Elsevier

Epilepsy Research

Volume 96, Issues 1–2, September 2011, Pages 89-95
Epilepsy Research

An epidemiological study of children with status epilepticus in Okayama, Japan: Incidence, etiologies, and outcomes

https://doi.org/10.1016/j.eplepsyres.2011.05.004Get rights and content

Summary

To clarify the incidence of first-ever episodes of status epilepticus (SE), their etiologies and outcomes among Japanese children, we performed an epidemiological study in Okayama City. One hundred and twenty patients (69 males, 51 females) experienced first-ever SE episodes between 2003 and 2005. Overall, the annual incidence of SE was 42.0 per 100,000 population (95% CI: 34.5⿿49.5). The highest incidence was seen in patients aged <2 years, especially in the second year of life. Febrile SE accounted for 59 (49.2%) cases, and acute-symptomatic etiologies accounted for 21. Ten were considered to have remote-symptomatic etiologies, and eight to have acute-on-remote-symptomatic etiologies. Ten were classified as cryptogenic/idiopathic epilepsy-related, and 12 were unclassified. Nineteen (15.8%) patients were diagnosed with exanthema subitum, including three with encephalitis/encephalopathy, and 17 (14.2%) patients with influenza, including four with encephalitis/encephalopathy. After SE, eight (6.7%) patients suffered from motor disturbance with or without mental disturbance. One of these died during the follow-up period. Ultimately 34 (28.3%) of the 120 patients had been diagnosed with epilepsy by the end of the follow-up. We conclude that the incidence of SE among Japanese children is higher than the reported incidence among Caucasian children. Febrile SE accounted for approximately half of the cases. Among the etiologies, exanthema subitum was the most important infectious disease, followed by influenza. Both types of infection caused encephalitis/encephalopathy associated with SE as well as febrile SE.

Introduction

Until recently, there were no population-based epidemiological studies on status epilepticus (SE) in children from Asian countries. In 2003, we performed this type of study on Japanese children in Okayama City, and reported that the incidence of SE among Japanese children was higher than that reported among Caucasian children (Nishiyama et al., 2007). Of the four population-based studies on SE reported from Western countries (Chin et al., 2006, Chin et al., 2009, Coeytaux et al., 2000, DeLorenzo et al., 1996, Hesdorffer et al., 1998), two of them evaluated the annual incidence of SE while stratifying the data by patient ethnicity.

DeLorenzo et al. (1996) investigated the incidence of SE in a racially mixed population aged 31 days or older in the US state of Virginia from 1989 to 1991. They reported their data separately for Caucasians and non-Caucasians, and uncovered substantially higher incidence of SE at all ages among non-Caucasians, most of whom were African Americans: 57/100,000 in non-white, compared with 20/100,000 in Caucasians. Chin et al. (2009) investigated the effects of socioeconomic and ethnic factors on the annual incidence of convulsive SE in children in North London. They concluded that these two factors independently affected risk for prolonged febrile seizures and acute-symptomatic convulsive SE, but not for other types of childhood convulsive SE. They reported that Asian children were 5.7 times more likely than white children to have a first-ever episode of convulsive SE.

Although our previous study suggested that different ethnic groups might tend to exhibit different incidences of SE and different etiological patterns, our data could not be taken as absolute proof of this because of the short study period. To address this problem, we undertook a larger-scale epidemiological study assessing the annual incidence of first-ever SE episodes, noting any variation in the incidence from year to year and determining the distribution of the etiologies underlying SE as well as outcomes in Japanese children in Okayama City from January 1, 2003 to December 31, 2005.

Section snippets

Methods

The methods used in this survey were the same as those used in our previous study (Nishiyama et al., 2007). Subjects were all patients aged 31 days to <15 years living in Okayama City who experienced a first-ever SE episode between January 1, 2003 and December 31, 2005.

