Intravenous Ketamine Bolus(es) for the Treatment of Status Epilepticus, Refractory Status Epilepticus, and Cluster Seizures: A Retrospective Study of 15 Dogs

Status epilepticus (SE) and cluster seizures (CS) are common occurrences in veterinary neurology and frequent reasons of admission to veterinary hospitals. With prolonged seizure activity, gamma amino-butyric acid (GABA) receptors (GABAa receptors) become inactive, leading to a state of pharmacoresistance to benzodiazepines and other GABAergic medications, which is called refractory status epilepticus (RSE). Prolonged seizure activity is also associated with overexpression of N-methyl-D-aspartic (NMDA) receptors. Rodent models have shown the efficacy of ketamine (KET) in treating RSE, and its use has been reported in one canine case of RSE. Boluses of KET 5 mg/kg IV have become the preferred treatment for RSE in our hospital. A retrospective study was performed to evaluate and report our experience with KET IV bolus to treat prolonged and/or repeated seizure activity in cases of canine CS, SE, and RSE. A total of 15 dogs were retrieved, for 20 hospitalizations and 28 KET IV injections over 3 years. KET IV boluses were used 12 times for RSE (9 generalized seizures, 3 focal seizures) and KET terminated the episode of RSE 12/12 times (100%); however, seizures recurred 4/12 times (33%) within ≤6 h of KET IV bolus. When used for CS apart from episodes of RSE, KET IV bolus was associated with termination of the CS episode only 4/14 times (29%). Only 4/28 (14%) KET IV boluses were associated with adverse effects imputable only to the use of KET. One dog experienced a short, self-limited seizure activity during administration of KET IV, which was most likely related to a pre-mature use of KET IV (i.e., before GABAergic resistance and NMDA receptor overexpression had taken place). This study indicates that KET 5 mg/kg IV bolus may be successful for the treatment of RSE in dogs.

Ketogenic diet in a patient with refractory status epilepticus due to POLG mutation

We present a 16-year-old female patient with POLG syndrome, treated with ketogenic diet after she presented with refractory status epilepticus. Initially, benefit of the ketogenic diet could be seen, but the outcome was fatal, with death 3 months after presenting symptoms. Additionally, we give a literature review of the utility of ketogenic diet in patients with POLG disease.

Refractory Status Epilepticus Responsive to Electroacupuncture at Shuigou Acupoint: A Case Report

Refractory status epilepticus (RSE) is a critical and intractable neurological emergency. Around 55% of RSE episodes still persist despite high dose of continuous infusion of anesthetics. It's a clinical urgency and challenge to search for novel alternative treatments to control RSE as soon as possible. Here, we reported a case of RSE in a 67-year-old woman with varicella-zoster virus encephalitis. She had persistent non-convulsive SE despite the continuous infusion of midazolam. On the basis of fundamental treatments, she was given electroacupuncture at Shuigou acupoint for 10 min. An immediate EEG suppression was seen after the electroacupuncture treatment and lasted for 9 min, and lasting epileptic discharges (> 10 s) and clinical seizures were not observed any more. Midazolam was withdrawn gradually 24 h later. This case report may bring an alternative treatment for RSE.

Post-COVID-19 inflammatory syndrome manifesting as refractory status epilepticus

There have been multiple descriptions of seizures during the acute infectious period in patients with COVID‐19. However, there have been no reports of status epilepticus after recovery from COVID‐19 infection. Herein, we discuss a patient with refractory status epilepticus 6 weeks after initial infection with COVID‐19. Extensive workup demonstrated elevated inflammatory markers, recurrence of a positive nasopharyngeal SARS‐CoV‐2 polymerase chain reaction, and hippocampal atrophy. Postinfectious inflammation may have triggered refractory status epilepticus in a manner similar to the multisystemic inflammatory syndrome observed in children after COVID‐19.

Treatment of Refractory Convulsive Status Epilepticus: A Comprehensive Review by the American Epilepsy Society Treatments Committee

Purpose:

Established tonic–clonic status epilepticus (SE) does not stop in one-third of patients when treated with an intravenous (IV) benzodiazepine bolus followed by a loading dose of a second antiseizure medication (ASM). These patients have refractory status epilepticus (RSE) and a high risk of morbidity and death. For patients with convulsive refractory status epilepticus (CRSE), we sought to determine the strength of evidence for 8 parenteral ASMs used as third-line treatment in stopping clinical CRSE.

