A Comparison of Parenteral Phenobarbital vs. Parenteral Phenytoin as Second-Line Management for Pediatric Convulsive Status Epilepticus in a Resource-Limited Setting

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.

High-Dose Midazolam for Pediatric Refractory Status Epilepticus: A Single-Center Retrospective Study

OBJECTIVES

We sought to describe the prevalence of midazolam treatment failure in children with refractory status epilepticus (RSE) and define a threshold dose associated with diminishing frequency of seizure cessation.

DESIGN

Single center retrospective cohort study.

SETTING

Single-center, quaternary-care PICU.

PATIENTS

Children younger than 18 years old admitted to the PICU from 2009 to 2018 who had RSE requiring a continuous midazolam infusion.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We identified individuals with RSE through a data analytics inquiry. Receiver operating characteristic (ROC) curve analysis and Youden's index were used to assess the midazolam dose threshold associated with the highest sensitivity and specificity in identifying seizure cessation. A logistic regression model was used to determine if there was an association between maximum midazolam dose and seizure cessation. Of the 45 patients who met inclusion criteria for this study, 27 (60%) had seizure cessation with a midazolam infusion, whereas 18 (40%) required an additional pentobarbital infusion for seizure cessation. There was an association between maximum midazolam dose and seizure cessation, with patients more likely to fail treatment when midazolam was administered at higher doses. The maximum midazolam dose displayed high area under the ROC curve value for seizure cessation, and the Youden's J index cut-off point was 525 μg/kg/hr. Treatment above this dose was associated with diminishing frequency of seizure cessation. The median time spent titrating midazolam above 500 μg/kg/hr for those patients who required pentobarbital for seizure cessation was 3.83 hours (interquartile range, 2.28-5.58 hr).

CONCLUSIONS

In pediatric patients with RSE requiring high dose midazolam, considerable time is spent titrating doses in a range (above 500 µg/kg/hr) that is associated with diminishing frequency of seizure cessation.

The Next Frontier in Neurocritical Care in Resource-Constrained Settings

Neurocritical care (NCC) is an emerging field within critical care medicine, reflecting the widespread prevalence of neurologic injury in critically ill patients. Morbidity and mortality from neurocritical illness (NCI) have been reduced substantially in resource-rich settings (RRS), owing to the development of advanced technologies, neuro-specific units, and subspecialized medical training. Despite shouldering much of the burden of NCI worldwide, resource-limited settings (RLS) face immense hurdles when implementing guidelines generated in RRS. This review summarizes the current epidemiology, management, and outcomes of the most common NCIs in RLS and offers commentary on future directions in NCC practiced in RLS.

Optimal Management of Status Epilepticus in Children in the Emergency Setting: A Review of Recent Advances

Convulsive status epilepticus (CSE) is the most common neurological emergency in children and the second most common neurological emergency in adults. Mortality is low, but morbidity, including neuro-disability, learning difficulties, and a de-novo epilepsy, may be as high as 22%. The longer the duration of CSE, the more difficult it is to terminate, and the greater the risk of morbidity. Convulsive status epilepticus is usually managed using specific national or local algorithms. The first-line treatment is administered when a tonic-clonic or focal motor clonic seizure has lasted five minutes (impending or premonitory CSE). Second-line treatment is administered when the CSE has persisted after two doses of a first-line treatment (established CSE). Randomised clinical trial (RCT) evidence supports the use of benzodiazepines as a first-line treatment of which the most common are buccal or intra-nasal midazolam, rectal diazepam and intravenous lorazepam. Alternative drugs, for which there are considerably less RCT data, are intra-muscular midazolam and intravenous clonazepam. Up until 2019, phenobarbital and phenytoin (or fosphenytoin) were the preferred second-line treatments but with no good supporting RCT evidence. Robust RCT data are now available which has provided important information on second-line treatments, specifically phenytoin (or fosphenytoin), levetiracetam and sodium valproate. Lacosamide is an alternative second-line treatment but with no supporting RCT evidence. Current evidence indicates that first, buccal or intranasal midazolam or intravenous lorazepam are the most effective and the most patient and carer-friendly first-line anti-seizure medications to treat impending or premonitory CSE and second, that there is no difference in efficacy between levetiracetam, phenytoin (or fosphenytoin) or sodium valproate for the treatment of established CSE. Pragmatically, levetiracetam or sodium valproate are preferred to phenytoin (or fosphenytoin) because of their ease of administration and lack of serious adverse side-effects, including potentially fatal cardiac arrhythmias. Sodium valproate must be used with caution in children aged three and under because of the rare risk of hepatotoxicity and particularly if there is an underlying mitochondrial disorder.

