Use of ketamine in a newborn with refractory status epilepticus: a case report

Midazolam and Ketamine for Convulsive Status Epilepticus in the Out-of-Hospital Setting

STUDY OBJECTIVE

To determine if ketamine, when added to midazolam for the treatment of out-of-hospital seizures, is associated with an increase in the rate of cessation of convulsions prior to hospital arrival.

METHODS

We performed a retrospective cohort study of out-of-hospital patients with an active convulsive seizure being transported to a hospital by a large emergency medical services system in Florida, using data from August 1, 2015 and August 5, 2024. Per protocol, patients received midazolam first for their seizure. Starting in June 2017, a new protocol was developed in which patients who continued to convulse after midazolam received ketamine. We used propensity score matching and multivariable logistic regression to determine if patients who received ketamine were more likely to stop convulsing prior to hospital arrival than those who received midazolam alone.

RESULTS

Overall, 479 (80.1%) of 598 actively convulsing patients who received 2 doses of midazolam (without subsequent ketamine) had resolution of their convulsions prior to hospital arrival compared with 85 (94.4%) of 90 who received ketamine after midazolam, an absolute difference between groups of 14.3% (95% CI 8.6% to 20.1%). After propensity matching, 82.0% of those in the midazolam only group had resolution of convulsions compared to 94.4% in the ketamine group, a difference of 12.4% (95% CI 3.1% to 21.7%).

CONCLUSION

In this retrospective study of out-of-hospital patients with active convulsive seizures, patients who received ketamine were more likely to have stopped convulsing prior to hospital arrival than those who received midazolam alone.

Effectiveness of Ketamine As a Rescue Drug for Patients Experiencing Benzodiazepine-Resistant Status Epilepticus in the Prehospital Setting

OBJECTIVES

Accumulating basic science data, early clinical findings and various feasibility considerations have provided rationales for administering ketamine as a proposed rescue medication for midazolam-resistant status epilepticus (SE) in the logistically challenging prehospital environment. This report details the multiyear experience of paramedics managing midazolam-resistant SE following the introduction of a ketamine-rescue protocol.

DESIGN

A 7-year, population-based, observational study was conducted to evaluate outcomes of patients treated with IV, intraosseous, intramuscular, or intranasal ketamine for SE despite sufficient midazolam dosings. Tracked outcomes included: 1) rapid/sustained termination of clinical seizures in adults while under paramedics' care; 2) corresponding evaluations in children/adolescents; 3) any concerning observations regarding need for assisted ventilation, intubation, or other active interventions post-ketamine; and 4) any identifiable associations between outcomes and circumstances, demographics, or medical history.

SETTING

Emergency response 9-1-1 system serving a large, diverse U.S. county (jurisdictional population, 961,000/1,769 sq miles).

PATIENTS

Those receiving ketamine from paramedics for persistent seizures.

INTERVENTIONS

Adults and adolescents: 100 mg ketamine IV/intraosseous/intramuscular/intranasal; children: 1 mg/kg intramuscular/intranasal.

MEASUREMENTS AND MAIN RESULTS

Among 81 total cases, 57 involved adults (18-86 yr old) receiving the SE-midazolam + ketamine protocol. Ketamine rapidly terminated convulsions in 56 (98.2%) without recurrence during prehospital and hospital arrival phases. For approved reasons, paramedics administered ketamine directly (no midazolam) in eight adults and one child, terminating convulsions in every case. Among 15 childhood/adolescent cases treated per protocol, ketamine rapidly terminated SE activity in 11, but only mitigated it in four, including two retrospectively judged to involve nonseizure activity and two involving intranasal administration. Among all 81 ketamine-treated cases, there were no identifiable clinically significant complications attributable to ketamine, particularly the need for any additional active interventions.

CONCLUSIONS

Ketamine appeared to be consistently effective in treating adults with ongoing out-of-hospital seizures that were resistant to sufficient dosings of midazolam. Similar results were observed in children/adolescents.

Defining neonatal status epilepticus: A scoping review from the ILAE neonatal task force

OBJECTIVE

To review the available literature concerning the definition of neonatal status epilepticus (SE) and/or seizure burden.

