Increased number of febrile seizures in children born very preterm: relation of neonatal, febrile and epileptic seizures and neurological dysfunction to seizure outcome at 16 years of age

Seizure prevalence in children aged up to 3 years: a longitudinal population-based cohort study in Japan

OBJECTIVE

To investigate the prevalence of seizures/febrile seizures in children up to 3 years of age and examine the effects of gestational age at birth on the risk for febrile seizures.

DESIGN

Retrospective longitudinal population-based cohort study.

SETTING

Kobe City public health center, Kobe, Japan, from 2010 to 2018.

PARTICIPANTS

Children who underwent a medical check-up at 3 years of age.

METHODS

Information regarding seizures was collected from the parents of 96 014 children. We identified the occurrence of seizure/febrile seizure in 74 017 children, whose gestational ages at birth were noted. We conducted a multivariate analysis with the parameter, gestational age at birth, to analyse the risk of seizure. We also stratified the samples by sex and birth weight (<2500 g or not) and compared the prevalence of seizure between those with the term and late preterm births.

RESULTS

The prevalence of seizure was 12.1% (11.8%-12.3%), 13.2% (12.2%-14.4%), 14.6% (12.4%-17.7%) and 15.7% (10.5%-22.8%) in children born at 37-41, 34-36, 28-33 and 22-27 gestational weeks, respectively. The prevalence of febrile seizures was 9.0% (8.8%-9.2%), 10.5% (9.5%-11.5%), 11.8% (9.7%-14.5%) and 11.2% (6.9%-17.7%) in children born at 37-41, 34-36, 28-33 and 22-27 gestational weeks, respectively. Male was an independent risk factor for seizures (OR: 1.15, 95% CI 1.09 to 1.20; absolute risk increase 0.014, 95% CI 0.010 to 0.019) and febrile seizures (OR: 1.21, 95% CI 1.15 to 1.28; absolute risk increase 0.016, 95% CI 0.012 to 0.020), respectively. Late preterm birth was not associated with an increased risk of seizure/febrile seizure.

CONCLUSIONS

Although very preterm birth may increase the risk of seizure/febrile seizure, the risk associated with late preterm birth is considerably small and less than that associated with male.

Incidence of epilepsy in children born prematurely and small for gestational age at term gestation: A population-based cohort study

AIM

This study assessed the incidence of epilepsy in preterm infants and those small for gestational age (SGA) at term and identified risk factors associated with higher epilepsy incidence in these children.

METHODS

We enrolled children (from 2000 to 2010) who were premature (n = 21 474) or SGA (n = 2206); we then included a matched control cohort (n = 94 720). Cox regression was used to assess the epilepsy risk in preterm and SGA children. To determine the associated factors for epilepsy, the preterm and SGA infants were divided into six groups according to the common complications related to brain development and were separated into three subgroups based on birthweight (BW).

RESULTS

The cumulative incidence of epilepsy was significantly higher in preterm or SGA children than in the control group. The overall incidence densities (per 1000 person-years) of epilepsy were: 0.37 in the control, 2.96 in the preterm, 2.90 in the SGA, 15.9 in the preterm with cerebral haemorrhage, 14.6 in the SGA with cerebral haemorrhage, 6.92 in the preterm with asphyxia, 3.82 in the SGA with asphyxia, 14.3 in the preterm with congenital brain anomalies, and 25.4 in the SGA with congenital brain anomalies cohorts. Infants with BW < 1000 g had a higher incidence of epilepsy than those with BW ≥2500 g.

CONCLUSIONS

Preterm and SGA infants had an increased risk of epilepsy in childhood, and the incidence of epilepsy increased with decreasing BW. Several perinatal factors (e.g. intracranial haemorrhage, birth asphyxia and congenital brain anomalies) are associated with a higher incidence of later epilepsy.

Neonatal seizures in preterm infants: A systematic review of mortality risk and neurological outcomes from studies in the 2000's

INTRODUCTION

Neonatal seizures (NS) are associated with increased mortality and risk of cerebral palsy, epilepsy and intellectual disability. We performed a systematic review with the primary objective to delineate the rate of these outcomes following NS in preterm infants from studies published in the 2000's and the secondary objective to identify risk factors.