Okayama City is a medium-sized city with two university hospitals; it has no major industrial areas or slums where poor people would tend to concentrate. Its population was 629,587, 631,638 and 633,841 in 2003, 2004, and 2005,

Demographics and incidence of SE

As shown in Table 2, 120 children who were confirmed residents of Okayama City (69 males and 51 females) experienced first-ever episodes of SE between January 1, 2003 and December 31, 2005. One hundred and fourteen of the 120 subjects came to the hospitals as emergency outpatients, and 109 of these 114 were hospitalized for treatment and further examination. Five subjects had their first SE during hospitalization in the children's ward, and the remaining one subject, who had a congenital heart

Discussion

In this study, the annual incidence of SE in children aged 31 days to <15 years was estimated to be 42.0 per 100,000 population (95% CI: 34.5⿿49.5) between January 1, 2003 and December 31, 2005. Reported annual incidence of first-ever SE in Caucasian children (defined as either ⿦14 or ⿦15 years of age) in Western countries tend to be lower (Chin et al., 2006, Chin et al., 2009, Coeytaux et al., 2000, DeLorenzo et al., 1996, Hesdorffer et al., 1998). Chin et al. (2009) reported that the annual

Acknowledgements

We thank late Dr. Eiji Oka (Asahigawa-so Rehabilitation Center Jidouin Hospital), Drs. Fumiko Kibayashi (Central City Hospital), Yoshiyuki Uchida (Okamura Isshindow Hospital), and Chiaki Kawashima (Okayama Kyoritsu Hospital) for their cooperation in this survey. This work was partly supported by a grant from Japanese Ministry of Health, Labor and Welfare promoting Research on the Clinical Evidence of Medical Treatment for Status Epilepticus in Childhood (H14-Child 004) within the framework of

References (20)

There are more references available in the full text version of this article.

Cited by (25)

  • Status epilepticus outcomes among vaccinated and unvaccinated children: A population-based study

    2022, Epilepsy and Behavior
    Citation Excerpt :

    The age distribution of SE in our study was comparable to previous studies, all reporting the highest incidence in <2 year olds. However, we found incidence peaked in 12–17-month olds, while three previous studies [2–4] reported peaks in <12-month olds and one study in 12–23-month olds [21]. We identified a higher SE incidence in Indigenous children compared to non-Indigenous children aged <12 years that has not previously been reported.

  • A Phase 3 open-label study of the efficacy, safety and pharmacokinetics of buccally administered midazolam hydrochloride for the treatment of status epilepticus in pediatric Japanese subjects

    2021, Epilepsy Research
    Citation Excerpt :

    The predominance of young children in the study population is to be expected because younger age is a risk factor for CSE (Fountain, 2000); a previous study found 40 % of cases were in children younger than 2 years (Shinnar et al., 1997), and a population study from the UK has reported the incidence of CSE to be highest among younger patients and lower in adolescents (Chin et al., 2006). This is consistent with findings from Japan, which showed that 48 % of first SE episodes occurred before 2 years of age, and that the highest incidence of CSE was in those aged 0–2 years old (Nishiyama et al., 2011). In our study population, 80 % of subjects achieved therapeutic success with MHOS administered in the healthcare setting (p < 0.001).

  • Clinical characteristics and prognosis in a large paediatric cohort with status epilepticus

    2020, Seizure
    Citation Excerpt :

    The proportion of CNS infections in this study was lower than that reported in studies from India (50.7 %) [20] and Taiwan (48.2 %) [21]. Febrile seizures (11.8 %) were the third leading cause of SE in the current study, but the proportion was lower than that reported in previous studies [2,4]. Population-based studies in children found that prolonged febrile seizures, occurring in 31.8 % of observed children in North London [2] and 49.2 % in Okayama, Japan, were the most common cause of convulsive SE.

  • Predictors of long-term mortality in status epilepticus

    2018, Epilepsy and Behavior
    Citation Excerpt :

    The annual SE incidence rate ranges from 1.84 to 42.0 per 100,000 population. This number is higher in populations at extreme ends of the age spectrum: children and elderly patients [1–6]. Although SE is more common in patients with epilepsy, the mortality risk is higher in patients with SE without epilepsy.

View all citing articles on Scopus
View full text