Neonatal seizures: When semiology points to etiology

Neurodevelopmental outcome of neonatal seizures: A longitudinal study

INTRODUCTION

Neonatal seizures (NS) are the most common neurological emergency in the neonatal period. The International League Against Epilepsy (ILAE) proposed a new classification of NS based on semiology and highlighted the correlation between semiology and aetiology. However, neurodevelopmental outcomes have not been comprehensively evaluated based on this new classification.

AIMS

To evaluate neurodevelopmental outcomes and potential risk factors for severe outcomes in NS.

METHODS

Patients with video electroencephalogram confirmed NS were evaluated. Seizure aetiology, cerebral magnetic resonance imaging (MRI) data, background electroencephalograms data, general movements, and neurodevelopmental outcomes were analysed. Severe outcomes were one of the following: death, cerebral palsy, Griffiths developmental quotient <70, epilepsy, deafness, or blindness.

RESULTS

A total of 74 neonates were evaluated: 62 (83.8 %) with acute provoked NS (primarily hypoxic-ischaemic encephalopathy), and 12 (16.2 %) with neonatal-onset epilepsies (self-limited neonatal epilepsy, developmental and epileptic encephalopathy, cerebral malformations). Of these, 32 (43.2 %) had electrographic seizures, while 42 (56.7 %) had electroclinical seizures - 38 (90.5 %) were motor (42.1 % clonic) and 4 (9.5 %) were non-motor phenomena. Severe outcomes occurred in 33 of the 74 (44.6 %) participants. In multivariate analysis, neonatal-onset epilepsies (odds ratio [OR]: 1.3; 95 % confidence interval [CI]: 1.1-1.6), status epilepticus (OR: 5.4; 95 % CI: 1.5-19.9), and abnormal general movements (OR: 3.4; 95 % CI: 1.9-7.6) were associated with severe outcomes.

CONCLUSIONS

At present, hypoxic-ischaemic encephalopathy remains the most frequent aetiology of NS. The prognosis of neonatal-onset epilepsies was worse than that of acute provoked NS, and status epilepticus was the most predictive factor for adverse outcomes.

Clinical and electroencephalography characteristics of 45 patients with neonatal seizures

OBJECTIVES

The aim of our study was to retrospectively research the semiology of neonatal seizures (NSs) based on the 2021 classification scheme of the International League Against Epilepsy, and the relationship between etiology and electroclinical features.

METHODS

Patients admitted to Children's Hospital of Chongqing Medical University from May 1, 2020 to March 30, 2022 and diagnosed with NSs were included to retrospectively investigate the etiology, seizure characteristics, prognosis, and ictal and interictal video electroencephalography (EEG) characteristics.

RESULTS

Of the 45 patients, 73.3% had definite etiology. Twenty-seven patients had electro-clinical seizures, of which two had both electro-clinical and electrographic-only seizures. Electrographic-only seizures were reported in 18 patients. The tonic, clonic, and electrographic-only seizures were associated with various etiologies. Both tonic and clonic seizures occurred in acute symptomatic seizures and were associated with neonatal epilepsy. 50% of tonic seizures were related to genetic factors. Among the clonic seizures, 50.0% occurred in acute symptomatic seizures. Epileptic spasms always indicated neonatal epilepsy. There were few patients who experienced automatisms and sequential seizures, and these two seizure types were associated with brain malformation and genetic factors, respectively. Patients with a normal interictal EEG had acute symptomatic seizures. whereas the interictal EEG of patients with neonatal epilepsy mainly showed burst-suppression or multifocal discharges. The ictal EEG recordings were related to seizure semiology.

CONCLUSION

Seizure semiology and video EEG are suggestive of potential causes but do not provide a definite etiology.

EEG and clinical characteristics of neonatal parechovirus encephalitis

RATIONALE

Human parechoviruses (HPeVs) are single -stranded ribonucleic (RNA) viruses belonging to the picornaviridae family with characteristics similar to enteroviruses. They either cause mild respiratory and gastrointestinal or no symptoms in older children and adults but can be a major cause of central nervous system (CNS) infection in the neonatal period and demonstrate a seasonal predilection. Starting in March 2022, we saw eight patients with polymerase chain reaction (PCR) proven HPeV encephalitis with seizures and some electroencephalographic (EEG) features raising concerns for neonatal genetic epilepsy. Although cerebrospinal fluid (CSF) and imaging findings have been previously described, there is little emphasis on seizure presentation and EEG findings of HPeV in the literature. We wish to highlight the EEG and seizure semiology of HPeV encephalitis that may mimic a genetic neonatal epilepsy syndrome.

