Behavioral and neurotransmitter changes on antiepileptic drugs treatment in the zebrafish pentylenetetrazol-induced seizure model

Epilepsy, a recurrent neurological disorder involving abnormal neurotransmitter kinetics in the brain, has emerged as a global health concern. The mechanism of epileptic seizures is thought to involve a relative imbalance between excitatory and inhibitory neurotransmitters. Despite the recent advances in clinical and basic research on the pathogenesis of epilepsy, the complex relationship between the neurotransmitter changes and behavior with and without antiepileptic drugs (AEDs) during seizures remains unclear. To investigate the effects of AEDs such as levetiracetam (LEV), carbamazepine (CBZ), and fenfluramine (FFR) on key neurotransmitters in the pentylenetetrazol (PTZ)-induced seizures in adult zebrafish, we examined the changes in glutamic acid, gamma-aminobutyric acid (GABA), serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), choline, acetylcholine, norepinephrine, dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), and adenosine. In this study, we observed that 5-HT and DA levels in the brain increased immediately after PTZ-induced seizures. Behavioral tests clearly showed that all of these AEDs suppressed the PTZ-induced seizures. Upon treatment of PTZ-induced seizures with these AEDs, CBZ decreased the glutamic acid and FFR increased the GABA levels; however, no neurotransmitter changes were observed in the brain after LEV administration. Thus, we demonstrated a series of neurotransmitter changes linked to behavioral changes during PTZ-induced epileptic seizures when LEV, CBZ, or FFR were administered. These findings will lead to a more detailed understanding of the pathogenesis of epilepsy associated with behavioral and neurotransmitter changes under AED treatment.

Ketamine in the treatment of refractory and super-refractory status epilepticus: Experience from two centres

PURPOSE

There is insufficient evidence on the management of refractory status epilepticus (RSE) and super-RSE (SRSE). Ketamine is a N-methyl-d-aspartate receptor antagonist in the treatment of these entities. Our objectives were to study the effectiveness and safety of ketamine in the treatment of adult patients with RSE and SRSE, to determine the factors that can influence the response to ketamine, and to explore its use in patients without mechanical ventilation.

METHODS

Adult patients who had received intravenous ketamine for the treatment of RSE or SRSE at Hospital Universitario Clínico San Carlos (Madrid, Spain) or Hospital Universitari Vall d'Hebron (Barcelona, Spain) from 2017 to 2023 were retrospectively analysed.

RESULTS

This study included 58 adult patients, mean (standard deviation) age 60.2 (15.7) years, of whom 41 (70.7 %) were male; 33 (56.9 %) patients responded to ketamine without recurrence, with a low rate of adverse effects (8.6 %). The presence of SRSE at the time of ketamine initiation (OR 0.287, p = 0.028) and the time elapsed between status epilepticus onset and ketamine administration (OR 0.991, p = 0.034) were associated with worse response to ketamine. Patients treated without mechanical ventilation had similar rates of response without recurrence (62.5% vs 56.9 %) and lower mortality (37.5% vs 53.5 %) compared to the overall group.

CONCLUSION

Ketamine is an effective drug with few adverse effects. Prompt administration should be considered in patients with RSE requiring anaesthesia, in patients with SRSE, and in patients with RSE who do not respond to standard antiseizure drugs and in whom mechanical ventilation is not advised.

Issues of Women with Epilepsy and Suitable Antiseizure Drugs

Seizure aggravation in women with epilepsy (WWE) tends to occur at two specific times during the menstrual cycle: the perimenstrual phase and the ovulation period. Antiseizure drugs (ASDs), especially those that induce enzymes, can accelerate the metabolism of hormones in oral contraceptives, rendering them less effective. Estrogen in contraceptive pills increases the metabolism of lamotrigine. Physiological changes during pregnancy can significantly impact the pharmacokinetics of ASDs, potentially necessitating adjustments in dosage for women with epilepsy to maintain seizure control. The use of valproate in pregnant women is associated with the highest risk of major congenital malformations among ASDs. Risks of major congenital malformations associated with lamotrigine, levetiracetam, and oxcarbazepine were within the range reported in the general population. Exposure to valproate can lead to lower IQ in offspring. Reduced folic acid levels are linked to orofacial clefts, cardiovascular malformations, and urogenital and limb anomalies in WWE. Decreased folate levels are expected with the use of enzyme-inducing ASDs. However, a high dose of folate was associated with an increased risk of cancer in children of mothers with epilepsy. Most ASDs are generally considered safe for breastfeeding and should be encouraged. However, no single ASD is considered ideal for childbearing WWE. Lamotrigine and levetiracetam are relatively more suitable options for this situation.