METHODS

Inclusion criteria: original articles published between 1/1/2000 and 12/31/2018, written in English, evaluating newborns ≤37 weeks of gestational age and suffering from NS, in which at least one of these was evaluated: epilepsy, cerebral palsy, intellectual disability/developmental delay, normal outcome, death.

RESULTS

Twenty-two papers were selected and all were observational, with a retrospective design in 15. Three were population-based and twenty-one have a comparison. It has been found a 22-80 % of mortality, 11.3-38.9 % of epilepsy, 12-84.6 % of cerebral palsy, and 20-42.7 % of intellectual disability/developmental delay rate. An increased risk for all outcomes considered was reported. Risk factors for specific outcomes were provided by a minority of studies. However, inclusion criteria, definition of NS and measured outcomes, follow-up lengths differed considerably between studies.

DISCUSSION

Results of the selected studies are only partially comparable or generalizable because of differences in study design. They have a risk for potential biases, although they provide (if analyzed) readily available prognostic factors, easy to apply in clinical practice. Prospective, population-based studies with EEG-defined NS are warranted in order to produce evidence-based guidance for management of preterm newborns with seizures.

Molecular Mechanism Involved in the Pathogenesis of Early-Onset Epileptic Encephalopathy

Recent studies have shown that neurologic inflammation may both precipitate and sustain seizures, suggesting that inflammation may be involved not only in epileptogenesis but also in determining the drug-resistant profile. Extensive literature data during these last years have identified a number of inflammatory markers involved in these processes of “neuroimmunoinflammation” in epilepsy, with key roles for pro-inflammatory cytokines such as: IL-6, IL-17 and IL-17 Receptor (IL-17R) axis, Tumor-Necrosis-Factor Alpha (TNF-α) and Transforming-Growth-Factor Beta (TGF-β), all responsible for the induction of processes of blood-brain barrier (BBB) disruption and inflammation of the Central Nervous System (CNS) itself. Nevertheless, many of these inflammatory biomarkers have also been implicated in the pathophysiologic process of other neurological diseases. Future studies will be needed to identify the disease-specific biomarkers in order to distinguish epilepsies from other neurological diseases, as well as recognize different epileptic semiology. In this context, biological markers of BBB disruption, as well as those reflecting its integrity, can be useful tools to determine the pathological process of a variety of neurological diseases. However; how these molecules may help in the diagnosis and prognostication of epileptic disorders remains yet to be determined. Herein, authors present an extensive literature review on the involvement of both, systemic and neuronal immune systems, in the early onset of epileptic encephalopathy.

Postvaccination Febrile Seizure Severity and Outcome

BACKGROUND

Febrile seizures (FSs) are a common pediatric condition caused by a sudden rise in temperature, affecting 3% to 5% of children aged ≤6 years. Although vaccination can cause FSs, little is known on whether FSs occurring in the time soon after vaccination (vaccine-proximate febrile seizures [VP-FSs] differ clinically from non-vaccine-proximate febrile seizures [NVP-FSs]). We compared the clinical profile and outcomes of VP-FS to NVP-FS.

METHODS

Prospective cohort study of children aged ≤6 years presenting with their first FS at 1 of 5 Australian pediatric hospitals between May 2013 and June 2014. Clinical features, management, and outcomes were compared between VP-FS and NVP-FS.

RESULTS

Of 1022 first FS cases (median age 19.8 months; interquartile range 13.6-27.6), 67 (6%) were VP-FSs. When comparing VP-FS to NVP-FS, there was no increased risk of prolonged (>1 day) hospitalization (odds ratio [OR] 1.61; 95% confidence interval [95% CI] 0.84-3.10), ICU admission (OR 0.72; 95% CI 0.10-5.48), seizure duration >15 minutes (OR 1.47; 95% CI 0.73-2.98), repeat FS within 24 hours (OR 0.80; 95% CI 0.34-1.89), or requirement for antiepileptic treatment on discharge (OR 1.81; 95% CI 0.41-8.02). VP-FS patients with a laboratory-confirmed infection (12%) were more likely to have a prolonged admission compared with those without.

