Neonatal seizures: an update on mechanisms and management

Case Report of Hyponatremic Seizures in a Term Neonate Attributed to Excessive Maternal Coconut Water Ingestion During Labor

We report the case of a term neonate who was somnolent at birth with ventilatory distress and experienced 2 seizures shortly after delivery. Laboratory tests revealed the neonate had a serum sodium of 113 mmol/L. The seizures stopped after treatment with midazolam, and the sodium was corrected slowly with 3% hypertonic saline without further sequelae. The severe neonatal hyponatremia and seizures were attributed to maternal consumption of excessive amounts of coconut water during labor. This case demonstrates the importance of careful consideration of both fluid volume and fluid electrolyte composition during labor to prevent adverse maternal and neonatal outcomes.

Determinants of neonatal seizure among neonates admitted to neonatal intensive care units in the Awi Zone hospitals, 2023: A multi-center unmatched case control study

Background

Neonatal seizure is a common medical emergency that signals severe insult to the neonatal brain. It is a major risk factor for neonatal morbidity and mortality. It has a wide worldwide variation, ranging from 5 per 1000 live births in the United States of America to 39.5 per 1000 live births in Kenya. To decrease this significant figure, it is better to investigate its causes further. Therefore, this study aimed to assess its determinants since there was no prior evidence about it in the context of study area.

Objective

Aim to assess the determinants of neonatal seizures among neonates admitted to neonatal intensive care units in the Awi Zone Hospitals, 2023.

Methods

An institution based unmatched case-control study was conducted on 531 admitted eligible neonates from January 1, 2023, to May 30, 2023. A pretested tool was employed to collect data. The collected data were coded, edited, and entered into Epi-data version 3.1 and then exported to SPSS 26. Chi-square and odds ratios were used to assess the relationship between factors associated with the occurrence of neonatal seizure. Model goodness of fit was tested by Hosmer and Lemeshow. Bivariate and multivariate analysis was declared at P < 0.25 and P < 0.05 respectively to show a significant association with neonatal seizure at a 95 % level of significance.

Results

A total of 506 (130 cases and 376 controls) of admitted neonates were used in the final analysis model. Neonates admitted within 24 h of birth [AOR; 5.98 (95 %, CI: 2.18-16.43)], gestational age <32 weeks [AOR; 2.89 (95 %, CI: 1.29-6.53)], body temperature >37.5 °C [AOR; 4.82 (95 %, CI: 1.82-12.76)], blood glucose level <40 g/dl [AOR; 4.95 (95 %, CI: 2.06,11.88)], neonatal sepsis [AOR; 2.79 (95 %, CI: 1.46-5.35)] and perinatal asphyxia [AOR; 8.25 (95 %, CI: 4.23, 16.12)] were found to be determinants of neonatal seizure.

Conclusion

and recommendations: In this study, neonatal seizure was determined by the factors of neonatal age, gestational age<32 weeks, body temperature >37.5 °C, blood glucose level <40 g/dl, neonatal sepsis, and perinatal asphyxia. Therefore, the presence of such factors requires prompt recognition and treatment.

Neonatal Seizures

Neonatal seizures are common among patients with acute brain injury or critical illness and can be difficult to diagnose and treat. The most common etiology of neonatal seizures is hypoxic-ischemic encephalopathy, with other common causes including ischemic stroke and intracranial hemorrhage. Neonatal clinicians can use a standardized approach to patients with suspected or confirmed neonatal seizures that entails laboratory testing, neuromonitoring, and brain imaging. The primary goals of management of neonatal seizures are to identify the underlying cause, correct it if possible, and prevent further brain injury. This article reviews recent evidence-based guidelines for the treatment of neonatal seizures and discusses the long-term outcomes of patients with neonatal seizures.

Can hyperoxic stress cause susceptibility to acute seizure in the neonatal period?: a rat study

Objective: Preterm neonates encounter hyperoxia relatively early, and are more exposed to hyperoxic stress due to their insufficient antioxidant defense mechanisms. This study was planned around the hypothesis that this hyperoxic effect may cause a disposition to future acute seizures. Methods: This study was composed of two main groups Hyperoxy and Control (Room air with normal O2 levels) Groups. Group 1 - hyperoxia (Study): The experimental group consisted of premature newborn rats exposed to hyperoxia with their dams from birth to postnatal day 5. Group 2 - room air (Control): The group was not exposed to hyperoxia and housed the same room air and temperature as their dams. Female, Acute Epilepsy Female, Male, Acute Epilepsy Male, and a total of eight subgroups were formed in both the control and hyperoxia groups. When the rats were two months old, intracranial electrodes were attached to obtain electrocorticography (ECoG) recordings. Pre-model recordings were taken, after which an acute pentylenetetrazole (PTZ) model of absence seizure was induced by the intraperitoneal administration of PTZ at 50 mg/kg. ECoG records were examined using the PowerLab system for 180 min. Spike wave number and duration, Spike wave frequency and amplitude data were evaluated.Results: Seven female and three male rats were exposed to hyperoxia, and a control group of five female and three male rats were included in the study. The median interquartile range for spike wave latency in the hyperoxia and control groups were 1112 (644-1545) and 654 (408-1152), frequency 4476 (3120-7421) and 3934 (2264-4704), and amplitude data 0.68 (0.59-0.79) and 0.52 (0.37-0.67), respectively. Although a difference was observed in median values capable of constituting susceptibility to epilepsy, the difference was not statistically significant (p > 0.05). In terms of gender, spike-wave counts were significantly higher in female rats (p < 0.05). Females exposed to hyperoxia were more susceptible to epilepsy than both males and females in the control group (p < 0.05).Conclusion: Exposure to hyperoxia in the first days of life of premature neonates due to their susceptibility to oxidative stress and insufficient antioxidant mechanisms, can cause a disposition to acute seizures. As a result, females exposed to hyperoxia during the neonatal period may be prone to epilepsy in maturity.

Anti-seizure medications for neonates with seizures

BACKGROUND

Newborn infants are more prone to seizures than older children and adults. The neuronal injury caused by seizures in neonates often results in long-term neurodevelopmental sequelae. There are several options for anti-seizure medications (ASMs) in neonates. However, the ideal choice of first-, second- and third-line ASM is still unclear. Further, many other aspects of seizure management such as whether ASMs should be initiated for only-electrographic seizures and how long to continue the ASM once seizure control is achieved are elusive.

OBJECTIVES

1. To assess whether any ASM is more or less effective than an alternative ASM (both ASMs used as first-, second- or third-line treatment) in achieving seizure control and improving neurodevelopmental outcomes in neonates with seizures. We analysed EEG-confirmed seizures and clinically-diagnosed seizures separately. 2. To assess maintenance therapy with ASM versus no maintenance therapy after achieving seizure control. We analysed EEG-confirmed seizures and clinically-diagnosed seizures separately. 3. To assess treatment of both clinical and electrographic seizures versus treatment of clinical seizures alone in neonates.

SEARCH METHODS

We searched MEDLINE, Embase, CENTRAL, Epistemonikos and three databases in May 2022 and June 2023. These searches were not limited other than by study design to trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that included neonates with EEG-confirmed or clinically diagnosed seizures and compared (1) any ASM versus an alternative ASM, (2) maintenance therapy with ASM versus no maintenance therapy, and (3) treatment of clinical or EEG seizures versus treatment of clinical seizures alone.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial eligibility, risk of bias and independently extracted data. We analysed treatment effects in individual trials and reported risk ratio (RR) for dichotomous data, and mean difference (MD) for continuous data, with respective 95% confidence interval (CI). We used GRADE to assess the certainty of evidence.

