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Purpose: Evaluate the relationship between first and second-line medication dosing and progression to refractory status epilepticus (RSE) in children., Methods: This is a retrospective analysis of prospectively collected data from September 2014 to February 2020 of children with status epilepticus (SE) who received at least two antiseizure medications (ASMs). We evaluated the risk of developing RSE after receiving a low total benzodiazepine dose (lower than 100 % of the minimum recommended dose for each benzodiazepine dose administered within 10 min) and a low first non-benzodiazepine ASM dose (lower than 100 % of the minimum recommended dose of non-benzodiazepine ASM given as the first single-dose) using a logistic regression model, adjusting for confounders such as time to ASMs. The proportion of patients receiving low first non-benzodiazepine ASM doses was calculated and a logistic regression model was used to evaluate risk factors for low dosing of the first non-benzodiazepine ASM., Results: Among 320 children, 170 (53.1 %) developed RSE, and 150 (46.9 %) responded to the first non-benzodiazepine ASM dose (non-RSE). One hundred thirty-seven (42.8 %) received a low total benzodiazepine dose, and 128 (40 %) received a low first non-benzodiazepine ASM dose. The odds of developing RSE were not higher after a low total benzodiazepine dose (OR=0.76, 95 %CI 0.47-1.23, p = 0.27) or low first non-benzodiazepine ASM dose (OR=0.85, 95 %CI 0.42-1.71, p = 0.65). Receiving a low first non-benzodiazepine ASM dose was independently associated with having received a low total benzodiazepine dose (OR=1.65, 95 %CI 1.01-2.70, p = 0.04)., Conclusion: For most patients, dosing variability in first and second-line medications for SE was not the sole clinical feature predicting progression to RSE in this cohort of benzodiazepine-resistant patients. Identification of additional modifiable clinical biomarkers that predict progression to RSE is needed. Though lower ASM doses did not predict RSE in this model, the administration of ASMs at doses likely to prevent RSE remains crucial in SE treatment., Competing Interests: Declaration of competig interest TL is part of pending patent applications to detect and predict seizures and to diagnose epilepsy. He receives research support from the NIH, the Epilepsy Research Fund, and Epitel. He received research grants from Sage, Lundbeck, Eisai, Upsher-Smith, Mallinckrodt, Pfizer, and MIKU in the past. He served as a consultant for Engage and Upsher Smith, in the past., (Copyright © 2024. Published by Elsevier Ltd.)

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., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Objective: For an antiseizure medication (ASM) to be effective in status epilepticus (SE), the drug should be administered intravenously (i.v.) to provide quick access to the brain. However, poor aqueous solubility is a major problem in the development of parenteral drug solutions. Given its multiple mechanisms of action, topiramate (TPM) is a promising candidate for the treatment of established or refractory SE, as supported by clinical studies using nasogastric tube TPM administration. However, TPM is not clinically available as a solution for i.v. administration, which hampers its use in the treatment of SE. Here, we describe a novel easy-to-use and easy-to-prepare i.v. TPM formulation using the U.S. Food and Drug Administration (FDA)-approved excipient meglumine., Methods: During formulation development, we compared the solubility of TPM in bi-distilled water with vs without a range of meglumine concentrations. Furthermore, the solubility of combinations of TPM and levetiracetam and TPM, levetiracetam, and atorvastatin in aqueous meglumine concentrations was determined. Subsequently, the pharmacokinetics and tolerability of meglumine-based solutions of TPM and TPM combinations were evaluated in rats, including animals following fluid percussion injury or pilocarpine-induced SE., Results: The amino sugar meglumine markedly enhances the aqueous solubility of TPM. A comparison with data on dissolving TPM using sulfobutylether-β-cyclodextrin (Captisol) demonstrates that meglumine is much more effective for dissolving TPM. Furthermore, meglumine can be used to prepare drug cocktails where TPM is co-administered with another ASM for SE treatment. The tolerability studies of the meglumine-based TPM solution and meglumine-based TPM combinations in normal rats and the rat fluid percussion injury and pilocarpine-induced SE models demonstrate excellent tolerability of the novel drug solutions. Preclinical studies on antiseizure efficacy in the SE model are underway., Significance: In conclusion, the novel meglumine-based solution of TPM presented here may be well suited for clinical development., (© 2023 The Authors. Epilepsia published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