CONCLUSIONS

VP-FS accounted for a small proportion of all FS hospital presentations. There was no difference in outcomes of VP-FS compared with NVP-FS. This is reassuring data for clinicians and parents of children who experience FS after vaccination and can help guide decisions on revaccination.

Thermoregulation and age

The thermoregulatory functions may vary with age. Thermosensitivity is active in neonates and children; both heat production and heat loss effector mechanisms are functional but easily exhaustable. Proportional and lasting defense against thermal challenges is difficult, and both hypothermia and hyperthermia may easily develop. Febrile or hypothermic responses to infections or endotoxin can also develop, together with confusion. In small children febrile convulsions may be dangerous. In old age the resting body temperature may be lower than in young adults. Further, thermosensitivity decreases, the thresholds for activating skin vasomotor and evaporative responses or metabolism are shifted, and responses to thermal challenges are delayed or insufficient: both hypothermia and hyperthermia may develop easily. Infection-induced fevers are often limited or absent, or replaced by hypothermia. Various types of brain damage may induce special forms of hypothermia, hyperthermia, or severe fever. Impaired mental state often accompanies hypothermia and hyperthermia, and may occasionally be a dominant feature of infection (instead of the most commonly observed fever). Aging brings about a turning point in women's life: the menopause. The well-known influence of regular hormonal cycles on the thermoregulation of a woman of fertile age gives way to menopausal hot flushes caused by estrogen withdrawal. Not all details of this thermoregulatory anomaly are fully understood yet.

Cumulative Incidence of Seizures and Epilepsy in Ten-Year-Old Children Born Before 28 Weeks' Gestation

OBJECTIVE

We evaluated the incidence of seizures and epilepsy in the first decade of life among children born extremely premature (less than 28 weeks' gestation).

METHOD

In a prospective, multicenter, observational study, 889 of 966 eligible children born in 2002 to 2004 were evaluated at two and ten years for neurological morbidity. Complementing questionnaire data to determine a history of seizures, all caregivers were interviewed retrospectively for postneonatal seizures using a validated seizure screen followed by a structured clinical interview by a pediatric epileptologist. A second pediatric epileptologist established an independent diagnosis based on recorded responses of the interview. A third epileptologist determined the final diagnosis when evaluators disagreed (3%). Life table survival methods were used to estimate seizure incidence through ten years.

RESULTS

By age ten years, 12.2% (95% confidence interval: 9.8, 14.5) of children had experienced one or more seizures, 7.6% (95% confidence interval: 5.7, 9.5) had epilepsy, 3.2% had seizure with fever, and 1.3% had a single, unprovoked seizure. The seizure incidence increased with decreasing gestational age. In more than 75% of children with seizures, onset was after one year of age. Seizure incidence was comparable in both sexes. Two-thirds of those with epilepsy had other neurological disorders. One third of children with epilepsy were not recorded on the medical history questionnaire.

SIGNIFICANCE

The incidence of epilepsy through age ten years among children born extremely premature is approximately 7- to 14-fold higher than the 0.5% to 1% lifetime incidence reported in the general pediatric population. Seizures in this population are under-recognized, and possibly underdiagnosed, by parents and providers.

Postnatal Steroids and Febrile Seizure Susceptibility in Preterm Children

OBJECTIVE

To investigate risk factors, seizure characteristics, and outcomes of febrile seizure (FS) in children born very preterm.

METHODS

This study used a prospective registry data set of 844 preterm infants (birth weight <1500 g and gestational age <32 weeks) admitted to NICUs from 2001 to 2009 in southern Taiwan. We investigated the prevalence, risks, seizure patterns, and outcomes of FS in children aged 5 years.