MAIN RESULTS

We included 18 trials (1342 infants) in this review. Phenobarbital versus levetiracetam as first-line ASM in EEG-confirmed neonatal seizures (one trial) Phenobarbital is probably more effective than levetiracetam in achieving seizure control after first loading dose (RR 2.32, 95% CI 1.63 to 3.30; 106 participants; moderate-certainty evidence), and after maximal loading dose (RR 2.83, 95% CI 1.78 to 4.50; 106 participants; moderate-certainty evidence). However, we are uncertain about the effect of phenobarbital when compared to levetiracetam on mortality before discharge (RR 0.30, 95% CI 0.04 to 2.52; 106 participants; very low-certainty evidence), requirement of mechanical ventilation (RR 1.21, 95% CI 0.76 to 1.91; 106 participants; very low-certainty evidence), sedation/drowsiness (RR 1.74, 95% CI 0.68 to 4.44; 106 participants; very low-certainty evidence) and epilepsy post-discharge (RR 0.92, 95% CI 0.48 to 1.76; 106 participants; very low-certainty evidence). The trial did not report on mortality or neurodevelopmental disability at 18 to 24 months. Phenobarbital versus phenytoin as first-line ASM in EEG-confirmed neonatal seizures (one trial) We are uncertain about the effect of phenobarbital versus phenytoin on achieving seizure control after maximal loading dose of ASM (RR 0.97, 95% CI 0.54 to 1.72; 59 participants; very low-certainty evidence). The trial did not report on mortality or neurodevelopmental disability at 18 to 24 months. Maintenance therapy with ASM versus no maintenance therapy in clinically diagnosed neonatal seizures (two trials) We are uncertain about the effect of short-term maintenance therapy with ASM versus no maintenance therapy during the hospital stay (but discontinued before discharge) on the risk of repeat seizures before hospital discharge (RR 0.76, 95% CI 0.56 to 1.01; 373 participants; very low-certainty evidence). Maintenance therapy with ASM compared to no maintenance therapy may have little or no effect on mortality before discharge (RR 0.69, 95% CI 0.39 to 1.22; 373 participants; low-certainty evidence), mortality at 18 to 24 months (RR 0.94, 95% CI 0.34 to 2.61; 111 participants; low-certainty evidence), neurodevelopmental disability at 18 to 24 months (RR 0.89, 95% CI 0.13 to 6.12; 108 participants; low-certainty evidence) and epilepsy post-discharge (RR 3.18, 95% CI 0.69 to 14.72; 126 participants; low-certainty evidence). Treatment of both clinical and electrographic seizures versus treatment of clinical seizures alone in neonates (two trials) Treatment of both clinical and electrographic seizures when compared to treating clinical seizures alone may have little or no effect on seizure burden during hospitalisation (MD -1871.16, 95% CI -4525.05 to 782.73; 68 participants; low-certainty evidence), mortality before discharge (RR 0.59, 95% CI 0.28 to 1.27; 68 participants; low-certainty evidence) and epilepsy post-discharge (RR 0.75, 95% CI 0.12 to 4.73; 35 participants; low-certainty evidence). The trials did not report on mortality or neurodevelopmental disability at 18 to 24 months. We report data from the most important comparisons here; readers are directed to Results and Summary of Findings tables for all comparisons.

AUTHORS' CONCLUSIONS

Phenobarbital as a first-line ASM is probably more effective than levetiracetam in achieving seizure control after the first loading dose and after the maximal loading dose of ASM (moderate-certainty evidence). Phenobarbital + bumetanide may have little or no difference in achieving seizure control when compared to phenobarbital alone (low-certainty evidence). Limited data and very low-certainty evidence preclude us from drawing any reasonable conclusion on the effect of using one ASM versus another on other short- and long-term outcomes. In neonates who achieve seizure control after the first loading dose of phenobarbital, maintenance therapy compared to no maintenance ASM may have little or no effect on all-cause mortality before discharge, mortality by 18 to 24 months, neurodevelopmental disability by 18 to 24 months and epilepsy post-discharge (low-certainty evidence). In neonates with hypoxic-ischaemic encephalopathy, treatment of both clinical and electrographic seizures when compared to treating clinical seizures alone may have little or no effect on seizure burden during hospitalisation, all-cause mortality before discharge and epilepsy post-discharge (low-certainty evidence). All findings of this review apply only to term and late preterm neonates. We need well-designed RCTs for each of the three objectives of this review to improve the precision of the results. These RCTs should use EEG to diagnose seizures and should be adequately powered to assess long-term neurodevelopmental outcomes. We need separate RCTs evaluating the choice of ASM in preterm infants.

Maternal hyperhomocysteinemia increases seizures susceptibility of neonatal rats

AIMS

Neonatal seizures are severe pathologies which may result in long-term neurological consequences. High plasma concentrations of homocysteine - hyperhomocysteinemia (hHCy) - are associated with epilepsy. In the present study, we evaluated susceptibility to seizure of neonatal rats with prenatal hHCy.

MAIN METHODS

Prenatal hHCy was induced by feeding females with a high-methionine diet. Experiments were performed on pups during the first three postnatal weeks. Flurothyl-induced epileptic behavior was assessed according to Racine's scale. Epileptiform activity in the hippocampus was recorded using electrophysiological methods. The balance of excitation/inhibition, functional GABAergic inhibition and GABA reversal potential in hippocampal neurons were analyzed.

KEY FINDINGS

Rats with hHCy developed more severe stages of behavioral patterns during flurothyl-induced epilepsy with shorter latency. Electrophysiological recordings demonstrated higher background neuronal activity in rats with hHCy. Seizure-like events triggered by flurothyl (in vivo) or 4-aminopyridine (in vitro) showed shorter latency, higher power and amplitude. An increased glutamate/GABA synaptic ratio was shown in the pyramidal neurons of rats with hHCy and more slices demonstrated excitation by isoguvacine, a selective GABA(A) receptor agonist, during the first and second postnatal weeks. The GABA driving force and the reversal potential of GABA(A) currents were more positive during the second postnatal week for hHCy rats.

SIGNIFICANCE

The higher susceptibility to seizures in rats with prenatal hHCy due to a shift in the balance of excitation/inhibition toward excitation may underlie the clinical evidence about the association of hHCy with an increased risk of epilepsy.

Pain and neurodevelopmental outcomes of infants born very preterm

AIM

To investigate the impact of the level of pain experienced by infants born preterm on neurodevelopmental outcomes during their stay in a neonatal intensive care unit.

METHOD

In this retrospective data analysis we included all surviving infants born preterm with a gestational age between 23 and 32 weeks from 2011 to 2015, who were assessed using the Neonatal Pain, Agitation, and Sedation Scale and examined at 1 year of age using the Bayley Scales of Infant Development. We excluded all infants who had suffered severe neurological morbidities and undergone surgical interventions.

RESULTS

A total of 196 infants born preterm were included in the analyses: 105 in the 'no pain group' and 91 in the 'pain group'. Significant differences between the groups were detected for both mental and motor development (p = 0.003, 95% confidence interval [CI] 2.23-10.92; p = 0.025, 95% CI 0.64-9.78). The results remained significant after controlling for other important medical conditions (p = 0.001, 95% CI -19.65 to -5.40; p = 0.010, 95% CI -16.18 to -2.29).

INTERPRETATION

Neonatal pain exposure was associated with altered neurodevelopmental outcomes of infants born very preterm at a corrected age of 12 months. This observation highlights the importance of adequate pain management to reduce the risk of poor neurodevelopmental outcomes in these vulnerable patients.

The P2X7 receptor contributes to seizures and inflammation-driven long-lasting brain hyperexcitability following hypoxia in neonatal mice

BACKGROUND AND PURPOSE

Neonatal seizures represent a clinical emergency. However, current anti-seizure medications fail to resolve seizures in ~50% of infants. The P2X7 receptor (P2X7R) is an important driver of inflammation, and evidence suggests that P2X7R contributes to seizures and epilepsy in adults. However, no genetic proof has yet been provided to determine what contribution P2X7R makes to neonatal seizures, its effects on inflammatory signalling during neonatal seizures, and the therapeutic potential of P2X7R-based treatments on long-lasting brain excitability.