Background: Time to treatment in pediatric refractory status epilepticus is delayed. We aimed to evaluate the influence of weekends and holidays on time to treatment of this pediatric emergency., Methods: We performed a retrospective analysis of prospectively collected observational data of pediatric patients with refractory status epilepticus., Results: We included 329 patients (56% males) with a median (p25 to p75) age of 3.8 (1.3 to 9) years. The median (p25 to p75) time to first BZD on weekdays and weekends/holidays was 20 (6.8 to 48.3) minutes versus 11 (5 to 35) minutes, P = 0.01; adjusted hazard ratio (HR) = 1.20 (95% confidence interval [CI]: 0.95 to 1.55), P = 0.12. The time to first non-BZD ASM was longer on weekdays than on weekends/holidays (68 [42.8 to 153.5] minutes versus 59 [27 to 120] minutes, P = 0.006; adjusted HR = 1.38 [95% CI: 1.08 to 1.76], P = 0.009). However, this difference was mainly driven by status epilepticus with in-hospital onset: among 108 patients, the time to first non-BZD ASM was longer during weekdays than during weekends/holidays (55.5 [28.8 to 103.5] minutes versus 28 [15.8 to 66.3] minutes, P = 0.003; adjusted HR = 1.65 [95% CI: 1.08 to 2.51], P = 0.01)., Conclusions: The time to first non-BZD ASM in pediatric refractory status epilepticus is shorter on weekends/holidays than on weekdays, mainly driven by in-hospital onset status epilepticus. Data on what might be causing this difference may help tailor policies to improve medication application timing., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: To identify factors associated with low benzodiazepine (BZD) dosing in patients with refractory status epilepticus (RSE) and to assess the impact of BZD treatment variability on seizure cessation., Methods: This was a retrospective study with prospectively collected data of children with convulsive RSE admitted between June 2011 and January 2019. We analyzed the initial and total BZD dose within 10 minutes of treatment initiation. We used logistic regression modeling to evaluate predictors of low BZD dosing and multivariate Cox regression analysis to assess the impact of low BZD dosing on time to seizure cessation., Results: We included 289 patients (55.7% male) with a median age of 4.3 (1.3-9.5) years. BZDs were the initial medication in 278 (96.2%). Of those, 161 patients (57.9%) received a low initial dose. Low initial BZD doses occurred in both out-of-hospital (57 of 106; 53.8%) and in-hospital (104 of 172; 60.5%) settings. One hundred three patients (37.1%) received low total BZD dose. Male sex (odds ratio [OR] 2, 95% confidence interval [CI] 1.18-3.49; p = 0.012), older age (OR 1.1, 95% CI 1.05-1.17; p < 0.001), no prior diagnosis of epilepsy (OR 2.1, 95% CI 1.23-3.69; p = 0.008), and delayed BZD treatment (OR 2.2, 95% CI 1.24-3.94; p = 0.007) were associated with low total BZD dose. Patients who received low total BZD dosing were less likely to achieve seizure cessation (hazard ratio 0.7, 95% CI 0.57-0.95)., Conclusion: BZD doses were lower than recommended in both out-of-hospital and in-hospital settings. Factors associated with low total BZD dose included male sex, older age, no prior epilepsy diagnosis, and delayed BZD treatment. Low total BZD dosing was associated with decreased likelihood of Seizure cessation., Classification of Evidence: This study provides Class III evidence that patients with RSE who present with male sex, older age, no prior diagnosis of epilepsy, and delayed BZD treatment are more likely to receive low total BZD doses. This study provides Class III evidence that in pediatric RSE low total BZD dose decreases the likelihood of seizure cessation., (© 2020 American Academy of Neurology.)