Methods:

A structured literature search (MEDLINE, Embase, CENTRAL, CINAHL) was performed to identify original studies on the treatment of CRSE in children and adults using IV brivaracetam, ketamine, lacosamide, levetiracetam (LEV), midazolam (MDZ), pentobarbital (PTB; and thiopental), propofol (PRO), and valproic acid (VPA). Adrenocorticotropic hormone (ACTH), corticosteroids, intravenous immunoglobulin (IVIg), magnesium sulfate, and pyridoxine were added to determine the effectiveness in treating hard-to-control seizures in special circumstances. Studies were evaluated by predefined criteria and were classified by strength of evidence in stopping clinical CRSE (either as the last ASM added or compared to another ASM) according to the 2017 American Academy of Neurology process.

Results:

No studies exist on the use of ACTH, corticosteroids, or IVIg for the treatment of CRSE. Small series and case reports exist on the use of these agents in the treatment of RSE of suspected immune etiology, severe epileptic encephalopathies, and rare epilepsy syndromes. For adults with CRSE, insufficient evidence exists on the effectiveness of brivaracetam (level U; 4 class IV studies). For children and adults with CRSE, insufficient evidence exists on the effectiveness of ketamine (level U; 25 class IV studies). For children and adults with CRSE, it is possible that lacosamide is effective at stopping RSE (level C; 2 class III, 14 class IV studies). For children with CRSE, insufficient evidence exists that LEV and VPA are equally effective (level U, 1 class III study). For adults with CRSE, insufficient evidence exists to support the effectiveness of LEV (level U; 2 class IV studies). Magnesium sulfate may be effective in the treatment of eclampsia, but there are only case reports of its use for CRSE. For children with CRSE, insufficient evidence exists to support either that MDZ and diazepam infusions are equally effective (level U; 1 class III study) or that MDZ infusion and PTB are equally effective (level U; 1 class III study). For adults with CRSE, insufficient evidence exists to support either that MDZ infusion and PRO are equally effective (level U; 1 class III study) or that low-dose and high-dose MDZ infusions are equally effective (level U; 1 class III study). For children and adults with CRSE, insufficient evidence exists to support that MDZ is effective as the last drug added (level U; 29 class IV studies). For adults with CRSE, insufficient evidence exists to support that PTB and PRO are equally effective (level U; 1 class III study). For adults and children with CRSE, insufficient evidence exists to support that PTB is effective as the last ASM added (level U; 42 class IV studies). For CRSE, insufficient evidence exists to support that PRO is effective as the last ASM used (level U; 26 class IV studies). No pediatric-only studies exist on the use of PRO for CRSE, and many guidelines do not recommend its use in children aged <16 years. Pyridoxine-dependent and pyridoxine-responsive epilepsies should be considered in children presenting between birth and age 3 years with refractory seizures and no imaging lesion or other acquired cause of seizures. For children with CRSE, insufficient evidence exists that VPA and diazepam infusion are equally effective (level U, 1 class III study). No class I to III studies have been reported in adults treated with VPA for CRSE. In comparison, for children and adults with established convulsive SE (ie, not RSE), after an initial benzodiazepine, it is likely that loading doses of LEV 60 mg/kg, VPA 40 mg/kg, and fosphenytoin 20 mg PE/kg are equally effective at stopping SE (level B, 1 class I study).

Conclusions:

Mostly insufficient evidence exists on the efficacy of stopping clinical CRSE using brivaracetam, lacosamide, LEV, valproate, ketamine, MDZ, PTB, and PRO either as the last ASM or compared to others of these drugs. Adrenocorticotropic hormone, IVIg, corticosteroids, magnesium sulfate, and pyridoxine have been used in special situations but have not been studied for CRSE. For the treatment of established convulsive SE (ie, not RSE), LEV, VPA, and fosphenytoin are likely equally effective, but whether this is also true for CRSE is unknown. Triple-masked, randomized controlled trials are needed to compare the effectiveness of parenteral anesthetizing and nonanesthetizing ASMs in the treatment of CRSE.

FARS2 Mutations: More Than Two Phenotypes? A Case Report

FARS2, a nuclear gene, encodes the mitochondrial phenylalanyl-tRNA synthetase (mtPheRS). Previous reports have described two distinct phenotypes linked to FARS2 gene mutation: an early onset epileptic encephalopathy and spastic paraplegia. This report describes a distinctive phenotype of FARS2-linked, juvenile onset refractory epilepsy, caused by a hemizygous mutation in a compound heterozygous state (p.V197M and exon 2 microdeletion). A 17-year- old woman with normal development presented with a super refractory focal motor status epilepticus. Only an emergency life-saving surgery aborted her status after all therapeutic interventions, including anesthesia, failed to control her seizures. Pathological and biochemical activities on muscle biopsy showed mitochondrial proliferation with enhanced isolated activities of complexes II and IV, suggestive of a compensatory mechanism for the bioenergetic deficiency. Postoperatively, the patient started experiencing focal aware motor seizures originating from the contralateral hemisphere after being seizure free for a few months. This report suggests a third phenotypic manifestation of FARS2 gene mutation.