EXPERIMENTAL APPROACH

Neonatal seizures were induced by global hypoxia in 7-day-old mouse pups (P7). The role of P2X7Rs during seizures was analysed in P2X7R-overexpressing and knockout mice. Treatment of wild-type mice after hypoxia with the P2X7R antagonist JNJ-47965567 was used to determine the effects of the P2X7R on long-lasting brain hyperexcitability. Cell type-specific P2X7R expression was analysed in P2X7R-EGFP reporter mice. RNA sequencing was used to monitor P2X7R-dependent hippocampal downstream signalling.

KEY RESULTS

P2X7R deletion reduced seizure severity, whereas P2X7R overexpression exacerbated seizure severity and reduced responsiveness to anti-seizure medication. P2X7R deficiency led to an anti-inflammatory phenotype in microglia, and treatment of mice with a P2X7R antagonist reduced long-lasting brain hyperexcitability. RNA sequencing identified several pathways altered in P2X7R knockout mice after neonatal hypoxia, including a down-regulation of genes implicated in inflammation and glutamatergic signalling.

CONCLUSION AND IMPLICATIONS

Treatments based on targeting the P2X7R may represent a novel therapeutic strategy for neonatal seizures with P2X7Rs contributing to the generation of neonatal seizures, driving inflammatory processes and long-term hyperexcitability states.

Variable Association of Physiologic Changes With Electrographic Seizure-Like Events in Infants Born Preterm

OBJECTIVES

To determine the incidence of seizure-like events in a cohort of infants born preterm as well as the prevalence of associated vital sign changes (heart rate [HR], respiratory rate, and pulse oximetry [SpO2]).

STUDY DESIGN

We performed prospective conventional video electroencephalogram monitoring on infants born at 23-30 weeks of gestational age during the first 4 postnatal days. For detected seizure-like events, simultaneously captured vital sign data were analyzed during the pre-event baseline and during the event. Significant vital sign changes were defined as HR or respiratory rate >±2 SD from the infant's own baseline physiologic mean, derived from a 10-minute interval before the seizure-like event. Significant change in SpO2 was defined as oxygen desaturation during the event with a mean SpO2 <88%.

RESULTS

Our sample included 48 infants with median gestational age of 28 weeks (IQR 26-29) and birth weight of 1125 g (IQR 963-1265). Twelve (25%) infants had seizure-like discharges with a total of 201 events; 83% (10/12) of infants had vital sign changes during these events, and 50% (6/12) had significant vital sign changes during the majority of the seizure-like events. Concurrent HR changes occurred the most frequently.

CONCLUSIONS

Individual infant variability was observed in the prevalence of concurrent vital sign changes with electroencephalographic seizure-like events. Physiologic changes associated with preterm electrographic seizure-like events should be investigated further as a potential biomarker to assess the clinical significance of such events in the preterm population.

Tolerability and Safety of Lacosamide in Neonatal Population

Lacosamide is a newer antiepileptic medication used in refractory neonatal seizures with limited safety and efficacy data. This case series spans 4 years and includes 38 neonates cared for in the neonatal, pediatric, and cardiovascular intensive care units, who received lacosamide for refractory seizures. Because lacosamide affects atrioventricular node function in adults, among other metrics, electrocardiogram (ECG) changes were monitored closely in these neonates. Within this cohort, 2 neonates were found to have atrial bigeminy on ECG and telemetry. Otherwise, lacosamide was generally well tolerated with sleepiness being the most common symptom noted. This case series reports data on the tolerability of lacosamide and emphasizes the importance of monitoring key cardiac intervals with ECG before and after the use of lacosamide in this population.

Rapid Genome Sequencing: Consent for New Technologies in the Neonatal Intensive Care Context

The clinical utility of rapid genome sequencing (rGS) in critically unwell infants has been consistently demonstrated, and there are calls for rGS to be implemented as a first-line test in the NICU. A diagnosis from rGS can enable rapid initiation of precision treatment, making it potentially lifesaving. However, in many patients rGS leads to the diagnosis of severe and life-limiting conditions, prompting discussion with families about withdrawal of life-sustaining treatment. The complexity of information about rGS, together with the heightened emotions of parents in the NICU, poses significant challenges for informed decision making in this context. We present a case where both parents are unable to provide informed consent, and the treating team must decide whether to proceed with rGS. Our discussion highlights the important differences between genome sequencing and other types of genetic testing, and the crucial role played by pre-test counseling in facilitating informed consent and preparing parents for a range of possible outcomes. We then discuss the consent paradigms at play in NICUs; whereas admission generally comes with an understanding that the treating team will perform interventions thought to be in the best interest of the child, rGS is substantially different because of its long-term implications for patients and family members. Finally, we look at the ethical interplay between parental consent and the interests of the child. We conclude by showing how cases like this are resolved at our tertiary center and how they may be resolved differently in future.

Preclinical efficacy of cannabidiol for the treatment of early-life seizures

BACKGROUND

The treatment of epilepsy during early life poses unique challenges-first-line therapies leave many individuals with poorly controlled seizures. In response to the pharmaco-resistance of current first-line anti-seizure drugs (ASDs) during early life, new therapies have emerged. One such therapy is cannabidiol (CBD). While well studied in adult models of epilepsy, it is poorly studied in immature animals. Here we assessed the efficacy of CBD in immature rodent models of the epilepsies.

METHODS

Pups were pre-treated with CBD (1, 10, 50, 100, 200 mg/kg) and assessed for anticonvulsant efficacy using two well-established anti-seizure screening models: the pentylenetetrazole (PTZ) and maximal electroshock (MES) models. We assessed drug efficacy in postnatal day (P)7 and P21 rats.

RESULTS

In the PTZ model, CBD delayed seizure onset in adolescent but not neonatal rats. By contrast, higher doses of CBD reduced seizure duration in both neonatal and adolescent rats in the MES model. The effects of CBD in both models were modest but consistent.

CONCLUSION

Efficacy of CBD increased in older as compared to younger animals, producing an age-, model-, and dose-dependent suppression of seizures. These data suggest neonatal seizures (modeled by P7 treatment) may be less responsive to CBD. They also suggest preferential efficacy against tonic seizures as compared to partial motor seizures.

Comparing the effect of different loading doses of phenobarbitone on serum phenobarbitone levels in babies with neonatal seizures and effect of therapeutic hypothermia on phenobarbitone levels

BACKGROUND

With current recommendation for phenobarbitone dosing, we have noted that babies are extremely sedated with elevated serum phenobarbitone levels. We postulate that asphyxiated neonates with hypoxic liver injury have impaired drug metabolism and renal injury affects drug elimination, thus elevating serum drug levels. Therapeutic hypothermia (TH) could further affect the drug levels.

OBJECTIVE

To determine the serum levels of the phenobarbitone in babies receiving different loading doses of phenobarbitone for neonatal seizures and to study the effect of asphyxia and TH on drug levels.

DESIGN

Prospective observational cohort study.

MATERIAL AND METHODS

Term neonates with seizures of any cause were given phenobarbitone up to a maximum loading of 40 mg/kg followed by maintenance dose of 5 mg/kg/day. Serum phenobarbitone levels were assessed after 4 h of the initial loading dose and subsequently at 24, 48 and 72 h from the time after maximum loading dose. Babies were divided into three groups Group 1 (HIE + TH-hypoxic ischemic encephalopathy undergoing TH), Group 2 (HIE - TH-hypoxic ischemic encephalopathy without TH) and Group 3 (non-HIE group).

RESULTS

A total of 47 babies completed the study. Twenty-three (49%) received 20 mg/kg, 14 (30%) received 30 mg/kg and 10 (21%) received 40 mg per kg of phenobarbitone as loading dose. HIE was the major cause of seizures 28 (59%) followed by hypoglycemia 7 (14%), cerebral malformations 4 (8%), inborn errors of metabolism 2 (4%) and hypocalcemia 1 (2%) while the cause of seizures was not known in 6 (13%). Median (IQR) Phenobarbitone levels at 72 h in babies who received 20 mg/kg loading dose of phenobarbitone was 46.72 (44.02-50.49) mcg/ml in HIE + TH group, 40.53 (28.66-65.09) mcg/ml in HIE - TH group and 49 (37-65) mcg/ml in non-HIE group. After a loading dose of 30 mg/kg, phenobarbitone level was 63.76 (59.5-65.94) mcg/ml in HIE + TH group, 42.5 (34.75-48.75) mcg/ml in HIE - TH group and 42.07 (40-49.05) mcg/ml in non-HIE group. After 40 mg/kg loading dose, it was 62.3 (60.2-64.9) mcg/ml in HIE + TH group, 57.0 (49.8-60.2) mcg/ml in HIE - TH group and 48.15 (40.8-50.97) mcg/ml in non-HIE group. In babies who received &gt;20 mg/kg loading dose, 100% of HIE + TH, 80% of HIE - TH and 60% of non-HIE had supratherapeutic levels of phenobarbitone.

