title: Encephalitis and encephalopathy associated with an influenza epidemic in Japan.
abstract: During the winter of 1998-1999, there was an outbreak of encephalitis/encephalopathy in Japan that appeared to be associated with influenza. We conducted a national survey of the prevalence and clinical features of disease and the associated outcomes and prognostic factors related to this outbreak. A total of 202 cases were analyzed, of which 148 were diagnosed as influenza-associated encephalitis/encephalopathy on the basis of virologic analysis. Of the 148 cases studied, 130 (87.8%) were type A influenza and 17 were type B. Encephalitis/encephalopathy developed mainly in children age <5 years, either on the day that influenza signs appeared or on the next day. The major signs included altered consciousness or loss of consciousness, convulsions, cough, and vomiting. In many patients, multiple-organ failure developed, and rates of mortality (31.8%) and disability (27.7%) were high. Thrombocytopenia and severely elevated transaminase levels were factors associated with a poor prognosis. Thus, influenza-associated encephalitis/encephalopathy progressed rapidly and was associated with poor outcomes.
authors.affiliation: Department of Health Science, Nagoya University, Nagoya, Nagoya 461-0047, Japan. morishim@met.nagoya-u.ac.jp
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Morishima
authors.forename: Takehiro
authors.initials: T
authors.lastname: Togashi
authors.forename: Shyumpei
authors.initials: S
authors.lastname: Yokota
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Okuno
authors.forename: Chiaki
authors.initials: C
authors.lastname: Miyazaki
authors.forename: Masato
authors.initials: M
authors.lastname: Tashiro
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Okabe
mesh_terms: D001219:Aspartate Aminotransferases / Q000097:blood; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D004660:Encephalitis / Q000150:complications / Q000453:epidemiology* / Q000401:mortality; D005260:Female; D006801:Humans; D007251:Influenza, Human / Q000150:complications / Q000453:epidemiology* / Q000401:mortality; D007564:Japan / Q000453:epidemiology; D008297:Male; D010976:Platelet Count; D011379:Prognosis
chemical_list: D015415:Biomarkers; D001219:Aspartate Aminotransferases