Treatment of severe myoclonic epilepsy in infants with bromide and its borderline variant

Bromovalerylurea modulates GABAA receptor-mediated inhibitory neurotransmission while inducing sleep

Bromovalerylurea (BU), an acyl urea derivative, was originally developed as a hypnotic/sedative. We recently reported that BU at a dose of 50 mg/kg ameliorates sepsis, Parkinson's disease, and traumatic brain injury in Wistar rat models through its anti-inflammatory actions on microglia and macrophages. However, since BU was developed more than 100 years ago, its hypnotic mechanism and characteristics are poorly understood. Herein, we conducted an electroencephalogram (EEG) study and found that BU, when administered at a dose of more than 125 mg/kg but not at a dose of 50 mg/kg in Wistar rats, significantly increased non-rapid eye movement (NREM) sleep duration and dose-dependently decreased rapid eye movement (REM) sleep duration. This characteristic of sleep induced by BU is similar to the effect of compounds such as barbiturate, benzodiazepine, and z-drugs, all of which require γ-aminobutyric acid _A receptors (GABA_AR) for hypnotic/sedative activity. To investigate whether BU could potentiate GABA_Aergic neurotransmission, we conducted a whole-cell patch-clamp recording from pyramidal neurons in rat cortical slices to detect spontaneous GABA_AR-mediated inhibitory postsynaptic currents (IPSCs). We found that BU dose-dependently prolonged IPSCs. Importantly, the prolonged IPSCs were not attenuated by flumazenil, a benzodiazepine receptor antagonist, suggesting that modulation of IPSCs by BU is mediated by different mechanisms from that of benzodiazepine. Taken together, these data elucidate the basic characteristics of the hypnotic effects of BU and suggest that the enhancement of GABA_AR-mediated Cl^- flux may be a possible mechanism that contributes to its hypnotic/sedative activity.

Psychobehavioural and Cognitive Adverse Events of Anti-Seizure Medications for the Treatment of Developmental and Epileptic Encephalopathies

The developmental and epileptic encephalopathies encompass a group of rare syndromes characterised by severe drug-resistant epilepsy with onset in childhood and significant neurodevelopmental comorbidities. The latter include intellectual disability, developmental delay, behavioural problems including attention-deficit hyperactivity disorder and autism spectrum disorder, psychiatric problems including anxiety and depression, speech impairment and sleep problems. Classical examples of developmental and epileptic encephalopathies include Dravet syndrome, Lennox-Gastaut syndrome and tuberous sclerosis complex. The mainstay of treatment is with multiple anti-seizure medications (ASMs); however, the ASMs themselves can be associated with psychobehavioural adverse events, and effects (negative or positive) on cognition and sleep. We have performed a targeted literature review of ASMs commonly used in the treatment of developmental and epileptic encephalopathies to discuss the latest evidence on their effects on behaviour, mood, cognition, sedation and sleep. The ASMs include valproate (VPA), clobazam, topiramate (TPM), cannabidiol (CBD), fenfluramine (FFA), levetiracetam (LEV), brivaracetam (BRV), zonisamide (ZNS), perampanel (PER), ethosuximide, stiripentol, lamotrigine (LTG), rufinamide, vigabatrin, lacosamide (LCM) and everolimus. Bromide, felbamate and other sodium channel ASMs are discussed briefly. Overall, the current evidence suggest that LEV, PER and to a lesser extent BRV are associated with psychobehavioural adverse events including aggressiveness and irritability; TPM and to a lesser extent ZNS are associated with language impairment and cognitive dulling/memory problems. Patients with a history of behavioural and psychiatric comorbidities may be more at risk of developing psychobehavioural adverse events. Topiramate and ZNS may be associated with negative effects in some aspects of cognition; CBD, FFA, LEV, BRV and LTG may have some positive effects, while the remaining ASMs do not appear to have a detrimental effect. All the ASMs are associated with sedation to a certain extent, which is pronounced during uptitration. Cannabidiol, PER and pregabalin may be associated with improvements in sleep, LTG is associated with insomnia, while VPA, TPM, LEV, ZNS and LCM do not appear to have detrimental effects. There was variability in the extent of evidence for each ASM: for many first-generation and some second-generation ASMs, there is scant documented evidence; however, their extensive use suggests favourable tolerability and safety (e.g. VPA); second-generation and some third-generation ASMs tend to have the most robust evidence documented over several years of use (TPM, LEV, PER, ZNS, BRV), while evidence is still being generated for newer ASMs such as CBD and FFA. Finally, we discuss how a variety of factors can affect mood, behaviour and cognition, and untangling the associations between the effects of the underlying syndrome and those of the ASMs can be challenging. In particular, there is enormous heterogeneity in cognitive, behavioural and developmental impairments that is complex and can change naturally over time; there is a lack of standardised instruments for evaluating these outcomes in developmental and epileptic encephalopathies, with a reliance on subjective evaluations by proxy (caregivers); and treatment regimes are complex involving multiple ASMs as well as other drugs.

Klinische Charakteristika und Lebensqualität beim Dravet-Syndrom: Ergebnisse der deutschen Kohorte des „Dravet syndrome caregiver survey“ (DISCUSS)

Hintergrund

Das Dravet-Syndrom (DS) ist ein seltenes, in der frühen Kindheit beginnendes, therapierefraktäres Epilepsiesyndrom, das mit einer hohen Morbidität und Mortalität verbunden ist.

Fragestellung

Ziele der Querschnittsstudie „Dravet syndrome caregiver survey“ (DISCUSS) sind die Identifizierung und Beschreibung der Faktoren, die einen Einfluss auf die Krankheitslast von Patienten mit DS und ihre Betreuer haben können. Die Ergebnisse der deutschen Kohorte werden vorgestellt.

Material und Methoden

Die Datenerhebung erfolgte durch eine anonyme Befragung von Eltern. Die Ergebnisse wurden für die verschiedenen Altersgruppen statistisch ausgewertet.

Ergebnisse

Der Fragebogen wurde von 68 Eltern der DS-Patienten mit einem durchschnittlichen Alter von 10 Jahren (Median: 9, Spanne: 1–26) ausgefüllt. Nur 3 Patienten (4,4 %) waren in den letzten 3 Monaten anfallsfrei. Insgesamt hatten 97 % der Patienten, die älter als 5 Jahre waren (n = 45), mindestens eine Komorbidität. Die zum Befragungszeitpunkt am häufigsten eingenommenen Antiepileptika waren Valproat, Kaliumbromid, Stiripentol, Clobazam und Topiramat. In der Vergangenheit wurden Natriumkanalblocker, Phenobarbital und Levetiracetam eingesetzt, aktuell fanden diese Antiepileptika nur selten Verwendung. Die Lebensqualität der Patienten war niedriger als die der Allgemeinbevölkerung. Die Erkrankung eines Familienmitglieds mit DS beeinflusst Eltern und Geschwister in hohem Maße.

Diskussion

Trotz individueller Kombinationstherapien sind die meisten Patienten mit DS nicht anfallsfrei. Insgesamt hat sich der Einsatz von beim DS wenig wirksamer Medikamente und der kontraindizierten Natriumkanalblocker zugunsten von wirksameren Medikamenten verschoben. Neue Therapie- und Versorgungskonzepte sind notwendig, um die Versorgung der Patienten mit DS zu verbessern und Eltern und Geschwister zu entlasten.