CONCLUSION

At higher loading doses of 30 and 40 mg/kg, steady state concentration of serum phenobarbitone is higher in babies with hypoxic ischemic encephalopathy who underwent TH than in babies with non-HIE causes of seizures. Loading dose beyond 20 mg/kg should be used with close monitoring of serum drug level.

Neonatal seizures treatment based on conventional multichannel EEG monitoring: an overview of therapeutic options

INTRODUCTION

Seizures are the main neurological emergency during the neonatal period and are mostly acute and focal. The prognosis mainly depends on the underlying etiology. Conventional multichannel video-electroencephalographic (cEEG) monitoring is the gold standard for diagnosis, but treatment remains a challenge.

AREAS COVERED

: This review, based on PubMed search over the last 4 decades, focuses on the current treatment options for neonatal seizures based on cEEG monitoring. There is still no consensus on seizure therapy, owing to poor scientific evidence. Traditionally, the first-line treatments are phenobarbital and phenytoin, followed by midazolam and lidocaine, but their efficacy is limited. Therefore, current evidence strongly suggests the use of alternative antiseizure medications. Randomized controlled trials of new drugs are ongoing.

EXPERT OPINION

: Therapy for neonatal seizures should be prompt and tailored, based on semeiology, mirror of the underlying cause, and cEEG features. Further research should focus on antiseizure medications that directly act on the etiopathogenetic mechanism responsible for seizures and are therefore more effective in seizure control.

SARS-CoV-2 Infection and Possible Neonatal Neurological Outcomes: A Literature Review

The virus responsible for COVID-19 is designated "severe acute respiratory syndrome coronavirus 2" (SARS-CoV-2), a highly transmissible and pathogenic coronavirus. Although people of all ages are susceptible to SARS-CoV-2 infection, clinical manifestations may vary with age. The response of neonates to SARS-CoV-2 infection or exposure differs from that of children and adults. Encephalitis due to viral infections in the central nervous system (CNS) and childhood multisystem inflammatory syndrome (MIS-C) are some of the possible neonatal consequences of SARS-CoV-2 infection. This review aims to verify possible neonatal neurological outcomes after SARS-CoV-2 infection. Overall, the cellular and molecular basis of the neurological sequelae of SARS-CoV-2 in neonates remains unclear, and attempts to elucidate the pathophysiology of COVID-19 involve a comparison with the mechanism of other viral diseases. There are a considerable number of case reports in the literature exploring neurological outcomes in the neonatal period. In this review, we present possible effects of SARS-CoV-2 in neonates, emphasizing the importance of monitoring this group. The mechanisms of SARS-CoV-2 entry into the CNS have not yet been fully elucidated, and the potential severity of SARS-CoV-2 infection in neonates, as well as the possible short- and long-term neurological sequelae, remain unclear.

Efficacy of Levetiracetam and Phenobarbital as First-Line Treatment for Neonatal Seizures

High neonatal seizure burden is associated with worsened neurodevelopmental outcomes. We compared the efficacy of initial treatment with levetiracetam vs phenobarbital for maintaining low seizure burden in a retrospective cohort of 25 neonates monitored with video electroencephalography (EEG). Video EEG tracing were reviewed and paired with medication bolus times to determine seizure burden after treatment. Initial cumulative dose of phenobarbital was 20 mg/kg in all but 1 case; initial cumulative dose of levetiracetam ranged from 50 to 100 mg/kg. Eleven of 17 (65%) patients sustained seizure burden <10% following initial treatment with levetiracetam, compared with 5 of 8 (63%) with phenobarbital. Thirteen (76%) patients treated with levetiracetam had sustained seizure burden <20% compared with 6 (75%) treated with phenobarbital. The phenobarbital group showed a larger absolute reduction in average seizure burden in the hour before and after treatment (-24.3  vs -14.2 minutes/h). Six of 17 (35%) patients treated with levetiracetam remained seizure free after initial treatment, compared with 2 of 8 (25%) patients treated with phenobarbital. Initial treatment with levetiracetam was associated with shorter average time to seizure freedom (15 vs 21 hours). None of these results were statistically significant. Cumulative doses of levetiracetam 100 mg/kg were well tolerated and associated with substantial decrease in seizure burden in several cases. Levetiracetam remains a promising first-line treatment for neonatal seizures; additional randomized controlled trials evaluating the effects of high-dose levetiracetam on seizure burden and long-term outcomes are warranted.

Neonatal Seizure Management: Is the Timing of Treatment Critical?

OBJECTIVE

To assess the impact of the time to treatment of the first electrographic seizure on subsequent seizure burden and describe overall seizure management in a large neonatal cohort.

STUDY DESIGN

Newborns (36-44 weeks of gestation) requiring electroencephalographic (EEG) monitoring recruited to 2 multicenter European studies were included. Infants who received antiseizure medication exclusively after electrographic seizure onset were grouped based on the time to treatment of the first seizure: antiseizure medication within 1 hour, between 1 and 2 hours, and after 2 hours. Outcomes measured were seizure burden, maximum seizure burden, status epilepticus, number of seizures, and antiseizure medication dose over the first 24 hours after seizure onset.

RESULTS

Out of 472 newborns recruited, 154 (32.6%) had confirmed electrographic seizures. Sixty-nine infants received antiseizure medication exclusively after the onset of electrographic seizure, including 21 infants within 1 hour of seizure onset, 15 between 1 and 2 hours after seizure onset, and 33 at >2 hours after seizure onset. Significantly lower seizure burden and fewer seizures were noted in the infants treated with antiseizure medication within 1 hour of seizure onset (P = .029 and .035, respectively). Overall, 258 of 472 infants (54.7%) received antiseizure medication during the study period, of whom 40 without electrographic seizures received treatment exclusively during EEG monitoring and 11 with electrographic seizures received no treatment.

CONCLUSIONS

Treatment of neonatal seizures may be time-critical, but more research is needed to confirm this. Improvements in neonatal seizure diagnosis and treatment are also needed.

Quercetin Administration Following Hypoxia-Induced Neonatal Brain Damage Attenuates Later-Life Seizure Susceptibility and Anxiety-Related Behavior: Modulating Inflammatory Response

BACKGROUND

Neonatal seizures commonly caused by hypoxia could lead to brain injury and cognitive deficits. Quercetin could cross the blood brain barrier and exerts neuroprotective effects in many neurological disease settings. In this study, we aim to investigate the role of quercetin in attenuating cognitive impairment following hypoxia-induced neonatal seizure (HINS).

METHOD

Sprague-Dawley rats at P7 were exposed to a premixed gas in a hypoxic chamber to induce brain injury, and then continuously administered with quercetin for 21 days. Pentylenetetrazol kindling was used to induce seizures in the evolution. After the hypoxic lesion was stablished, anxiety-related behavior of rats after HINS was assessed using open field test. Memory impairment of rats after HINS was evaluated using novel object-recognition test and elevated plus maze test. The serum and hippocampal concentrations of TNF-a, iNOS, IL-6 MCP-1, and IL-1β were measured using ELISA. The mRNA expression levels of TNF-a, iNOS, IL-6 in the hippocampus were determined using qRT-PCR. The protein levels of TLR4, NF-κB p65, and p-NF-κB p65 in the hippocampus were determined using Western blot.