Predictors of outcome in refractory generalized convulsive status epilepticus

Objective

Refractory status epilepticus is a serious condition in which seizure continues despite use of two antiepileptic medications. Retrospective studies have shown that 29%‐43% of SE patients progress into RSE despite treatment. Mortality following RSE is high. We aimed to evaluate the predictors of outcome in patients with RSE at a tertiary care center.

Methods

Sixty‐eight consecutive patients with RSE who presented to our hospital between February 2018 and January 2020 were evaluated for outcome.

Result

In our study 28(41.2%), patients who failed to respond to first‐ and second‐line antiepileptic drug responded to the third‐line antiepileptic drug thus avoiding mechanical ventilation and intravenous anesthesia. Low GCS at admission (P < .001), need for mechanical ventilation and intravenous anesthesia (P = .018), and long duration of RSE before recovery (P = .035) were strongly associated with worse outcome. Duration of RSE before starting treatment (P = .147), previous history of seizure (P = .717), and age of the patient (P = .319) did not influence the outcome.

Significance

In our study, we prospectively evaluated patients with RSE and followed them for one month after discharge from the hospital. Unlike some of the previous studies, we identified an interesting finding whereby a significant proportion of the patients responded to the third‐line antiepileptic drug and thus avoiding the complications related to mechanical ventilation.

The Epileptor Model: A Systematic Mathematical Analysis Linked to the Dynamics of Seizures, Refractory Status Epilepticus, and Depolarization Block

One characteristic of epilepsy is the variety of mechanisms leading to the epileptic state, which are still largely unknown. Refractory status epilepticus (RSE) and depolarization block (DB) are other pathological brain activities linked to epilepsy, whose patterns are different and whose mechanisms remain poorly understood. In epileptogenic network modeling, the Epileptor is a generic phenomenological model that has been recently developed to describe the dynamics of seizures. Here, we performed a detailed qualitative analysis of the Epileptor model based on dynamical systems theory and bifurcation analysis, and investigate the dynamic evolution of "normal" activity toward seizures and to the pathological RSE and DB states. The mechanisms of the transition between states are called bifurcations. Our detailed analysis demonstrates that the generic model undergoes different bifurcation types at seizure offset, when varying some selected parameters. We show that the pathological and normal activities can coexist within the same model under some conditions, and demonstrate that there are many pathways leading to and away from these activities. We here archive systematically all behaviors and dynamic regimes of the Epileptor model to serve as a resource in the development of patient-specific brain network models, and more generally in epilepsy research.

Delayed midazolam dose effects against soman in male and female plasma carboxylesterase knockout mice

Chemical warfare nerve agent exposure leads to status epilepticus that may progress to epileptogenesis and severe brain pathology when benzodiazepine treatment is delayed. We evaluated the dose-response effects of delayed midazolam (MDZ) on toxicity induced by soman (GD) in the plasma carboxylesterase knockout (Es1^-/- ) mouse, which, similar to humans, lacks plasma carboxylesterase. Initially, we compared the median lethal dose (LD₅₀ ) of GD exposure in female Es1^-/- mice across estrous with male mice and observed a greater LD₅₀ during estrus compared with proestrus or with males. Subsequently, male and female GD-exposed Es1^-/- mice treated with a dose range of MDZ 40 min after seizure onset were evaluated for survivability, seizure activity, and epileptogenesis. GD-induced neuronal loss and microglial activation were evaluated 2 weeks after exposure. Similar to our previous observations in rats, delayed treatment with MDZ dose-dependently increased survival and reduced seizure severity in GD-exposed mice, but was unable to prevent epileptogenesis, neuronal loss, or gliosis. These results suggest that MDZ is beneficial against GD exposure, even when treatment is delayed, but that adjunct therapies to enhance protection need to be identified. The Es1^-/- mouse GD exposure model may be useful to screen for improved medical countermeasures against nerve agent exposure.

Factors affecting mortality of refractory status epilepticus

OBJECTIVE

The aim of this study was to determine the factors affecting the mortality of refractory status epilepticus (RSE) in comparison with non-refractory status epilepticus (non-RSE).

MATERIAL-METHOD

Included in this retrospective study were 109 status epilepticus cases who were hospitalized in the neurological intensive care unit Katip Celebi University. Fifty-two were RSE and 57 were non-RSE. All clinical data were gathered from the hospital archives. Factors which may cause mortality were categorized for statistical analysis.