Why won't it stop? The dynamics of benzodiazepine resistance in status epilepticus

Status epilepticus is a life-threatening neurological emergency that affects both adults and children. Approximately 36% of episodes of status epilepticus do not respond to the current preferred first-line treatment, benzodiazepines. The proportion of episodes that are refractory to benzodiazepines is higher in low-income and middle-income countries (LMICs) than in high-income countries (HICs). Evidence suggests that longer episodes of status epilepticus alter brain physiology, thereby contributing to the emergence of benzodiazepine resistance. Such changes include alterations in GABA_A receptor function and in the transmembrane gradient for chloride, both of which erode the ability of benzodiazepines to enhance inhibitory synaptic signalling. Often, current management guidelines for status epilepticus do not account for these duration-related changes in pathophysiology, which might differentially impact individuals in LMICs, where the average time taken to reach medical attention is longer than in HICs. In this Perspective article, we aim to combine clinical insights and the latest evidence from basic science to inspire a new, context-specific approach to efficiently managing status epilepticus.

Status Epilepticus Australasian Registry for Children: A pilot prospective, observational, cohort study of paediatric status epilepticus

OBJECTIVE

Paediatric status epilepticus (SE) has potential for long-term sequelae. Existing data demonstrate delays to aspects of care. The objective of the present study was to examine the feasibility of collecting data on children with paediatric SE and describe current management strategies in pre-hospital and in-hospital settings.

METHODS

A pilot, prospective, observational cohort study of children 4 weeks to 16 years of age with SE, in four EDs in Australia. Clinical details including medications administered, duration of seizure and short-term outcomes were collected. Follow up occurred by telephone at 1 month.

RESULTS

We enrolled 167 children with SE. Mean age was 5.4 years (standard deviation [SD] 4.1), and 81 (49%) male. Median seizure duration was 10 min (interquartile range 7-30). Midazolam was the first medication administered in 87/100 (87%) instances, mean dose of 0.21 mg/kg (SD 0.13). The dose of midazolam was adequate in 30 (35%), high (>0.2 mg/kg) in 44 (51%) and low (<0.1 mg/kg) in 13 (15%). For second-line agents, levetiracetam was administered on 33/55 (60%) occasions, whereas phenytoin and phenobarbitone were administered on 11/55 (20%) occasions each. Mean dose of levetiracetam was 26.4 mg/kg (SD 13.5). One hundred and four (62%) patients were admitted to hospital, with 13 (8%) admitted to ICU and seven (4%) intubated.

CONCLUSION

In children presenting with SE in Australia medical management differed from previous reports, with midazolam as the preferred benzodiazepine, and levetiracetam replacing phenytoin as the preferred second-line agent. This pilot study indicates the feasibility of a paediatric SE registry and its utility to understand and optimise practice.

[Paediatric Life Support]

The European Resuscitation Council (ERC) Paediatric Life Support (PLS) guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations of the International Liaison Committee on Resuscitation (ILCOR). This section provides guidelines on the management of critically ill or injured infants, children and adolescents before, during and after respiratory/cardiac arrest.

Levetiracetam for convulsive status epilepticus in childhood: systematic review and meta-analysis

IMPORTANCE

Prolonged seizures are life-threatening emergencies associated with significant morbidity.

OBJECTIVE

To determine the efficacy and safety of levetiracetam in treating convulsive status epilepticus (CSE) in childhood.

DATA SOURCES AND STUDY SELECTIONS

PubMed, Embase, the Cochrane Central Register of Controlled Trials and Cumulative Index to Nursing and Allied Health Literature were searched from inception up to April 2020. Only randomised controlled trials (RCTs) that included children aged 1 month-18 years were assessed. Two reviewers performed data assessment and extraction.

DATA EXTRACTION AND SYNTHESIS

Ten studies out of the 20 637 citations identified were included.

MAIN OUTCOMES

Cessation of seizure activities, time to cessation of seizure activities, need for rapid sequence intubation (RSI), intensive care unit (ICU) admission, recurrence of seizures at 24 hours, adverse events and all-cause mortality.

RESULTS

We included 10 RCTs (n=1907). There was no significant difference in cessation of seizure activities when levetiracetam was compared with phenytoin (risk ratio (RR)=1.03, 95% CI 0.98 to 1.09), levetiracetam to fosphenytoin (RR=1.16, 95% CI 1.00 to 1.35) or levetiracetam to valproate (RR=1.10, 95% CI 0.94 to 1.27). No differences were found in relation to the timing of cessation of seizures for levetiracetam versus phenytoin (mean difference (MD)=-0.45, 95% CI -1.83 to 0.93), or levetiracetam versus fosphenytoin (MD=-0.70, 95% CI -4.26 to 2.86). There were no significant differences with regard to ICU admissions, adverse events, recurrence of seizure at 24 hours, RSI and all-cause mortality.