Objective: To determine whether publication of evidence on delays in time to treatment shortens time to treatment in pediatric refractory convulsive status epilepticus (rSE), we compared time to treatment before (2011-2014) and after (2015-2019) publication of evidence of delays in treatment of rSE in the Pediatric Status Epilepticus Research Group (pSERG) as assessed by patient interviews and record review., Methods: We performed a retrospective analysis of a prospectively collected dataset from June 2011 to September 2019 on pediatric patients (1 month-21 years of age) with rSE., Results: We studied 328 patients (56% male) with median (25th-75th percentile [p 25 -p 75 ]) age of 3.8 (1.3-9.4) years. There were no differences in the median (p 25 -p 75 ) time to first benzodiazepine (BZD) (20 [5-52.5] vs 15 [5-38] minutes, p = 0.3919), time to first non-BZD antiseizure medication (68 [34.5-163.5] vs 65 [33-142] minutes, p = 0.7328), and time to first continuous infusion (186 [124.2-571] vs 160 [89.5-495] minutes, p = 0.2236). Among 157 patients with out-of-hospital onset whose time to hospital arrival was available, the proportion who received at least 1 BZD before hospital arrival increased after publication of evidence of delays (41 of 81 [50.6%] vs 57 of 76 [75%], p = 0.0018), and the odds ratio (OR) was also increased in multivariable logistic regression (OR 4.35 [95% confidence interval 1.96-10.3], p = 0.0005)., Conclusion: Publication of evidence on delays in time to treatment was not associated with improvements in time to treatment of rSE, although it was associated with an increase in the proportion of patients who received at least 1 BZD before hospital arrival., (Copyright © 2020 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Objective: To describe the pharmacology, efficacy, and safety of stiripentol in the treatment of refractory seizures in patients with Dravet syndrome. Data Sources: A search of the English language literature was conducted using PubMed and MEDLINE (1978 to April 2019) with the search terms stiripentol, Dravet syndrome , and refractory epilepsy . Other resources included article bibliographies, prescribing information, and relevant trials at https://clinicaltrials.gov/ . Study Selection and Data Extraction: All phase 1, 2, or 3 trials; observational studies; and retrospective studies were analyzed. Data Synthesis : In controlled studies, stiripentol has been shown to reduce seizure frequency by 50% or more in 40% to 70% of patients with Dravet syndrome. Reductions in seizure duration and episodes of status epilepticus have also been documented. Common adverse effects include somnolence and anorexia. Stiripentol inhibits the metabolism of clobazam and valproate, often requiring dose adjustment. Relevance to Patient Care and Clinical Practice: Stiripentol, a direct allosteric modulator of GABA A receptors, offers a novel approach to treatment in patients with Dravet syndrome, both with and without pathogenic variants of the sodium channel α-1 subunit gene, and potentially other refractory seizures. Although available outside the United States for a decade, it was only recently approved by the Food and Drug Administration for patients 2 years of age and older with Dravet syndrome taking clobazam. Conclusions: Stiripentol is an effective adjunctive therapy for reducing the frequency and duration of refractory seizures in patients with Dravet syndrome. Its role in the treatment of other refractory epilepsies requires further study.