RESULTS

While elderly age, continuous clinical seizure activity, absence of former seizure, infection, prolonged stay of ICU, anesthesia, and cardiac comorbidity were significantly related to mortality in the RSE subgroup, potentially fatal accompanying diseases were significantly related to mortality in the non-RSE subgroup. No significant relationship was found between mortality and refractoriness. Multivariate analysis revealed that a Glasgow Coma Score (GCS) at presentation of 8 or lower was the independent predictor of mortality both in the general SE population (P = .017) and in the RSE subgroup (P = .007). Intubation (P = .011) and hypotension (P = .011) were the other independent predictors of mortality in the general SE population. No independent predictor of mortality was detected in the non-RSE subgroup.

DISCUSSION/CONCLUSION

Intubation, hypotension, and a low GCS at presentation could be the main factors which could alert clinicians of an increased risk of mortality in SE patients. Although non-RSE and RSE had similar rates of mortality in the ICU, the mortality-related factors of SE vary in the RSE and the non-RSE subgroups.

Clinical Approach to Autoimmune Epilepsy

Autoimmune epilepsy is a newly emerging area of epilepsy. The concept of “autoimmune” as an etiology has recently been revisited thanks to advances in autoimmune encephalitis and precision medicine with immunotherapies. Autoimmune epilepsy presents with specific clinical manifestations, and various diagnostic approaches including cerebrospinal fluid analysis, neuroimaging, and autoantibody tests are essential for its differential diagnosis. The diagnosis is often indeterminate despite performing a thorough evaluation, and therefore empirical immunotherapy may be applied according to the judgment of the clinician. Autoimmune epilepsy often manifests as new-onset refractory status epilepticus (NORSE). A patient classified as NORSE should receive empirical immunotherapy as soon as possible. On the other hand, a morecautious, stepwise approach is recommended for autoimmune epilepsy that presents with episodic events. The type of autoimmune epilepsy is also an important factor to consider when choosing from among various immunotherapy options. Clinicians should additionally take the characteristics of antiepileptic drugs into account when using them as an adjuvant therapy. This expert opinion discusses the diagnostic and treatment approaches for autoimmune epilepsy from a practical point of view.

Neurosteroid and benzodiazepine combination therapy reduces status epilepticus and long-term effects of whole-body sarin exposure in rats

OBJECTIVE

Our objective was to evaluate the protective efficacy of the neurosteroid pregnanolone (3α-hydroxy-5β pregnan-20-one), a GABAA receptor-positive allosteric modulator, as an adjunct to benzodiazepine therapy against the chemical warfare nerve agent (CWNA) sarin (GB), using whole-body exposure, an operationally relevant route of exposure to volatile GB.

METHODS

Rats implanted with telemetry transmitters for the continuous measurement of cortical electroencephalographic (EEG) activity were exposed for 60 minutes to 3.0 LCt50 of GB via whole-body exposure. At the onset of toxic signs, rats were administered an intramuscular injection of atropine sulfate (2 mg/kg) and the oxime HI-6 (93.6 mg/kg) to increase survival rate and, 30 minutes after seizure onset, treated subcutaneously with diazepam (10 mg/kg) and intravenously with pregnanolone (4 mg/kg) or vehicle. Animals were evaluated for GB-induced status epilepticus (SE), spontaneous recurrent seizures (SRS), impairment in spatial memory acquisition, and brain pathology, and treatment groups were compared.

RESULTS

Delayed dual therapy with pregnanolone and diazepam reduced time in SE in GB-exposed rats compared to those treated with delayed diazepam monotherapy. The combination therapy of pregnanolone with diazepam also prevented impairment in the Morris water maze and reduced the neuronal loss and neuronal degeneration, evaluated at one and three months after exposure.

SIGNIFICANCE

Neurosteroid administration as an adjunct to benzodiazepine therapy offers an effective means to treat benzodiazepine-refractory SE, such as occurs following delayed treatment of GB exposure. This study is the first to present data on the efficacy of delayed pregnanolone and diazepam dual therapy in reducing seizure activity, performance deficits and brain pathology following an operationally relevant route of exposure to GB and supports the use of a neurosteroid as an adjunct to standard anticonvulsant therapy for the treatment of CWNA-induced SE.

A patient with juvenile-onset refractory status epilepticus caused by two novel compound heterozygous mutations in FARS2 gene

FARS2 encodes mitochondrial phenylalanyl transfer ribonucleic acid (RNA) synthetase and is implicated in autosomal recessive combined oxidative phosphorylation deficiency 14. The clinical manifestation can be divided into early onset epileptic phenotype and spastic paraplegia phenotype. The purpose of this study was to report a case of juvenile manifesting refractory epilepsy caused by two novel compound heterozygous mutations in the FARS2 gene. Microscopic and histochemical examination as well as next-generation sequencing and reconstruction of the three-dimensional structure of FARS2 protein were performed. A 17-year-old man with no developmental delays suffered from generalized tonic-clonic convulsion since 12 years of age and developed refractory status epilepticus 5 years later. No specific etiology was found following brain imaging, muscle biopsy and metabolic studies. DNA sequencing identified two novel compound heterozygous mutations in FARS2, (p.V197M and p.F402S), derived from each parents, respectively. These mutations affected the structure or thermodynamic stability of the protein. This is a case report of juvenile-onset refractory epilepsy caused by two novel compound heterozygous mutations in the FARS2 gene. This case confirms and expands the clinicalphenotype and the genotypic spectrum of the FARS2 gene.