Safety considerations selecting antiseizure medications for the treatment of individuals with Dravet syndrome

Introduction: Management of individuals with Dravet Syndrome has evolved significantly over the past 10 years. Progress has been made in understanding the pathophysiology, the long-term outcome and possible consequences of inappropriate therapies, new drugs have been approved by the regulatory authorities and patients and families expressed their needs beyond seizures' control.Areas covered: The authors aimed at providing an overview of the main antiseizure medications used in Dravet syndrome with a particular focus on safety considerations. As the highly active phase of seizures takes place before the age of 5 years, the characteristics of antiseizure medications in infancy and childhood have also been considered due to their impact on antiseizure medication safety.Expert opinion: Recent treatments, evaluated via randomized clinical trials, are promising in terms of efficacy and safety in individuals with DS. However, the balance between expected benefits and risks taken must be accurately assessed on an individual basis. There is a lack of data to understand the needs of patients and families, a major point particularly in this population, where the evaluation of efficacy and safety beyond seizures is difficult due to cognitive delay and behavioral disorders and where this evaluation is coming almost exclusively from caregivers.

Therapeutic advances in Dravet syndrome: a targeted literature review

INTRODUCTION

Dravet syndrome (DS), a prototypic developmental and genetic epileptic encephalopathy (DEE), is characterized by an early onset of treatment-refractory seizures, together with impairments in motor control, behavior, and cognition. Even with multiple conventional anti-epileptic drugs, seizures remain poorly controlled, and there has been a considerable unmet need for effective and tolerable treatments.

AREAS COVERED

This targeted literature review aims to highlight recent changes to the therapeutic landscape for DS by summarizing the most up-to-date, evidence-based research, including pivotal data from the clinical development of stiripentol, cannabidiol, and fenfluramine, which are important milestones for DS treatment, together with the latest findings of other pharmacotherapies in development. In phase III, double-blind, placebo-controlled randomized controlled trials stiripentol, cannabidiol, and fenfluramine have shown clinically relevant reductions in convulsive seizure frequency, and are generally well tolerated. Stiripentol was associated with responder rates (greater than 50% reduction in convulsive seizure frequency) of 67%-71%, when added to valproic acid and clobazam; cannabidiol was associated with responder rates of 43%-49% (48%-63% in conjunction with clobazam), and fenfluramine of 54%-68% across studies. Therapies in development include soticlestat, ataluren, verapamil, and clemizole, with strategies to treat the underlying cause of DS, including gene therapy and antisense oligonucleotides beginning to emerge from preclinical studies.

EXPERT OPINION

Despite the challenges of drug development in rare diseases, this is an exciting time for the treatment of DS, with the promise of new efficacious and well-tolerated therapies, which may pave the way for treatment advances in other DEEs.

A two-year-old male child with Doose syndrome: An unusual entity

Introduction: Myoclonic-astatic epilepsy of early childhood (MAE)/Doose syndrome (DS) is an infrequent entity causing myoclonic-astatic seizures. Case Report: A 2-year-old male child presenting with history of seizures from one year, inability to speak and choreiform movements. He had isolated speech delay with other quadrants being normal (speaks monosyllables at two years). Parents noticed brief jerky movements of both upper and lower limbs with increasing intensity over 2–3 months which became a daily occurrence. Also, the child had episodes of abrupt loss of contact with surroundings and prolonged staring (3–5 minutes) and few eye blinks. Subsequently, by 1.5 years, he started having episodes of sudden forward bending of head followed by frequent falls. Jerks either preceded or followed falls. Decreased attention and hyperactivity had started by one year of the illness. Electroencephalography depicted polysharp waves with maximum voltage of 180 μV and 3–4 Hz@ an interval of 20–30 seconds bilaterally. He responded to oral sodium valproate, levetiracetam, and ketogenic diet. Conclusion: We report a 2-year-old male child with Doose syndrome, a distinct yet rare entity.

Potassium Bromide in the Treatment of Pediatric Refractory Epilepsy

OBJECTIVE

We evaluated potassium bromide's (KBr's) efficacy and tolerability for pediatric refractory epilepsy.

METHODS

We retrospectively reviewed the records of 42 patients treated with KBr in our hospital between 2008 and 2016 (age: 4 months to 19 years; mean: 6.2 years). Thirteen of them had 2 seizure types. The treatment durations ranged from 1 month to 6 years (mean: 15.0 months).

RESULTS

KBr had an excellent effect (seizure-free status) in 3 patients (7.1%), a moderate effect (>50% reduction in seizure frequency from the pretreatment baseline) in 21 patients (50.0%), and no effect (<50% reduction in seizure frequency from the pretreatment baseline) in 18 patients (42.9%). The effective daily doses ranged from 20 to 80 mg/kg (mean: 50.0 mg/kg). KBr was effective in 59.1% patients with generalized epilepsy (n = 22), 55.6% patients with focal epilepsy (n = 18), and both patients with Dravet syndrome. An excellent or moderate effect was found in 72.2% patients with tonic seizures (n = 18), 66.6% patients with generalized tonic-clonic seizures (n = 6), 75.0% patients with secondary generalized seizures (n = 4), 46.2% patients with focal seizures (n = 13), and 20% patients with infantile spasms (n = 10) but no patients with myoclonic seizures (n = 2). Adverse effects including drowsiness, excitement, and rashes were reported in 13 patients (31.0%).

CONCLUSIONS

These findings suggest that KBr is particularly effective for tonic seizures, generalized tonic-clonic seizures, and secondary generalized seizures. Although the adverse effects need further attention, KBr should be considered for pediatric refractory epilepsy.

Seizure management and prescription patterns of anticonvulsants in Dravet syndrome: A multicenter cohort study from Germany and review of literature

OBJECTIVE

The aim of this study was to describe the treatment pattern of patients with Dravet syndrome (DS) in Germany with routine antiepileptic drugs (AEDs) and emergency medication, and to review the literature of real-world evidence on medicine utilization of patients with DS in Europe.

METHODS

Patient use of routine AEDs and emergency medications over 3-6 months was analyzed from a 2018 multicenter survey of 93 caregivers of patients with DS throughout Germany. Results were contextualized in a review of real-world evidence on medicine utilization of patients with DS in Europe.

RESULTS

The variety of medications and the most frequent combinations routinely used by patients with DS (AEDs and others) are described. Patients use a large number of pharmaceutical treatments to manage seizures. The five most commonly used AEDs were sodium valproate (66% of the patients; mean daily dose: 660 mg; 24.5 mg per kg bodyweight), bromide (44%; 1462 mg; 51.2 mg per kg), clobazam (41%; 10.4 mg; 0.32 mg per kg), stiripentol (35%; 797 mg; 27.6 mg per kg), and topiramate (24%; 107 mg; 3.5 mg per kg). Ninety percent had reported using emergency medications in the last 3 months;, with the most common medications being Buccolam (40%, an oromucosal form of midazolam) and diazepam (20%, mostly rectal application). No discernable relationships between current medication and age or seizure frequency were observed.

SIGNIFICANCE

This is the first comprehensive report of routine AEDs and emergency medication use in a large sample of patients with DS in Germany over a period of 3-6 months and shows that despite the most common AED combinations being in line with clinical guidelines/best practice, there is no discernable impact of best treatment on seizure frequency. We find a higher use of bromide in Germany compared with other real-world evidence in Europe.