METHODS

The International League Against Epilepsy Neonatal Task Force performed a scoping review of the definitions of neonatal SE. Following a systematic literature review, articles were screened and data were abstracted regarding: (1) article characteristics (author identification, publication year, journal name, digital object identifier, title, objective, and study design); (2) cohort characteristics (sample size, gestational age, seizure etiology); (3) definition of SE and/or seizure burden; and (4) the method used to identify and classify SE, including routine EEG (EEG), continuous EEG monitoring (cEEG), amplitude-integrated EEG (aEEG), or clinical features.

RESULTS

The scoping review yielded 44 articles containing a definition of neonatal SE. Studies mainly included infants with hypoxic-ischemic encephalopathy or neonates considered at risk for seizures. SE identification and classification most often relied on cEEG. The majority of studies based the definition of SE on seizure duration, including summed duration of seizures comprising ≥50% of any 1-h epoch, recurrent seizures for >50% of the total recording time, or either electrographic seizures lasting >30 min and/or repeated electrographic seizures totaling >50% in any 1-h period. Seizure burden was reported in 20 studies, and the most commonly used approach assessed total seizure burden, defined as total duration of EEG seizures in minutes. Sixteen studies assessed the relationship between seizure burden and outcomes, and most identified a significant association between higher seizure burden and unfavorable outcomes.

SIGNIFICANCE

This scoping review demonstrates a substantial variation in neonatal SE definitions across the literature. The most common definitions were based around a 30-min seizure duration criterion, but evidence was insufficient to support that 30 min was a cutoff defining prolonged seizures or that seizures exceeding this burden were more likely to be pharmacoresistant or associated with worse outcomes. As a next step, the Neonatal Task Force intends to develop a standardized approach to assessing and describing neonatal seizure burden and defining neonatal SE.

PLAIN LANGUAGE SUMMARY

Prolonged seizures are a neurologic emergency, if untreated, can lead to permanent injury or death. In adults and children, seizures lasting longer than 30 min are believed to cause brain damage. However, it is not clear if this definition can be applied to neonates. The International League Against Epilepsy Neonatal Taskforce performed a scoping literature review which identified 44 articles containing a definition of neonatal status epilepticus. In this article, the authors reviewed the current used definitions for prolonged seizures in neonates to establish a relationship between seizure duration and neurological outcome. As a next step, the Neonatal Task Force intends to develop a standardized approach to assessing and describing neonatal seizure burden and defining neonatal SE.

A systematic review and meta-analysis of ketamine in pediatric status epilepticus

OBJECTIVE

Status epilepticus (SE) is a common neurological medical emergency in the pediatric population, with 10%-40% of cases progressing to refractory SE (RSE), requiring treatment with anesthetic infusions. We present a systematic review and meta-analysis of the use of ketamine for the treatment of pediatric SE and its potential advantages over other anesthetic infusions.

METHODS

This review follows the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Electronic databases, including PubMed, Cochrane Library, Ovid, Embase, and Google Scholar, were searched with the keywords "pediatrics," "status epilepticus," and "ketamine treatment." Randomized trials, prospective and retrospective cohort studies, and case reports were considered for inclusion.

RESULTS

Eighteen publications met the initial inclusion criteria. The 18 publications comprise 11 case reports, one nonconclusive clinical trial, two case series, and four retrospective cohorts. After excluding the case reports because of reporting bias, only the six case series and cohorts were included in the final analysis. There were 172 patients in the six included studies. The weighted age was 9.93 (SD = 10.29) years. The weighted maximum dose was 7.44 (SD = 9.39) mg/kg/h. SE cessation was attained in 51% (95% confidence interval = 43-59) of cases with the addition of ketamine. The heterogeneity was I2 = 0%, t2 = 0, χ2 (5) = 3.39 (p = .64).

SIGNIFICANCE

Pediatric RSE is difficult to treat, resulting in increased morbidity and mortality. Without strong recommendations and evidence regarding preferred agents, this review provides evidence that ketamine may be considered in managing SE in the pediatric population.

Efficacy and safety of ketamine for neonatal refractory status epilepticus: case report and systematic review

Background

Evidence-based data on treatment of neonatal status epilepticus (SE) are scarce. We aimed to collect data on the efficacy and safety of ketamine for the treatment of neonatal SE and to assess its possible role in the treatment of neonatal SE.