Febrile Infection-Related Epilepsy Syndrome (FIRES): A Literature Review and Case Study

Febrile infection-related epilepsy syndrome (FIRES) is a catastrophic epileptic syndrome that strikes previously healthy children aged 3-15 years and has an unknown pathogenesis and few treatments. These children experience a nonspecific febrile illness that is followed by prolonged refractory status epilepticus. Although the etiology is unknown, FIRES has a biphasic presentation, with the acute phase beginning as seizure activity lasting 1-12 weeks, then followed by the chronic phase, which is characterized by refractory seizures that cluster every 2-4 weeks, and may continue to be multifocal and independent. Treatment of FIRES is difficult, typically unresponsive to antiepileptic drugs. Some children resolve temporarily with drug-induced burst suppression comas. Other therapies such as a ketogenic diet have limited benefit. The outcome varies with the length of the acute phase and is usually poor, with up to 30% of cases ending in death and 66-100% of survivors having intellectual disability. The authors present a case of a 6-year-old child presenting with FIRES and refractory status epilepticus, which continued despite multidrug therapy. The patient underwent immunomodulatory therapy with the eventual resolution of status, but she developed a chronic, moderately severe encephalopathy, including intractable epilepsy. This case highlights the challenges of FIRES and the potential of immunomodulatory therapies for children with this disorder.

Duration of therapeutic coma and outcome of refractory status epilepticus

OBJECTIVE

Examine the association of duration of therapeutic coma (TC) with seizure recurrence, morbidity, and mortality in refractory status epilepticus (RSE). Define an optimal window for TC that provides sustained seizure control and minimizes complications.

METHODS

Retrospective, observational cohort study involving patients who presented with RSE to the University of Alabama at Birmingham or the University of California at San Francisco from 2010 to 2016. Relationship of duration of TC with primary and secondary outcomes was evaluated using two-sample t tests, simple linear regression, and chi-square tests. Multivariable linear and logistic regression models were used to identify independent predictors. Predictive ability of TC for seizure recurrence was quantified using a receiver-operating characteristic curve. Youden index was used to determine an optimal cutoff value.

RESULTS

Multivariable analysis of clinical and treatment characteristics of 182 patients who were treated predominantly with propofol as anesthetic agent showed that longer duration of the first trial of TC (27.2 vs 15.6 hours) was independently associated with a higher chance of seizure recurrence following the first weaning attempt (P = 0.038) but not with poor functional neurologic outcome upon discharge, in-hospital complications, or mortality. Furthermore, higher doses of anesthetic utilized during the first trial of TC were independently associated with fewer in-hospital complications (P = 0.003) and associated with a shorter duration of mechanical ventilation and total length of stay. Duration of TC was identified as an independent predictor of seizure recurrence with an optimal cutoff point at 35 hours.

SIGNIFICANCE

This study suggests that a shorter duration yet deeper TC as treatment for RSE may be more effective and safer than the currently recommended TC duration of 24-48 hours. Prospective and randomized trials should be conducted to validate these assertions.

Perampanel for treatment of status epilepticus in Austria, Finland, Germany, and Spain

OBJECTIVE

Novel treatments are needed to control treatment-resistant status epilepticus (SE). We report a summary of clinical cases where perampanel was used in established SE, refractory SE (RSE), or super-refractory SE (SRSE).

METHODS

Medical records were retrospectively reviewed for perampanel administration in SE at five European hospitals between 2011 and 2015.

RESULTS

Of 1319 patients identified as experiencing SE, 52 (3.9%) received perampanel. Median latency from SE onset to perampanel initiation was 10 days. Patients with SE had previously failed benzodiazepines (when received) and a median of five other antiepileptic drugs (AEDs). Median initial perampanel dose was 6 mg/d, up-titrated to a median maximum dose of 10 mg/d. Perampanel was the last drug added in 32/52 (61.5%) patients, with response attributed to perampanel in 19/52 (36.5%) patients. A greater proportion of perampanel non-responders had SRSE (51.5%; 17/33) vs perampanel responders (31.6%; 6/19), and had failed a higher mean number of AEDs before initiating perampanel (5.9 vs 5.1, respectively). Most commonly reported adverse effects during perampanel treatment were dizziness (n = 1 [1.9%]) and somnolence (n = 1 [1.9%]). No serious adverse effects were documented, and none led to discontinuation of perampanel.

