Fenfluramine for the treatment of status epilepticus: use in an adult with Lennox-Gastaut syndrome and literature review

BACKGROUND

Novel treatments are needed to control refractory status epilepticus (SE). This study aimed to assess the potential effectiveness of fenfluramine (FFA) as an acute treatment option for SE. We present a summary of clinical cases where oral FFA was used in SE.

METHODS

A case of an adult patient with Lennox-Gastaut syndrome (LGS) who was treated with FFA due to refractory SE is presented in detail. To identify studies that evaluated the use of FFA in SE, we performed a systematic literature search.

RESULTS

Four case reports on the acute treatment with FFA of SE in children and adults with Dravet syndrome (DS) and LGS were available. We report in detail a 30-year-old woman with LGS of structural etiology, who presented with generalized tonic and dialeptic seizures manifesting at high frequencies without a return to clinical baseline constituting the diagnosis of SE. Treatment with anti-seizure medications up to lacosamide 600 mg/d, brivaracetam 300 mg/d, valproate 1,600 mg/d, and various benzodiazepines did not resolve the SE. Due to ongoing refractory SE and following an unremarkable echocardiography, treatment was initiated with FFA, with an initial dose of 10 mg/d (0.22 mg/kg body weight [bw]) and fast up-titration to 26 mg/d (0.58 mg/kg bw) within 10 days. Subsequently, the patient experienced a resolution of SE within 4 days, accompanied by a notable improvement in clinical presentation and regaining her mobility, walking with the assistance of physiotherapists. In the three cases reported in the literature, DS patients with SE were treated with FFA, and a cessation of SE was observed within a few days. No treatment-emergent adverse events were observed during FFA treatment in any of the four cases.

CONCLUSIONS

Based on the reported cases, FFA might be a promising option for the acute treatment of SE in patients with DS and LGS. Observational data show a decreased SE frequency while on FFA, suggesting a potentially preventive role of FFA in these populations.

KEY POINTS

We summarize four cases of refractory status epilepticus (SE) successfully treated with fenfluramine. Refractory SE resolved after 4-7 days on fenfluramine. Swift fenfluramine up-titration was well-tolerated during SE treatment. Treatment-emergent adverse events on fenfluramine were not observed. Fenfluramine might be a valuable acute treatment option for SE in Dravet and Lennox-Gastaut syndromes.

Transcranial static magnetic stimulation reduces seizures in a mouse model of Dravet syndrome

Dravet syndrome is a rare form of severe genetic epilepsy characterized by recurrent and long-lasting seizures. It appears around the first year of life, with a quick evolution toward an increase in the frequency of the seizures, accompanied by a delay in motor and cognitive development, and does not respond well to antiepileptic medication. Most patients carry a mutation in the gene SCN1A encoding the α subunit of the voltage-gated sodium channel Nav1.1, resulting in hyperexcitability of neural circuits and seizure onset. In this work, we applied transcranial static magnetic stimulation (tSMS), a non-invasive, safe, easy-to-use and affordable neuromodulatory tool that reduces neural excitability in a mouse model of Dravet syndrome. We demonstrate that tSMS dramatically reduced the number of crises. Furthermore, crises recorded in the presence of the tSMS were shorter and less intense than in the sham condition. Since tSMS has demonstrated its efficacy at reducing cortical excitability in humans without showing unwanted side effects, in an attempt to anticipate a possible use of tSMS for Dravet Syndrome patients, we performed a numerical simulation in which the magnetic field generated by the magnet was modeled to estimate the magnetic field intensity reached in the cerebral cortex, which could help to design stimulation strategies in these patients. Our results provide a proof of concept for nonpharmacological treatment of Dravet syndrome, which opens the door to the design of new protocols for treatment.

