title: Neurological complications after H1N1 influenza vaccination: magnetic resonance imaging findings.
abstract: OBJECTIVE
  To report 4 different neurological complications of H1N1 virus vaccination.
  
  
  METHODS
  Four patients (9, 16, 37 and 69 years of age) had neurological symptoms (intracranial hypertension, ataxia, left peripheral facial palsy of abrupt onset, altered mental status, myelitis) starting 4-15 days after H1N1 vaccination. MRI was obtained during the acute period.
  
  
  RESULTS
  One patient with high T2 signal in the cerebellum interpreted as acute cerebellitis; another, with left facial palsy, showed contrast enhancement within both internal auditory canals was present, however it was more important in the right side; one patient showed gyriform hyperintensities on FLAIR with sulcal effacement in the right fronto-parietal region; and the last one showed findings compatible with thoracic myelitis.
  
  
  CONCLUSIONS
  H1N1 vaccination can result in important neurological complications probably secondary to post-vaccination inflammation. MRI detected abnormalities in all patients.
authors: Setor de Radiologia, Universidade de Pernambuco, Recife, PE, Brazil.
authors: Ronaldo
authors: R
authors: Lessa
authors: University of North Carolina, Chapel Hill, North Carolina, United States.
authors: Maurício
authors: M
authors: Castillo
authors: Setor de Neurologia, Hospital Santa Joana, Recife, PE, Brazil.
authors: Renata
authors: R
authors: Azevedo
authors: Setor de Neurologia, Hospital Correia Picanço, Recife, PE, Brazil.
authors: Fernanda
authors: F
authors: Azevedo
authors: Universidade de Pernambuco, Recife, PE, Brazil.
authors: Hildo
authors: H
authors: Azevedo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002524:Cerebellar Ataxia / Q000209:etiology; D002648:Child; D005158:Facial Paralysis / Q000209:etiology; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000009:adverse effects*; D019586:Intracranial Hypertension / Q000209:etiology; D008279:Magnetic Resonance Imaging; D008297:Male; D009187:Myelitis / Q000209:etiology; D009422:Nervous System Diseases / Q000175:diagnosis / Q000209:etiology*
chemical_list: D007252:Influenza Vaccines