Neonatal Cardiac Arrest Following Lacosamide Treatment: A Case Report

BACKGROUND

Lacosamide is an antiepileptic drug with US Food and Drug Administration approval for the treatment of partial-onset seizures in patients older than one month. Lacosamide works by selective enhancement of proteins that induce preferential slow promotion of sodium channels to the hyperpolarized inactive state. Lacosamide is generally well-tolerated; however, clinical and nonclinical studies have linked its use with cardiac side effects including PR prolongation and atrioventricular (AV) block.

RESULTS

We present the case of a three-week-old female neonatal patient born at 25 weeks' gestation who developed second-degree AV heart block and cardiac arrest after initiating lacosamide therapy. The patient was being treated for neonatal seizure complicated by intraventricular hemorrhage (grade II) and electrolyte disturbances with phenobarbital, levetiracetam, and phenytoin. Before addition of lacosamide therapy, the patient had an unremarkable electrocardiogram and no known cardiac risk factors for lacosamide. After medication discontinuation, the patient experienced no reoccurring episodes or other cardiac events.

CONCLUSION

Use of lacosamide for neonatal populations is currently under evaluation. This is the first report of adverse cardiac event (AV block) in the setting of neonatal lacosamide use. Risk of future adverse cardiac events should be evaluated when determining the safety and efficacy of lacosamide in the neonatal population.

Parents' priorities for decision-making of pediatric epilepsy treatments and perceived needs for decision support in multi-ethnic Asian clinical setting: A qualitative analysis

OBJECTIVE

To identify parents' priorities when making a decision on genetic testing and antiseizure drug (ASD) options for pediatric epilepsy and their support needs for informed decision-making in multi-ethnic Asian clinical settings.

METHODS

Qualitative in-depth interviews, using a semi-structured interview guide, were conducted with purposively selected parents of pediatric patients with newly diagnosed epilepsy or known diagnosis of epilepsy (n = 26). Interviews were audio recorded and transcribed verbatim. Thematic analysis was undertaken to generate themes.

RESULTS

Parents' narratives showed difficulty assimilating information, while knowledge deficit and emotional vulnerability led parents' desire to defer a decision for testing and ASDs to mitigate decisional burden. Priorities for decisions were primarily based on intuitive ideas of the treatment's risks and benefits, yet very few could elaborate on tradeoffs between risks and efficacy. Priorities outside the purview of the healthcare team, such as children's emotional wellbeing and family burden of ASD administration, were also considered important. Authority-of-medical-professional heuristic facilitated the ASD decision for parents who preferred shared rather than sole responsibility for a decision. Importantly, parents' support needs for informed decision-making were very much related to the availability of support mechanisms in post-treatment decisions owing to perceived uncertainty of the chosen ASD.

CONCLUSIONS

Findings suggest that multiple priorities influenced ASD decision process. To address support needs of parents for informed decision-making, more consideration should be given to post-treatment decision support through the provision of educational opportunities, building peer support networks, and developing a novel communication channel between healthcare providers and parents.

The novel dual-mechanism Kv7 potassium channel/TSPO receptor activator GRT-X is more effective than the Kv7 channel opener retigabine in the 6-Hz refractory seizure mouse model

Epilepsy, one of the most common and most disabling neurological disorders, is characterized by spontaneous recurrent seizures, often associated with structural brain alterations and cognitive and psychiatric comorbidities. In about 30% of patients, the seizures are resistant to current treatments; so more effective treatments are urgently needed. Among the ∼30 clinically approved antiseizure drugs, retigabine (ezogabine) is the only drug that acts as a positive allosteric modulator (or opener) of voltage-gated Kv7 potassium channels, which is particularly interesting for some genetic forms of epilepsy. Here we describe a novel dual-mode-of-action compound, GRT-X (N-[(3-fluorophenyl)-methyl]-1-(2-methoxyethyl)-4-methyl-2-oxo-(7-trifluoromethyl)-1H-quinoline-3-carboxylic acid amide) that activates both Kv7 potassium channels and the mitochondrial translocator protein 18 kDa (TSPO), leading to increased synthesis of brain neurosteroids. TSPO activators are known to exert anti-inflammatory, neuroprotective, anxiolytic, and antidepressive effects, which, together with an antiseizure effect (mediated by Kv7 channels), would be highly relevant for the treatment of epilepsy. This prompted us to compare the antiseizure efficacy of retigabine and GRT-X in six mouse and rat models of epileptic seizures, including the 6-Hz model of difficult-to-treat focal seizures. Furthermore, the tolerability of the two compounds was compared in mice and rats. Potency comparisons were based on both doses and peak plasma concentrations. Overall, GRT-X was more effective than retigabine in three of the six seizure models used here, the most important difference being the high efficacy in the 6-Hz (32 mA) seizure model in mice. Based on drug plasma levels, GRT-X was at least 30 times more potent than retigabine in the latter model. These data indicate that GRT-X is a highly interesting novel anti-seizure drug with a unique (first-in-class) dual-mode mechanism of action.