METHODS

Retrospective chart review of all neonates seen at Children's Health Dallas, UTSW Medical Center between 03/18/2022-06/01/2022 with HPeV encephalitis.

RESULTS

Term neonates (postmenstrual age 37-40 weeks) presented with a variable combination of fever, lethargy, irritability, poor oral intake, erythematous rash, and focal seizures. One patient with a single episode of limpness and pallor did not undergo EEG due to a low suspicion for seizures. CSF indices were normal in all patients. EEG was abnormal in all patients where performed (n = 7). EEG features included dysmaturity (7/7, 100 %); excessive discontinuity (6/7, 86 %); excessive asynchrony (6/7, 86 %); multifocal sharp transients (7/7, 100 %). Focal/multifocal seizures were captured in 6/7 (86 %); tonic in 3/7 (42 %) and described as migrating in 2 patients. Subclinical seizures were noted in 6/7 (86 %) with status epilepticus in 5/7 (71 %) patients. In 2/7 (28 %) the EEG showed a burst suppression pattern with poor state variation and voltages of < 5-10 uV/mm during the inter-burst intervals. Repeat EEG (3-11 days post initial EEG) showed improvement in 3 of 4 patients. No patient had ongoing seizures beyond day two of admission (22.5 h after EEG initiation). MRI showed extensive restricted diffusion in the supratentorial white matter, thalami, and less frequently the cortex, mimicking imaging findings of a metabolic or hypoxic-ischemic encephalopathy (7/8). Seizures responded within 36 h of presentation to treatment with acute bolus doses of medications. One patient died due to diffuse cerebral edema and status epilepticus. Six patients had a normal clinical exam at discharge. All patients started on maintenance antiseizure medication (ASM) were sent home on either a single medication or two medications (phenobarbital and levetiracetam) with plans to wean phenobarbital after discharge.

CONCLUSIONS

HPeV is a rare cause of seizures and encephalopathy in neonates. Prior studies have emphasized specific patterns of white matter injury on imaging. We demonstrate that HPeV also commonly presents with clonic or tonic seizures with or without apnea and often subclinical multifocal and migrating focal seizures that could mimic a genetic neonatal epilepsy syndrome. Interictal EEG shows a dysmature background with excessive asynchrony, discontinuity, burst-suppression pattern, and multifocal sharp transients. However, we note that 100 % of patients responded quickly to standard ASM, and did not have seizures after hospital discharge- a factor that can help distinguish it from a genetic epilepsy syndrome.

EEG in neonatal seizures: where to look and what to see

INTRODUCTION

Neonatal seizures are frequent and carry a detrimental prognostic outlook. Diagnosis is based on EEG confirmation. Classification has recently changed.

AREAS COVERED

We consulted original papers, book chapters, atlases, and reviews to provide a narrative overview on EEG characteristics of neonatal seizures. We searched PubMed, without time restrictions (last visited: 31 May 2022). Additional papers were extracted from the references list of selected papers. We describe the typical neonatal ictal EEG discharges morphology, location, and propagation, together with age-dependent features. Etiology-dependent electroclinical features, when identifiable, are presented for both acute symptomatic neonatal seizures and neonatal-onset epilepsies and developmental/epileptic encephalopathies. The few ictal variables known to predict long-term outcome have been discussed.

EXPERT OPINION

Multimodal neuromonitoring in critically ill newborns, high-density EEG, and functional neuroimaging might increase our insight into the neurophysiological bases of seizures in newborns. Increasing availability of long-term monitoring with conventional video-EEG and automated detection methods will allow clinicians and researchers to gather an ever expanding bulk of clinical and neurophysiological data to enhance accuracy with deep phenotyping. The latest classification proposal represents an input for critically revising our diagnostic abilities with respect to seizure definition, duration, and semiology, possibly further promoting clinical research.

Neonatal seizures—diagnostic options and treatment recommendations

Seizures in neonates should prompt rapid evaluation to verify the diagnosis, determine etiology, and initiate appropriate treatment. Neonatal seizure diagnosis requires EEG confirmation and clinical observation alone is insufficient. Although most neonatal seizures are related to acute brain injury, some neonates present early-onset structural or metabolic/genetic epilepsy. Video-EEG monitoring, the gold standard for neonatal seizure detection and quantification, is resource-intensive and often unavailable, with amplitude-integrated EEG offering a reasonable alternative in guiding treatment. Whereas new-generation antiseizure medication (ASM), such as levetiracetam, appear promising, particularly in terms of tolerability, older-generation ASM, such as phenobarbital and phenytoin, are yet to be replaced. Acute treatment should aim at stopping both electroclinical and electrographic-only seizures. In neonates with acute provoked seizures, ASM should be discontinued without tapering after 72 h of seizure freedom and before hospital discharge.