Dravet Syndrome as an Example of Precision Medicine in Epilepsy

Dravet syndrome (DS) is a drug-resistant, early-onset, developmental and epileptic encephalopathy where there have been many recently approved therapies with many more in development. With the availability of more syndrome specific treatment options coupled with an earlier diagnosis, DS is well-positioned to be an example of how a precise syndromic diagnosis can guide treatment choices and improve overall outcomes and also allow for the development of potential disease modifying therapies to address more than just seizures. In this review we summarize the current state of DS approved therapies and those that are in various stages of development.

COVID-19 vaccine in patients with Dravet syndrome: Observations and real-world experiences

OBJECTIVE

Vaccination against the SARS-CoV-2 virus is a primary tool to combat the COVID-19 pandemic. However, vaccination is a common seizure trigger in individuals with Dravet syndrome (DS). Information surrounding COVID-19 vaccine side effects in patients with DS would aid caregivers and providers in decisions for and management of COVID-19 vaccination.

METHODS

A survey was emailed to the Dravet Syndrome Foundation's Family Network and posted to the Dravet Parent & Caregiver Support Group on Facebook between May and August 2021. Deidentified information obtained included demographics and vaccination status for individuals with DS. Vaccine type, side effects, preventative measures, and changes in seizure activity following COVID-19 vaccination were recorded. For unvaccinated individuals, caregivers were asked about intent to vaccinate and reasons for their decision.

RESULTS

Of 278 survey responses, 120 represented vaccinated individuals with DS (median age = 19.5 years), with 50% reporting no side effects from COVID-19 vaccination. Increased seizures following COVID-19 vaccination were reported in 16 individuals, but none had status epilepticus. Of the 158 individuals who had not received a COVID-19 vaccination, 37 were older than 12 years (i.e., eligible at time of study), and only six of these caregivers indicated intent to seek vaccination. The remaining 121 responses were caregivers to children younger than 12 years, 60 of whom indicated they would not seek COVID-19 vaccination when their child with DS became eligible. Reasons for vaccine hesitancy were fear of increased seizure activity and concerns about vaccine safety.

SIGNIFICANCE

These results indicate COVID-19 vaccination is well tolerated by individuals with DS. One main reason for vaccine hesitancy was fear of increased seizure activity, which occurred in only 13% of vaccinated individuals, and none had status epilepticus. This study provides critical and reassuring insights for caregivers and health care providers making decisions about the safety of COVID-19 vaccinations for individuals with DS.

An interactive framework for the detection of ictal and interictal activities: Cross-species and stand-alone implementation

BACKGROUND AND OBJECTIVE

Despite advances on signal analysis and artificial intelligence, visual inspection is the gold standard in event detection on electroencephalographic recordings. This process requires much time of clinical experts on both annotating and training new experts for this same task. In scenarios where epilepsy is considered, the need for automatic tools is more prominent, as both seizures and interictal events can occur on hours- or days-long recordings. Although other solutions have already been proposed, most of them are not integrated on clinical and basic science environments due to their complexity and required specialization. Here we present a pipeline that arises from coordinated efforts between life-science researchers, clinicians and data scientists to develop an interactive and iterative workflow to train machine-learning tools for the automatic detection of electroencephalographic events in a variety of scenarios.

METHODS

The approach consists on a series of subsequent steps covering data loading and configuration, event annotation, model training/re-training and event detection. With slight modifications, the combination of these blocks can cope with a variety of scenarios. To illustrate the flexibility and robustness of the approach, three datasets from clinical (patients of Dravet Syndrome) and basic research environments (mice model of the same disease) were evaluated. From them, and in response to researchers' daily needs, four real world examples of interictal event detection and seizure classification tasks were selected and processed.

RESULTS

Results show that the current approach was of great aid for event annotation and model development. It was capable of creating custom machine-learning solutions for each scenario with slight adjustments on the analysis protocol, easily accessible to users without programming skills. Final annotator similarity metrics reached values above 80% on all cases of use, reaching 92.3% on interictal event detection on human recordings.