Therapeutic drug monitoring of newer generation antiseizure medications at the point of treatment failure

PURPOSE

The benefit of therapeutic drug monitoring (TDM) of newer generation antiseizure medications (ASM) has been little studied. A recent randomized study suggested that TDM at each medical visit did not bring a significant benefit, but the study did not investigate TDM in cases of treatment failure. Accordingly, we realized a post hoc analysis of this trial.

METHODS

We analyzed 282 TDMs in 136 patients. We compared TDM performed at visits after treatment failure versus without treatment failure, reporting the proportion of drug levels out of range and the prescriber's adherence to dosage recommendations according to measured drug levels.

RESULTS

There was no statistical difference in terms of proportion of out of range plasma drug levels (47% vs 50%, p = 0.7) or adherence of prescribers to the clinical pharmacologists' dosage recommendations (21% vs 30%, p = 0.6) between visits after treatment failure and visits without treatment failure, respectively. Knowledge of prior drug levels did not modify the results.

CONCLUSION

Systematic TDM at appointments following treatment failure showed similar results to TDM at visits without treatment failure. The prescribers' adherence with dosage recommendations was low in both cases. It is not clear whether better prescriber adherence would improve patient outcome. Furthermore, the ability to detect poor patient compliance is limited in a planned outpatient appointment. The study setting does not reflect on the general usefulness of TDM.

Alzheimer's Disease and Epilepsy: A Perspective on the Opportunities for Overlapping Therapeutic Innovation

Early-onset Alzheimer's disease (AD) is associated with variants in amyloid precursor protein (APP) and presenilin (PSEN) 1 and 2. It is increasingly recognized that patients with AD experience undiagnosed focal seizures. These AD patients with reported seizures may have worsened disease trajectory. Seizures in epilepsy can also lead to cognitive deficits, neuroinflammation, and neurodegeneration. Epilepsy is roughly three times more common in individuals aged 65 and older. Due to the numerous available antiseizure drugs (ASDs), treatment of seizures has been proposed to reduce the burden of AD. More work is needed to establish the functional impact of seizures in AD to determine whether ASDs could be a rational therapeutic strategy. The efficacy of ASDs in aged animals is not routinely studied, despite the fact that the elderly represents the fastest growing demographic with epilepsy. This leaves a particular gap in understanding the discrete pathophysiological overlap between hyperexcitability and aging, and AD more specifically. Most of our preclinical knowledge of hyperexcitability in AD has come from mouse models that overexpress APP. While these studies have been invaluable, other drivers underlie AD, e.g. PSEN2. A diversity of animal models should be more frequently integrated into the study of hyperexcitability in AD, which could be particularly beneficial to identify novel therapies. Specifically, AD-associated risk genes, in particular PSENs, altogether represent underexplored contributors to hyperexcitability. This review assesses the available studies of ASDs administration in clinical AD populations and preclinical studies with AD-associated models and offers a perspective on the opportunities for further therapeutic innovation.

Use of antipyretics for preventing febrile seizure recurrence in children: a systematic review and meta-analysis

The efficacy of antipyretics for preventing febrile seizure recurrence has been reported by a recent study, and the results might overturn previous evidence. We systematically reviewed the efficacy of antipyretics in the prevention of febrile seizure recurrence in children focused on the timing of its administration. We searched the Medline, Embase, and Cochrane Central Register of Controlled Trials databases for randomized and quasi-randomized trials and prospective non-randomized studies of aged up to 60 months, diagnosed with febrile seizure, who were treated with antipyretics. Data were extracted from eight studies. Only one study reported that antipyretics prevented the recurrence of febrile seizures within the same fever episode (9.1% in the acetaminophen group vs. 23.5% in the control group, p < 0.01). Four studies found no evidence for the efficacy of antipyretics in preventing febrile seizure recurrence in distant fever episodes (odds ratio, 0.92; 95% confidence interval, 0.57-1.48, for two randomized controlled studies).Conclusion: This review provides very limited support for the use of antipyretics in preventing febrile seizure recurrence within the same fever episode and no evidence for its use in distant fever episodes. New studies are required to evaluate this topic further and determine whether the effectiveness of antipyretics is based on intervention timing. What is Known: • Reviews of prophylactic drug management among febrile seizure children found that antipyretics had no significant benefits. • Recent data suggest that antipyretics are effective in preventing febrile seizures. What is New: • Weak evidence suggests a possible role in preventing febrile seizure recurrence within the same fever episode. • There is clearly no role for antipyretic prophylaxis in preventing febrile seizures during distant fever episodes.