Neonatal seizures: diagnostic updates based on new definition and classification

Neonatal seizures are the most common neurological symptoms caused by various etiologies in the neonatal period, but their diagnosis and treatment are challenging because their pathophysiology and electroclinical manifestations differ from those of patients in older age groups. Many seizures present as electrographic-only events without clinical signs or as obscure clinical manifestations that are difficult to distinguish from other neonatal behaviors. Accordingly, a new definition and classification of neonatal seizures was recently proposed by the International League Against Epilepsy Task Force on neonatal seizures, highlighting the role of electroencephalography in diagnosing and treating neonatal seizures. Neonatal seizures are defined as electrographic events with sudden, paroxysmal, and abnormal alteration of activity and divided into electroclinical seizures and electrographic-only seizures according to their clinical signs, thus excluding clinical events without an electrographic correlation. Seizure types are described by their predominant clinical features and divided into motor (automatisms, clonic, epileptic spasms, myoclonic, tonic, and sequential), nonmotor (autonomic and behavioral arrest), and unclassified. Although many neonatal seizures are acute reactive events caused by hypoxic-ischemic encephalopathy or vascular insults, structural, genetic, or metabolic etiologies of neonatal-onset epilepsy should also be thoroughly evaluated to determine their appropriate management.

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.

Epidemiology, management and outcome of status epilepticus in adults: single-center Italian survey

The official variations of status epilepticus (SE) International League Against Epilepsy (ILAE, 2015) diagnostic criteria and the non-convulsive SE (NCSE) Salzburg Consensus Criteria (2013), impose the collection of updated population-based epidemiological Italian data. In this study, we aimed at evaluating (a) the frequency of SE in our hospital adopting the new ILAE 2015 SE diagnostic criteria and NCSE Salzburg Consensus Criteria, (b) the frequency of adherence to current treatment guidelines for SE and their relationship with patients' outcome, and (c) reliability of standardized prognostic scales (Status Epilepticus Severity Score-STESS-and modified STESS) for short-term outcome prediction in the setting of the newest diagnostic criteria for SE and NCSE. Detailed clinical and electrophysiological data collected in a 1-year retrospective hospital-based single-center survey on SE at Parma Hospital, Northern Italy are provided. Non-adherence to current treatment guidelines was recorded in around 50% cases, but no relation to outcome was appreciated. Mortality in our cohort increased from 30 to 50% when follow-up was extended to 30 days. STESS score was strongly correlated with short-term mortality risk (OR 18.9, 2.2-163.5, CI), and we confirm its role as easy-to-use tool for outcome evaluation also when the new ILAE diagnostic SE criteria are applied.

Neonatal presentation of genetic epilepsies: Early differentiation from acute provoked seizures

OBJECTIVE

Although most seizures in neonates are due to acute brain injury, some represent the first sign of neonatal onset genetic epilepsies. Delay in recognition and lack of expert assessment of neonates with epilepsy may result in worse developmental outcomes. As in older children and adults, seizure semiology in neonates is an essential determinant in diagnosis. We aimed to establish whether seizure type at presentation in neonates can suggest a genetic etiology.

METHODS

We retrospectively analyzed the clinical and electroencephalographic (EEG) characteristics of seizures in neonates admitted in two Level IV neonatal intensive care units, diagnosed with genetic epilepsy, for whom a video-EEG recording at presentation was available for review, and compared them on a 1:2 ratio with neonates with seizures due to stroke or hypoxic-ischemic encephalopathy.

RESULTS

Twenty neonates with genetic epilepsy were identified and compared to 40 neonates with acute provoked seizures. Genetic epilepsies were associated with pathogenic variants in KCNQ2 (n = 12), KCNQ3 (n = 2), SCN2A (n = 2), KCNT1 (n = 1), PRRT2 (n = 1), and BRAT1 (n = 2). All neonates with genetic epilepsy had seizures with clinical correlates that were either tonic (18/20) or myoclonic (2/20). In contrast, 17 of 40 (42%) neonates with acute provoked seizures had electrographic only seizures, and the majority of the remainder had clonic seizures. Time to first seizure was longer in neonates with genetic epilepsies (median = 60 h of life) compared to neonates with acute provoked seizures (median = 15 h of life, p < .001). Sodium channel-blocking antiseizure medications were effective in 13 of 14 (92%) neonates with tonic seizures who were trialed at onset or during the course of the epilepsy.

SIGNIFICANCE

Seizure semiology is an easily accessible sign of genetic epilepsies in neonates. Early identification of the seizure type can prompt appropriate workup and treatment. Tonic seizures are associated with channelopathies and are often controlled by sodium channel-blocking antiseizure medications.