CONCLUSIONS

The presented framework is easily adaptable to multiple real world scenarios and the interactive and ease-to-use approach makes it manageable to clinical and basic researches without programming skills. Nevertheless, it is conceived so data scientists can optimize it for specific scenarios, improving the knowledge transfer between these fields.

Vaccination and childhood epilepsies

INTRODUCTION

The evidence relating vaccination to febrile seizures and epilepsy is evaluated with an emphasis on febrile seizures (FS), Dravet syndrome (DS), West syndrome, and other developmental and epileptic encephalopathies.

METHODS

A systematic literature review using search words vaccination/immunization AND febrile seizures/epilepsy/Dravet/epileptic encephalopathy/developmental encephalopathy was performed. The role of vaccination as the cause/trigger/aggravation factor for FS or epilepsies and preventive measures were analyzed.

RESULTS

From 1428 results, 846 duplicates and 447 irrelevant articles were eliminated; 120 were analyzed.

CONCLUSIONS

There is no evidence that vaccinations cause epilepsy in healthy populations. Vaccinations do not cause epileptic encephalopathies but may be non-specific triggers to seizures in underlying structural or genetic etiologies. The first seizure in DS may be earlier in vaccinated versus non-vaccinated patients, but developmental outcome is similar in both groups. Children with a personal or family history of FS or epilepsy should receive all routine vaccinations. This recommendation includes DS. The known risks of the infectious diseases prevented by immunization are well established. Vaccination should be deferred in case of acute illness. Acellular pertussis DTaP (diphtheria-tetanus-pertussis) is recommended. The combination of certain vaccine types may increase the risk of febrile seizures however the public health benefit of separating immunizations has not been proven. Measles-containing vaccine should be administered at age 12-15 months. Routine prophylactic antipyretics are not indicated, as there is no evidence of decreased FS risk and they can attenuate the antibody response following vaccination. Prophylactic measures (preventive antipyretic medication) are recommended in DS due to the increased risk of prolonged seizures with fever.

Dravet syndrome: A quick transition guide for the adult neurologist

INTRODUCTION

Dravet syndrome (DS) is still seen as a "pediatric disease", where patients receive excellent care in pediatric centers, but care is less than optimal in adult health care systems (HCS). This creates a barrier when young adults need to leave the family-centered pediatric system and enter the adult, patient-centered HCS. Here we create a guide to help with the transition from pediatric to adult for patients with DS.

METHODS

Experts in Dravet syndrome flagged the main barriers in caring for adults with DS and created a 2-page transition summary guide based on their expertise and a literature review.

RESULTS

The 2-page guide addresses: DS diagnosis in children and adults; clinical manifestations, including the differences in seizures types and frequencies between children and adults with DS; the natural history of intellectual disability, behavior, gait, motor disorders and dysautonomia; a review of optimal treatments (including medications not commonly used in adult epilepsy settings such as stiripentol and fenfluramine), as well as emergency seizure management; avoidance of triggers, preventive measures, and vaccine administration in adults with DS.

CONCLUSION

Several young adults with DS are still followed by their child neurologist. This 2-page transition guide should help facilitate the transition of patients with DS to the adult HCS and should be given to families as well as adult health care providers that may not be familiar with DS.

Stiripentol in the treatment of adults with focal epilepsy- a retrospective analysis

OBJECTIVES

The aim of the present study was to evaluate the safety and efficacy of the add-on treatment of stiripentol (STP) in adult patients with severely pharmacoresistant focal or multifocal epilepsy.

METHODS

Data on adult patients treated with STP from March 2007 to July 2020 and with at least one clinical follow-up (FU) were retrospectively reviewed. Data on tolerability, efficacy and concomitant medication were evaluated at baseline, 6 months (5.5 ± 1.6 months (mean ± SD)) and 12 months (13.1 ± 3.9 months (mean ± SD)).