RESULTS

Quercetin administration significantly reduced later-life seizure susceptibility, anxiety-related behavior, and memory impairments in the rats following the HINS when compared to the HINS group without treatment. Both serum and hippocampal proinflammatory cytokines levels were significantly elevated in the rat after HINS. TLR4 protein expressions were increased in the HINS group when compared to control group, and decreased in the group of quercetin. The protein level of p-NF-κB p65 was significantly lower in the quercetin group compared to the HINS group.

CONCLUSION

We demonstrated that Quercetin significantly reduced susceptibility to later-life seizures. Quercetin could downregulate inflammatory response through TLR4/ NF-κB pathway, thereby attenuating HINS-induced anxiety, hippocampal memory impairment, and cognitive impairment in later life following HINS.

Treating Seizures after Hypoxic-Ischemic Encephalopathy-Current Controversies and Future Directions

Seizures are common in newborn infants with hypoxic-ischemic encephalopathy and are highly associated with adverse neurodevelopmental outcomes. The impact of seizure activity on the developing brain and the most effective way to manage these seizures remain surprisingly poorly understood, particularly in the era of therapeutic hypothermia. Critically, the extent to which seizures exacerbate brain injury or merely reflect the underlying evolution of injury is unclear. Current anticonvulsants, such as phenobarbital and phenytoin have poor efficacy and preclinical studies suggest that most anticonvulsants are associated with adverse effects on the developing brain. Levetiracetam seems to have less potential neurotoxic effects than other anticonvulsants but may not be more effective. Given that therapeutic hypothermia itself has significant anticonvulsant effects, randomized controlled trials of anticonvulsants combined with therapeutic hypothermia, are required to properly determine the safety and efficacy of these drugs. Small clinical studies suggest that prophylactic phenobarbital administration may improve neurodevelopmental outcomes compared to delayed administration; however, larger high-quality studies are required to confirm this. In conclusion, there is a distinct lack of high-quality evidence for whether and to what extent neonatal seizures exacerbate brain damage after hypoxia-ischemia and how best to manage them in the era of therapeutic hypothermia.

A Decision-Tree Approach to Assist in Forecasting the Outcomes of the Neonatal Brain Injury

Neonatal brain injury or neonatal encephalopathy (NE) is a significant morbidity and mortality factor in preterm and full-term newborns. NE has an incidence in the range of 2.5 to 3.5 per 1000 live births carrying a considerable burden for neurological outcomes such as epilepsy, cerebral palsy, cognitive impairments, and hydrocephaly. Many scoring systems based on different risk factor combinations in regression models have been proposed to predict abnormal outcomes. Birthweight, gestational age, Apgar scores, pH, ultrasound and MRI biomarkers, seizures onset, EEG pattern, and seizure duration were the most referred predictors in the literature. Our study proposes a decision-tree approach based on clinical risk factors for abnormal outcomes in newborns with the neurological syndrome to assist in neonatal encephalopathy prognosis as a complementary tool to the acknowledged scoring systems. We retrospectively studied 188 newborns with associated encephalopathy and seizures in the perinatal period. Etiology and abnormal outcomes were assessed through correlations with the risk factors. We computed mean, median, odds ratios values for birth weight, gestational age, 1-min Apgar Score, 5-min Apgar score, seizures onset, and seizures duration monitoring, applying standard statistical methods first. Subsequently, CART (classification and regression trees) and cluster analysis were employed, further adjusting the medians. Out of 188 cases, 84 were associated to abnormal outcomes. The hierarchy on etiology frequencies was dominated by cerebrovascular impairments, metabolic anomalies, and infections. Both preterms and full-terms at risk were bundled in specific categories defined as high-risk 75-100%, intermediate risk 52.9%, and low risk 0-25% after CART algorithm implementation. Cluster analysis illustrated the median values, profiling at a glance the preterm model in high-risk groups and a full-term model in the inter-mediate-risk category. Our study illustrates that, in addition to standard statistics methodologies, decision-tree approaches could provide a first-step tool for the prognosis of the abnormal outcome in newborns with encephalopathy.

Cannabinoids: A New Perspective on Epileptogenesis and Seizure Treatment in Early Life in Basic and Clinical Studies

Neural hyperexcitability in the event of damage during early life, such as hyperthermia, hypoxia, traumatic brain injury, status epilepticus, or a pre-existing neuroinflammatory condition, can promote the process of epileptogenesis, which is defined as the sequence of events that converts a normal circuit into a hyperexcitable circuit and represents the time that occurs between the damaging event and the development of spontaneous seizure activity or the establishment of epilepsy. Epilepsy is the most common neurological disease in the world, characterized by the presence of seizures recurring without apparent provocation. Cannabidiol (CBD), a phytocannabinoid derived from the subspecies Cannabis sativa (CS), is the most studied active ingredient and is currently studied as a therapeutic strategy: it is an anticonvulsant mainly used in children with catastrophic epileptic syndromes and has also been reported to have anti-inflammatory and antioxidant effects, supporting it as a therapeutic strategy with neuroprotective potential. However, the mechanisms by which CBD exerts these effects are not entirely known, and the few studies on acute and chronic models in immature animals have provided contradictory results. Thus, it is difficult to evaluate the therapeutic profile of CBD, as well as the involvement of the endocannabinoid system in epileptogenesis in the immature brain. Therefore, this review focuses on the collection of scientific data in animal models, as well as information from clinical studies on the effects of cannabinoids on epileptogenesis and their anticonvulsant and adverse effects in early life.

Neonatal Seizures and Purinergic Signalling

Neonatal seizures are one of the most common comorbidities of neonatal encephalopathy, with seizures aggravating acute injury and clinical outcomes. Current treatment can control early life seizures; however, a high level of pharmacoresistance remains among infants, with increasing evidence suggesting current anti-seizure medication potentiating brain damage. This emphasises the need to develop safer therapeutic strategies with a different mechanism of action. The purinergic system, characterised by the use of adenosine triphosphate and its metabolites as signalling molecules, consists of the membrane-bound P1 and P2 purinoreceptors and proteins to modulate extracellular purine nucleotides and nucleoside levels. Targeting this system is proving successful at treating many disorders and diseases of the central nervous system, including epilepsy. Mounting evidence demonstrates that drugs targeting the purinergic system provide both convulsive and anticonvulsive effects. With components of the purinergic signalling system being widely expressed during brain development, emerging evidence suggests that purinergic signalling contributes to neonatal seizures. In this review, we first provide an overview on neonatal seizure pathology and purinergic signalling during brain development. We then describe in detail recent evidence demonstrating a role for purinergic signalling during neonatal seizures and discuss possible purine-based avenues for seizure suppression in neonates.

Utility of Rapid Sequence Magnetic Resonance Imaging in Guiding Management of Patients With Neonatal Seizures

OBJECTIVE

To determine whether the use of rapid sequence magnetic resonance imaging (rsMRI) is associated with improved efficiency of care when managing infants with suspected neonatal onset seizures.

METHODS

We conducted a preintervention and postintervention study of the use of rsMRI in term infants with suspected neonatal onset seizures without evidence of hypoxic ischemic encephalopathy. Study patients were collected from a contemporary cohort from 2016 to 2017 and were compared with a historical cohort from 2014. The primary outcome was hospital length of stay. Secondary outcomes included use of other imaging modalities (head ultrasound, computed tomography [CT], and MRI), use of antiseizure medications at the time of discharge, and cost of hospitalization. Continuous variables were compared using the Mann-Whitney U test and categorical variables using the Fisher's exact or χ² tests. A two-tailed P < 0.05 was considered statistically significant.

RESULTS

Ninety-five patients met inclusion criteria, 47 in the preintervention and 48 in the postintervention group. Incorporation of the protocol-guided rsMRI in the evaluation of patients with neonatal seizures was associated with decreased use of CT scans (34% vs 10%, P = 0.007) and full MRIs (85% vs 62%, P = 0.019). Use of head ultrasound, length of stay, and costs were not different between groups.

CONCLUSIONS

In patients with neonatal seizures, rsMRI was not associated with a reduced hospital length of stay. The use of rsMRI resulted in fewer neonates receiving CT scans during their hospitalization. rsMRI may hasten the identification of stroke or hemorrhage in neonates with seizures.

