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. 2018 Jun 1;66(12):1831-1837.
doi: 10.1093/cid/cix1126.

Characteristics and Outcomes of Influenza-Associated Encephalopathy Cases Among Children and Adults in Japan, 2010-2015

Hideo Okuno  1   2 , Yuichiro Yahata  1 , Keiko Tanaka-Taya  1 , Satoru Arai  1 , Hiroshi Satoh  1 , Saeko Morino  1 , Tomoe Shimada  1 , Tomimasa Sunagawa  1 , Timothy M Uyeki  3 , Kazunori Oishi  1
Affiliations

Characteristics and Outcomes of Influenza-Associated Encephalopathy Cases Among Children and Adults in Japan, 2010-2015

Hideo Okuno et al. Clin Infect Dis. .

Abstract

Background: Influenza-associated encephalopathy (IAE) can result in severe neurologic disease with high mortality. Most IAE cases are reported among children worldwide. Understanding of IAE among adults is limited.

Methods: Data were collected on IAE cases reported through the National Epidemiological Surveillance of Infectious Diseases database in Japan from 2010 through 2015. IAE cases were stratified by age category and analyzed using descriptive statistics to assess differences in characteristics and outcomes.

Results: Among 385 IAE cases, median age at diagnosis was 7 years (range, 0-90), and 283 (74%) were aged <18 years. Mean seasonal incidence of IAE cases among children and adults (aged ≥18 years) was 2.83 and 0.19 cases per 1000000 population, respectively. IAE incidence did not vary by predominant influenza A virus subtype. IAE frequency was highest in school-aged (5-12 years) children (38%), followed by children aged 2-4 years (21%) and adults aged 18-49 years (11%). The proportion of cases with seizures was more common in children. There were more cases with cerebrospinal fluid pleocytosis among adults than in children (P < .01), especially among those aged 18-49 (17%) and 50-64 (19%) years. Case fatality proportion was highest in those aged 40-64 (17%) and ≥65 (20%) years.

Conclusions: We found differences in the clinical features of IAE between adults and children in Japan. Although IAE incidence was higher in children, mortality was higher in adults. Efforts are needed to prevent and improve survival of patients with IAE, especially in adults.

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Figures

Figure 1.
Figure 1.
Epidemiologic curve of influenza-associated encephalopathy cases, influenza-like illness cases, and proportion of influenza A virus subtypes detected during each season in Japan, 2010–2015.
Figure 2.
Figure 2.
Age distribution of influenza-associated encephalopathy cases per 1 million population, 2010–2015. The population for each age group was based on national census data (http://www.stat.go.jp/data/jinsui/2.htm). A(H3N2) virus was predominant among influenza A virus subtypes in 2011–2012, 2012–2013, and 2014–2015. A(H1N1)pdm09 virus was predominant during 2010–2011 and 2013–2014.
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References

    1. Hoshino A, Saitoh M, Oka A et al. . Epidemiology of acute encephalopathy in Japan, with emphasis on the association of viruses and syndromes. Brain Dev 2012; 34:337–43. - PubMed
    1. Morishima T, Togashi T, Yokota S et al. ; Collaborative Study Group on Influenza-Associated Encephalopathy in Japan Encephalitis and encephalopathy associated with an influenza epidemic in Japan. Clin Infect Dis 2002; 35:512–7. - PubMed
    1. Steininger C, Popow-Kraupp T, Laferl H et al. . Acute encephalopathy associated with influenza A virus infection. Clin Infect Dis 2003; 36:567–74. - PMC - PubMed
    1. Amin R, Ford-Jones E, Richardson SE et al. . Acute childhood encephalitis and encephalopathy associated with influenza: a prospective 11-year review. Pediatr Infect Dis J 2008; 27:390–5. - PubMed
    1. Gu Y, Shimada T, Yasui Y, Tada Y, Kaku M, Okabe N. National surveillance of influenza-associated encephalopathy in Japan over six years, before and during the 2009-2010 influenza pandemic. PLoS One 2013; 8:e54786. - PMC - PubMed

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