Purpose: To summarize the pathophysiology of convulsive status epilepticus (SE) with a focus on practical implications for treatment., Method: Narrative review of the medical literature on the pathophysiology of convulsive SE. We considered both animal models of SE and clinical studies., Results: Convulsive SE is an emergency in which prolonged convulsive seizures are associated with cardiorespiratory instability, hypoxia, hypoglycemia, and hyperthermia. Supportive treatment helps correct these physiological imbalances. When treatment is delayed, the ability of first line seizure suppressing medications to terminate the seizure can be reduced. Animal studies have suggested that GABA A receptor trafficking may contribute to the failure of the first line therapies and that NMDA receptor antagonists such as ketamine may become more effective as seizures last longer. Potential strategies to take advantage of these changes in pathophysiology include a rapid escalation from benzodiazepines to non-benzodiazepine antiepileptic drugs (AEDs), early polytherapy and use of NMDA antagonists such as ketamine for refractory convulsive SE. Despite the importance of a timely treatment of convulsive SE, major treatment delays are frequent in clinical practice. Policies to improve time to treatment, especially in convulsive SE that starts outside the hospital, may improve response to treatment and convulsive SE outcomes., Conclusions: Convulsive SE is a time-sensitive emergency in which the underlying pathophysiology may provide targets for improving treatment strategies. A timely transition from benzodiazepines to other AEDs may help reduce treatment resistance in convulsive SE., (Copyright © 2018 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Objective: We aimed to evaluate and compare the status epilepticus treatment pathways used by pediatric status epilepticus research group (pSERG) hospitals in the United States and the American Epilepsy Society (AES) status epilepticus guideline., Methods: We undertook a descriptive analysis of recommended timing, dosing, and medication choices in 10 pSERG hospitals' status epilepticus treatment pathways., Results: One pathway matched the timeline in the AES guideline; nine pathways described more rapid timings. All pathways matched the guideline's stabilization phase in timing and five suggested that first-line benzodiazepine (BZD) be administered within this period. For second-line therapy timing (initiation of a non-BZD antiepileptic drug within 20 to 40 minutes), one pathway matched the guideline; nine initiated the antiepileptic drug earlier (median 10 [range five to 15] minutes). Third-line therapy timings matched the AES guideline (40 minutes) in two pathways; eight suggested earlier timing (median 20 [range 15 to 30] minutes). The first-line BZD recommended in all hospitals was intravenous lorazepam; alternatives included intramuscular midazolam or rectal diazepam. In second-line therapy, nine pathways recommended fosphenytoin. For third-line therapy, eight pathways recommended additional boluses of second-line medications; most commonly phenobarbital. Two pathways suggested escalation to third-line medication; most commonly midazolam. We found variance in dosing for the following medications: midazolam as first-line therapy, fosphenytoin, and levetiracetam as second-line therapy, and phenobarbital as third-line therapy medications., Conclusions: The pSERG hospitals status epilepticus pathways are consistent with the AES status epilepticus guideline in regard to the choice of medications, but generally recommend more rapid escalation in therapy than the guideline., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Importance: Treatment delay for seizures can lead to longer seizure duration. Whether treatment delay is associated with major adverse outcomes, such as death, remains unknown., Objective: To evaluate whether untimely first-line benzodiazepine treatment is associated with unfavorable short-term outcomes., Design, Setting, and Participants: This multicenter, observational, prospective cohort study included 218 pediatric patients admitted between June 1, 2011, and July 7, 2016, into the 11 tertiary hospitals in the United States within the Pediatric Status Epilepticus Research Group. Patients, ranging in age from 1 month to 21 years, with refractory convulsive status epilepticus (RCSE) that did not stop after the administration of at least 2 antiseizure medications were included. Patients were divided into 2 cohorts: those who received the first-line benzodiazepine treatment in less than 10 minutes and those who received it 10 or more minutes after seizure onset (untimely). Data were collected and analyzed from June 1, 2011, to July 7, 2016., Main Outcomes and Measures: The primary outcome was death during the related hospital admission. The secondary outcome was the need for continuous infusion for seizure termination. Multivariate analysis of mortality controlled for structural cause, febrile RCSE, age, and previous neurological history (including previous RCSE events). Use of continuous infusions was additionally adjusted for generalized RCSE, continuous RCSE, and 5 or more