title: Clinical and MRI features of neurological complications after influenza A (H1N1) infection in critically ill children.
abstract: BACKGROUND
  Influenza A (H1N1) can cause severe neurological complications.
  
  
  OBJECTIVE
  The purpose of this study was to analyze clinical and MRI features of neurological complications after H1N1 infection in critically ill children.
  
  
  METHODS
  We retrospectively analyzed clinical and neuroimaging findings in 17 children who were hospitalized in an intensive care unit with severe neurological complications after H1N1 infection in South China between September 2009 and December 2011. All children underwent pre- and post-contrast-enhanced brain MRI. Postmortem studies were performed in two children.
  
  
  RESULTS
  Six children died, five because of acute necrotizing encephalopathy (ANE) and one because of intracranial fungal infection. Eleven recovered; their manifestations of H1N1 were meningitis (3), encephalitis (1) and influenza encephalopathy (7). MRI features of ANE included multiple symmetrical brain lesions demonstrating prolonged T1 and T2 signal in the thalami, internal capsule, lenticular nucleus and pontine tegmentum. Postmortem MRI in two children with acute necrotizing encephalopathy showed diffuse prolonged T1 and T2 signal in the bilateral thalami, brainstem deformation and tonsillar herniation.
  
  
  CONCLUSIONS
  Fatal neurological complications in children after H1N1 infection include ANE and opportunistic fungal infection. MRI is essential for identification of neurological complications and for clinical evaluation.
authors.affiliation: Department of Radiology, Shenzhen Children's Hospital, Guangdong, China.
authors.forename: Hongwu
authors.initials: H
authors.lastname: Zeng
authors.forename: Stephen
authors.initials: S
authors.lastname: Quinet
authors.forename: Wenxian
authors.initials: W
authors.lastname: Huang
authors.forename: Yungen
authors.initials: Y
authors.lastname: Gan
authors.forename: Chunxi
authors.initials: C
authors.lastname: Han
authors.forename: Yanxia
authors.initials: Y
authors.lastname: He
authors.forename: Yonker
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D016638:Critical Illness; D018792:Encephalitis, Viral / Q000150:complications* / Q000473:pathology*; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000150:complications* / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male