OBJECTIVE The current study aimed to identify and compare the clinical characteristics of human parechovirus type 3 (HPeV3)-associated acute encephalitis/encephalopathy (HPeV3E/E) between infants with abnormal brain magnetic resonance imaging (MRI) findings (typical, or MRI-positive HPeV3E/E) and those with MRI-negative findings (MRI-negative HPeV3E/E). METHODS This is a retrospective study on patients with HPeV3 infection, and a two-step questionnaire survey performed on 837 hospitals in Japan between 2014 and 2016. RESULTS We identified 240 infants with HPeV3 infection, of which 34 had been clinically-diagnosed HPeV3E/E (cHPeV3E/E). However, detailed clinical data were provided by 32 of the 34 patients. Among these 32, 23 had undergone MRI and were categorized into two groups, MRI-positive (n = 17) and -negative (n = 6). There were no significant intergroup differences in clinical lab results or symptoms, except for gastrointestinal symptoms that were only present in the MRI-negative patients. The MRI-positive group showed white matter involvement on brain MRI during the acute phase, and 8 patients presented with lesions on follow-up MRI. Furthermore, 4 (50%) of the 8 patients had neurological sequelae. CONCLUSION Clinical characteristics of cHPeV3E/E patients with and without lesions on brain MRI showed no significant differences. Therefore, considering the difficulty in distinguishing febrile infants with cHPeV3E/E from those with a sepsis-like illness, during an HPeV3 infection epidemic, it is imperative to frequently perform brain MRI in febrile infants presenting with severe disease for the early diagnosis of HPeV3E/E presenting with brain lesions.

中文翻译：

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日本婴儿中 HPeV3 相关的急性脑炎/脑病

目的 本研究旨在识别和比较具有异常脑磁共振成像 (MRI) 结果（典型或 MRI 阳性HPeV3E/E）和 MRI 阴性结果（MRI 阴性 HPeV3E/E）。方法 回顾性研究 HPeV3 感染患者，2014 年至 2016 年对日本 837 家医院进行两步问卷调查。 结果 我们确定了 240 名 HPeV3 感染婴儿，其中 34 名已被临床诊断为 HPeV3E/E (cHPeV3E/E)。然而，34 名患者中的 32 名提供了详细的临床数据。在这 32 名患者中，23 名接受了 MRI 并分为两组，MRI 阳性（n = 17）和阴性（n = 6）。除了仅在 MRI 阴性患者中出现的胃肠道症状外，临床实验室结果或症状没有显着的组间差异。MRI 阳性组在急性期脑 MRI 显示白质受累，8 例患者在随访 MRI 中出现病变。此外，8 名患者中有 4 名 (50%) 有神经系统后遗症。结论 cHPeV3E/E患者脑部MRI有无病灶的临床特​​征无显着差异。因此，考虑到 cHPeV3E/E 发热婴儿与脓毒症样疾病发热婴儿难以区分，在 HPeV3 感染流行期间，对于 HPeV3E/ E 表现为脑损伤。