administrations of antiseizure medication., Results: A total of 218 patients were included, among whom 116 (53.2%) were male and the median (interquartile range) age was 4.0 (1.2-9.6) years. The RCSE started in the prehospital setting for 139 patients (63.8%). Seventy-four patients (33.9%) received their first-line benzodiazepine treatment in less than 10 minutes, and 144 (66.1%) received untimely first-line benzodiazepine treatment. Multivariate analysis showed that patients who received untimely first-line benzodiazepine treatment had higher odds of death (adjusted odds ratio [AOR], 11.0; 95% CI, 1.43 to ∞; P = .02), had greater odds of receiving continuous infusion (AOR, 1.8; 95% CI, 1.01-3.36; P = .047), had longer convulsive seizure duration (AOR, 2.6; 95% CI, 1.38-4.88; P = .003), and had more frequent hypotension (AOR 2.3; 95% CI, 1.16-4.63; P = .02). In addition, the timing of the first-line benzodiazepine treatment was correlated with the timing of the second-line (95% CI, 0.64-0.95; P < .001) and third-line antiseizure medications (95% CI, 0.25-0.78; P < .001)., Conclusions and Relevance: Among pediatric patients with RCSE, an untimely first-line benzodiazepine treatment is independently associated with a higher frequency of death, use of continuous infusions, longer convulsion duration, and more frequent hypotension. Results of this study raise the question as to whether poor outcomes could, in part, be prevented by earlier administration of treatment.

Objective: To describe pediatric patients with convulsive refractory status epilepticus in whom there is intention to use an IV anesthetic for seizure control., Design: Two-year prospective observational study evaluating patients (age range, 1 mo to 21 yr) with refractory status epilepticus not responding to two antiepileptic drug classes and treated with continuous infusion of anesthetic agent., Setting: Nine pediatric hospitals in the United States., Patients: In a cohort of 111 patients with refractory status epilepticus (median age, 3.7 yr; 50% male), 54 (49%) underwent continuous infusion of anesthetic treatment., Main Results: The median (interquartile range) ICU length of stay was 10 (3-20) days. Up to four "cycles" of serial anesthetic therapy were used, and seizure termination was achieved in 94% by the second cycle. Seizure duration in controlled patients was 5.9 (1.9-34) hours for the first cycle and longer when a second cycle was required (30 [4-120] hr; p = 0.048). Midazolam was the most frequent first-line anesthetic agent (78%); pentobarbital was the most frequently used second-line agent after midazolam failure (82%). An electroencephalographic endpoint was used in over half of the patients; higher midazolam dosing was used with a burst suppression endpoint. In midazolam nonresponders, transition to a second agent occurred after a median of 1 day. Most patients (94%) experienced seizure termination with these two therapies., Conclusions: Midazolam and pentobarbital remain the mainstay of continuous infusion therapy for refractory status epilepticus in the pediatric patient. The majority of patients experience seizure termination within a median of 30 hours. These data have implications for the design and feasibility of future intervention trials. That is, testing a new anesthetic anticonvulsant after failure of both midazolam and pentobarbital is unlikely to be feasible in a pediatric study, whereas a decision to test an alternative to pentobarbital, after midazolam failure, may be possible in a multicenter multinational study.

Objective: To describe the time elapsed from onset of pediatric convulsive status epilepticus (SE) to administration of antiepileptic drug (AED)., Methods: This was a prospective observational cohort study performed from June 2011 to June 2013. Pediatric patients (1 month-21 years) with convulsive SE were enrolled. In order to study timing of AED administration during all stages of SE, we restricted our study population to patients who failed 2 or more AED classes or needed continuous infusions to terminate convulsive SE., Results: We enrolled 81 patients (44 male) with a median age of 3.6 years. The first, second, and third AED doses were administered at a median (p25-p75) time of 28 (6-67) minutes, 40 (20-85) minutes, and 59 (30-120) minutes after SE onset. Considering AED classes, the initial AED was a benzodiazepine in 78 (96.3%) patients and 2 (2-3) doses of benzodiazepines were administered before switching to nonbenzodiazepine AEDs. The first and second doses of nonbenzodiazepine AEDs were administered at 69 (40-120) minutes and 120 (75-296) minutes. In the 64 patients with out-of-hospital SE onset, 40 (62.5%) patients did not receive any AED before hospital arrival. In the hospital setting, the first and second in-hospital AED doses were given at 8 (5-15) minutes and 16 (10-40) minutes after SE onset (for patients with in-hospital SE onset) or after hospital arrival (for patients with out-of-hospital SE onset)., Conclusions: The time elapsed from SE onset to AED administration and escalation from one class of AED to another is delayed, both in the prehospital and in-hospital settings., (© 2015 American Academy of Neurology.)