Seizures and epilepsy after intracerebral hemorrhage: an update

Seizures are common after intracerebral hemorrhage, occurring in 6-15% of the patients, mostly in the first 72 h. Their incidence reaches 30% when subclinical or non-convulsive seizures are diagnosed by continuous electroencephalogram. Several risk factors for seizures have been described including cortical location of intracerebral hemorrhage, presence of intraventricular hemorrhage, total hemorrhage volume, and history of alcohol abuse. Seizures after intracerebral hemorrhage may theoretically be harmful as they can lead to sudden blood pressure fluctuations, increased intracranial pressure, and neuronal injury due to increased metabolic demand. Some recent studies suggest that acute symptomatic seizures (occurring within 7 days of stroke) are associated with worse functional outcome and increased risk of death despite accounting for other known prognostic factors such as age and baseline hemorrhage volume. However, the impact of seizures on prognosis is still debated and it remains unclear if treating or preventing seizures might lead to improved clinical outcome. Thus, the currently available scientific evidence does not support the routine use of antiseizure medication as primary prevention among patients with intracerebral hemorrhage. Only prospective adequately powered randomized-controlled trials will be able to answer whether seizure prophylaxis in the acute or longer term settings is beneficial or not in patients with intracerebral hemorrhage.

Managing epilepsy in Ramadan: Guidance for healthcare providers and patients

Ramadan is a regularly recurring period of fasting that takes place in the ninth month of the Islamic calendar. For this period, adult Muslims refrain from eating and drinking between dawn and sunset. The variation in summer daylight hours means that at temperate latitudes, fasting can last up to 20 h. It is already recognized that epilepsy control can deteriorate during Ramadan, and this may be explained by fasting-related changes to adherence to antiseizure drug regimes. This article provides specific advice to help Muslim patients prepare for Ramadan and reduce chances of exacerbation in epilepsy. In addition to advice around sleep hygiene, it explores the use of drugs or preparations of drugs that will demonstrate reduced variation during periods of fasting.

Novel brain permeant mTORC1/2 inhibitors are as efficacious as rapamycin or everolimus in mouse models of acquired partial epilepsy and tuberous sclerosis complex

Mechanistic target of rapamycin (mTOR) regulates cell proliferation, growth and survival, and is activated in cancer and neurological disorders, including epilepsy. The rapamycin derivative ("rapalog") everolimus, which allosterically inhibits the mTOR pathway, is approved for the treatment of partial epilepsy with spontaneous recurrent seizures (SRS) in individuals with tuberous sclerosis complex (TSC). In contrast to the efficacy in TSC, the efficacy of rapalogs on SRS in other types of epilepsy is equivocal. Furthermore, rapalogs only poorly penetrate into the brain and are associated with peripheral adverse effects, which may compromise their therapeutic efficacy. Here we compare the antiseizure efficacy of two novel, brain-permeable ATP-competitive and selective mTORC1/2 inhibitors, PQR620 and PQR626, and the selective dual pan-PI3K/mTORC1/2 inhibitor PQR530 in two mouse models of chronic epilepsy with SRS, the intrahippocampal kainate (IHK) mouse model of acquired temporal lobe epilepsy and Tsc1^GFAP CKO mice, a well-characterized mouse model of epilepsy in TSC. During prolonged treatment of IHK mice with rapamycin, everolimus, PQR620, PQR626, or PQR530; only PQR620 exerted a transient antiseizure effect on SRS, at well tolerated doses whereas the other compounds were ineffective. In contrast, all of the examined compounds markedly suppressed SRS in Tsc1^GFAP CKO mice during chronic treatment at well tolerated doses. Thus, against our expectation, no clear differences in antiseizure efficacy were found across the three classes of mTOR inhibitors examined in mouse models of genetic and acquired epilepsies. The main advantage of the novel 1,3,5-triazine derivatives is their excellent tolerability compared to rapalogs, which would favor their development as new therapies for TORopathies such as TSC.

Mechanisms of action of currently used antiseizure drugs

Antiseizure drugs (ASDs) prevent the occurrence of seizures; there is no evidence that they have disease-modifying properties. In the more than 160 years that orally administered ASDs have been available for epilepsy therapy, most agents entering clinical practice were either discovered serendipitously or with the use of animal seizure models. The ASDs originating from these approaches act on brain excitability mechanisms to interfere with the generation and spread of epileptic hyperexcitability, but they do not address the specific defects that are pathogenic in the epilepsies for which they are prescribed, which in most cases are not well understood. There are four broad classes of such ASD mechanisms: (1) modulation of voltage-gated sodium channels (e.g. phenytoin, carbamazepine, lamotrigine), voltage-gated calcium channels (e.g. ethosuximide), and voltage-gated potassium channels [e.g. retigabine (ezogabine)]; (2) enhancement of GABA-mediated inhibitory neurotransmission (e.g. benzodiazepines, tiagabine, vigabatrin); (3) attenuation of glutamate-mediated excitatory neurotransmission (e.g. perampanel); and (4) modulation of neurotransmitter release via a presynaptic action (e.g. levetiracetam, brivaracetam, gabapentin, pregabalin). In the past two decades there has been great progress in identifying the pathophysiological mechanisms of many genetic epilepsies. Given this new understanding, attempts are being made to engineer specific small molecule, antisense and gene therapies that functionally reverse or structurally correct pathogenic defects in epilepsy syndromes. In the near future, these new therapies will begin a paradigm shift in the treatment of some rare genetic epilepsy syndromes, but targeted therapies will remain elusive for the vast majority of epilepsies until their causes are identified. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.

