments prove ineffective or not tolerated. This approach may leverage VNS's potential anti-inflammatory effects and neuromodulation, enhancing patient-specific treatments. Expanding case studies and prolonged follow-ups are recommended to strengthen these clinical insights.

Effect of vagus nerve stimulation against generalized seizure and status epilepticus recurrence

Objective

Vagus nerve stimulation (VNS) is a palliative surgery for drug-resistant epilepsy. The two objectives of this study were to (1) determine the seizure type most responsive to VNS and (2) investigate the preventive effect on status epilepticus (SE) recurrence.

Methods

We retrospectively reviewed 136 patients with drug-resistant epilepsy who underwent VNS implantation. We examined seizure outcomes at 6, 12, and 24 months following implantation of VNS as well as at the last visit to the Juntendo Epilepsy Center. Univariate analysis and multivariate logistic regression models were used to estimate the prognostic factors.

Results

125 patients were followed up for at least 1 year after VNS implantation. The percentage of patients with at least a 50% reduction in seizure frequency compared with prior to VNS implantation increased over time at 6, 12, and 24 months after VNS implantation: 28, 41, and 52%, respectively. Regarding overall seizure outcomes, 70 (56%) patients responded to VNS. Of the 40 patients with a history of SE prior to VNS implantation, 27 (67%) showed no recurrence of SE. The duration of epilepsy, history of SE prior to VNS implantation and seizure type were correlated with seizure outcomes after VNS implantation in univariate analysis (p = 0.05, p < 0.01, and p = 0.03, respectively). In multivariate logistic regression analysis, generalized seizure was associated with VNS response [odds ratio (OR): 4.18, 95% CI: 1.13-15.5, p = 0.03]. A history of SE prior to VNS implantation was associated with VNS non-responders [(OR): 0.221, 95% CI: 0.097-0.503, p < 0.01]. The duration of epilepsy, focal to bilateral tonic-clonic seizure and epileptic spasms were not significantly associated with VNS responders (p = 0.07, p = 0.71, and p = 0.11, respectively).

Conclusion

Following 125 patients with drug-resistant epilepsy for an average of 69 months, 56% showed at least 50% reduction in seizure frequency after VNS implantation. This study suggests that generalized seizure is the most responsive to VNS, and that VNS may reduce the risk of recurrence of SE. VNS was shown to be effective against generalized seizure and also may potentially influence the risk of further events of SE, two marker of disease treatment that can lead to improved quality of life.

Lidocaine as a potential therapeutic option for super-refractory status epilepticus: A case report

New-onset refractory status epilepticus (NORSE) is a rare and devastating condition and the prognosis is often poor, with half to two-thirds of survivors experiencing drug-resistant epilepsy, residual cognitive impairment, or functional disability, and the mortality rate is 16% to 27% for adults. We describe a patient with cryptogenic NORSE and favorable recovery from drug-resistant super-refractory SE after the use of intravenous lidocaine. The patient experienced fever and presented with refractory generalized tonic-clonic seizures. The cause was not found by performing extensive examinations, including cell surface autoantibodies and rat brain immunohistochemistry evaluations. The refractory SE with unresponsiveness to multiple anti-epileptic and prolonged sedative medications, which are necessary for prolonged mechanical ventilation, were ameliorated by additive treatment with intravenous lidocaine initiating at 1 mg/kg/h and maintaining at 2 mg/kg/h for 40 days, which led to freedom from intravenous sedative medication and mechanical ventilation. The patient was able to return to school. Lidocaine may be an optional treatment for cryptogenic NORSE.

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.

Evaluating salvage electroconvulsive therapy for the treatment of prolonged super refractory status epilepticus: A case series

BACKGROUND AND OBJECTIVES

Clinicians have treated super refractory status epilepticus (SRSE) with electroconvulsive therapy (ECT); however, data supporting the practice are scant and lack rigorous evaluation of continuous electroencephalogram (cEEG) changes related to therapy. This study aims to describe a series of patients with SRSE treated at our institution with ECT and characterize cEEG changes using a blinded review process.

METHODS

We performed a single-center retrospective study of consecutive patients admitted for SRSE and treated with ECT from January 2014 to December 2022. Our primary outcome was the resolution of SRSE. Secondary outcomes included changes in ictal-interictal EEG patterns, anesthetic burden, treatment-associated adverse events, and changes in clinical examination. cEEG was reviewed pre- and post-ECT by blinded epileptologists.

RESULTS

Ten patients underwent treatment with ECT across 11 admissions (8 female, median age 57 years). At the time of ECT initiation, nine patients had ongoing SRSE while two had highly ictal patterns and persistent encephalopathy following anesthetic wean, consistent with late-stage SRSE. Super-refractory status epilepticus resolution occurred with a median time to cessation of 4 days (interquartile range [IQR]: 3-9 days) following ECT initiation. Background continuity improved in five patients and periodic discharge frequency decreased in six. There was a decrease in anesthetic use following the completion of ECT and an improvement in neurological exams. There were no associated adverse events.

DISCUSSION

In our cohort, ECT was associated with improvement of ictal-interictal patterns on EEG, and resolution of SRSE, and was not associated with serious adverse events. Further controlled studies are needed.