Methods

We described a novel case and conducted a systematic literature review on neonatal SE treated with ketamine. The search was carried out in Pubmed, Cochrane, Clinical Trial Gov, Scopus and Web of Science.

Results

Seven published cases of neonatal SE treated with ketamine were identified and analyzed together with our novel case. Seizures typically presented during the first 24 h of life (6/8). Seizures were resistant to a mean of five antiseizure medications. Ketamine, a NMDA receptor antagonist, appeared to be safe and effective in all neonates treated. Neurologic sequelae including hypotonia and spasticity were reported for 4/5 of the surviving children (5/8). 3/5 of them were seizure free at 1-17 months of life.

Discussion

Neonatal brain is more susceptible to seizures due to a shift towards increased excitation because of a paradoxical excitatory effect of GABA, a greater density of NMDA receptors and higher extracellular concentrations of glutamate. Status epilepticus and neonatal encephalopathy could further enhance these mechanisms, providing a rationale for the use of ketamine in this setting.

Conclusions

Ketamine in the treatment of neonatal SE showed a promising efficacy and safety profile. However, further in-depth studies and clinical trials on larger populations are needed.

Use of Continuous Ketamine Infusion as an Adjunctive Agent in Young Infants With Refractory and Super Refractory Status Epilepticus: A Case Series

Continuous ketamine infusions have been studied as an adjunctive agent for refractory status epilepticus (RSE) and super refractory status epilepticus (SRSE) in older children and adults. However, minimal information exists on the efficacy, safety, and dosing for continuous ketamine in young infants. We present the clinical course of 3 young infants with RSE and SRSE who received continuous ketamine in conjunction with other antiseizure medications. The condition of these patients was refractory to an average of 6 antiseizure medications before initiation of continuous ketamine infusion. For each patient, a continuous ketamine infusion was initiated at a rate of 1 mg/kg/hr with 1 patient requiring titration to a maximum of 6 mg/kg/hr. In 1 case, the concomitant use of continuous ketamine allowed for a reduction in the benzodiazepine continuous infusion rate. In all cases, ketamine was well tolerated especially in the setting of hemodynamic instability. Ketamine may provide a safe adjunct in the acute setting in severe RSE and SRSE. This is the first case series to document the use of continuous ketamine as a treatment modality in young infants with RSE or SRSE secondary to various underlying etiologies, without adverse events. Further studies are needed to evaluate the long-term safety and efficacy of continuous ketamine in this patient population.

Ketamine for Management of Neonatal and Pediatric Refractory Status Epilepticus

BACKGROUND AND OBJECTIVES

Few data are available regarding the use of anesthetic infusions for refractory status epilepticus (RSE) in children and neonates, and ketamine use is increasing despite limited data. We aimed to describe the impact of ketamine for RSE in children and neonates.

METHODS

Retrospective single-center cohort study of consecutive patients admitted to the intensive care units of a quaternary care children's hospital treated with ketamine infusion for RSE.

RESULTS

Sixty-nine patients were treated with a ketamine infusion for RSE. The median age at onset of RSE was 0.7 years (interquartile range 0.15-7.2), and the cohort included 13 (19%) neonates. Three patients (4%) had adverse events requiring intervention during or within 12 hours of ketamine administration, including hypertension in 2 patients and delirium in 1 patient. Ketamine infusion was followed by seizure termination in 32 patients (46%), seizure reduction in 19 patients (28%), and no change in 18 patients (26%).

DISCUSSION

Ketamine administration was associated with few adverse events, and seizures often terminated or improved after ketamine administration. Further data are needed comparing first-line and subsequent anesthetic medications for treatment of pediatric and neonatal RSE.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence on the therapeutic utility of ketamine for treatment of RSE in children and neonates.

Neonatal seizures treatment based on conventional multichannel EEG monitoring: an overview of therapeutic options

INTRODUCTION

Seizures are the main neurological emergency during the neonatal period and are mostly acute and focal. The prognosis mainly depends on the underlying etiology. Conventional multichannel video-electroencephalographic (cEEG) monitoring is the gold standard for diagnosis, but treatment remains a challenge.