Phenotypic Characterization of Larval Zebrafish (Danio rerio) with Partial Knockdown of the cacna1a Gene

The CACNA1A gene encodes the pore-forming α1 subunit of voltage-gated P/Q type Ca²⁺ channels (Ca_v2.1). Mutations in this gene, among others, have been described in patients and rodents suffering from absence seizures and episodic ataxia type 2 with/without concomitant seizures. In this study, we aimed for the first time to assess phenotypic and behavioral alterations in larval zebrafish with partial cacna1aa knockdown, placing special emphasis on changes in epileptiform-like electrographic discharges in larval brains. Whole-mount in situ hybridization analysis revealed expression of cacna1aa in the optic tectum and medulla oblongata of larval zebrafish at 4 and 5 days post-fertilization. Next, microinjection of two antisense morpholino oligomers (individually or in combination) targeting all splice variants of cacna1aa into fertilized zebrafish eggs resulted in dose-dependent mortality and decreased or absent touch response. Over 90% knockdown of cacna1aa on protein level induced epileptiform-like discharges in the optic tectum of larval zebrafish brains. Incubation of morphants with antiseizure drugs (sodium valproate, ethosuximide, lamotrigine, topiramate) significantly decreased the number and, in some cases, cumulative duration of epileptiform-like discharges. In this context, sodium valproate seemed to be the least effective. Carbamazepine did not affect the number and duration of epileptiform-like discharges. Altogether, our data indicate that cacna1aa loss-of-function zebrafish may be considered a new model of absence epilepsy and may prove useful both for the investigation of Cacna1a-mediated epileptogenesis and for in vivo drug screening.

Sexual dysfunction in people with epilepsy

Sexual dysfunction is a common comorbidity in people with epilepsy (PWE) that adversely affects their quality of life. Nearly one-half of men and women with epilepsy have sexual dysfunction, but in the majority, this often goes unnoticed. The wide variation in the reported prevalence of sexual dysfunction in PWE is due to the significant heterogeneity among the studies with regard to patient population, type and severity of epilepsy, number and type of antiseizure drugs (ASDs) used, and the tools used for assessing sexual dysfunction. Generally, patients with uncontrolled epilepsy, longer duration of epilepsy, focal epilepsy, higher seizure frequency, and those receiving enzyme-inducing and multiple ASDs are more likely to have sexual dysfunction. Women generally have dysfunction in the domains of desire, while males usually have arousal disorders such as erectile dysfunction and premature ejaculation. There is limited evidence to indicate that sexual function improves in patients rendered seizure-free following epilepsy surgery. Multiple mechanisms including direct effects of epilepsy, effects of ASDs, and psychosocial factors contribute to sexual dysfunction in epilepsy. Circumstantial evidence indicates that seizures and interictal epileptiform discharges can directly affect the hypothalamic-pituitary axis as well as production of gonadal steroids. Enzyme-inducing ASDs cause sexual dysfunction by affecting the metabolism of gonadal steroids. Limited data suggest that newer ASDs including oxcarbazepine, lamotrigine, and levetiracetam cause no or minimal sexual dysfunction. Depression and anxiety significantly contribute to sexual dysfunction in PWE. A multipronged and multidisciplinary approach is essential for optimizing the sexual functions. Every effort should be made to identify and treat reversible causes including changing to nonenzyme-inducing ASDs and to provide symptomatic relief. Large, prospective studies are required to improve our understanding on prevalence and mechanisms of sexual dysfunction in PWE.

No prevention or cure of epilepsy as yet

Approximately 20% of all epilepsy is caused by acute acquired injury such as traumatic brain injury, stroke and CNS infection. The known onset of the injury which triggers the epileptogenic process, early presentation to medical care, and a latency between the injury and the development of clinical epilepsy present an opportunity to intervene with treatment to prevent epilepsy. No such treatment exists and yet there has been remarkably little clinical research during the last 20 years to try to develop such treatment. We review possible reasons for this, possible ways to rectify the situations and note some of the ways currently under way to do so. Resective surgical treatment can achieve "cure" in some patients but is sparsely utilized. In certain "self-limiting" syndromes of childhood and adolescence epilepsy remits spontaneously. In a proportion of patients who become seizure free on medications or with dietary treatment, seizure freedom persists when treatment is discontinued. We discuss these situations which can be considered "cures"; and note that at present we have little understanding of mechanism of such cures, and cannot therefore translate them into a treatment paradigm targeting a "cure" of epilepsy. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.

Balance and reaction time do not rapidly improve off antiseizure drugs

OBJECTIVE

People with epilepsy (PWE) exercise less than the general population and describe a lower level of fitness. Exercise improves comorbidities associated with epilepsy and may help seizure control. We aimed to record balance and reaction time in patients undergoing antiseizure drug (ASD) taper in the epilepsy monitoring unit (EMU) to determine if there is a reversible, dose-dependent effect of these medications.