Recent Advances in the Drug Treatment of Dravet Syndrome

Dravet syndrome is a rare but severe epilepsy syndrome that begins in the first year of life with recurrent seizures triggered by fever that are typically prolonged and hemiclonic. The epilepsy is highly drug resistant. Although development is normal at onset, over time, most patients develop moderate-to-severe intellectual disability, behavior disorders, and a characteristic crouch gait. There is a significant mortality, predominantly owing to sudden unexpected death in epilepsy. Complete seizure control is rarely attainable. Initial therapy includes valproic acid and clobazam, but response is typically inadequate. The results of new drugs for Dravet syndrome, including stiripentol, cannabidiol, and fenfluramine, are very promising. Stiripentol was associated with a greater than 50% reduction in convulsive seizure frequency in 71% of cases, when added to valproic acid and clobazam, and also markedly reduced status epilepticus. Pharmaceutical-grade cannabidiol resulted in a median change in monthly motor seizures from baseline of - 36.5%. Fenfluramine was associated with a greater than 50% reduction in seizures of 70%, with one quarter of cases achieving near seizure freedom over the duration of the trial. These agents are generally well tolerated, with few patients discontinuing for adverse effects. There is limited evidence to date regarding improvement in cognition with these newer agents; however, a meaningful change is challenging to assess over short trial periods and requires longer follow-up studies. While current treatments focus predominantly on seizure control, newer therapies including genetic treatments and antisense oligonucleotides can target the SCN1A channelopathy, and thus, may also significantly impact the important co-morbidities associated with this syndrome.

The Problem of Rarity: Estimation of Prevalence in Rare Disease

BACKGROUND

From a disease's first description to its wider recognition, factors such as changes over time in diagnostic criteria, available therapies, and subsequent mortality rates may influence diagnosed prevalence of rare diseases.

OBJECTIVES

To propose a novel methodology for estimating the true prevalence of rare diseases using current incidence adjusted to changing diagnostic practice over time. This article focuses on rare diseases whose diagnosis may have changed over time, and raises the hypothesis that prevalence calculated from current incidence may be higher than diagnosed prevalence, which may lag behind the current disease definition and diagnostic methods. A rare epileptic encephalopathy, Dravet syndrome (DS), is explored as an illustrative example.

METHODS

A targeted literature review was performed for DS to identify all reported incidence, prevalence, and mortality and depict how diagnostic practice has evolved over time. A conceptual model was developed to calculate prevalence derived from current incidence figures alone (incidence-derived prevalence) or incidence adjusted with factors that cause a diagnostic drag (diagnostic awareness-adjusted prevalence).

RESULTS

We identified sufficient publications of incidence and prevalence to test the conceptual model. For pediatric patients with DS, diagnosed prevalence in the field (as reported in current literature) matches incidence-derived prevalence, whereas for adult patients, it is overestimated by incidence-derived prevalence, but not by diagnostic awareness-adjusted prevalence.

CONCLUSIONS

Care should be taken with current incidence-derived prevalence figures to not overstate the prevalence in rare diseases, as methodological challenges in counting small populations, coupled with advances in rare disease discovery, may cause discrepancies.

Vagus Nerve Stimulation in Intractable Epilepsy Associated With SCN1A Gene Abnormalities

Mutations in the SCN1A gene cause a spectrum of epilepsy syndromes. There are 2 syndromes that are on the severe end of this spectrum. The classic severe form, Dravet syndrome, is an epileptic encephalopathy of childhood, causing cognitive decline as well as intractable seizures. Severe Myoclonic Epilepsy of Infancy-Borderline (SMEIB) is a term used to include cases with similar severities as those with Dravet syndrome, but lacking a single feature of classic severe myoclonic epilepsy of infancy. Vagus nerve stimulation is a nonpharmacologic treatment for intractable epilepsy. A retrospective review was conducted of patients with deleterious SCN1A mutations who had vagus nerve stimulation placement for treatment of their intractable epilepsy. These children had onset of their epilepsy between 3 and 29 months of age. Seizure control was assessed 6 months after implantation. Twenty patients are included in the study, with 12 implanted at our institution. Nine of the 12 patients implanted at our institution, who had confirmed pre- and post-implantation seizure assessments, showed improvement in seizure control, which was defined as >50% reduction in generalized tonic-clonic seizures, and 4 of those 12 reported improvement in cognitive or speech development. Seven of the 8 patients not implanted at our institution reported subjective benefit, with 4 relating "marked improvement" or seizure freedom. Vagus nerve stimulation appears to impart a benefit to children with deleterious SCN1A gene abnormalities associated with intractable epilepsy.

Optimizing the Diagnosis and Management of Dravet Syndrome: Recommendations From a North American Consensus Panel

OBJECTIVES

To establish standards for early, cost-effective, and accurate diagnosis; optimal therapies for seizures; and recommendations for evaluation and management of comorbidities for children and adults with Dravet syndrome, using a modified Delphi process.

METHODS

An expert panel was convened comprising epileptologists with nationally recognized expertise in Dravet syndrome and parents of children with Dravet syndrome, whose experience and understanding was enhanced by their active roles in Dravet syndrome associations. Panelists were asked to base their responses to questions both on their clinical expertise and results of a literature review that was forwarded to each panelist. Three rounds of online questionnaires were conducted to identify areas of consensus and strength of that consensus, as well as areas of contention.

RESULTS

The panel consisted of 13 physicians and five family members. Strong consensus was reached regarding typical clinical presentation of Dravet syndrome, range of electroencephalography and magnetic resonance imaging findings, need for genetic testing, critical information that should be conveyed to families at diagnosis, priorities for seizure control and typical degree of control, seizure triggers and recommendations for avoidance, first- and second-line therapies for seizures, requirement and indications for rescue therapy, specific recommendations for comorbidity screening, and need for family support. Consensus was not as strong regarding later therapies, including vagus nerve stimulation and callosotomy, and for specific therapies of associated comorbidities. Beyond the initial treatment with benzodiazepines and use of valproate, there was no consensus on the optimal in-hospital management of convulsive status epilepticus.

CONCLUSIONS

We were able to identify areas where there was strong consensus that we hope will (1) inform health care providers on optimal diagnosis and management of patients with Dravet syndrome, (2) support reimbursement from insurance companies for genetic testing and Dravet syndrome-specific therapies, and (3) improve quality of life for patients with Dravet syndrome and their families by avoidance of unnecessary testing and provision of an early accurate diagnosis allowing optimal selection of therapeutic strategies.

Treatment of Dravet Syndrome

Dravet syndrome is among the most challenging electroclinical syndromes. There is a high likelihood of recurrent status epilepticus; seizures are medically refractory; and patients have multiple co-morbidities, including intellectual disability, behaviour and sleep problems, and crouch gait. Additionally, they are at significant risk of sudden unexplained death. This review will focus predominantly on the prophylactic medical management of seizures, addressing both first-line therapies (valproate and clobazam) as well as second-line (stiripentol, topiramate, ketogenic diet) or later options (levetiracetam, bromides, vagus nerve stimulation). Sodium channel agents-including carbamazepine, oxcarbazepine, phenytoin and lamotrigine-should be avoided, as they typically exacerbate seizures. Several agents in development may show promise, specifically fenfluramine and cannabidiol, but they need further evaluation in randomized, controlled trials. In addition to prophylactic treatment, all patients need home-rescue medication and a status epilepticus protocol that can be carried out in their local hospital. Families must be counselled on non-pharmacologic strategies to reduce seizure risk, including avoidance of triggers that commonly induce seizures (including hyperthermia, flashing lights and patterns). In addition to addressing seizures, holistic care for a patient with Dravet syndrome must involve a multidisciplinary team that includes specialists in physical, occupational and speech therapy, neuropsychology, social work and physical medicine.