AREAS COVERED

: This review, based on PubMed search over the last 4 decades, focuses on the current treatment options for neonatal seizures based on cEEG monitoring. There is still no consensus on seizure therapy, owing to poor scientific evidence. Traditionally, the first-line treatments are phenobarbital and phenytoin, followed by midazolam and lidocaine, but their efficacy is limited. Therefore, current evidence strongly suggests the use of alternative antiseizure medications. Randomized controlled trials of new drugs are ongoing.

EXPERT OPINION

: Therapy for neonatal seizures should be prompt and tailored, based on semeiology, mirror of the underlying cause, and cEEG features. Further research should focus on antiseizure medications that directly act on the etiopathogenetic mechanism responsible for seizures and are therefore more effective in seizure control.

Resolution of status epilepticus after ketamine administration

BACKGROUND

Status Epilepticus is the most common non-traumatic neurologic emergency in childhood. Current algorithms prioritize the use of benzodiazepines as first line treatment followed by Levetiracetam or Valproic Acid, possibly Fosphenytoin and eventually high dose Propofol and intubation.

CASE REPORT

A 9-month old girl was brought to the emergency department with a continuous seizure involving the right upper and lower extremity for 45 min prior to arrival. Patient received a dose of rectal Diazepam, intramuscular Midazolam, 2 doses of Lorazepam, Levetiracetam, Fosphenytoin and 2 additional doses of Lorazepam. The seizure remained refractory and generalized. In anticipation of intubation, and because of its action on the NMDA receptor, Ketamine (1 mg/kg IV) was administered. The clonic movements and eye deviations stopped. Patient was intubated for airway protection, sedated with Propofol, then admitted to the PICU. EEG showed no evidence of a seizure pattern. Labs (CBC, CMP, COVID) were unremarkable except for WBC 24.5, blood glucose of 346 and CO2 of 17 with normal anion gap. Urinalysis showed a urinary tract infection. Patient was at her baseline on 1 week post-discharge re-evaluation. Ketamine theoretically may abort seizures through blockade of NMDA receptors which are unregulated in status epilepticus. To date, no randomized controlled trials have been reported. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Ketamine may have a role in treating status epilepticus. It may be considered for induction for rapid sequence intubation and possibly as a third or fourth line agent in refractory cases.

Novel Therapeutics for Neonatal Seizures

Neonatal seizures are a common neurologic emergency for which therapies have not significantly changed in decades. Improvements in diagnosis and pathophysiologic understanding of the distinct features of acute symptomatic seizures and neonatal-onset epilepsies present exceptional opportunities for development of precision therapies with potential to improve outcomes. Herein, we discuss the pathophysiology of neonatal seizures and review the evidence for currently available treatment. We present emerging therapies in clinical and preclinical development for the treatment of acute symptomatic neonatal seizures. Lastly, we discuss the role of precision therapies for genetic neonatal-onset epilepsies and address barriers and goals for developing new therapies for clinical care.

Treating the symptom or treating the disease in neonatal seizures: a systematic review of the literature

Aim

The existing treatment options for neonatal seizures have expanded over the last few decades, but no consensus has been reached regarding the optimal therapeutic protocols. We systematically reviewed the available literature examining neonatal seizure treatments to clarify which drugs are the most effective for the treatment of specific neurologic disorders in newborns.

Method

We reviewed all available, published, literature, identified using PubMed (published between August 1949 and November 2020), that focused on the pharmacological treatment of electroencephalogram (EEG)-confirmed neonatal seizures.

Results

Our search identified 427 articles, of which 67 were included in this review. Current knowledge allowed us to highlight the good clinical and electrographic responses of genetic early-onset epilepsies to sodium channel blockers and the overall good response to levetiracetam, whose administration has also been demonstrated to be safe in both full-term and preterm newborns.

Interpretation

Our work contributes by confirming the limited availability of evidence that can be used to guide the use of anticonvulsants to treat newborns in clinical practice and examining the efficacy and potentially harmful side effects of currently available drugs when used to treat the developing newborn brain; therefore, our work might also serve as a clinical reference for future studies.

Are Ketamine Infusions a Viable Therapeutic Option for Refractory Neonatal Seizures?

