BACKGROUND We previously reported the nationwide, epidemiological data of acute encephalopathy in Japan during 2007-2010. Here we conducted the second national survey of acute encephalopathy during 2014-2017, and compared the results between the two studies to elucidate the trends in the seven years' interval as well as the influence of changes in pediatric viral infections and guidelines for acute encephalopathy in Japan. METHODS The Research Committee on Acute Encephalopathy supported by the Japanese Government sent a questionnaire to 507 hospitals throughout Japan, and collected the responses by mail. RESULTS A total of 1115 cases from 267 hospitals reportedly had acute encephalopathy during April 2014-June 2017. In this study, the age at onset was younger, the ratios of recently established syndromes, such as acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) and clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS), were higher, and the ratio of influenza-associated encephalopathy was lower, than in the previous study. The age at onset of influenza-associated encephalopathy was lower, and that of HHV-6/7-associated encephalopathy higher, compared to the first survey. The outcomes of entire acute encephalopathy remained unchanged. CONCLUSION Some of these changes reflected the recent trends of viral infectious diseases including 2009 influenza pandemic, and others the standardization of the diagnosis of acute encephalopathy in Japan.

中文翻译：

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基于2014-2017年全国监测的日本急性脑病流行病学变化

背景 我们之前报道了 2007-2010 年日本全国范围内的急性脑病流行病学数据。在这里，我们进行了 2014-2017 年第二次全国急性脑病调查，并比较了两项研究的结果，以阐明七年间隔的趋势以及儿科病毒感染变化的影响和急性脑病指南。日本。方法 由日本政府支持的急性脑病研究委员会向日本全国 507 家医院发送问卷，并通过邮件收集答复。结果 2014 年 4 月至 2017 年 6 月期间，267 家医院共报告 1115 例急性脑病病例。与之前的研究相比，例如伴有双相发作和迟发性弥散减少的急性脑病 (AESD) 和临床轻度脑炎/脑病伴可逆性脾脏病变 (MERS) 较高，而流感相关脑病的比例较低。与第一次调查相比，流感相关脑病的发病年龄较低，而 HHV-6/7 相关脑病的发病年龄较高。整个急性脑病的结果保持不变。结论 这些变化中的一些反映了病毒性传染病的近期趋势，包括 2009 年流感大流行，另一些反映了日本急性脑病诊断的标准化。流感相关脑病的比例低于之前的研究。与第一次调查相比，流感相关脑病的发病年龄较低，而 HHV-6/7 相关脑病的发病年龄较高。整个急性脑病的结果保持不变。结论 这些变化中的一些反映了病毒性传染病的近期趋势，包括 2009 年流感大流行，另一些反映了日本急性脑病诊断的标准化。流感相关脑病的比例低于之前的研究。与第一次调查相比，流感相关脑病的发病年龄较低，而 HHV-6/7 相关脑病的发病年龄较高。整个急性脑病的结果保持不变。结论 这些变化中的一些反映了病毒性传染病的近期趋势，包括 2009 年流感大流行，另一些反映了日本急性脑病诊断的标准化。