Successful treatment of migrating partial seizures in Wolf-Hirschhorn syndrome with bromide

A girl with mild psychomotor developmental delay developed right or left hemiclonic convulsion at 10months of age. One month later, clusters of hemiclonic or bilateral tonic seizures with eyelid twitching emerged, resulting in status epilepticus. Treatment with phenobarbital and potassium bromide completely terminated the seizures within 10days. Ictal electroencephalography revealed a migrating focus of rhythmic 3-4Hz waves from the right temporal to right frontal regions and then to the left frontal regions. Genetic analysis was conducted based on the characteristic facial appearance of the patient, which identified a 2.1-Mb terminal deletion on chromosome 4p. This is the first case of Wolf-Hirschhorn syndrome complicated by epilepsy with migrating partial seizures.

Pharmacotherapy for Dravet Syndrome

Dravet syndrome (DS) is an intractable pediatric epilepsy syndrome, starting in early childhood. This disorder typically manifests with febrile status epilepticus, and progresses to a multifocal epilepsy with febrile and non-febrile seizures with encephalopathy. Most cases are due to a mutation in the SCN1A gene. This article reviews treatments for DS, with an emphasis on pharmacotherapy. While many medications are used in treating the seizures associated with DS, these patients typically have medically refractory epilepsy, and polytherapy is often required. First-line agents include valproate and clobazam, although there are supportive data for topiramate, levetiracetam, stiripentol and the ketogenic diet. Other agents such as fenfluramine are promising therapies for Dravet syndrome. Sodium channel-blocking anticonvulsants such as carbamazepine and lamotrigine are generally contraindicated in this syndrome. Nonpharmacologic therapies (such as neurostimulation or surgery) are understudied in DS. Because DS is a global encephalopathy, pharmacologic treatment of non-epileptic manifestations of the disease is often necessary. Attention-deficit hyperactivity disorder is often encountered in patients with DS, and psychostimulants can be helpful for this indication. Other psychoactive drugs are less studied in this context. Extrapyramidal and gait disorders are often encountered in DS as well. While DS is a severe epileptic encephalopathy with a high (up to 15 %) mortality rate in childhood, careful pharmacologic management can improve these patients' clinical picture and quality of life.

Efficacy of antiepileptic drugs for the treatment of Dravet syndrome with different genotypes

OBJECTIVE

Evaluation of the efficacy of antiepileptic drugs (AEDs) used in the treatment of Dravet syndrome (DS) with different genotypes.

METHODS

Patients with DS were recruited from different tertiary hospitals. Using a direct sequencing method and Multiplex Ligation-Dependent Probe Amplification (MLPA), genetic abnormalities were assessed within the exons and flanking introns of SCN1A gene, which encodes the α1 subunit of neuronal sodium channels. Patients were divided into SCN1A-positive and SCN1A-negative groups according to the results of genetic tests. Medical records, including detailed treatment information, were surveyed to compare the effect of different AEDs on clonic or tonic-clonic seizures (GTCS). Efficacy variable was responder rate with regard to seizure reduction.

RESULTS

One hundred and sixty of 276 (57.97%) patients had mutation in SCN1A gene (only 128 of them had provided detailed medical records). Among the 116 patients without SCN1A mutations, 87 had provided detailed medical records. Both older AEDs (valproate, phenobarbital, bromide, carbamazepine, clonazepam, and clobazam) and newer AEDs such as zonisamide were used in these patients. Valproate was the most frequently used AED (86.72% in the SCN1A-positive group, 78.16% in the SCN1A-negative group), with 52.25% and 41.18% responder rates in SCN1A-positive and SCN1A-negative patients, respectively (P=0.15). Bromide was used in 40.63% of the SCN1A-positive patients and 20.69% of the SCN1A-negative patients, and its responder rates were 71.15% and 94.44% in SCN1A-positive and SCN1A-negative patients, respectively (P=0.05). Efficacy rates of clonazepam, clobazam, phenobarbital, and zonisamide ranged from 30% to 50%, and these rates were not correlated with different genotypes (P>0.05). Carbamazepine had either no effect or aggravated seizures in all SCN1A-positive patients.

SIGNIFICANCE

Bromide is most effective and is a well-tolerated drug among DS patients, especially among SCN1A-negative patients. Carbamazepine should be avoided in patients with SCN1A mutations.

Antiepileptic drugs for the treatment of severe myoclonic epilepsy in infancy

BACKGROUND

Severe myoclonic epilepsy in infants (SMEI), also known as Dravet syndrome, is a rare, refractory form of epilepsy, for whose treatment stiripentol (STP) has been recently licensed for add-on use.

OBJECTIVES

To evaluate the efficacy and tolerability of STP and other antiepileptic drug treatments (including ketogenic diet) as therapy for patients with SMEI.

SEARCH METHODS

We searched the Cochrane Epilepsy Group Specialised Register (15 May 2013), the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 4 of 12, The Cochrane Library, April 2013), MEDLINE (1946 to May 2013) and SCOPUS (1823 to May 2013). The online trials registries ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform were systematically searched. The bibliographies of any identified study were searched for further references. We handsearched selected journals and conference proceedings. No language restrictions were imposed.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-randomised controlled trials; double- or single-blinded or unblinded trials; and parallel-group studies. Administration of at least one antiepileptic drug therapy given singly (monotherapy) or in combination (add-on therapy) compared with add-on placebo or no add-on treatment.

DATA COLLECTION AND ANALYSIS

Review authors independently selected trials for inclusion according to predefined criteria, extracted relevant data and evaluated the methodological quality of trials. The following outcomes were assessed: at least 50% seizure reduction, seizure freedom, adverse effects, proportion of dropouts and quality of life. Outcomes were assessed using a Mantel-Haenszel meta-analysis to calculate risk ratio (RR) with 95% confidence intervals (95% CIs).

MAIN RESULTS

No RCTs assessing drugs other than STP were found. Two RCTs evaluating the use of STP (total of 64 children) were included. Both studies were generally at unclear risk of bias. A significantly higher proportion of participants had 50% or greater reduction in seizure frequency in the STP group compared with the placebo group (22/33 vs 2/31; RR 10.40, 95% CI 2.64 to 40.87). A significantly higher proportion of participants achieved seizure freedom in the STP group compared with the placebo group (12/33 vs 1/31; RR 7.93, 95% CI 1.52 to 41.21). No significant difference in the proportion of dropouts was found in the STP group compared with the placebo group (2/33 vs 8/31; RR 0.24, 95% CI 0.06 to 1.03). Only one study explicitly reported the occurrence of side effects; higher proportions of participants were reported to experience side effects in the STP group compared with the placebo group (100% vs 25%; RR 3.73, 95% CI 1.81 to 7.67).