CONCLUSIONS

Perampanel was administered to patients with established SE, RSE, or SRSE at greater initial doses than those administered in clinical practice to patients with epilepsy. The SE cases reported here represent a refractory and heterogeneous population, and rate of seizure cessation attributed to perampanel treatment (36.5%) represents a notable response. These data should be confirmed in a larger patient population.

Use of Newer Anticonvulsants for the Treatment of Status Epilepticus

Status epilepticus (SE) has a high mortality rate and is one of the most common neurologic emergencies. Fast progression of this neurologic emergency and lack of response to traditional antiepileptic drugs (AEDs) in most cases has challenged clinicians to use new agents. This article evaluates the efficacy and safety of AEDs released to the market after 2000 for SE, refractory status epilepticus (RSE), and super-refractory status epilepticus (SRSE). The PubMed database was searched for clinical trials published between January 2000 and July 2018 using the search terms status epilepticus, refractory status epilepticus, super refractory status epilepticus, brivaracetam, clobazam, cannabidiol, eslicarbazepine, lacosamide, perampanel, rufinamide, stiripentol, and zonisamide. Trials that evaluated these agents in adults with SE, RSE, and SRSE were included. Brivaracetam use was identified in two retrospective reviews with success rates of 27% and 57%. One unsuccessful case report of cannabidiol use in SE was found. Four clobazam studies were identified in SE and RSE with success rates ranging from 25-100%. No evidence for the use of eslicarbazepine and zonisamide was found. Using the search terms for lacosamide identified 38 articles: 1 systematic review, 5 prospective studies, 15 retrospective reviews, and 17 case reports. Success rates and dosing varied, but studies that included focal or partial types of SE showed higher success rates. Five articles were identified regarding perampanel use in this setting. Three were retrospective reviews with success rates ranging from 17-60%, and two were case reports. Only one case report regarding the use of rufinamide was found; rufinamide titrated up to 4.4 mg/day allowed discontinuation of barbiturate and clobazam. One case report and two case series of stiripentol were found with reported efficacy between 60% and 100% in SRSE. Evidence is currently insufficient to support the use of these agents in this setting.

Inadequate benzodiazepine dosing may result in progression to refractory and non-convulsive status epilepticus

Status epilepticus (SE) is defined as ongoing seizures lasting longer than five minutes or multiple seizures without recovery. Benzodiazepines (BZDs) are first-line agents for the management of SE. Our objective was to evaluate BZD dosing in SE patients and its effects on clinical/electrographic outcomes. A retrospective analysis was conducted from a prospective database of SE patients admitted to a university-based neurocritical care unit. The initial presentation and progression to refractory SE (RSE) and non-convulsive SE (NCSE) with coma was evaluated. Outcome measures included length of stay (LOS), rates of intubation, ventilator-dependent days, and Glasgow outcome scale (GOS). The lorazepam equivalent (LE) dosage of BZDs administered was calculated and we analysed variations in progression if 4 mg or more of LE (adequate BZDs) was administered. Among 100 patients, the median dose of LE was 3 mg (IQR: 2-5 mg). Only 31% of patients received adequate BZDs. Only 18.9% of patients with NCSE without coma received adequate BZDs (p=0.04). Among patients progressing to RSE, 75.4% had not received adequate BZDs (p=0.04) and among patients developing NCSE with coma, 80.6% did not receive adequate BZDs (p=0.07). Escalating doses of BZDs were associated with a decrease in cumulative incidences of RSE (correlation coefficient r=-0.6; p=0.04) and NCSE with coma (correlation coefficient r=-0.7; p=0.003). Outcome measures were not influenced by BZD dosing. The majority of our patients were not adequately dosed with BZDs. Inadequate BZD dosing progressed to RSE and had a tendency to lead to NCSE with coma. Our study demonstrates the need to develop a hospital-wide protocol to guide first responders in the management of SE.

De Novo DNM1L Variant in a Teenager With Progressive Paroxysmal Dystonia and Lethal Super-refractory Myoclonic Status Epilepticus

BACKGROUND

The dynamin 1-like gene ( DNM1L) encodes a GTPase that mediates mitochondrial and peroxisomal fission and fusion. We report a new clinical presentation associated with a DNM1L pathogenic variant and review the literature.