RESULTS

Data of 22 patients (54.5% male, mean age 34.4 ± 17.79 years (mean ± SD), including mean duration of epilepsy 17.6 ± 25.5 years (mean ± SD), median seizure frequency 30 ± 20 (median ± MAD) per month, and 63.6% being severely intellectually disabled, with 3 to 18 previous anti-seizure-drugs (ASD), were collected. After 6 months, 72.7% of the patients were still taking STP, and 31% of the patients were responders, including 13% who were seizure-free. The 12-month retention rate was 54.4 %, the response rate was 36.4% and 13.6% of patients were seizure-free at the 12-month FU. Reasons for discontinuation were increased seizure frequency, hyperammonaemia and encephalopathy.

CONCLUSION

STP seems to be a useful option in the treatment of patients with severely pharmacoresistant epilepsy. Prospective trials are necessary to examine the efficacy of STP in adult patients with pharmacoresistant focal epilepsy.

The MinION as a cost-effective technology for diagnostic screening of the SCN1A gene in epilepsy patients

The MinION is a portable DNA sequencer that allows real time sequencing at low capital cost investment. We assessed accuracy and cost-effectivess of the MinION for genetic diagnostic testing of known SCN1A mutations that cause Dravet Syndrome (DS). DNA samples (n = 7) from DS patients previously shown to carry SCN1A mutations via Ion Torrent and Sanger sequencing were sequenced using the MinION. SCN1A amplicons for 8 exons were sequenced using the MinION with 1D chemistry on an R9.4 flow cell. All known missense mutations were detected in all samples showing 100 % concordance with results from other methods. However, the MinION failed to detect the insertions/deletions (INDELs) present in these patients. Nevertheless, these results indicate that MinION is a cost-effective platform for use as an initial screening step in the detection of nucleotide substitution mutations in in SCN1A, especially in under-resourced laboratories or hospitals. Further improvements are required to reliably detect INDELS in this gene.

Epilepsy and cannabidiol: a guide to treatment

The growing interest in cannabidiol (CBD), specifically a pure form of CBD, as a treatment for epilepsy, among other conditions, is reflected in recent changes in legislation in some countries. Although there has been much speculation about the therapeutic value of cannabis-based products as an anti-seizure treatment for some time, it is only within the last two years that Class I evidence has been available for a pure form of CBD, based on placebo-controlled RCTs for patients with Lennox-Gastaut syndrome and Dravet syndrome. However, just as we are beginning to understand the significance of CBD as a treatment for epilepsy, in recent years, a broad spectrum of products advertised to contain CBD has emerged on the market. The effects of these products are fundamentally dependent on the purity, preparation, and concentration of CBD and other components, and consensus and standardisation are severely lacking regarding their preparation, composition, usage and effectiveness. This review aims to provide information to neurologists and epileptologists on the therapeutic value of CBD products, principally a purified form, in routine practice for patients with intractable epilepsy.

Slow Titration of Cannabidiol Add-On in Drug-Resistant Epilepsies Can Improve Safety With Maintained Efficacy in an Open-Label Study

Objective: To assess adverse events (AEs) and efficacy of add-on cannabidiol (CBD) with a slower titration protocol in pediatric clinical practice. Methods: We conducted a prospective, open-label, multicenter study in seven French reference centers for rare epilepsies. Patients had slow titration to reach a target dose of 10 mg/kg/day within at least 1 month and then gradually increased to a maximum dose of 20 mg/kg/day. We analyzed AEs and efficacy at M1 (month 1), M2, and M6, comparing two sets of subgroups: Dravet syndrome (DS) vs. Lennox-Gastaut (LGS) and patients with clobazam (CLB+) vs. patients without (CLB-). Results: One hundred and twenty-five patients were enrolled (62 LGS, 48 DS, 5 Tuberous sclerosis, and 10 other etiologies). Median concomitant antiepileptic drugs (AEDs) was three (25th percentile: 3, 75th percentile: 4). Patients received a dose of 10 (10-12), 14 (10-20), and 15.5 mg/kg/day (10-20) at M1, M2, and M6, respectively. Twenty-six patients discontinued CBD, 19 due to lack of efficacy, 2 due to AEs, 4 for both, and 1 had a sudden unexpected death in epilepsy. AEs were reported in 61 patients (48.8%), mainly somnolence (n = 26), asthenia (n = 20), and behavior disorders (n = 16). Abnormal transaminases (≥3 times) were reported in 11 patients receiving both valproate and clobazam. AEs were significantly higher at M2 (p = 0.03) and increased with the number of AEDs (p = 0.03). At M6, total seizure frequency change from baseline was -41% ± 37.5% (mean ± standard deviation), and 28 patients (37.8%) had a reduction ≥50%. AE and efficacy did not differ between DS vs. LGS and CLB+ vs. CLB- patients. Significance: A slower titration of CBD dose delivered better tolerance with comparable efficacy to previous trials. Concomitant CLB did not increase efficacy rates but in a few cases increased AEs. This slow titration scheme should help guide clinicians prescribing CBD and allow patients to benefit from its potential efficacy.