AUTHORS' CONCLUSIONS

Data derived from two small RCTs indicate that STP is significantly better than placebo with regards to 50% or greater reduction in seizure frequency and seizure freedom. Adverse effects occurred more frequently with STP. Further adequately powered studies with long-term follow-up should be conducted to unequivocally establish the long-term efficacy and tolerability of STP in the treatment of SMEI.

Advancing the management of childhood epilepsies

Childhood epilepsies comprise a heterogeneous group of disorders and syndromes that vary in terms of severity, prognosis and treatment requirements. Effective management requires early, accurate recognition and diagnosis, and a holistic approach that addresses each individual's medical and psychosocial needs within the context of their overall health status and quality of life. With increasing understanding of underlying aetiologies, new approaches to management and treatment are emerging. For example, genetic testing is beginning to provide a tool to aid differential diagnosis and a means of predicting predisposition to particular types of epilepsy. Despite the availability of an increasing number of antiepileptic drugs (AEDs)--due not only to the development of new AEDs, but also to changes in regulatory requirements that have facilitated clinical development--seizure control and tolerability continue to be suboptimal in many patients, and there is therefore a continuing need for new treatment strategies. Surgery and other non-pharmacological treatments (e.g. vagus nerve stimulation, ketogenic diet) are already relatively well established in paediatric epilepsy. New pharmacological treatments include generational advances on existing AEDs and AEDs with novel modes of action, and non-AED pharmacological interventions, such as immunomodulation. Emerging technologies include novel approaches allowing the delivery of medicinal agents to specific areas of the brain, and 'closed-loop' experimental devices employing algorithms that allow treatment (e.g., electrical stimulation) to be targeted both spatially and temporally. Although in early stages of development, cell-based approaches (e.g., focal targeting of adenosine augmentation) and gene therapy may also provide new treatment choices in the future.

The clinical utility of an SCN1A genetic diagnosis in infantile-onset epilepsy

AIM

Genetic testing in the epilepsies is becoming an increasingly accessible clinical tool. Mutations in the sodium channel alpha 1 subunit (SCN1A) gene are most notably associated with Dravet syndrome. This is the first study to assess the impact of SCN1A testing on patient management from both carer and physician perspectives.

METHOD

Participants were identified prospectively from referrals to the Epilepsy Genetics Service in Glasgow and contacted via their referring clinicians. Questionnaires exploring the consequences of SCN1A genetic testing for each case were sent to carers and physicians.

RESULTS

Of the 244 individuals contacted, 182 (75%) carried a SCN1A mutation. Carers of 187 (77%) patients responded (90 females, 97 males; mean age at referral 4 y 10 mo; interquartile range 9 y 1 mo). Of those participants whose children tested positive for a mutation, 87% reported that genetic testing was helpful, leading to treatment changes resulting in fewer seizures and improved access to therapies and respite care. Out of 187 physicians, 163 responded (87%), of whom 48% reported that a positive test facilitated diagnosis earlier than with clinical and electroencephalography data alone. It prevented additional investigations in 67% of patients, altered treatment approach in 69%, influenced medication choice in 74%, and, through medication change, improved seizure control in 42%.

INTERPRETATION

In addition to confirming a clinical diagnosis, a positive SCN1A test result influenced treatment choice and assisted in accessing additional therapies, especially in the very young.

Dravet syndrome (severe myoclonic epilepsy in infancy)

Severe myoclonic epilepsy in infancy (SMEI) is a rare disease, characterized by febrile and afebrile, generalized and unilateral, clonic or tonic-clonic seizures that occur in the first year of life in an otherwise apparently normal infant. They are later associated with myoclonus, atypical absences, and partial seizures. Developmental delay becomes apparent within the second year of life and is followed by definite cognitive impairment and personality disorders of variable intensity. In the borderline form, children do not present with myoclonic symptoms but have the same general picture. SMEI is a channelopathy and the genetic studies have shown a mutation in the SCN1A gene in 70 to 80% of the patients, including the borderline forms. At present, there are no well-established correlations between genotype and phenotype. The electroencephalograms, often normal at the onset, display both generalized and focal anomalies, without a specific electroencephalographic pattern. As a rule, neuroimaging is normal. All seizure types are resistant to antiepileptic drugs and status epilepticus is frequent. Some drugs have been shown to aggravate the seizures and must be avoided. Two recent drugs have been proved to partially control the convulsive seizures and the status epilepticus. Therefore, it is crucial to diagnose this epilepsy soon after its onset in order to prescribe the most appropriate treatment.

Short-term effects of combined treatment with potassium bromide and methimazole in patients with Graves' disease

BACKGROUND

Potassium bromide is used as a sedative and an anti-epileptic drug for children and adolescents. Rodent animal studies have shown that bromide ions inhibit thyroid hormone synthesis by decreasing the iodine concentration in thyroid tissue.

AIM

To observe the short-term clinical effects of combined treatment with potassium bromide and methimazole in patients with Graves' disease.

MATERIALS AND METHODS

Sixty patients with Graves' diseases were randomized in groups. Thirty patients in the combined treatment group were treated with methimazole (10 mg, tid) and potassium bromide (1 g, tid); 30 patients in the methimazole only group were treated with methimazole (10 mg, tid) and starch placebo (1 g, tid). All the patients were treated with metoprolol tartrate (25 mg, bid) to control the symptoms and signs of hyperthyroidism. Patients were treated for one month. Clinical symptoms and potential side effects were monitored. Serum thyroid hormone levels were measured before and after the treatments.

RESULTS

Clinical hyperthyroidism symptoms were improved in both groups, with or without potassium bromide. Patients in the combined treatment group displayed improved clinical hyperthyroidism symptoms 10 days earlier on average (p<0.05). Furthermore, blood thyroid hormone levels decreased to normal levels in 93% (28/30) of patients in the combined treatment group, compared with only 37% (5/30) of patients in the methimazole only group (p<0.05).

CONCLUSIONS

Treatment of patients with Graves' disease with a novel combination therapy consisting of potassium bromide and methimazole resulted in a rapid improvement in clinical symptoms and decreased blood thyroid hormone levels to homeostatic levels faster than methimazole treatment alone.

A systematic review of the safety of potassium bromide in dogs

OBJECTIVE

To critically evaluate and summarize available information on the safety of potassium bromide in dogs.

DESIGN

Systematic review.

SAMPLE

111 references reporting safety information relevant to potassium bromide published between 1938 and 2011.

PROCEDURES

PubMed searches without date limitations were conducted with the terms "potassium bromide" and "sodium bromide" in December 2009 and October 2011. Additional articles were identified through examination of article reference lists and book chapters on seizures in dogs and pharmacology.

RESULTS

Reversible neurologic signs were the most consistently reported toxicoses and were generally associated with adjunctive potassium bromide treatment or high serum bromide concentrations. Dermatologic and respiratory abnormalities were rare in dogs. Insufficient information was available to assess the effects of potassium bromide on behavior or to determine the incidence of vomiting, weight gain, polyphagia, pancreatitis, polyuria, polydipsia, or reproductive abnormalities associated with potassium bromide administration. Evidence suggested that administration of potassium bromide with food may alleviate gastrointestinal irritation and that monitoring for polyphagia, thyroid hormone abnormalities, and high serum bromide concentrations may be beneficial.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that potassium bromide is not an appropriate choice for treatment of every dog with seizures and that practitioners should tailor therapeutic regimens and clinical monitoring to each dog. Abrupt dietary changes or fluid therapy may compromise seizure control or increase the likelihood of adverse events. Availability of an appropriately labeled, approved potassium bromide product could provide better assurance for veterinarians and their clients of the quality, safety, and effectiveness of the product for veterinary use.