METHODS

We tested 21 patients and 21 controls using a Wii Balance Board (WBB) and online reaction time test. The patients were recruited during an EMU stay and were tested before and after medication taper. Drug levels were also checked. Sway from center of pressure (COP) and speed of sway were tested with eyes open on two legs, eyes closed on two legs, and eyes open on one leg. Reaction time was tested.

RESULTS

Compared with controls, patients on ASDs had more sway from COP (with eyes open on two legs: p = 0.0022 in the anterior-posterior axis and p = 0.022 in the medial-lateral axis using linear regression) and worse reaction time (p < 0.001 using linear regression, adjusted for age and gender). There was no difference in reaction time or sway from COP between trials 1 and 2, before and after stopping ASDs (p = 0.2 using a paired t test for reaction time and p = 0.08 using a paired t test for speed of sway with eyes closed). There was no relationship between time since last seizure or duration of seizures and balance or reaction time.

DISCUSSION

Balance and reaction time in patients on ASD is impaired compared with controls. There is no immediate improvement in these measures following ASD withdrawal. This difference may result from vestibular or cerebellar effects. More research is needed to determine the individual effects of particular medications on balance and reaction time.

How often is antiseizure drug-free ketogenic diet therapy achieved?

The ketogenic diet (KD) is often started not only for seizure reduction but also to potentially wean antiseizure drugs (ASDs) in children with epilepsy. Although there have been several publications regarding ASD reduction on the KD, it is unknown how often complete medication withdrawal occurs. We reviewed the charts of all children started on the KD at Johns Hopkins Hospital and Johns Hopkins All Children's Hospital from 1/11 to 4/18. Children were defined as achieving drug-free diet (DFD) status if they started the KD on at least 1 ASD and achieved a period of time where they were on the KD alone. Over the time period, 232 children were evaluated; DFD status occurred in 43 (18.5%), of which 32 (13.8% of the full cohort) remained off ASDs for the remainder of their KD treatment course. Eleven children restarted ASD after a mean of 7 months. Children achieving DFD therapy were more likely to be younger, have fewer ASDs at KD onset, have Glut1 deficiency or epilepsy with myoclonic-atonic seizures, but were less likely to have Lennox-Gastaut syndrome or a gastrostomy tube.

Drug-resistant epilepsy development following stem cell transplant and cyclosporine neurotoxicity induced seizures: Case report in an adult and analysis of reported cases in the literature

Introduction

Drug-resistant epilepsy (DRE) occurs in 20–30% of all patients who develop epilepsy and can occur from diverse causes. Cyclosporine-A (CSA) is an immunosuppressive drug utilized to prevent graft-versus-host disease (GvHD) in transplant patients and is known to cause neurotoxicity, including seizures. In some cases, however, patients can develop DRE. Only a limited number of cases have been reported in which DRE has developed after CSA exposure — all in children. Here we present a rare case of an adult developing DRE after post-transplant CSA neurotoxicity. In addition, we provide a comprehensive review and analysis of all reported cases in the literature.

Case report

A 29-year-old man with Non-Hodgkin's Lymphoma underwent an allogenic hematopoietic stem cell transplant and experienced a CSA-induced seizure at 7.5 months' post-transplant. The patient was discontinued on CSA and began a low dose tacrolimus regimen. At 33 months' post-transplant, he had seizure recurrence and developed DRE. Imaging revealed right mesial temporal sclerosis (MTS) and video EEG localized ictal activity to the right anterior temporal lobe. He was successfully treated with a right anterior temporal lobectomy and amygdalohippocampectomy.

Literature review

Seven peer-reviewed studies described 15 patients who underwent transplantation with post-transplant CSA administration and subsequently developed DRE following an initial CSA-induced seizure. All 15 patients were children suggesting that young age is a risk factor for DRE after CSA-induced seizures. Initial CSA-induced seizures occurred at an average of 1.6 ± 1.1 months after transplant and seizure recurrence 9.2 ± 8.0 months after transplant. All reported CSA routes of administration (n = 6) were intravenous and 7 of 9 (78%) reported CSA blood levels above the therapeutic range. The incidence of MTS (40%) in these 15 patients was significantly higher than the incidence in the general DRE population (24%) and was most effectively treated via epilepsy surgery.

Conclusions

The use of cyclosporine for GvHD prophylaxis and treatment following transplantation may cause seizures and be associated with DRE. Although discontinuation and dose decrease of CSA often reverse adverse neurological events, initial CSA-induced seizures may be associated with MTS that and subsequent greater risk of DRE development.