Ketamine is an N-methyl-d-aspartate (NMDA) receptor antagonist that works by binding to the phencyclidine-binding site, thereby blocking influx of cations through the NMDA receptor channel. The use of ketamine to treat refractory status epilepticus in adults and older children is well documented. Maturational changes in neonatal NMDA and γ-aminobutyric acid receptor expression and function make NMDA receptor antagonists, like ketamine, attractive potential therapeutic agents for treatment of refractory seizures in the newborn. However, descriptions of its use in this age group are limited to two case reports. Concerns regarding potential ketamine-mediated neurotoxicity in the immature brain require further investigation.

Potential consequences of high-dose infusion of ketamine for refractory status epilepticus: case reports and systematic literature review

Our goal was to provide comprehensive data on the effectiveness of ketamine in refractory status epilepticus (RSE) and to describe the potential consequences of long-term ketamine infusion. Ketamine, an N-methyl D-aspartate (NMDA) receptor antagonist, blocks excitatory pathways contributing to ongoing seizure. While ketamine use is standard in anaesthetic induction, no definitive protocol exists for its use in RSE, and little is known about its adverse effects in long-term, high-dose administration. We present two cases of RSE that responded rapidly to ketamine infusion, both with fatal outcomes secondary to metabolic acidosis and cardiovascular collapse. We performed a systematic review of the application and consequences of ketamine use in RSE. PubMed, Ovid, MEDLINE and PMC were searched for articles describing ketamine treatment for RSE according to a predetermined search strategy and inclusion criteria. The systematic review revealed wide discrepancies in ketamine dosing (infusion maintenance dose range 0.0075-10.5 mg/kg/hour), but good outcomes in medically managed RSE (75% of studies reported moderate or complete seizure control in adults, 62.5% in paediatrics). Additionally, literature review elucidated a potentially causal relationship between prolonged ketamine infusion and both cardiovascular and metabolic dysregulation. Ketamine is effective in RSE by antagonising excitotoxic NMDA receptors. However, there is high variability in ketamine dosing and scarce data on its safety in long-term infusion. Metabolic acidosis and haemodynamic instability associated with the use of long-term, high-dose ketamine infusions must be of concern to clinicians administering ketamine to critically ill patients.

Ketamine for Refractory Status Epilepticus: A Systematic Review

BACKGROUND

Ketamine is an emerging third-line medication for refractory status epilepticus, a medical and neurological emergency requiring prompt and appropriate treatment. Owing to its pharmacological properties, ketamine represents a practical alternative to conventional anaesthetics.

OBJECTIVE

The objective of this study was to assess the efficacy and safety of ketamine to treat refractory status epilepticus in paediatric and adult populations.

METHODS

We conducted a literature search using the PubMed database, Cochrane Database of Systematic Reviews and ClinicalTrials.gov website.

RESULTS

We found no results from randomised controlled trials. The literature included 27 case reports accounting for 30 individuals and 14 case series, six of which included children. Overall, 248 individuals (29 children) with a median age of 43.5 years (range 2 months to 67 years) were treated in 12 case series whose sample size ranged from 5 to 67 patients (median 11). Regardless of the status epilepticus type, ketamine was twice as effective if administered early, with an efficacy rate as high as 64% in refractory status epilepticus lasting 3 days and dropping to 32% when the mean refractory status epilepticus duration was 26.5 days. Ketamine doses were extremely heterogeneous and did not appear to be an independent prognostic factor. Endotracheal intubation, a negative prognostic factor for status epilepticus, was unnecessary in 12 individuals (10 children), seven of whom were treated with oral ketamine for non-convulsive status epilepticus.

CONCLUSIONS

Although ketamine has proven to be effective in treating refractory status epilepticus, available studies are hampered by methodological limitations that prevent any firm conclusion. Results from two ongoing studies (ClinicalTrials.gov identification number: NCT02431663 and NCT03115489) and further clinical trials will hopefully confirm the better efficacy and safety profile of ketamine compared with conventional anaesthetics as third-line therapy in refractory status epilepticus, both in paediatric and adult populations.

Novel drugs and early polypharmacotherapy in status epilepticus

PURPOSE

Rescue medications for status epilepticus (SE) have a relatively high rate of failure. The purpose of this review is to summarize the evidence for the efficacy of novel drugs and early polypharmacotherapy for SE.

METHOD

Literature review.