Therapy for hyperthermia-induced seizures in Scn1a mutant rats

PURPOSE

Mutations in the SCN1A gene, which encodes the α1 subunit of voltage-gated sodium channels, cause generalized epilepsy with febrile seizures plus (GEFS+) and severe myoclonic epilepsy of infancy (SMEI). N1417H-Scn1a mutant rats are considered to be an animal model of human FS+ or GEFS+. To assess the pharmacologic validity of this model, we compared the efficacies of eight different antiepileptic drugs (AEDs) for the treatment of hyperthermia-induced seizures using N1417H-Scn1a mutant rats.

METHODS

AEDs used in this study included valproate, carbamazepine (CBZ), phenobarbital, gabapentin, acetazolamide, diazepam (DZP), topiramate, and potassium bromide (KBr). The effects of these AEDs were evaluated using the hot water model, which is a model of experimental FS. Five-week-old rats were pretreated with each AED and immersed in water at 45°C to induce hyperthermia-induced seizures. The seizure manifestations and video-electroencephalographic recordings were evaluated. Furthermore, the effects of each AED on motor coordination and balance were assessed using the balance-beam test.

KEY FINDINGS

KBr significantly reduced seizure durations, and its anticonvulsant effects were comparable to those of DZP. On the other hand, CBZ decreased the seizure threshold. In addition, DZP and not KBr showed significant impairment in motor coordination and balance.

SIGNIFICANCE

DZP and KBr showed potent inhibitory effects against hyperthermia-induced seizures in the Scn1a mutant rats, whereas CBZ exhibited adverse effects. These responses to hyperthermia-induced seizures were similar to those in patients with GEFS+ and SMEI. N1417H-Scn1a mutant rats may, therefore, be useful for testing the efficacy of new AEDs against FS in GEFS+ and SMEI patients.

Managing severe epilepsy syndromes of early childhood

Managing severe epilepsy syndromes of early childhood is challenging as the seizures are typically resistant to treatment and may cause disabling mental and behavioral problems in later life. A comprehensive treatment plan includes pharmacologic, nonpharmacologic, and surgical options. This article reviews clinical studies examining the efficacies of antiepileptic medications in reducing seizure frequency in Dravet syndrome, Doose syndrome, and Lennox-Gastaut syndrome. The benefits of the ketogenic diet for children with these severe epilepsies, together with the advantages of vagus nerve stimulation and corpus callosotomy in those patients with Lennox-Gastaut syndrome, are also discussed. Special treatment considerations for each syndrome are also highlighted to improve the management of patients with these syndromes.

Management of and prophylaxis against status epilepticus in children with severe myoclonic epilepsy in infancy (SMEI; Dravet syndrome)--a nationwide questionnaire survey in Japan

The aim of this study was to establish strategies for prophylaxis against status epilepticus (SE) associated with high fever and for management of ongoing SE in children with severe myoclonic epilepsy in infancy (SMEI).

METHODS

The investigation was performed retrospectively using a questionnaire, asking about medications, which was distributed to epilepsy specialists throughout Japan. All respondents were members of the Japan Epilepsy Society (JES) and/or the Japanese Society of Child Neurology (JSCN). Data from 109 SMEI patients (51 males and 58 females), 1-37 (M+/-SD, 10.7+/-6.53) years old, were used for this study. Of these 109 patients, 10 were excluded because they had not experienced SE, such that data from 99 patients were analyzed.

RESULTS

Among the anti-epileptic drugs (AEDs) used daily, excellent efficacy against SE evolution was obtained with the following: potassium bromide (KBr) (41.7%), zonisamide (ZNS) (13.5%), clobazam (CLB) (10.0%), valproate (VPA) (8.0%), phenobarbital (PB) (6.7%), and phenytoin (PHT) (2.6%). Excellent efficacy was not obtained with either clonazepam (CZP) or carbamazepine (CBZ). The diazepam (DZP) suppository was the most frequently given drug for prophylaxis against SE triggered by fever, but only 2 (2.4%) cases showed excellent results. Excellent efficacy in terminating ongoing SE was obtained with the following medications; intravenous barbiturates (75-100%), intravenous midazolam (MDZ) (68.8%), intravenous DZP (54.3%), intravenous lidocaine (Lid) (21.4%), and intravenous PHT (15.4%).

CONCLUSIONS

Daily KBr was most efficacious for controlling seizures in SMEI patients. Early use of intravenous barbiturates is the most effective strategy in stopping SE in a subset of patients. Reliable efficacy in SE was not obtained with prophylactic DZP, intravenous benzodiazepines (BZPs), PHT and Lid.

Pharmacology, efficacy, and tolerability of potassium bromide in childhood epilepsy

This study investigated the efficacy and tolerability of potassium bromide in 113 patients (aged, 1-20 years) with severe epilepsy and generalized tonic-clonic seizures. Potassium bromide was started at 45 mg/kg and raised to 70 mg/kg (median). Steady-state blood level was reached after a median of 28 days (range, 5-95 days). The number of patients who had suffered generalized tonic-clonic seizures during the last month dropped from 82 to 41, and the median frequency, dropped from 4.5 to 0 per month. Of the patients with generalized tonic-clonic seizures during baseline, 49% showed none in the last 4 weeks of the study, and another 31% showed a reduction by more than 50%. Potassium bromide should have a place as a drug of tertiary choice in the treatment of children with epilepsy. Experience with the drug and close clinical and pharmacologic monitoring are necessary to achieve the greatest possible benefit and avoid side effects.

Clinical spectrum of mutations in SCN1A gene: severe myoclonic epilepsy in infancy and related epilepsies

Severe myoclonic epilepsy in infancy (SMEI) manifests very frequent generalized tonic-clonic seizures (GTC), accompanied by myoclonic seizures, absences and partial seizures [Dravet, C., 1978. Les épilepsie grave de l'enfant. Vie Méd. 8, 543-548; Dravet, C., Roger, J., Bureau, M., Dalla Bernardina, B., 1982. Myoclonic epilepsies in childhood. In: Akimoto, H., Kazamatsuri, H., Seino, M., Ward, A. (Eds.), Advances in Epileptology. Raven Press, New York, pp. 135-140; Dravet, C., Bureau, M., Oguni, H., Fukuyama, Y., Cokar, O., 2002. Severe myoclonic epilepsy of infancy (Dravet syndrome). In: Roger, J., Bureau, M., Dravet, C., Genton, P., Tassinari, C.A., Wolf, P. (Eds.), Epileptic Syndromes in Infancy, Childhood and Adolescence, third ed. John Libbey, London, pp. 81-103]. However, there is a group of severe epilepsy that has many characteristics common to SMEI except for myoclonic seizures. We reported this group of epilepsy as intractable childhood epilepsy with GTC (ICEGTC) [Watanabe, M., Fujiwara, T., Yagi, K., Seino, M., Higashi, T., 1989b. Intractable childhood epilepsy with generalized tonic-clonic seizures. J. Jpn. Epil. Soc. 7, 96-105 (in Japanese); Fujiwara, T., Watanabe, M., Takahashi, Y., Higashi, T., Yagi, K., Seino, M., 1992. Long-term course of childhood epilepsy with intractable grand mal seizures. Jpn. J. Psychiatr. Neurol. 46, 297-302]. Recently, mutations of the neuronal voltage-gated sodium channel alphasubunit type 1 gene (SCN1A) have been found in SMEI [Claes, L., Del-Favero, J., Ceulemans, B., Lagae, L., Van Broeckhoven, C., De Jonghe, P., 2001, De novo mutations in the sodium-channel gene SCN1A cause severe myoclonic epilepsy of infancy. Am. J. Hum. Genet. 68, 327-1332]. Mutations in SCN1A are found in both SMEI and ICEGTC at high rates of 70-81%. The loci of the mutations seen in ICEGTC are quite similar to those found in SMEI, suggesting a genotypic continuity between these entities. The clinical spectrum of epilepsies harboring SCN1A mutations may be consisted of various phenotypes with GEFS+ on the mildest end and SMEI on the severest end of the spectrum.