Investigating and managing neonatal seizures in the UK: an explanatory sequential mixed methods approach

Background

Neonatal seizures are difficult to diagnose and, when they are, tradition dictates first line treatment is phenobarbital. There is little data on how consultants diagnose neonatal seizures, choose when to treat or how they choose aetiological investigations or drug treatments. The purpose of this study was to assess the variation across the UK in the management of neonatal seizures and explore paediatricians’ views on their diagnosis and treatment.

Methods

An explanatory sequential mixed methods approach was used (QUAN→QUAL) with equal waiting between stages. We collected quantitative data from neonatology staff and paediatric neurologists using a questionnaire sent to neonatal units and via emails from the British Paediatric Neurology Association. We asked for copies of neonatal unit guidelines on the management of seizures. The data from questionnaires was used to identify16 consultants using semi-structured interviews. Thematic analysis was used to interpret qualitative data, which was triangulated with quantitative questionnaire data.

Results

One hundred questionnaires were returned: 47.7% thought levetiracetam was as, or equally, effective as phenobarbital; 9.2% thought it was less effective. 79.6% of clinicians had seen no side effects in neonates with levetiracetam. 97.8% of unit guidelines recommended phenobarbital first line, with wide variation in subsequent drug choice, aetiological investigations, and advice on when to start treatment. Thematic analysis revealed three themes: ‘Managing uncertainty with neonatal seizures’, ‘Moving practice forward’ and ‘Multidisciplinary team working’. Consultants noted collecting evidence on anti-convulsant drugs in neonates is problematic, and recommended a number of solutions, including collaboration to reach consensus guidelines, to reduce diagnostic and management uncertainty.

Conclusions

There is wide variation in the management of neonatal seizures and clinicians face many uncertainties. Our data has helped reveal some of the reasons for current practice and decision making. Suggestions to improve certainty include: educational initiatives to improve the ability of neonatal staff to describe suspicious events, greater use of video, closer working between neonatologists and neurologists, further research, and a national discussion to reach a consensus on a standardised approach to managing neonatal epileptic seizures.

Effects of early postnatal exposure to fine particulate matter on emotional and cognitive development and structural synaptic plasticity in immature and mature rats

INTRODUCTION

Fine particulate matter (PM2.5) is closely associated with many neurological disorders including neurodegenerative disease, stroke, and brain tumors. However, the toxic effects of PM2.5 on neurodevelopment remain unclear. In this study, we aimed to determine the neurotoxic effects of early postnatal exposure to PM2.5 in immature and mature rats.

METHODS

We exposed neonatal rats to PM2.5 (2 or 10 mg/kg body weight) through intranasal instillation from postnatal day (PND) 3-15, once a day. Emotional and cognitive development were evaluated using the elevated plus maze, forced swimming, and Morris water maze tests. Hippocampal tissue was collected and subjected to transmission electron microscopy observation and western blot analysis.

RESULTS

Rats had lower body weight after exposure to high dose of PM2.5. The behavioral test results indicated that high-dose PM2.5 exposure led to increased anxiety-like symptoms in immature and mature rats, apparent depressive-like behaviors in mature rats, and impaired spatial learning and memory abilities in immature rats, and low-dose PM2.5 exposure increased anxiety-like behaviors in immature rats. Further, high-dose PM2.5 exposure contributed to fewer synapses, thinner postsynaptic density, and shorter active zone in immature and mature rats, and also decreased expressions of synaptophysin (SYP), growth associated protein-43 (GAP43), and postsynaptic density-95 (PSD95) in immature rats, SYP and PSD95 in mature rats. Moreover, low-dose PM2.5 exposure diminished the expression of PSD95 in immature rats. In addition, high-dose PM2.5 exposure reduced brain-derived neurotrophic factor (BDNF) expression and cAMP response element binding protein (CREB) phosphorylation in both immature and mature rats, and low-dose PM2.5 exposure lessened BDNF expression and CREB phosphorylation in immature rats.

CONCLUSIONS

Our findings indicate that PM2.5 impairs emotional and cognitive development by disrupting structural synaptic plasticity, possibly via the CREB/BDNF signaling pathway.

Early Seizures Prematurely Unsilence Auditory Synapses to Disrupt Thalamocortical Critical Period Plasticity

Heightened neural excitability in infancy and childhood results in increased susceptibility to seizures. Such early-life seizures are associated with language deficits and autism that can result from aberrant development of the auditory cortex. Here, we show that early-life seizures disrupt a critical period (CP) for tonotopic map plasticity in primary auditory cortex (A1). We show that this CP is characterized by a prevalence of “silent,” NMDA-receptor (NMDAR)-only, glutamate receptor synapses in auditory cortex that become “unsilenced” due to activity-dependent AMPA receptor (AMPAR) insertion. Induction of seizures prior to this CP occludes tonotopic map plasticity by prematurely unsilencing NMDAR-only synapses. Further, brief treatment with the AMPAR antagonist NBQX following seizures, prior to the CP, prevents synapse unsilencing and permits subsequent A1 plasticity. These findings reveal that early-life seizures modify CP regulators and suggest that therapeutic targets for early post-seizure treatment can rescue CP plasticity.

Gluconate suppresses seizure activity in developing brains by inhibiting CLC-3 chloride channels

Neonatal seizures are different from adult seizures, and many antiepileptic drugs that are effective in adults often fail to treat neonates. Here, we report that gluconate inhibits neonatal seizure by inhibiting CLC-3 chloride channels. We detect a voltage-dependent outward rectifying Cl⁻ current mediated by CLC-3 Cl⁻ channels in early developing brains but not adult mouse brains. Blocking CLC-3 Cl⁻ channels by gluconate inhibits seizure activity both in neonatal brain slices and in neonatal animals with in vivo EEG recordings. Consistently, neonatal neurons of CLC-3 knockout mice lack the outward rectifying Cl⁻ current and show reduced epileptiform activity upon stimulation. Mechanistically, we demonstrate that activation of CLC-3 Cl⁻ channels alters intracellular Cl⁻ homeostasis and enhances GABA excitatory activity. Our studies suggest that gluconate can suppress neonatal seizure activities through inhibiting CLC-3 Cl⁻ channels in developing brains.

How Early Can a Seizure Happen? Pathophysiological Considerations of Extremely Premature Infant Brain Development

Seizures in neonates represent a neurologic emergency requiring prompt recognition, determination of etiology, and treatment. Yet, the definition and identification of neonatal seizures remain challenging and controversial, in part due to the unique physiology of brain development at this life stage. These issues are compounded when considering seizures in premature infants, in whom the complexities of brain development may engender different clinical and electrographic seizure features at different points in neuronal maturation. In extremely premature infants (< 28 weeks gestational age), seizure pathophysiology has not been explored in detail. This review discusses the physiological and structural development of the brain in this developmental window, focusing on factors that may lead to seizures and their consequences at this early time point. We hypothesize that the clinical and electrographic phenomenology of seizures in extremely preterm infants reflects the specific pathophysiology of brain development in that age window.

Thalamic inhibitory circuits and network activity development

Inhibitory circuits in thalamus and cortex shape the major activity patterns observed by electroencephalogram (EEG) in the adult brain. Their delayed maturation and circuit integration, relative to excitatory neurons, suggest inhibitory neuronal development could be responsible for the onset of mature thalamocortical activity. Indeed, the immature brain lacks many inhibition-dependent activity patterns, such as slow-waves, delta oscillations and sleep-spindles, and instead expresses other unique oscillatory activities in multiple species including humans. Thalamus contributes significantly to the generation of these early oscillations. Compared to the abundance of studies on the development of inhibition in cortex, however, the maturation of thalamic inhibition is poorly understood. Here we review developmental changes in the neuronal and circuit properties of the thalamic relay and its interconnected inhibitory thalamic reticular nucleus (TRN) both in vitro and in vivo, and discuss their potential contribution to early network activity and its maturation. While much is unknown, we argue that weak inhibitory function in the developing thalamus allows for amplification of thalamocortical activity that supports the generation of early oscillations. The available evidence suggests that the developmental acquisition of critical thalamic oscillations such as slow-waves and sleep-spindles is driven by maturation of the TRN. Further studies to elucidate thalamic GABAergic circuit formation in relation to thalamocortical network function would help us better understand normal as well as pathological brain development.

