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

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 <2years, 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.

Genetic seizure susceptibility underlying acute encephalopathies in childhood.

We herein investigated risk factors of pediatric acute encephalopathy (AE) regarding the hitherto uncharacterized genetic background of seizure susceptibility underlying the pathogenesis of AE. The study included 15 patients with a history of various types of AE in childhood. We undertook the mutational analysis of the neuronal sodium channel alpha 1 subunit (SCN1A) gene which is the most representative gene for hyperthermia-induced seizure susceptibility. Six patients (40%) had a positive family history of seizures or AE, especially febrile seizures, in first- or second-degree relatives. The SCN1A-R1575C mutation was detected in a patient with a history of acute encephalitis with refractory, repetitive partial seizures (AERRPS) and also in the patient's apparently healthy father. In the present study, dense familial seizure predisposition was present in the patients with AE. Although the presence of seizure susceptibility alone is insufficient to cause AE, it can exacerbate seizures and the subsequent development of inflammatory reactions in the brain when environmental factors are included. Genetic seizure susceptibility may contribute to some types of AE in childhood.

An epidemiological study of children with status epilepticus in Okayama, Japan.

BACKGROUND: The incidence of status epilepticus (SE) in Asian children, including Japanese, has not been reported. METHODS: In 2003, we performed an epidemiological study of SE on Japanese children (31 days or older to <15 years of age) in Okayama City by ascertaining all lifetime first episodes of SE. RESULTS: Thirty-seven patients (22 males and 15 females) were identified. The annual incidence of SE was 38.8 per 100,000 population (95% CI: 24.5-49.5). Febrile SE in the absence of CNS infection accounted for 17. Acute symptomatic etiologies other than febrile SE were observed in eight patients, including three cases of influenza encephalitis/encephalopathy. Five were classified as remote symptomatic and the remaining seven as cryptogenic. The highest incidence (155.1/100,000) was seen in the age range of 31 days or older to <1 year, followed by 101.5/100,000 in the age range of one year, and the incidence decreased after eight years. In 26 of the 37 patients, SE was their first seizure. As for seizure types, 32 had convulsive SE, including tonic status in one. Five others showed nonconvulsive SE, including complex partial SE in four and absence status in one. No one died of SE. Two patients who brought on SE because of influenza encephalitis/encephalopathy suffered from motor disturbance with or without mental disturbance after SE. CONCLUSIONS: The incidence of SE tended to be higher in Japanese children than reported in Caucasians. The Japanese had an age-specific incidence pattern similar to that of Caucasians.

[Clinical and electroencephalographic analysis of epilepsy in children with hydrocephalus].

Clinical and electroencephalographic features of epilepsy and the prognosis of intelligence were investigated in 156 children with hydrocephalus. Of these 53 (34.0%) had epilepsy. The incidence and outcome of epilepsy were determined by the etiology of hydrocephalus. The incidence was high in children with hydrocephalus caused by intra-cranial infection and dysgenetic hydrocephalus without dysraphism. Furthermore, it was difficult to control the epileptic seizures in these patients. In contrast, children with dysgenetic hydrocephalus caused by dysraphism and simple hydrocephalus had lower incidence of epilepsy and epileptic seizures had been well controlled in these cases. In hydrocephalic children, localization-related epilepsy was the most common. Complex partial seizures and focal motor seizures were frequently observed. Common electroencephalographic findings were focal spikes or multi-focal spikes. The intelligence quotient was significantly lower in children with epilepsy than in those without epilepsy. All these findings suggest that the incidence of epilepsy may be a crucial prognostic factor in children with hydrocephalus.