RESULTS

New drugs and treatment strategies aim to target the pathophysiology of SE in order to improve seizure control and outcomes. Changes at the synapse level during SE include a progressive decrease in synaptic GABA_A receptors and increase in synaptic NMDA receptors. These changes tend to promote self-sustaining seizures. Current SE guidelines recommend a rapid stepwise treatment using benzodiazepines in monotherapy as the first-line treatment, targeting GABA_A synaptic receptors. Novel treatment approaches target GABA_A synaptic and extrasynaptic receptors with allopregnanolone, and NMDA receptors with ketamine. Novel rescue treatments used for SE include topiramate, brivaracetam, and perampanel, which are already marketed in epilepsy. Some available drugs not marketed for use in epilepsy have been used in the treatment of SE, and other agents are being studied for this purpose. Early polytherapy, most frequently combining a benzodiazepine with a second-line drug or an NMDA receptor antagonist, might potentially increase seizure control with relatively minor increase in side effects. Although many preclinical studies support novel drugs and early polytherapy in SE, human studies are scarce and inconclusive. Currently, evidence is lacking to recommend specific combinations of these new agents.

CONCLUSIONS

Novel drugs and strategies target the underlying pathophysiology of SE with the intent to improve seizure control and outcomes.

Trafficking patterns of NMDA and GABAA receptors in a Mg2+-free cultured hippocampal neuron model of status epilepticus

An altered pattern of receptor trafficking is one of the pathophysiologic mechanisms of status epilepticus (SE). The gradual internalization of GABA_A receptors (GABARs) occurs in both in vitro and in vivo models of SE and is thought to be a cause of decreased GABAergic inhibition. Unlike GABARs, little is known about alterations in NMDA receptor (NMDAR) trafficking during SE, even though increased activity of NMDARs is indispensable for the induction and maintenance of SE. Therefore, we aimed to simultaneously investigate the changes in the trafficking patterns of GABARs and NMDARs in an in vitro cultured hippocampal neuron model of SE. For induction of epileptiform discharges, hippocampal neurons were exposed to external medium without Mg²⁺. Biotinylation assay and immunofluorescence staining for GABAR β2,3 and NMDAR NR1 subunits were performed to quantify and visualize surface GABARs and NMDARs, respectively. The frequency of spontaneous action potentials increased more than 4-fold after Mg²⁺-free induction. The level of surface GABARs decreased over time after Mg²⁺-free induction, dropping to approximately 50% of control levels an hour after Mg²⁺-free induction. By contrast, the trafficking of NMDARs to the surface was enhanced after a slight time lag, increasing by 30% of control levels an hour after Mg²⁺-free induction. Our data showed the changes of both NMDAR and GABAR trafficking during prolonged SE induced by a Mg²⁺-free extracellular environment and confirmed that this in vitro SE model is suitable for examining alterations in the receptor trafficking pattern by prolonged seizure activity. These results suggest that targeting of surface NMDAR could be a promising method in controlling benzodiazepine-resistant SE.

Increasing Ketamine Use for Refractory Status Epilepticus in US Pediatric Hospitals

Ketamine is an emerging therapy for pediatric refractory status epilepticus. The circumstances of its use, however, are understudied. The authors described pediatric refractory status epilepticus treated with ketamine from 2010 to 2014 at 45 centers using the Pediatric Hospital Inpatient System database. For comparison, they described children treated with pentobarbital. The authors estimated that 48 children received ketamine and pentobarbital for refractory status epilepticus, and 630 pentobarbital without ketamine. Those receiving only pentobarbital were median age 3 [interquartile range 0-10], and spent 30 [18-52] days in-hospital, including 17 [9-28] intensive care unit (ICU) days; 17% died. Median cost was $148 000 [81 000-241 000]. The pentobarbital-ketamine group was older (7 [2-11]) with longer hospital stays (51 [30-93]) and more ICU days (29 [20-56]); 29% died. Median cost was $298 000 [176 000-607 000]. For 71%, ketamine was given ≥1 day after pentobarbital. Ketamine cases per half-year increased from 2 to 9 ( P < .05). Ketamine is increasingly used for severe pediatric refractory status epilepticus, typically after pentobarbital. Research on its effectiveness is indicated.