Status Epilepticus in the Neonate: Updates in Treatment Strategies

PURPOSE OF REVIEW

The purpose of this review is to report recent advances in treatment of neonatal seizures, with a specific focus on new literature since a 2013 systematic review performed by this author (Slaughter) and others. There is a paucity of data with regard to well-defined status epilepticus (SE) in neonates, so treatment of recurrent seizures was also included in this inquiry. We aimed to summarize the efficacy and safety profiles of current therapeutic options as well as describe trends in medication selection in the neonatal intensive care unit (NICU) setting.

RECENT FINDINGS

Phenobarbital remains first-line therapy in practice, though there is increasing evidence of its neurotoxicity and long-term sequelae. Bumetanide failed an open-label trial for efficacy, demonstrated an increased risk for hearing loss, and has since fallen out of favor for use in this population. New agents, such as levetiracetam and topiramate, still have very limited data but appear to be as efficacious as older medications, with more favorable side effect profiles. There are limited high-level evidence-based data to guide treatment of neonatal seizures. Emerging research focusing on drug mechanisms and safety profiles may provide additional information to guide decisions; however, further research is needed.

Diagnosis of seizures and encephalopathy using conventional EEG and amplitude integrated EEG

Seizures are more common in the neonatal period than at any other time of life, partly due to the relative hyperexcitability of the neonatal brain. Brain monitoring of sick neonates in the NICU using either conventional electroencephalography or amplitude integrated EEG is essential to accurately detect seizures. Treatment of seizures is important, as evidence increasingly indicates that seizures damage the brain in addition to that caused by the underlying etiology. Prompt treatment has been shown to reduce seizure burden with the potential to ameliorate seizure-mediated damage. Neonatal encephalopathy most commonly caused by a hypoxia-ischemia results in an alteration of mental status and problems such as seizures, hypotonia, apnea, and feeding difficulties. Confirmation of encephalopathy with EEG monitoring can act as an important adjunct to other investigations and the clinical examination, particularly when considering treatment strategies such as therapeutic hypothermia. Brain monitoring also provides useful early prognostic indicators to clinicians. Recent use of machine learning in algorithms to continuously monitor the neonatal EEG, detect seizures, and grade encephalopathy offers the exciting prospect of real-time decision support in the NICU in the very near future.

Seizure classification, etiology, and management

The first weeks of life are a time of heightened risk for seizures due to age-dependent physiologic features of the developing brain that lead to increased neuronal excitation and decreased inhibition. Usually, seizures in neonates are a symptom of an acute brain injury; seizures are only rarely due to neonatal-onset epilepsy syndromes. Neonatal seizures are harmful to the developing brain; early and accurate diagnosis is critical. For suspected seizures, EEG monitoring should be initiated as soon as is feasible, in order to evaluate for events of concern, screen for subclinical seizures, and assess the EEG background. Amplitude-integrated EEG can provide excellent complementary data, particularly with regard to evolution of background patterns, but has limited sensitivity to detect individual neonatal seizures. An urgent and systematic approach to precise etiologic diagnosis is key for optimal management and estimates of prognosis. Evaluation of the seizure etiology must occur in parallel with initiation of appropriate treatment. It is critical that neonatologists and neurologists develop hospital-specific, consensus-based practice pathways for neonatal seizure evaluation and treatment. Such practice pathways can streamline medical decision making, facilitate rapid medication administration, and potentially decrease seizure burden and optimize outcomes. Herein, the pathophysiology, epidemiology, treatment, and long-term management considerations for neonatal seizures are presented.

Long-term outcome in children with neonatal seizures: A tertiary center experience in cohort of 168 patients

PURPOSE

The purpose of this study was to evaluate long-term outcome and assess predictors of prognosis in children with neonatal seizures (NS).

METHOD

This retrospective study includes children with NS treated at our Institute from January the 1st 2005 until December the 31st 2015. The data were collected from medical charts and the electroencephalogram (EEG) database at the Institute. The predictive value was evaluated for following parameters: (1) characteristics of the patients, such as gender, gestational age, birth body weight, Apgar score, artificial ventilation; (2) etiology; (3) characteristics of seizures such as type, time of onset, resistance to treatment; and (4) EEG background activity and paroxysmal discharges. The outcome of NS was assessed at the end of the follow-up period and was categorized as one of the following: (1) lethal outcome, (2) neurological abnormalities, (3) intellectual disability, and (4) epilepsy. Univariate and multivariate logistic regression analyses were used to assess predictors of NS outcome.

RESULTS

The study included 168 children with NS (of which 109 are males, and 59 are females), mean aged 5.6 (SD 3.5) years at the end of the follow-up (with a range of 1 to 12 years). There was normal neurological development without epilepsy in 131 patients (78%), neurological abnormality in 31 (19.0%), intellectual disability in 28 (17.2%), epilepsy in 12 (7.4%), and lethal outcome in 7 patients (4.17%).

CONCLUSIONS

Long-term outcome in children with NS could be favorable in most patients, and it appears to be related to specific early clinical and paraclinical variables. Newborns with an abnormal background EEG activity, with seizures resistant to antiepileptic drugs and/or low Apgar score are at a higher risk of a poor outcome. Females are at a much higher risk of lethal outcome than males.

Regulation of seizure-induced MeCP2 Ser421 phosphorylation in the developing brain

Neonatal seizures disrupt normal synaptic maturation and often lead to later-life epilepsy and cognitive deficits. During early life, the brain exhibits heightened synaptic plasticity, in part due to a developmental overabundance of Ca_V1.2 L-type voltage gated calcium (Ca²⁺) channels (LT-VGCCs) and Ca²⁺-permeable AMPARs (CP-AMPARs) lacking GluA2 subunits. We hypothesized that early-life seizures overactivate these channels, in turn dysregulating Ca²⁺-dependent signaling pathways including that of methyl CPG binding protein 2 (MeCP2), a transcription factor implicated in the autism spectrum disorder (ASD) Rett Syndrome. Here, we show that in vivo hypoxia-induced seizures (HS) in postnatal day (P)10 rats acutely induced phosphorylation of the neuronal-specific target of activity-dependent MeCP2 phosphorylation, S421, as well as its upstream activator CaMKII T286. We next identified mechanisms by which activity-dependent Ca²⁺ influx induced MeCP2 phosphorylation using in vitro cortical and hippocampal neuronal cultures at embryonic day (E)18 + 10 days in vitro (DIV). In contrast to the prevalent role of NMDARs in the adult brain, we found that both CP-AMPARs and LT-VGCCs mediated MeCP2 S421 and CaMKII T286 phosphorylation induced by kainic acid (KA) or high potassium chloride (KCl) stimulation. Furthermore, in vivo post-seizure treatment with the broad-spectrum AMPAR antagonist NBQX, the CP-AMPAR blocker IEM-1460, or the LT-VGCC antagonist nimodipine blocked seizure-induced MeCP2 phosphorylation. Collectively, these results demonstrate that early-life seizures dysregulate critical activity-dependent developmental signaling pathways, in part via CP-AMPAR and LT-VGCC activation, providing novel age-specific therapeutic targets for convergent pathways underlying epilepsy and ASDs.