RESULTS

A 13-year-old boy with mild developmental delays and paroxysmal dystonia presented acutely with multifocal myoclonic super-refractory status epilepticus. Despite sustained and aggressive treatment, seizures persisted and care was ultimately withdrawn in the context of extensive global cortical atrophy. Rapid trio-whole exome sequencing revealed a de novo heterozygous c.1207C>T (p.R403C) pathogenic variant in DNM1L. Immunofluorescence staining of fibroblast mitochondria revealed abnormally elongated and tubular morphology.

CONCLUSIONS

This case highlights the diagnostic importance of rapid whole exome sequencing within a critical care setting and reveals the expanding phenotypic spectrum associated with DNM1L variants. This now includes progressive paroxysmal dystonia and adolescent-onset super-refractory myoclonic status epilepticus contributing to strikingly rapid and progressive cortical atrophy and death.

Perampanel in patients with refractory and super-refractory status epilepticus in a neurological intensive care unit: A single-center audit of 30 patients

In refractory status epilepticus (SE), γ-aminobutyric acidergic drugs become less effective and glutamate plays a major role in seizure perpetuation. Data on the efficacy of perampanel (PER) in treatment of refractory SE in humans are limited. Here, we present a single-center case series of patients with refractory SE who received PER orally in an intensive care unit. We retrospectively analyzed treatment response, outcome, and adverse effects of all patients with refractory SE in our Neurological Intensive Care Unit who received add-on PER between September 2012 and February 2018. Thirty patients with refractory SE (median = 72 years, range = 18-91, 77% women) were included. In 14 patients (47%), a high-dose approach was used, with a median initial dose of 24 mg (range = 16-32). In five patients (17%), SE could be terminated after PER administration (median dose = 6 mg, range = 6-20 mg, 2/5 patients in high-dose group). Clinical response was observed after a median of 24 hours (range = 8-48 hours), whereas electroencephalogram resolved after a median of 60 hours (range = 12-72 hours). Time to treatment response tended to be shorter in patients receiving high-dose PER (median clinical response = 16 hours vs 18 hours; electroencephalographic response = 24 hours vs 72 hours), but groups were too small for statistical analysis. Continuous cardiorespiratory monitoring showed no changes in cardiorespiratory function after "standard" and "high-dose" treatment. Elevated liver enzymes without clinical symptoms were observed after a median of 6 days in seven of 30 patients (23%; 57% high dose vs 43% standard dose), of whom six also received treatment with phenytoin (PHT). Outcome was unfavorable (death, persistent vegetative state) in 13 patients (43%; 39% high dose vs 61% standard dose), and good recovery (no significant disability, moderate disability) was achieved in nine patients (56% high dose vs 44% standard dose). Oral PER in loading doses up to 32 mg were well tolerated but could terminate SE only in a few patients (5/30; 17%). Long duration of SE, route of administration, and severe underlying brain dysfunction might be responsible for the modest result. An intravenous formulation is highly desired to explore the full clinical utility in the treatment of refractory SE.

Perioperative management of massive fat embolism syndrome presenting as refractory status epilepticus

Fat embolism syndrome (FES) most commonly can occur after trauma in patients with long bone fractures. While the majority of FES cases present as a mild decrease in mental status, some may manifest as seizure activity. We describe a case of a young patient with traumatic fractures who developed FES leading to refractory status epilepticus and simultaneously required damage controlled orthopedic surgery. The role of imaging modalities including magnetic resonance imaging, transcranial Doppler, and transesophageal echocardiography in diagnosis is discussed, and a multidisciplinary approach to successful perioperative management is described.

Treatment of Refractory and Super-refractory Status Epilepticus

Refractory and super-refractory status epilepticus (SE) are serious illnesses with a high risk of morbidity and even fatality. In the setting of refractory generalized convulsive SE (GCSE), there is ample justification to use continuous infusions of highly sedating medications-usually midazolam, pentobarbital, or propofol. Each of these medications has advantages and disadvantages, and the particulars of their use remain controversial. Continuous EEG monitoring is crucial in guiding the management of these critically ill patients: in diagnosis, in detecting relapse, and in adjusting medications. Forms of SE other than GCSE (and its continuation in a "subtle" or nonconvulsive form) should usually be treated far less aggressively, often with nonsedating anti-seizure drugs (ASDs). Management of "non-classic" NCSE in ICUs is very complicated and controversial, and some cases may require aggressive treatment. One of the largest problems in refractory SE (RSE) treatment is withdrawing coma-inducing drugs, as the prolonged ICU courses they prompt often lead to additional complications. In drug withdrawal after control of convulsive SE, nonsedating ASDs can assist; medical management is crucial; and some brief seizures may have to be tolerated. For the most refractory of cases, immunotherapy, ketamine, ketogenic diet, and focal surgery are among several newer or less standard treatments that can be considered. The morbidity and mortality of RSE is substantial, but many patients survive and even return to normal function, so RSE should be treated promptly and as aggressively as the individual patient and type of SE indicate.