Modifier genes in SCN1A-related epilepsy syndromes

Background

SCN1A is one of the most important epilepsy‐related genes, with pathogenic variants leading to a range of phenotypes with varying disease severity. Different modifying factors have been hypothesized to influence SCN1A‐related phenotypes. We investigate the presence of rare and more common variants in epilepsy‐related genes as potential modifiers of SCN1A‐related disease severity.

Methods

87 patients with SCN1A‐related epilepsy were investigated. Whole‐exome sequencing was performed by the Beijing Genomics Institute (BGI). Functional variants in 422 genes associated with epilepsy and/or neuronal excitability were investigated. Differences in proportions of variants between the epilepsy genes and four control gene sets were calculated, and compared to the proportions of variants in the same genes in the ExAC database.

Results

Statistically significant excesses of variants in epilepsy genes were observed in the complete cohort and in the combined group of mildly and severely affected patients, particularly for variants with minor allele frequencies of <0.05. Patients with extreme phenotypes showed much greater excesses of epilepsy gene variants than patients with intermediate phenotypes.

Conclusion

Our results indicate that relatively common variants in epilepsy genes, which would not necessarily be classified as pathogenic, may play a large role in modulating SCN1A phenotypes. They may modify the phenotypes of both severely and mildly affected patients. Our results may be a first step toward meaningful testing of modifier gene variants in regular diagnostics for individual patients, to provide a better estimation of disease severity for newly diagnosed patients.

Hippocampal deletion of NaV1.1 channels in mice causes thermal seizures and cognitive deficit characteristic of Dravet Syndrome

Dravet Syndrome is a severe childhood epileptic disorder caused by haploinsufficiency of the SCN1A gene encoding brain voltage-gated sodium channel Na_V1.1. Symptoms include treatment-refractory epilepsy, cognitive impairment, autistic-like behavior, and premature death. The specific loci of Na_V1.1 function in the brain that underlie these global deficits remain unknown. Here we specifically deleted Scn1a in the hippocampus using the Cre-Lox method in weanling mice. Local gene deletion caused selective reduction of inhibitory neurotransmission measured in dentate granule cells. Mice with local Na_V1.1 reduction had thermally evoked seizures and spatial learning deficits, but they did not have abnormalities of locomotor activity or social interaction. Our results show that local gene deletion in the hippocampus can induce two of the most severe dysfunctions of Dravet Syndrome: Epilepsy and cognitive deficit. Considering these results, the hippocampus may be a potential target for future gene therapy for Dravet Syndrome.

Influence of common SCN1A promoter variants on the severity of SCN1A-related phenotypes

Background

Pathogenic variants in SCN1A cause variable epilepsy disorders with different disease severities. We here investigate whether common variation in the promoter region of the unaffected SCN1A allele could reduce normal expression, leading to a decreased residual function of Nav1.1, and therefore to more severe clinical outcomes in patients affected by pathogenic SCN1A variants.