Neonatal Seizure Models to Study Epileptogenesis

Current therapeutic strategies for epilepsy include anti-epileptic drugs and surgical treatments that are mainly focused on the suppression of existing seizures rather than the occurrence of the first spontaneous seizure. These symptomatic treatments help a certain proportion of patients, but these strategies are not intended to clarify the cellular and molecular mechanisms underlying the primary process of epilepsy development, i.e., epileptogenesis. Epileptogenic changes include reorganization of neural and glial circuits, resulting in the formation of an epileptogenic focus. To achieve the goal of developing “anti-epileptogenic” drugs, we need to clarify the step-by-step mechanisms underlying epileptogenesis for patients whose seizures are not controllable with existing “anti-epileptic” drugs. Epileptogenesis has been studied using animal models of neonatal seizures because such models are useful for studying the latent period before the occurrence of spontaneous seizures and the lowering of the seizure threshold. Further, neonatal seizure models are generally easy to handle and can be applied for in vitro studies because cells in the neonatal brain are suitable for culture. Here, we review two animal models of neonatal seizures for studying epileptogenesis and discuss their features, specifically focusing on hypoxia-ischemia (HI)-induced seizures and febrile seizures (FSs). Studying these models will contribute to identifying the potential therapeutic targets and biomarkers of epileptogenesis.

Time and sex dependent effects of magnesium sulphate on post-asphyxial seizures in preterm fetal sheep

KEY POINTS

We evaluated the effect of magnesium sulphate (MgSO₄ ) on seizures induced by asphyxia in preterm fetal sheep. MgSO₄ did not prevent seizures, but significantly reduced the total duration, number of seizures, seizure amplitude and average seizure burden. Saline-asphyxia male fetuses had significantly more seizures than female fetuses, but male fetuses showed significantly greater reduction in seizures during MgSO₄ infusion than female fetuses. A circadian profile of seizure activity was observed in all fetuses, with peak seizures seen around 04.00-06.00 h on the first and second days after the end of asphyxia. This study is the first to demonstrate that MgSO₄ has utility as an anti-seizure agent after hypoxia-ischaemia. More information is needed about the mechanisms mediating the effect of MgSO₄ on seizures and sexual dimorphism, and the influence of circadian rhythms on seizure expression.

ABSTRACT

Seizures are common in newborns after asphyxia at birth and are often refractory to anti-seizure agents. Magnesium sulphate (MgSO₄ ) has anticonvulsant effects and is increasingly given to women in preterm labour for potential neuroprotection. There is limited information on its effects on perinatal seizures. We examined the hypothesis that MgSO₄ infusion would reduce fetal seizures after asphyxia in utero. Preterm fetal sheep at 0.7 gestation (104 days, term = 147 days) were given intravenous infusions of either saline (n = 14) or MgSO₄ (n = 12, 160 mg bolus + 48 mg h^-1 infusion over 48 h). Fetuses underwent umbilical cord occlusion (UCO) for 25 min, 24 h after the start of infusion. The start time for seizures did not differ between groups, but MgSO₄ significantly reduced the total number of seizures (P < 0.001), peak seizure amplitude (P < 0.05) and seizure burden (P < 0.005). Within the saline-asphyxia group, male fetuses had significantly more seizures than females (P < 0.05). Within the MgSO₄ -asphyxia group, although both sexes had fewer seizures than the saline-asphyxia group, the greatest effect of MgSO₄ was on male fetuses, with reduced numbers of seizures (P < 0.001) and seizure burden (P < 0.005). Only 1 out of 6 MgSO₄ males had seizures on the second day post-UCO compared to 5 out of 6 MgSO₄ female fetuses (P = 0.08). Finally, seizures showed a circadian profile with peak seizures between 04.00 and 06.00 h on the first and second day post-UCO. Collectively, these results suggest that MgSO₄ may have utility in treating perinatal seizures and has sexually dimorphic effects.

NMDA Receptor GluN2 Subtypes Control Epileptiform Events in the Hippocampus

NMDA receptors (NMDARs) play a key role in synaptic plasticity and excitotoxicity. Subtype-specific role of NMDAR in neural disorders is an emerging area. Recent studies have revealed that mutations in NMDARs are a cause for epilepsy. Hippocampus is a known focal point for epilepsy. In hippocampus, expression of the NMDAR subtypes GluN1/GluN2A and GluN1/GluN2B is temporally regulated. However, the pharmacological significance of these subtypes is not well understood in epileptic context/models. To investigate this, epilepsy was induced in hippocampal slices by the application of artificial cerebrospinal fluid that contained high potassium but no magnesium. Epileptiform events (EFEs) were recorded from the CA1 and DG areas of hippocampus with or without subtype-specific antagonists. Irrespective of the age group, CA1 and DG showed epileptiform activity. The NMDAR antagonist AP5 was found to reduce the number of EFEs significantly. However, the application of subtype-specific antagonists (TCN 201 for GluN1/GluN2A and Ro 25-69811 for GluN1/GluN2B) revealed that EFEs had area-specific and temporal components. In slices from neonates, EFEs in CA1 were effectively reduced by Ro 25-69811, but were largely insensitive to TCN 201. In contrast, EFEs in DG were equally sensitive to both of the subtype-specific antagonists. However, the differential sensitivity for the antagonists observed in neonates was absent in later developmental stages. The study provides a functional insight into the NMDAR subtype-dependent contribution of EFEs in hippocampus of young rats, which may have implications in treating childhood epilepsy and avoiding unnecessary side effects of broad spectrum antagonists.

Treatment issues for children with epilepsy transitioning to adult care

This is the third of three papers that summarize the second symposium on Transition in Epilepsies held in Paris in June 2016. This paper focuses on treatment issues that arise during the course of childhood epilepsy and make the process of transition to adult care more complicated. Some AEDs used during childhood, such as stiripentol, vigabatrin, and cannabidiol, are unfamiliar to adult epilepsy specialists. In addition, new drugs are being developed for treatment of specific childhood onset epilepsy syndromes and have no indication yet for adults. The ketogenic diet may be effective during childhood but is difficult to continue in adult care. Regional adult epilepsy diet clinics could be helpful. Polytherapy is common for patients transitioning to adult care. Although these complex AED regimes are difficult, they are often possible to simplify. AEDs used in childhood may need to be reconsidered in adulthood. Rescue medications to stop prolonged seizures and clusters of seizures are in wide home use in children and can be continued in adulthood. Adherence/compliance is notoriously difficult for adolescents, but there are simple clinical approaches that should be helpful. Mental health issues including depression and anxiety are not always diagnosed and treated in children and young adults even though effective treatments are available. Attention deficit hyperactivity disorder and aggressive behavior disorders may interfere with transition and successful adulthood but these can be treated. For the majority, the adult social outcome of children with epilepsy is unsatisfactory with few proven interventions. The interface between pediatric and adult care for children with epilepsy is becoming increasingly complicated with a need for more comprehensive transition programs and adult epileptologists who are knowledgeable about special treatments that benefit this group of patients.

Development and validation of AIIMS modified INCLEN diagnostic instrument for epilepsy in children aged 1 month-18 years

OBJECTIVES

There is shortage of specialists for the diagnosis of children with epilepsy, especially in resource limited settings. Existing INCLEN (International Clinical Epidemiology Network) instrument was validated for children aged 2-9 years. The current study validated modifications of the same including wider symptomatology and age group.

METHODS

The Modified INCLEN tool was validated by a team of experts by modifying the existing tools (2-9 years) to widen the age range from 1 month to 18 years and include broader symptomatology in a tertiary care teaching hospital of North India between January and June 2015. A qualified medical graduate applied the candidate tool which was followed by gold standard evaluation by a Pediatric Neurologist (both blinded to each other).

RESULTS

A total of 197 children {128 boys (65%) and 69 girls (35%)}, with a mean age of 72.08 (±50.96) months, completed the study. The sensitivity, specificity, positive and negative predictive value, positive and negative likelihood ratio of the modified epilepsy tool were 91.5% (84.5-96.1), 88.6% (80.0-93.5), 89.7% (81.9-95.3), 90.8% (83.7-95.7), 8 (6.6-9.8) and 0.09 (0.07-0.12) respectively.

SIGNIFICANCE

The new modified diagnostic instruments for epilepsy is simple, structured and valid instruments covering 1month to 18 years for use in resource limited settings with acceptable diagnostic accuracy. All seizure semiologies as well as common seizure mimics like breath-holding spells are included in the tool. It also provides for identification of acute symptomatic and febrile seizures.