CONCLUSION

Levetiracetam is comparable to phenytoin, fosphenytoin and valproate as a second line treatment of paediatric CSE.

Effectiveness and adverse drug reactions of levetiracetam and midazolam in refractory neonatal seizure: A cross-sectional comparative study

BACKGROUND

Neonatal seizure (NS) reflects serious underlying brain injury, requiring immediate evaluation and early treatment. In neonates, phenobarbitone and phenytoin are used primarily to control the seizures. If uncontrolled, widespread off-label use of midazolam and levetiracetam was practiced. These drugs gained popularity though there are no such studies available on literature search comparing them. The present study was designed to explore these lacunae using these two drugs in refractory cases. To study the efficacy and adverse drug reactions (ADRs) of midazolam and levetiracetam not responding to usual line of therapy.

MATERIALS AND METHODS

This was a prospective cross-sectional study conducted on 69 neonates in the NICU and Department of Pharmacology in Burdwan Medical College and Hospital, West Bengal. Patients receiving midazolam or levetiracetam when uncontrolled with first line antiepileptics, namely, phenobarbitone and phenytoin, were considered eligible. The study variables were time to control seizure, seizure recurrence and frequency, and treatment-related adverse events. analysis used Mann-Whitney U-test were applied Comparison with respect to time to control and Chi-square test were applied to detect difference in proportion for ADRs. The SPSS Statistics 17.0 was used for analysis.

RESULTS

We compared the time periods to control neonatal seizure for effectiveness between levetiracetam and midazolam showing no significant difference (P = 0.190). Comparing the portion of recurrences in two groups gives statistically nonsignificant (P = 0.878) result. Only respiratory depression was seen in the levetiracetam group (12.90%) and midazolam group (18.42%). All adverse events were 'probable' as per the WHO-UMC criteria, and there was no statistically significant difference between the two drugs (P = 0.533).

CONCLUSIONS

Both midazolam and levetiracetam are equally effective and safe in NS not responding to usual line of treatment.

Advances in the management of generalized convulsive status epilepticus: what have we learned?

Convulsive status epilepticus is the most serious manifestation of an epileptic diathesis. In the early stages (5-30 min), there exists class A evidence to support the efficacy of benzodiazepines as first-line treatment. As status epilepticus progresses into the later stages, the evidence for treatment becomes less robust until we are depending upon short case series and case reports for the treatment of refractory status epilepticus. However, the past year saw the publication of three randomized controlled trials in the setting of benzodiazepine-resistant established convulsive status epilepticus: the EcLiPSE and ConSEPT studies, compared levetiracetam to phenytoin in children; and the ESETT study compared fosphenytoin, levetiracetam and sodium valproate in adults and children. In addition, the emergence of data from the SENSE study, a multicentre multinational prospective cohort study and the publication of a systematic review and meta-analysis of the mortality of status epilepticus over the past 30 years, has brought the treatment of status epilepticus into sharp focus. In this update we provide a detailed analysis of these studies and their impact on clinical practice. We review contentious areas of management in status epilepticus where a consensus is lacking and advance the case for more research on existing and alternative treatment strategies.

European Resuscitation Council Guidelines 2021: Paediatric Life Support

These European Resuscitation Council Paediatric Life Support (PLS) guidelines, are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the management of critically ill infants and children, before, during and after cardiac arrest.

Preferential Antiseizure Medications in Pediatric Patients with Convulsive Status Epilepticus: A Systematic Review and Network Meta-Analysis

BACKGROUND AND OBJECTIVE

The optimal choice for first- and second-line antiseizure medications for pediatric patients with convulsive status epilepticus remains ambiguous. The present study aimed to estimate the comparative effect on the efficacy and safety of different antiseizure medications in pediatric patients with status epilepticus and provide evidence for clinical practice.

METHODS

We searched PubMed, EMBASE, and the Cochrane Library for eligible randomized controlled trials. Inclusion criteria included: (1) pediatric patients; (2) diagnosis of status epilepticus; and (3) randomized controlled trials. Exclusion criteria were: (1) mixed population without a pediatric subgroup analysis; (2) not status epilepticus; (3) received the study drug prior to admission; (4) sample size fewer than 30; and (5) not randomized controlled trials. Primary outcome was seizure cessation. Secondary outcomes were seizure recurrence within 24 h, respiratory depression, and admission to an intensive care unit. The hierarchy of competing antiseizure medications was presented using the surface under the cumulative ranking curve.