Methods

Five different SCN1A promoter‐haplotypes were functionally assessed in SH‐SY5Y cells using Firefly and Renilla luciferase assays. The SCN1A promoter region was analyzed in a cohort of 143 participants with SCN1A pathogenic variants. Differences in clinical features and outcomes between participants with and without common variants in the SCN1A promoter‐region of their unaffected allele were investigated.

Results

All non‐wildtype haplotypes showed a significant reduction in luciferase expression, compared to the wildtype promoter‐region (65%–80%, p = 0.039–0.0023). No statistically significant differences in clinical outcomes were observed between patients with and without common promoter variants. However, patients with a wildtype promoter‐haplotype on their unaffected SCN1A allele showed a nonsignificant trend for milder phenotypes.

Conclusion

The nonsignificant observed trends in our study warrant replication studies in larger cohorts to explore the potential modifying role of these common SCN1A promoter‐haplotypes.

Cannabidiol: A New Hope for Patients With Dravet or Lennox-Gastaut Syndromes

OBJECTIVE

To review the efficacy, safety, pharmacology and pharmacokinetics of pure, plant-derived cannabidiol (CBD; Epidiolex) in the treatment of Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS).

DATA SOURCES

Relevant information was identified through EMBASE and Ovid MEDLINE (1946 to October 2018). Product labeling and https://www.clinicaltrials.gov were also reviewed.

STUDY SELECTION/DATA EXTRACTION

English language articles evaluating efficacy and safety in humans with treatment-resistant epilepsies were reviewed; additional pharmacology and pharmacokinetic studies in humans, animals, and in vitro were also included.

DATA SYNTHESIS

Pure, plant-based CBD is a pharmaceutical grade extract that exhibits clinically significant antiseizure properties, with a hypothesized multimodal mechanism of action. In the GWPCARE trial series, CBD displayed superior efficacy in reducing key seizure frequencies (convulsive seizures in DS; drop seizures in LGS) by 17% to 23% compared with placebo as adjunctive therapy to standard antiepileptic drugs in patients 2 years of age and older. Common adverse effects were somnolence, diarrhea, and elevated hepatic transaminases. Noteworthy drug-drug interactions included clobazam, valproates, and significant inducers/inhibitors of CYP2C19 and 3A4 enzymes. Relevance to Patient Care and Clinical Practice: A discussion regarding CBD dosing, administration, adverse effects, monitoring parameters, and interactions is provided to guide clinicians. CBD offers patients with DS and LGS a new treatment option for refractory seizures.

CONCLUSION

This is the first cannabis-derived medication with approval from the US Food and Drug Administration. This CBD formulation significantly reduces seizures as an adjunct to standard antiepileptic therapies in patients ≥2 years old with DS and LGS and is well tolerated.

Outcomes and comorbidities of SCN1A-related seizure disorders

PURPOSE

Differentiating between Dravet syndrome and non-Dravet SCN1A-related phenotypes is important for prognosis regarding epilepsy severity, cognitive development, and comorbidities. When a child is diagnosed with genetic epilepsy with febrile seizures plus (GEFS+) or febrile seizures (FS), accurate prognostic information is essential as well, but detailed information on seizure course, seizure freedom, medication use, and comorbidities is lacking for this milder patient group. In this cross-sectional study, we explore disease characteristics in milder SCN1A-related phenotypes and the nature, occurrence, and relationships of SCN1A-related comorbidities in both patients with Dravet and non-Dravet syndromes.

METHODS

A cohort of 164 Dutch participants with SCN1A-related seizures was evaluated, consisting of 116 patients with Dravet syndrome and 48 patients with either GEFS+, febrile seizures plus (FS+), or FS. Clinical data were collected from medical records, semi-structured telephone interviews, and three questionnaires: the Functional Mobility Scale (FMS), the Pediatric Quality of Life Inventory (PedsQL) Measurement Model, and the Child or Adult Behavior Checklists (CBCL/ABCL).