Immunity and inflammation in status epilepticus and its sequelae: possibilities for therapeutic application

Status epilepticus (SE) is a life-threatening neurological emergency often refractory to available treatment options. It is a very heterogeneous condition in terms of clinical presentation and causes, which besides genetic, vascular and other structural causes also include CNS or severe systemic infections, sudden withdrawal from benzodiazepines or anticonvulsants and rare autoimmune etiologies. Treatment of SE is essentially based on expert opinions and antiepileptic drug treatment per se seems to have no major impact on prognosis. There is, therefore, urgent need of novel therapies that rely upon a better understanding of the basic mechanisms underlying this clinical condition. Accumulating evidence in animal models highlights that inflammation ensuing in the brain during SE may play a determinant role in ongoing seizures and their long-term detrimental consequences, independent of an infection or auto-immune cause; this evidence encourages reconsideration of the treatment flow in SE patients.

Intramuscular allopregnanolone and ganaxolone in a mouse model of treatment-resistant status epilepticus

Allopregnanolone (5α-pregnan-3α-ol-20-one) and its synthetic 3β-methyl analog, ganaxolone, are positive allosteric modulators of synaptic and extrasynaptic γ-aminobutyric acid (GABA)_A receptors that exhibit antiseizure activity in diverse animal seizure models, including models of status epilepticus (SE). The 2 neuroactive steroids are being investigated as treatments for SE, including as a treatment for SE induced by chemical threat agents. Intramuscular injection is the preferred route of administration in the prehospital treatment of SE. The objective of this study was to assess the efficacy of intramuscular allopregnanolone and ganaxolone in the treatment of SE induced by the chemical threat agent tetramethylenedisulfotetramine (TETS). The test agents were administered 40 minutes after the onset of SE when mice are refractory to treatment. Allopregnanolone and ganaxolone (each at 3 mg/kg) terminated SE in, respectively, 92% and 75% of animals, and prevented mortality in 85% and 50% of animals; the mean times to termination of behavioral seizures were, respectively, 172 ± 16 and 447 ± 52 seconds. In a separate series of experiments, mice were dosed with the neuroactive steroids by intramuscular injection, and plasma and brain levels were sampled at various time points following injection to estimate pharmacokinetic parameters. Plasma C_max (maximum concentration) values for allopregnanolone and ganaxolone were 645 and 550 ng/mL, respectively. Brain exposure of both steroids was approximately 3-fold the plasma exposure. Two-compartment pharmacokinetic analysis revealed that the central compartment V_d (volume of distribution), CL (clearance), t_½ (terminal half-life), and F (intramuscular bioavailability) values for allopregnanolone and ganaxolone were, respectively, 4.95 L/kg 12.88 L/kg/h,16 minutes, 97%, and 5.07 L/kg, 8.35 L/kg/h, 25 minutes, 95%. Allopregnanolone and ganaxolone are effective in the treatment of TETS-induced SE when administered by the intramuscular route. Allopregnanolone is more rapidly acting and modestly more effective, possibly because it has greater potency on GABA_A receptors.

A Comparative Study of Midazolam and Target-Controlled Propofol Infusion in the Treatment of Refractory Status Epilepticus

Background:

The recommended treatment for refractory status epilepticus (RSE) is the use of anesthetic agents, but evidence regarding the agent of choice is lacking. This study was designed to compare target-controlled infusion of propofol versus midazolam for the treatment of RSE regarding seizure control and complications.

Methods:

This prospective, randomized study recruited 23 adult patients with RSE due to any etiology and treated with either propofol or midazolam titrated to clinical seizure cessation and gradual tapering thereafter. The primary outcome measure was seizure control and the secondary outcomes were duration of the Intensive Care Unit stay and duration of mechanical ventilation, occurrence of super RSE (SRSE), and complications.

Results:

We recruited 23 patients (male:female = 18:5) into this study (propofol Group-11; midazolam Group-12). Overall, seizure control was noted in 34.8%, with successful seizure control in 45% of patients in the propofol group and 25% in midazolam group (P = 0.4). Mortality was similar in both the groups (propofol group [8/11; 72.7%] compared to the midazolam group [7/12; 58.3%] [P = 0.667]). The duration of hospital stay was significantly shorter in the propofol group compared to midazolam (P = 0.02). The overall incidence of SRSE was 69.5% in this study. The complication rate was not significantly different between the groups.

Conclusions:

The choice of anesthetic agent does not seem to affect the overall outcome in RSE and SRSE. Target-controlled propofol infusion was found to be equal in its efficacy to midazolam for the treatment of RSE. High mortality might be due to SRSE secondary to the underlying brain pathology.