title: Acute encephalopathy with pandemic (H1N1) 2009 virus infection.
abstract: OBJECTIVE
  In April 2009, a novel influenza A (H1N1) pdm virus was identified in Mexico and spread quickly around the world. However, the clinical features of acute encephalopathy associated with 2009 pandemic influenza have not yet been elucidated.
  
  
  METHODS
  We treated 8 patients (3 boys and 5 girls) aged 4 to 11 years (average age, 8 y 3 months) with influenza virus-associated encephalopathy, who presented at our 2 hospitals between July 2009 and March 2010. We investigated the clinical characteristics, treatments, and outcomes in the patients.
  
  
  RESULTS
  In all patients, brain computed tomography showed mild to severe diffuse cerebral edema, and electroencephalography revealed diffuse high-voltage slow waves. They were all treated with oseltamivir and methylprednisolone pulse therapy. Six patients recovered without any sequelae; however, the remaining 2 had residual neurological sequelae. These 2 patients presented with severe disturbance of consciousness, and their central nervous system symptoms appeared within 12 hours after the onset of fever. One patient had periventricular leukomalacia and symptomatic epilepsy by perinatal brain hypoxia, and the other patient had 1 complex febrile and 2 febrile seizures.
  
  
  CONCLUSIONS
  This study showed that patients with influenza-associated encephalopathy caused by influenza A (H1N1) pdm infection were all older than those with seasonal influenza. Underlying neurological disease or history may be associated with poor prognosis.
authors.affiliation: Department of Pediatrics, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan. fuchigami.tatsuo@nihon-u.ac.jp
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Fuchigami
authors.forename: Yuki
authors.initials: Y
authors.lastname: Imai
authors.forename: Maki
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Wakako
authors.initials: W
authors.lastname: Ishii
authors.forename: Ayumi
authors.initials: A
authors.lastname: Endo
authors.forename: Chikako
authors.initials: C
authors.lastname: Arakawa
authors.forename: Ryutaro
authors.initials: R
authors.lastname: Kohira
authors.forename: Koji
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Fujita
authors.forename: Yasuji
authors.initials: Y
authors.lastname: Inamo
authors.forename: Hideo
authors.initials: H
authors.lastname: Mugishima
mesh_terms: D002648:Child; D002675:Child, Preschool; D004279:DNA, Viral / Q000032:analysis; D004569:Electroencephalography; D018792:Encephalitis, Viral / Q000175:diagnosis / Q000453:epidemiology* / Q000821:virology; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics*; D007251:Influenza, Human / Q000150:complications* / Q000453:epidemiology / Q000821:virology; D007564:Japan / Q000453:epidemiology; D008279:Magnetic Resonance Imaging; D008297:Male; D058873:Pandemics; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D004279:DNA, Viral