RESULTS

Among 575 children (follow-up rate, 85.8%) followed up for 5 years, 35 (6.1%) developed FS. The FS and non-FS groups were comparable regarding their mean gestational age, birth weight, 5-minute Apgar score <6, and prenatal and postnatal complications. No difference was observed in the use of prenatal corticosteroids between the 2 groups. The FS group had a significantly higher rate of postnatal corticosteroid treatment than the non-FS group, even after adjusting for confounding factors (odds ratio, 5.4 [95% confidence interval, 1.9-15.8]; P = .006). No differences were observed in IQs or subsequent epilepsy rates between the 2 groups. Although no difference was observed in the age of FS onset or neurodevelopmental outcomes between the 2 groups, children with FS who received postnatal corticosteroid treatment had a significantly lower mean body temperature during the first FS attack compared with those who did not receive postnatal corticosteroid treatment (38.6 ± 0.4°C vs 39.2 ± 0.6°C; P = .034).

CONCLUSIONS

Children born very preterm have a higher rate of FS, and postnatal corticosteroid treatment was associated with FS susceptibility in these children.

Symptomatic neonatal seizures followed by febrile status epilepticus: the two-hit hypothesis for the subsequent development of epilepsy

Neonatal seizures have been associated with the later development of postneonatal epilepsy, mainly beginning within the first year of life. Mechanisms of epileptogenesis in the immature brain still need to be fully elucidated but a two-hit hypothesis, showing that an early insult heightens later susceptibility to seizure-induced brain damage, has been demonstrated in animal models. We describe 2 cases of preterm babies sustaining recurrent neonatal seizures in the context of a severe perinatal brain damage who presented with symptomatic epilepsy only after the occurrence of an episode of febrile status epilepticus. In the context of preexisting perinatal brain damage, febrile status epilepticus acted as a second hit for developing epilepsy, confirming animal evidence.

Vaccines and febrile seizures

Vaccine administration is the second leading cause of febrile seizures (FS). FS occurrence in children is a serious concern because it leads to public apprehension of vaccinations. This review discusses the clinical implications of FS, its potential link to vaccinations and its impact on official recommendations for vaccinations in children. Vaccines such as the pertussis antigen-containing vaccine, the measles-containing vaccine and the influenza vaccine have been linked to FS. However, FS events are very rare and are not usually associated with downstream complications or severe neurologic diseases. Considering their significant health benefits, vaccinations have not been restricted in the pediatric population. Nevertheless, vaccine-induced FS could be a problem, particularly in genetically predisposed children. Therefore, post-marketing surveillance studies are required to accurately assess the incidence of FS and identify individuals who are particularly susceptible to FS after vaccination.

Signal identification and evaluation for risk of febrile seizures in children following trivalent inactivated influenza vaccine in the Vaccine Safety Datalink Project, 2010-2011

In fall 2010 in the southern hemisphere, an increased risk of febrile seizures was noted in young children in Australia in the 24 h after receipt of trivalent inactivated influenza vaccine (TIV) manufactured by CSL Biotherapies. Although the CSL TIV vaccine was not recommended for use in young children in the US, during the 2010-2011 influenza season near real-time surveillance was conducted for febrile seizures in the 0-1 days following first dose TIV in a cohort of 206,174 vaccinated children ages 6 through 59 months in the Vaccine Safety Datalink Project. On a weekly basis, surveillance was conducted with the primary approach of a self-controlled risk interval design and the secondary approach of a current vs. historical vaccinee design. Sequential statistical methods were employed to account for repeated analyses of accumulating data. Signals for seizures based on computerized data were identified in mid November 2010 using a current vs. historical design and in late December 2010 using a self-controlled risk interval design. Further signal evaluation was conducted with chart-confirmed febrile seizure cases using only data from the primary approach (i.e. self-controlled risk interval design). The magnitude of the incidence rate ratio and risk difference comparing risk of seizures in the 0-1 days vs. 14-20 days following TIV differed by receipt of concomitant 13-valent pneumococcal conjugate vaccine (PCV13). Among children 6-59 months of age, the incidence rate ratio (IRR) for TIV adjusted for concomitant PCV13 was 2.4 (95% CI 1.2, 4.7) while the IRR for PCV13 adjusted for concomitant TIV was 2.5 (95% CI 1.3, 4.7). The IRR for concomitant TIV and PCV13 was 5.9 (95% CI 3.1, 11.3). Risk difference estimates varied by age due to the varying baseline risk for seizures in young children, with the highest estimates occurring at 16 months (12.5 per 100,000 doses for TIV without concomitant PCV13, 13.7 per 100,000 doses for PCV13 without concomitant TIV, and 44.9 per 100,000 doses for concomitant TIV and PCV13) and the lowest estimates occurring at 59 months (1.1 per 100,000 doses for TIV without concomitant PCV13, 1.2 per 100,000 doses for PCV13 without concomitant TIV, and 4.0 per 100,000 doses for concomitant TIV and PCV13). Incidence rate ratio and risk difference estimates were lower for children receiving TIV without concomitant PCV13 or PCV13 without concomitant TIV. Because of the importance of preventing influenza and pneumococcal infections and associated complications, our findings should be placed in a benefit-risk framework to ensure that population health benefits are maximized.