Focal semiologic and electroencephalographic features in patients with juvenile myoclonic epilepsy

PURPOSE

A few reports have described focal electroencephalographic or clinical features or both of juvenile myoclonic epilepsy (JME), but without video-EEG documentation. We examined focal clinical and EEG features in patients with JME who underwent video-EEG monitoring.

METHODS

Twenty-six patients (nine males and 17 females) who had seizures recorded during video-EEG monitoring were included. Age at seizure onset was 0 to 22 years (mean, 12.3 years), and age at monitoring was 12 to 44 years (mean, 26.5 years). In one patient with left parietooccipital epilepsy, primary generalized tonic-clonic seizures developed after resection of the parietal tumor. Two patients had both temporal lobe epilepsy and JME. Videotaped seizures in each patient were analyzed. Interictal and ictal EEG also were analyzed for any focal features.

RESULTS

Focal semiologic features were observed in 12 (46%) of 26 patients. Six patients had focal myoclonic seizures, and two had Figure 4 sign: one with version to the left, and another had left version followed by Figure 4 sign, and left arm clonic seizure. Their ictal EEGs were generalized at onset but with a lateralized evolution over the right hemisphere. The patient who had both JME and left parietooccipital epilepsy, right arm clonic seizure, and Figure 4 sign was seen during a generalized EEG seizure. Interictally, one patient had temporal sharp waves, and another had run of spikes in the right frontal region.

CONCLUSIONS

Fourteen (54%) of 26 patients with JME exhibited focal semiologic or electroencephalographic features or both. Video-EEG was essential in reaching a correct diagnosis and choosing an appropriate antiepileptic drug regimen.

Pharmacokinetics of potassium bromide in adult horses

OBJECTIVE

To determine the pharmacokinetics of potassium bromide (KBr) in horses after single and multiple oral doses.

ANIMALS

Twelve adult Standardbred and Thoroughbred mares.

PROCEDURE

Horses were randomly assigned to two treatment groups. Group 1 horses were given a single oral dose of 120 mg/kg potassium bromide. Part 2 of the study evaluated a loading dose of 120 mg/kg KBr daily by stomach tube for 5 days, followed by 40 mg/kg daily in feed for 7 days. Serum concentrations of KBr were measured to construct concentration versus time curves and to calculate pharmacokinetic parameters. Treated horses were monitored twice daily by clinical examination. Serum concentrations of sodium, potassium and chloride ions and partial pressures of venous blood gases were determined.

RESULTS

Maximum mean serum concentration following a single dose of KBr (120 mg/kg) was 423 +/- 22 microg/mL and the mean elimination half-life was 75 +/- 14 h. Repeated administration of a loading dose of KBr (120 mg/kg once daily for 5 d) gave a maximum serum concentration 1639 +/- 156 microg/mL. The administration of lower, maintenance doses (40 mg/kg once daily) was associated with decreased serum bromide concentrations, which plateaued at approximately 1000 microg/mL. Administration of KBr was associated with significant but transient changes in serum potassium and sodium concentrations, and possible changes in base excess and plasma bicarbonate concentrations. High serum concentrations of bromide were associated with an apparent increase in serum chloride concentrations, when measured on an ion specific electrode.

CONCLUSIONS

and clinical relevance Loading doses of 120 mg/kg daily over 5 d and maintenance doses of approximately 90 mg/kg of KBr administered once daily resulted in serum bromide concentrations consistent with therapeutic efficacy for the management of seizures in other species. The clinical efficacy of this agent as an anticonvulsant medication and/or calmative in horses warrants further investigation.

Epilepsy in Wolf-Hirschhorn Syndrome (4p-)

PURPOSE

We investigated the evolution of epilepsy, seizure types, and effective drugs in Wolf-Hirschhorn syndrome, which is a malformation syndrome often with refractory seizures and status epilepticus.

METHODS

We reviewed 11 cases of Wolf-Hirschhorn syndrome (age range, 2-25 years; SD, 7.2 years) and who were treated in Osaka University or Osaka Medical Center of Research Institute for Maternal and Child Health.

RESULTS

In all patients, febrile or afebrile convulsions had developed. Epileptic seizures included alternative hemiconvulsions, generalized tonic-clonic seizures, focal clonic seizures, tonic seizures, and epileptic spasms. Seizures were often induced by a high fever or a hot bath. Status epilepticus occurred in all patients, including one patient who died at the first status epilepticus. In some cases, intratracheal intubation was needed because of respiratory insufficiency. The effective antiepileptic drugs for long-term use were sodium bromide (four of four), followed by clorazepate (CLP; one of two), and nitrazepam (NZP; two of four). Sodium bromide was particularly effective for preventing status epilepticus. The mean age of last status epilepticus in patients receiving sodium bromide (1 year 8 months) was significantly younger than that in those not treated with sodium bromide (3 year 4 months).

CONCLUSIONS

We identified that, in most patients of Wolf-Hirschhorn syndrome, the frequency of both seizures and status epilepticus decreased gradually after age 5 years. However, during infancy, status epilepticus sometimes resulted in permanent disability or even death. We propose that sodium bromide should be used as the initial treatment for the prevention of the development of status epilepticus associated with Wolf-Hirschhorn syndrome.

18FDG-PET in epilepsies of infantile onset with pharmacoresistant generalised tonic-clonic seizures

AIMS

To investigate the pathophysiology of pharmacoresistant epilepsies with cryptogenic generalised tonic-clonic seizures (GTCS) from infancy.

METHODS

18F-Deoxy-Glucose-Positron Emission Tomography 18FDG-PET) with statistical parametric mapping (SPM). Inclusion criteria were: pharmacoresistant chronic epilepsy with GTCS commencing in infancy, no focal seizures except alternating hemiconvulsions and no focal epileptic discharges in the EEG during the first year of the disease, no focal changes upon routine neuroradiological investigations, no indication of brain damage according to history and clinical examination.

RESULTS

15 boys and 15 girls with a mean age of 6.4 years (range l-14 years) were included. All still suffered from seizures despite past treatment with a mean of five drugs. Nearly all were mentally retarded, 19 to a severe and 10 to a minor degree. Fifteen were ataxic and 11 hypotonic. The EEG in 23 showed irregular generalised spike-wave discharges. PET SPM analysis revealed bioccipital hypometabolism related to sedation. Pathological monofocal hypometabolic areas were found in three, multifocal hypometabolic areas in 22 and diffuse bilateral hypometabolism in three patients. Frontal hypometabolism correlated to the degree of mental retardation, hypotonia, and ataxia. Temporomesial hypometabolism correlated to the occurrence of obtunded states and prominent delta rhythms in the EEG. Central and parietal changes were associated with the occurrence of myoclonic seizures and spike-wave discharges.