RESULTS

Walking disabilities and severe behavioral problems affect 71% and 43% of patients with Dravet syndrome respectively and are almost never present in patients with non-Dravet syndromes. These comorbidities are strongly correlated to lower quality-of-life (QoL) scores. Less severe comorbidities occur in patients with non-Dravet syndromes: learning problems and psychological/behavioral problems are reported for 27% and 38% respectively. The average QoL score of the non-Dravet group was comparable with that of the general population. The majority of patients with non-Dravet syndromes becomes seizure-free after 10 years of age (85%).

CONCLUSIONS

Severe behavioral problems and walking disabilities are common in patients with Dravet syndrome and should receive specific attention during clinical management. Although the epilepsy course of patients with non-Dravet syndromes is much more favorable, milder comorbidities frequently occur in this group as well. Our results may be of great value for clinical care and informing newly diagnosed patients and their parents about prognosis.

Efficacy of Stiripentol and the Clinical Outcome in Dravet Syndrome

Dravet syndrome is a rare and progressive epileptic encephalopathy of infancy. Stiripentol reduces the seizure frequency in patients with Dravet syndrome. We evaluated the clinical characteristics of patients with Dravet syndrome and their response to stiripentol. We retrospectively collected the data of 21 patients (11 females; mean age, 8.2 years, range: 5.4-15 years) with Dravet syndrome who were treated with stiripentol in our outpatient clinic between June 2016 and June 2017. Patients with seizure reduction ≥50% were considered responders. Most of our patients had severe (47%) or moderate (33%) cognitive disabilities, although 14% had mild cognitive disability. There was a significant difference in both status epilepticus and age between the groups with normal/mild versus severe/moderate neurocognitive prognoses. Of the patients, 85.7% were using stiripentol. The mean duration of stiripentol use was 41.2 months (range: 24-64 months). In 12 patients (57%), the seizure frequency decreased by more than 50%, and 2 of them were seizure-free. Status epilepticus was not recorded after stiripentol treatment in 8 of 11 patients with status epilepticus. Despite the small sample size, our results suggest that stiripentol has a favorable efficacy. In addition, considering the absence of status epilepticus after treatment and the negative effects of status epilepticus on cognitive development, early treatment should be initiated in SD patients, for whom disease control is difficult.

Mortality in Dravet syndrome: A review

INTRODUCTION

Premature mortality is a major issue in Dravet syndrome (DS). To improve understanding of DS premature mortality, we conducted a comprehensive literature search with a particular emphasis on SUDEP.

METHODS

We searched PubMed, Embase, Web of Science, Cochrane, CENTRAL, CINAHL, PsycINFO, Academic Search Premier, and ScienceDirect on the following terms: "Dravet syndrome", "severe myoclonic epilepsy", "SMEI", "mortality", "survivors", "prognosis", and "death". DS cases or cohorts studies reporting mortality were included.

RESULTS

The search yielded 676 articles and 86 meeting abstracts. After removing duplicates and screening titles and abstracts, full text of 73 articles was reviewed. Only 28 articles and six meeting abstracts met inclusion criteria. Five articles and four meeting abstracts were excluded, as the case(s) were also described elsewhere. After checking the references, five additional studies were included. The 30 items reported 177 unique cases. Sudden unexpected death in epilepsy was the likely cause in nearly half of the cases (n=87, 49%), followed by status epilepticus (n=56, 32%). Drowning or accidental death was reported in 14 cases (8%), infections in 9 (5%), other causes in six (3%), and unknown in five (3%). Age at death was reported for 142 of the 177 cases (80%), with a mean age of 8.7±9.8years (SD); 73% died before the age of 10years.

DISCUSSION

Dravet syndrome is characterized by high epilepsy-related premature mortality and a marked young age at death. Sudden unexpected death in epilepsy is the leading reported cause of death in DS, accounting for nearly half of all deaths. The cause of this excess mortality remains elusive but may be explained by epilepsy severity, as well as genetic susceptibility to SUDEP.