Pediatric Status Epilepticus: Treat Early and Avoid Delays

Pediatric convulsive status epilepticus (cSE) is a neurologic emergency with potential for morbidity and mortality. Rapid treatment and escalation of therapies to achieve early seizure control is paramount in preventing complications and providing the best patient outcomes. Although guidelines recommend early treatment, cessation of out-of-hospital SE is undermined by treatment delay and inadequate dosing. Logistical challenges include prompt seizure recognition, first-line benzodiazepine (BZD) availability, comfort and expertise in administration of BZD, and timely arrival of emergency personnel. In-hospital, SE onset is additionally impacted by delays to first- and second-line treatment and availability of resources. This review presents an evidence-based, clinically oriented review of pediatric cSE, including its definitions and treatments. It provides evidence and rationale for timely treatment of first-line BZD treatment followed by prompt escalation to second-line antiseizure medication therapies for established SE. Treatment delays and barriers to care are discussed, with practical considerations for opportunities for areas of improvement in the initial treatment of cSE.

Super-refractory status epilepticus during blinatumomab initiation for B-cell acute lymphoblastic leukemia

Seizures have been reported as an adverse effect of blinatumomab, a bispecific T-cell engager monoclonal antibody, which is mainly used for the treatment of pediatric relapsed/refractory leukemia. Here, we present the first reported case of super-refractory status epilepticus in an 11-year-old boy with B-cell acute lymphoblastic leukemia (B-ALL) while receiving blinatumomab. Our patient had a complete return to baseline despite enduring encephalopathy, refractory subclinical seizures requiring prolonged therapeutic burst suppression and MRI signal changes. This case demonstrates that super-refractory status epilepticus is a possible neurotoxic adverse effect of blinatumomab treatment, which responds well to conventional protocols for acute refractory seizures.

Super-refractory status epilepticus in adults

Introduction

Super-refractory status epilepticus (SRSE) represents the culmination of refractory status epilepticus (RSE) and carries a significant risk of poor neurological outcome and high mortality. RSE is not defined primarily by seizure duration, but by failure to respond to appropriate antiseizure treatment. SRSE is present when a RSE persists or recurs after more than 24 h of treatment with anesthetics. No evidence-based treatment algorithms can be provided for SRSE. Therefore, we propose a pragmatic standard operating procedure (SOP) for the management of SRSE that addresses the existing uncertainties in the treatment of SRSE and provides options for resolution and decision-making.

Comments

First, we recommend the assessment of persistent seizure activity and the evaluation of differential diagnoses to confirm correct diagnosis. Relevant differential diagnoses include psychogenic non-epileptic seizures, hypoxic, metabolic, or toxic encephalopathies, and tetanus. During SE or in severe encephalopathies, a so-called electroclinical ictal-interictal continuum may occur, which denotes an intermediate stage that cannot be defined with certainty as ictal or interictal by EEG and should not lead to harmful overtreatment. Because both prognosis and specific treatment options depend crucially on the etiology of SRSE, the etiological evaluation should be performed rapidly. When SRSE is confirmed, various pharmacological and non-pharmacological treatment options are available.

Conclusion

We provide a pragmatical SOP for adult people with SRSE.

Dogs as a Natural Animal Model of Epilepsy

Epilepsy is a common neurological disease in both humans and domestic dogs, making dogs an ideal translational model of epilepsy. In both species, epilepsy is a complex brain disease characterized by an enduring predisposition to generate spontaneous recurrent epileptic seizures. Furthermore, as in humans, status epilepticus is one of the more common neurological emergencies in dogs with epilepsy. In both species, epilepsy is not a single disease but a group of disorders characterized by a broad array of clinical signs, age of onset, and underlying causes. Brain imaging suggests that the limbic system, including the hippocampus and cingulate gyrus, is often affected in canine epilepsy, which could explain the high incidence of comorbid behavioral problems such as anxiety and cognitive alterations. Resistance to antiseizure medications is a significant problem in both canine and human epilepsy, so dogs can be used to study mechanisms of drug resistance and develop novel therapeutic strategies to benefit both species. Importantly, dogs are large enough to accommodate intracranial EEG and responsive neurostimulation devices designed for humans. Studies in epileptic dogs with such devices have reported ictal and interictal events that are remarkably similar to those occurring in human epilepsy. Continuous (24/7) EEG recordings in a select group of epileptic dogs for >1 year have provided a rich dataset of unprecedented length for studying seizure periodicities and developing new methods for seizure forecasting. The data presented in this review substantiate that canine epilepsy is an excellent translational model for several facets of epilepsy research. Furthermore, several techniques of inducing seizures in laboratory dogs are discussed as related to therapeutic advances. Importantly, the development of vagus nerve stimulation as a novel therapy for drug-resistant epilepsy in people was based on a series of studies in dogs with induced seizures. Dogs with naturally occurring or induced seizures provide excellent large-animal models to bridge the translational gap between rodents and humans in the development of novel therapies. Furthermore, because the dog is not only a preclinical species for human medicine but also a potential patient and pet, research on this species serves both veterinary and human medicine.

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.

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.