Low birth weight as a risk factor for seizure following acute subdural hematoma

PURPOSE

The purpose of this study is to determine the factors associated with posttraumatic seizure in patients under 2 years old with acute subdural hematoma (ASDH).

METHODS

Twenty-one patients under 2 years old (15 males and six females) with ASDH, who were admitted to our hospital between January 2002 and September 2008, were studied retrospectively. Clinical findings including birth weight and gestational age were defined. A head computed tomography scan was conducted at admission. Outcome at time of discharge was assessed using the score.

RESULTS

Seizures occurred in eight patients (38%). Recurrent seizures occurred in three of eight patients (38%). In patients with seizures, birth weight, gestational age, and birth weight ratio were significantly lower than for those without seizure (p < 0.05).

CONCLUSIONS

Special attention should be paid to infants with ASDH who have a history of low birth weight, low gestational age, and low birth weight ratio because risk for posttraumatic seizure is considered higher in these infants than in other infants.

Incidence of epilepsy in extremely low-birthweight infants (<1,000 g): a population study of central and southern Sardinia

PURPOSE

With the development of intensive care, the survival of extremely low-birthweight (ELBW) infants (<1,000 g) has greatly improved. The aim of our study was to report the incidence of epilepsy after a follow-up of >7 years in a population of ELBW children, born in central and southern Sardinia between 1991 and 2000.

METHODS

We analyzed data of 104 children. All infants had had serial cranial ultrasound echography (CUE) in the neonatal period and some also had magnetic resonance imaging (MRI). At last follow-up we evaluated the occurrence of epilepsy through a review of clinical charts and a structured telephone interview.

RESULTS

In 11 (10.6%) of 104 of children we observed febrile seizures (FS). Epilepsy occurred in 9 (8.6%) of 104 ELBW children, and in these patients a frequent positive family history for epilepsy and/or FS was present. In four epilepsy patients CUE was highly pathologic, showing intraventricular hemorrhage (IVH) of grade IV and in two mildly abnormal (IVH of grade I-II). In three additional children with normal neonatal ultrasound scan, a later magnetic resonance imaging (MRI) study revealed lesions related to neonatal insult.

DISCUSSION

In our ELBW population, epilepsy had an incidence clearly superior to that expected in infancy (8.6% vs. 0.6-0.8%). A frequent positive familiar history for epilepsy and/or FS suggests that a genetic predisposition may also play a role. Subjects with highly abnormal CUE are a subgroup with high risk for seizures; however, epilepsy can occur even with normal CUE.

Childhood febrile seizures: overview and implications

This article provides an overview of the latest knowledge and understanding of childhood febrile seizures. This review also discusses childhood febrile seizure occurrence, health services utilization and treatment costs. Parental reactions associated with its occurrence and how healthcare providers can assist parents with dealing effectively with this potentially frightening and anxiety-producing event are also discussed.