CONCLUSIONS

18FDG-PET in many of these children with cryptogenic generalised epilepsies showed multifocal hypometabolic areas of unknown aetiology. Primary cortical microdysgenesis and secondary changes due to the severe and long-standing epilepsy must be considered. Only a minority of patients showed restricted focal hypometabolism as a possible indication for surgical treatment.

Epileptic Encephalopathies with Myoclonic Seizures in Infants and Children (Severe Myoclonic Epilepsy and Myoclonic-Astatic Epilepsy)

Myoclonic attacks are not characteristic of a specific syndrome. In infancy and early childhood, they are often observed in the context of syndromes that are associated with other types of seizures and with cognitive impairment but no obvious brain lesion. Characterization of the associated seizures and age of expression allows inclusion of a number of cases in two main subgroups: severe myoclonic epilepsy (SME, or Dravet syndrome) and myoclonic-astatic epilepsy (MAE). Severe myoclonic epilepsy is an epileptic encephalopathy with invariably poor outcome in which myoclonic seizures, though frequently observed, may be absent altogether in some children. Prolonged and repeated febrile and afebrile convulsive seizures starting in infancy are the main feature and are probably causally related to cognitive decline. One third of children harbor mutation of the SCN1A gene, but the genetics of SME is probably more complex than expected with simple monogenic disorders. Treatment is usually disappointing. Myoclonic-astatic epilepsy is perhaps more a conceptual category of idiopathic myoclonic epilepsy than a discrete syndrome. Childhood-onset myoclonic-astatic attacks are the characteristic seizures associated in most with episodes of nonconvulsive status and generalized tonic-clonic seizures. Outcome is unpredictable. Either remission within a few years with normal cognition or long-lasting intractability with cognitive impairment is possible. Likewise, the effectiveness of antiepileptic drugs is variable. A number of cases of myoclonic epilepsies in infancy and early childhood, however, remain unclassified, and intermediate forms between the different syndromes exist. They must be distinguished from other syndromes with frequent brief attacks and repeated falls, especially the Lennox-Gastaut syndrome. This differentiation is often difficult and may require extensive neurophysiologic studies.

Two successful cases of bromide therapy for refractory symptomatic localization-related epilepsy

Potassium bromide was tried for two children with daily convulsive focal motor seizures with unconsciousness and focal motor seizure status. The treatment resulted in complete cessation of the attacks. It has been reported that bromide is effective for generalized tonic-clonic seizures and not for complex partial seizures, such as convulsive focal motor seizures with unconsciousness. However, our experiences provide evidence that bromide is one of the useful therapeutic agents for intractable symptomatic localization-related epilepsy.

Refractory grand mal seizures with onset during infancy including severe myoclonic epilepsy in infancy

In 1978, Dravet proposed a clinical entity called severe myoclonic epilepsy in infancy (SMEI). In the same year, a patient group, which was later called high voltage slow wave-grand mal syndrome (HVSW-GM), is reported in Japan. Both syndromes are very similar, except for seizure manifestation: generalized tonic-clonic convulsions (GTC) with myoclonic and other polymorphic seizures in SMEI vs. GTC only in HVSW-GM. To study the pathophysiology of these refractory epilepsies, the author formulated new clinical diagnostic criteria common to both syndromes as follows: GTC with onset before the age of 1 year as the principal seizure type; an epilepsy entity unclassifiable either as partial or generalized by all the clinical data including EEG findings; mental and motor dysfunction absent prior to seizure onset but appearing later; absence of epileptiform activities on EEG in the initial stage; stubborn refractoriness to conventional antiepileptic medication. Twenty-two patients meeting all of five clinical criteria above mentioned were recruited in the study. Detailed analysis of clinico-electrical features and long-term follow-up of these patients led the author to the conclusion that GTC in combination with seizures of other types will contribute to an unfavorable pathophysiological or prognostic conditions, and, especially when GTC exists in combination with myoclonic seizures, the severity of epilepsy will increase. The author claimed that the three clinical entities, SMEI, HVSW-GM, and their variant form, share certain characteristics in common and may constitute a unique epilepsy syndrome for which a new name of infantile refractory grand mal syndrome (IRGMS) was offered. This is a more basic concept with broader spectrum than SMEI, encompassing not only SMEI but also related borderlands like HVSW-GM. More recently, the author observed that early zonisamide medication within 1 year after seizure onset may improve seizure prognosis in IRGMS, by preventing the development of myoclonic seizures.

Severe myoclonic epilepsy in infants--a review based on the Tokyo Women's Medical University series of 84 cases

Severe myoclonic epilepsy in infants (SME) is one of the most malignant epileptic syndromes recognized in the latest classification of epileptic syndromes. The clinical details and electroencephalographic (EEG) characteristics have been elucidated by Dravet et al. The diagnosis of SME depends largely on the combination of clinical and EEG manifestations at different ages, of which the presence of myoclonic seizures appears to be the most important. However, because of the inclusion of different types of myoclonic attack and the lack of strict criteria for diagnosing SME, there has been some confusion as to whether patients without myoclonic seizures or myoclonus should be classified as SME, despite other identical clinical symptoms (SME borderlands (SMEB) group). Among the various clinical manifestations characterizing SME, special attention has been paid to seizures easily precipitated by fever and hot baths in Japan. We have demonstrated that the onset of myoclonic attack in these patients is very sensitive to the elevation of body temperature itself rather than its etiology. Using simultaneous EEG and rectal temperature monitoring during hot water immersion, we showed that epileptic discharges increased in frequency, and eventually developed into seizures at temperatures over 38 degrees C. We believe that the unique fever sensitivity observed in SME is similar to, but more intense than that of febrile convulsions. We have also identified a group of cases who have had innumerous myoclonic and atypical absence seizures daily which were sensitive to the constant bright light illumination. In these cases, spike discharges increased or decreased depending on the intensity of constant light illumination. Although these cases form the most resistant SME group, they lost the constant light sensitivity with increasing age, leaving only relatively common types of fever-sensitive grand mal seizures (FSGM) at the age of around 5 years. In the long run, only convulsive seizures continue, while myoclonic or absence seizures and photosensitivity disappear with advancing age, thus it is conceivable that SMEB constitutes a basic epileptic condition underlying SME. There is a clinical continuum that extends from the mildest end of SMEB to the severest end of SME with constant light sensitivity, with intermediates of frequent or infrequent myoclonic and absence seizures in-between. This spectrum concept appropriately explains the clinical variabilities between SME and SMEB during early childhood.

Successful control with bromide of two patients with malignant migrating partial seizures in infancy

A 3-month-old male and a 4-month-old female infant with intractable seizures were diagnosed as having malignant migrating partial seizures in infancy (MMPSI) with developmental arrest on the basis of characteristics of symptoms, clinical courses and EEGs. We treated these two patients with potassium bromide (80 mg/kg) after conventional antiepileptic drugs failed to adequately control the seizures. The potassium bromide therapy resulted in complete control of seizures in one patient, and more than 95% reduction in seizure frequency in the other.