RESULTS

Eight first-line antiseizure medication studies involving 1686 participants and eight second-line antiseizure medication studies involving 1711 participants were eligible for analysis. Midazolam, diazepam, lorazepam, and paraldehyde were administered as first-line antiseizure medications. Valproate, phenobarbital, phenytoin, fosphenytoin, and levetiracetam were investigated as second-line antiseizure medications. No significant differences were observed across first- and second-line antiseizure medications. Midazolam ranked the best for primary and secondary outcomes among the first-line antiseizure medications. Phenobarbital ranked the best for seizure cessation and a lower risk of admission to the intensive care unit. Valproate had superiority in preventing recurrence within 24 h. Levetiracetam had the lowest probability of developing respiratory depression.

CONCLUSIONS

This study demonstrated the hierarchy of competing interventions. Midazolam could be a better option for first-line treatment. Phenobarbital, levetiracetam, and valproate had their respective superiority in the second-line intervention. This study may provide useful information for clinical decision making under different circumstances.

The burden of decisional uncertainty in the treatment of status epilepticus

OBJECTIVE

Treatments for convulsive status epilepticus (SE) have a wide range of effectiveness. The estimated effectiveness of non-intravenous benzodiazepines (non-IV BZDs) ranges from approximately 70% to 90% and the estimated effectiveness of non-benzodiazepine antiseizure medications (non-BZD ASMs) ranges from approximately 50% to 80%. This study aimed to quantify the clinical and economic burden of decisional uncertainty in the treatment of SE.

METHODS

We performed a decision analysis that evaluates how decisional uncertainty on treatment choices for SE impacts hospital admissions, intensive care unit (ICU) admissions, and costs in the United States. We evaluated treatment effectiveness based on the available literature.

RESULTS

Use of a non-IV BZD with high estimated effectiveness, like intranasal midazolam, rather than one with low estimated effectiveness, like rectal diazepam, would result in a median (p₂₅ -p₇₅ ) reduction in hospital admissions from 6 (3.9-8.8) to 1.1 (0.7-1.8) per 100 cases and associated cost reductions of $638 ($289-$1064) per pediatric patient and $1107 ($972-$1281) per adult patient. For BZD-resistant SE, use of a non-BZD ASM with high estimated effectiveness, like phenobarbital, rather than one with low estimated effectiveness, like phenytoin/fosphenytoin, would result in a reduction in ICU admissions from 9.1 (7.3-11.2) to 3.9 (2.6-5.5) per 100 cases and associated cost reduction of $1261 ($445-$2223) per pediatric patient and $319 ($-93-$806) per adult patient. Sensitivity analyses showed that relatively minor improvements in effectiveness may lead to substantial reductions in downstream hospital admissions, ICU admissions, and costs.

SIGNIFICANCE

Decreasing decisional uncertainty and using the most effective treatments for SE may substantially decrease hospital admissions, ICU admissions, and costs.

Excitatory GABAergic signalling is associated with benzodiazepine resistance in status epilepticus

Status epilepticus is defined as a state of unrelenting seizure activity. Generalized convulsive status epilepticus is associated with a rapidly rising mortality rate, and thus constitutes a medical emergency. Benzodiazepines, which act as positive modulators of chloride (Cl-) permeable GABAA receptors, are indicated as first-line treatment, but this is ineffective in many cases. We found that 48% of children presenting with status epilepticus were unresponsive to benzodiazepine treatment, and critically, that the duration of status epilepticus at the time of treatment is an important predictor of non-responsiveness. We therefore investigated the cellular mechanisms that underlie acquired benzodiazepine resistance, using rodent organotypic and acute brain slices. Removing Mg2+ ions leads to an evolving pattern of epileptiform activity, and eventually to a persistent state of repetitive discharges that strongly resembles clinical EEG recordings of status epilepticus. We found that diazepam loses its antiseizure efficacy and conversely exacerbates epileptiform activity during this stage of status epilepticus-like activity. Interestingly, a low concentration of the barbiturate phenobarbital had a similar exacerbating effect on status epilepticus-like activity, while a high concentration of phenobarbital was effective at reducing or preventing epileptiform discharges. We then show that the persistent status epilepticus-like activity is associated with a reduction in GABAA receptor conductance and Cl- extrusion capability. We explored the effect on intraneuronal Cl- using both gramicidin, perforated-patch clamp recordings and Cl- imaging. This showed that during status epilepticus-like activity, reduced Cl- extrusion capacity was further exacerbated by activity-dependent Cl- loading, resulting in a persistently high intraneuronal Cl-. Consistent with these results, we found that optogenetic stimulation of GABAergic interneurons in the status epilepticus-like state, actually enhanced epileptiform activity in a GABAAR dependent manner. Together our findings describe a novel potential mechanism underlying benzodiazepine-resistant status epilepticus, with relevance to how this life-threatening condition should be managed in the clinic.