Dynamic changes of depolarizing GABA in a computational model of epileptogenic brain: Insight for Dravet syndrome

Abnormal reemergence of depolarizing GABAA current during postnatal brain maturation may play a major role in paediatric epilepsies, Dravet syndrome (DS) being among the most severe. To study the impact of depolarizing GABA onto distinct patterns of EEG activity, we extended a neural mass model as follows: one sub-population of pyramidal cells was added as well as two sub-populations of interacting interneurons, perisomatic-projecting interneurons (basket-like) with fast synaptic kinetics GABAA (fast, I1) and dendritic-projecting interneurons with slow synaptic kinetics GABAA (slow, I2). Basket-like cells were interconnected to reproduce mutual inhibition mechanisms (I1➔I1). The firing rate of interneurons was adapted to mimic the genetic alteration of voltage gated sodium channels found in DS patients, SCN1A(+/-). We implemented the "dynamic depolarizing GABAA" mediated post-synaptic potential in the model, as some studies reported that the chloride reversal potential can switch from negative to more positive value depending on interneuron activity. The "shunting inhibition" promoted by GABAA receptor activation was also implemented. We found that increasing the proportion of depolarizing GABAA mediated IPSP (I1➔I1 and I1➔P) only (i.e., other parameters left unchanged) was sufficient to sequentially switch the EEG activity from background to (1) interictal isolated polymorphic epileptic spikes, (2) fast onset activity, (3) seizure like activity and (4) seizure termination. The interictal and ictal EEG patterns observed in 4 DS patients were reproduced by the model via tuning the amount of depolarizing GABAA postsynaptic potential. Finally, we implemented the modes of action of benzodiazepines and stiripentol, two drugs recommended in DS. Both drugs blocked seizure-like activity, partially and dose-dependently when applied separately, completely and with a synergic effect when combined, as has been observed in DS patients. This computational modeling study constitutes an innovative approach to better define the role of depolarizing GABA in infantile onset epilepsy and opens the way for new therapeutic hypotheses, especially in Dravet syndrome.

Low-dose fenfluramine in the treatment of neurologic disorders: experience in Dravet syndrome

In this paper, we review the experience with fenfluramine in epileptic and other paroxysmal disorders. Since the best available data are from the treatment of Dravet syndrome, we will focus primarily on this condition. Originally fenfluramine was launched as an anorectic agent. As early as 1985, seizure reduction in children could be demonstrated in a few cases with photosensitive, self-induced epilepsy. Hereafter, a small study was launched in patients with self-induced epilepsy. Results showed a significant seizure reduction, and review of the patient data showed that 5 of the 12 patients had Dravet syndrome. During that observation period, fenfluramine was withdrawn from the market because of cardiovascular side effects associated with prescribing higher doses in combination with phentermine for weight loss. In March 2002, a Belgian Royal Decree was issued permitting further study of fenfluramine in pediatric patients with intractable epilepsy. In 2011 under the Royal Decree, a prospective study of patients with Dravet syndrome treated with low-dose fenfluramine was initiated and is currently ongoing. The initial results are promising in terms of reduction of seizure frequency and overall tolerability.

The ketogenic diet in Dravet syndrome

Dravet syndrome is an infantile epilepsy syndrome with intractable pleomorphic seizures, cognitive impairment, and a number of comorbidities including ataxia/gait abnormalities and behavioral issues. Antiseizure medications are only partially effective in controlling seizures. Secondary to the intractable epilepsy, patients are often on multiple antiseizure medications with significant accumulative neurotoxic side effects. Specifically for Dravet syndrome, the medical literature includes both laboratory and clinical research that supports the use of the ketogenic diet. In addition, a review of the children with Dravet syndrome who were treated with the ketogenic diet at our center was undertaken. Thirteen of the 20 children (65%) with Dravet syndrome treated with the ketogenic diet experienced a greater than 50% reduction in seizure frequency. The ketogenic diet is a good alternative to medication for seizure management in children with Dravet syndrome.