Valproic acid as a monotherapy in drug-resistant methyl-CpG-binding protein 2 gene (MECP2) duplication-related epilepsy

Duplication of the methyl-CpG-binding protein 2 gene (MECP2) is a rare condition that results in epilepsy in half of the cases. Although this condition has been well characterized in the literature, there is a lack of research on MECP2 duplication-related epilepsy and its management. We present the case of an eleven-year old male with MECP2 duplication and epilepsy, who was resistant to polytherapy. The patient responded well to valproic acid (VPA) initially and upon re-challenge. This case report provides evidence for the use of VPA as an initial monotherapy for treatment of drug-resistant MECP2 duplication-related epilepsy.

Drug-induced hypersensitivity syndrome caused by valproic acid as a monotherapy for epilepsy: First case report in Asian population

Valproic acid (VPA) is a broad-spectrum antiseizure drug used for a variety of clinical conditions, such as epilepsy and mood disorders. Drug-induced hypersensitivity syndrome (DRESS) accompanied by hyponatremia, thrombocytopenia, hypoalbuminemia and elevated aminotransferase has never been reported as an adverse effect of VPA monotherapy during titration for epilepsy in Asian population. Hereby, we present the case of a 73-year-old Chinese male who suffered from DRESS and other complications two weeks after initiating VPA treatment for epilepsy. Understanding the risk associated with VPA-induced DRESS, and taking effective measures to avoid the severe side effects are necessary.

Development and pharmacologic characterization of the rat 6 Hz model of partial seizures

OBJECTIVE

The mouse 6 Hz model of psychomotor seizures is a well-established and commonly used preclinical model for antiseizure drug (ASD) discovery. Despite its widespread use both in the identification and differentiation of novel ASDs in mice, a corresponding assay in rats has not been developed. We established a method for 6 Hz seizure induction in rats, with seizure behaviors similar to those observed in mice including head nod, jaw clonus, and forelimb clonus.

METHODS

A convulsive current that elicits these seizure behaviors in 97% of rats (CC₉₇ ) was determined using a Probit analysis. Numerous prototype ASDs were evaluated in this model using stimulus intensities of 1.5× and 2× the CC₉₇ , which is comparable to the approach used in the mouse 6 Hz seizure model (e.g., 32 and 44 mA stimulus intensities). The ASDs evaluated include carbamazepine, clobazam, clonazepam, eslicarbazepine, ethosuximide, ezogabine, gabapentin, lacosamide, lamotrigine, levetiracetam, phenobarbital, phenytoin, rufinamide, tiagabine, topiramate, and sodium valproate. Median effective dose (ED₅₀ ) and median toxic (motor impairment) dose (TD₅₀ ) values were obtained for each compound.

RESULTS

Compounds that were effective at the 1.5 × CC₉₇ stimulus intensity at protective index (PI) values >1 included clobazam, ethosuximide, ezogabine, levetiracetam, phenobarbital, and sodium valproate. Compounds that were effective at the 2 × CC₉₇ stimulus intensity at PI values >1 included ezogabine, phenobarbital, and sodium valproate.

SIGNIFICANCE

In a manner similar to the use of the mouse 6 Hz model, development of a rat 6 Hz test will aid in the differentiation of ASDs, as well as in study design and dose selection for chronic rat models of pharmacoresistant epilepsy. The limited number of established ASDs with demonstrable efficacy at the higher stimulus intensity suggests that, like the mouse 6 Hz 44 mA model, the rat 6 Hz seizure model may be a useful screening tool for pharmacoresistant seizures.

Validation of a Preclinical Drug Screening Platform for Pharmacoresistant Epilepsy

The successful identification of promising investigational therapies for the treatment of epilepsy can be credited to the use of numerous animal models of seizure and epilepsy for over 80 years. In this time, the maximal electroshock test in mice and rats, the subcutaneous pentylenetetrazol test in mice and rats, and more recently the 6 Hz assay in mice, have been utilized as primary models of electrically or chemically-evoked seizures in neurologically intact rodents. In addition, rodent kindling models, in which chronic network hyperexcitability has developed, have been used to identify new agents. It is clear that this traditional screening approach has greatly expanded the number of marketed drugs available to manage the symptomatic seizures associated with epilepsy. In spite of the numerous antiseizure drugs (ASDs) on the market today, the fact remains that nearly 30% of patients are resistant to these currently available medications. To address this unmet medical need, the National Institute of Neurological Disorders and Stroke (NINDS) Epilepsy Therapy Screening Program (ETSP) revised its approach to the early evaluation of investigational agents for the treatment of epilepsy in 2015 to include a focus on preclinical approaches to model pharmacoresistant seizures. This present report highlights the in vivo and in vitro findings associated with the initial pharmacological validation of this testing approach using a number of mechanistically diverse, commercially available antiseizure drugs, as well as several probe compounds that are of potential mechanistic interest to the clinical management of epilepsy.