Purpose: Investigate whether patients on vigabatrin demonstrated new-onset and reversible T(2)-weighted magnetic resonance imaging (MRI) abnormalities., Methods: MRI of patients treated during vigabatrin therapy was reviewed, following detection of new basal ganglia, thalamus, and corpus callosum hyperintensities in an infant treated for infantile spasms. Patients were assessed for age at time of MRI, diagnosis, duration, and dose, MRI findings pre-, on, and postvigabatrin, concomitant medications, and clinical correlation. These findings were compared to MRI in patients with infantile spasms who did not receive vigabatrin., Results: Twenty-three patients were identified as having MRI during the course of vigabatrin therapy. After excluding the index case, we detected new and reversible basal ganglia, thalamic, brainstem, or dentate nucleus abnormalities in 7 of 22 (32%) patients treated with vigabatrin. All findings were reversible following discontinuation of therapy. Diffusion-weighted imaging (DWI) was positive with apparent diffusion coefficient (ADC) maps demonstrating restricted diffusion. Affected versus unaffected patients, respectively, had a median age of 11 months versus 5 years, therapy duration 3 months versus 12 months, and dosage 170 mg/kg/day versus 87 mg/kg/day. All affected patients were treated for infantile spasms; none of 56 patients with infantile spasms who were not treated with vigabatrin showed the same abnormalities., Discussion: MRI abnormalities attributable to vigabatrin, characterized by new-onset and reversible T(2)-weighted hyperintensities and restricted diffusion in thalami, globus pallidus, dentate nuclei, brainstem, or corpus callosum were identified in 8 of 23 patients. Young age and relatively high dose appear to be risk factors.

Purpose: Ample evidence exists from both clinical and animal studies that the success of benzodiazepine intervention during status epilepticus (SE) in the mature nervous system is inversely related to seizure duration. This relationship has not been well studied in the developing nervous system., Methods: The objective of this study was to investigate the relation of age and success of diazepam (DZP) treatment in the lithium-pilocarpine model of secondarily generalized seizure in the rat by using naïve rats of three age groups, roughly corresponding to the human ages of infancy (P15), adolescence (P20), and adult (P60)., Results: In all age groups, the dosage of DZP that stopped the seizures at 5 min was not effective in terminating seizures at 60 min. This decline in efficacy was present as early as 15 min after seizure onset., Conclusions: These findings demonstrate that the inverse relation between the success of benzodiazepine intervention and seizure duration is observed in young as well as in adult rats and provide further evidence that intervention for SE should commence early.

Zonisamide is a broad-spectrum antiepileptic drug used to treat various types of seizures. Although visual hallucinations have not been reported as an adverse effect of this agent, we describe three patients who experienced complex visual hallucinations and altered mental status after zonisamide treatment was begun or its dosage increased. All three had been diagnosed earlier with epilepsy, and their electroencephalogram (EEG) findings were abnormal. During monitoring, visual hallucinations did not correlate with EEG readings, nor did video recording capture any of the described events. None of the patients had experienced visual hallucinations before this event. The only recent change in their treatment was the introduction or increased dosage of zonisamide. With either discontinuation or decreased dosage of the drug the symptoms disappeared and did not recur. Further observations and reports will help clarify this adverse effect. Until then, clinicians need to be aware of this possible complication associated with zonisamide.