Cost-utility analysis of competing treatment strategies for drug-resistant epilepsy in children with Tuberous Sclerosis Complex

BACKGROUND

The management of drug-resistant epilepsy in children with Tuberous Sclerosis Complex (TSC) is challenging because of the multitude of treatment options, wide range of associated costs, and uncertainty of seizure outcomes. The most cost-effective approach for children whose epilepsy has failed to improve with first-line medical therapy is uncertain.

METHODS

A review of MEDLINE from 1990 to 2015 was conducted. A cost-utility analysis, from a third-party payer perspective, was performed for children with drug-resistant epilepsy that had failed to improve with 2 antiseizure drugs (ASDs) and that was amenable to resective epilepsy surgery, across a time-horizon of 5years. Four strategies were included: (1) resective epilepsy surgery, (2) vagus nerve stimulator (VNS) implantation, (3) ketogenic diet, and (4) addition of a third ASD (specifically, carbamazepine). The incremental cost per quality-adjusted life year (QALY) gained was analyzed.

RESULTS

Given a willingness-to-pay (WTP) of $100,000 per QALY, the addition of a third ASD ($6600 for a gain of 4.14 QALYs) was the most cost-effective treatment strategy. In a secondary analysis, if the child whose epilepsy had failed to improve with 3 ASDs, ketogenic diet, addition of a fourth ASD, and resective epilepsy surgery were incrementally cost-effective treatment strategies. Vagus nerve stimulator implantation was more expensive yet less effective than alternative strategies and should not be prioritized.

CONCLUSIONS

The addition of a third ASD is a universally cost-effective treatment option in the management of children with drug-resistant epilepsy that has failed to improve with 2 ASDs. For children whose epilepsy has failed to improve with 3 ASDs, the most cost-effective treatment depends on the health-care resources available reflected by the WTP.

The effects of carbamazepine in the intrahippocampal kainate model of temporal lobe epilepsy depend on seizure definition and mouse strain

Objective

Mesial temporal lobe epilepsy (TLE) with hippocampal sclerosis is a predominant form of acquired epilepsy, characterized by recurrent simple and complex partial seizures that are often resistant to treatment. Mice developing spontaneous recurrent nonconvulsive and convulsive seizures after intrahippocampal injection of the excitotoxic glutamate agonist kainate are thought to represent a valuable model of mesial TLE. Epileptic electroencephalogram (EEG) activity recorded in this model from the kainate focus in the ipsilateral hippocampus is resistant to antiseizure drugs such as carbamazepine (CBZ). We compared the efficacy of CBZ in this model in two different mouse strains (FVB/N and NMRI). Furthermore, we evaluated whether changes in the definition of electrographic seizures affect the antiseizure efficacy of CBZ.

Methods

As in previous studies, two types of epileptic EEG activity were defined: high-voltage sharp waves (HVSWs) and hippocampal paroxysmal discharges (HPDs). The characteristics of these paroxysmal EEG events in epileptic mice were compared with EEG criteria for nonconvulsive seizures in patients. For HVSWs, different spike frequencies, interevent intervals, and amplitudes were used as inclusion and exclusion criteria. In addition to CBZ, some experiments were performed with diazepam (DZP) and phenobarbital (PB).

Results

Female epileptic FVB/N mice predominantly exhibited frequent HVSWs, but only infrequent HPDs or secondarily generalized convulsive seizures. Slight changes in HVSW definition determined whether they were resistant or responsive to CBZ. Male NMRI mice exhibited both HVSWs and HPDs. HVSWs were more resistant than HPDs to suppression by CBZ. Both types of epileptic EEG activity were rapidly suppressed by DZP and PB.

Significance

The data demonstrate that focal electrographic seizures in the intrahippocampal kainate mouse model are less resistant than previously thought. Both mouse strain and the criteria chosen for definition of EEG seizures determine whether such seizures are drug-resistant or -responsive.

Neuronal Injury, Gliosis, and Glial Proliferation in Two Models of Temporal Lobe Epilepsy

It is estimated that 30%-40% of epilepsy patients are refractory to therapy and animal models are useful for the identification of more efficacious therapeutic agents. Various well-characterized syndrome-specific models are needed to assess their relevance to human seizure disorders and their validity for testing potential therapies. The corneal kindled mouse model of temporal lobe epilepsy (TLE) allows for the rapid screening of investigational compounds, but there is a lack of information as to the specific inflammatory pathology in this model. Similarly, the Theiler murine encephalomyelitis virus (TMEV) model of TLE may prove to be useful for screening, but quantitative assessment of hippocampal pathology is also lacking. We used immunohistochemistry to characterize and quantitate acute neuronal injury and inflammatory features in dorsal CA1 and dentate gyrus regions and in the directly overlying posterior parietal cortex at 2 time points in each of these TLE models. Corneal kindled mice were observed to have astrogliosis, but not microgliosis or neuron cell death. In contrast, TMEV-injected mice had astrogliosis, microgliosis, neuron death, and astrocyte and microglial proliferation. Our results suggest that these 2 animal models might be appropriate for evaluation of distinct therapies for TLE.