title: Neurological events related to influenza A (H1N1) pdm09.
abstract: OBJECTIVE
  To review neurological complications after the influenza A (H1N1) pdm09, highlighting the clinical differences between patients with post-vaccine or viral infection.
  
  
  METHODS
  A search on Medline, Ovid, EMBASE, and PubMed databases using the keywords “neurological complications of Influenza AH1N1” or “post-vaccine Influenza AH1N1.”
  
  
  METHODS
  Only papers written in English, Spanish, German, French, Portuguese, and Italian published from March 2009 to December 2012 were included.
  
  
  METHODS
  We included 104 articles presenting a total of 1636 patient cases. In addition, two cases of influenza vaccine-related neurological events from our neurological care center, arising during the period of study, were also included.
  
  
  METHODS
  Demographic data and clinical diagnosis of neurological complications and outcomes: death, neurological sequelae or recovery after influenza A (H1N1) pdm09 vaccine or infection.
  
  
  RESULTS
  The retrieved cases were divided into two groups: the postvaccination group, with 287 patients, and the viral infection group, with 1349 patients. Most patients in the first group were adults. The main neurological complications were Guillain-Barre syndrome (GBS) or polyneuropathy (125), and seizures (23). All patients survived. Pediatric patients were predominant in the viral infection group. In this group, 60 patients (4.7%) died and 52 (30.1%) developed permanent sequelae. A wide spectrum of neurological complications was observed.
  
  
  CONCLUSIONS
  Fatal cases and severe, permanent, neurological sequelae were observed in the infection group only. Clinical outcome was more favorable in the post-vaccination group. In this context, the relevance of an accurate neurological evaluation is demonstrated for all suspicious cases, as well as the need of an appropriate long-term clinical and imaging follow-up of infection and post-vaccination events related to influenza A (H1N1) pdm09, to clearly estimate the magnitude of neurological complications leading to permanent disability.
authors.forename: Graciela
authors.initials: G
authors.lastname: Cárdenas
authors.forename: José Luis
authors.initials: JL
authors.lastname: Soto-Hernández
authors.forename: Alexandra
authors.initials: A
authors.lastname: Díaz-Alba
authors.forename: Yair
authors.initials: Y
authors.lastname: Ugalde
authors.forename: Jorge
authors.initials: J
authors.lastname: Mérida-Puga
authors.forename: Marcos
authors.initials: M
authors.lastname: Rosetti
authors.forename: Edda
authors.initials: E
authors.lastname: Sciutto
mesh_terms: D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000502:physiology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000009:adverse effects*; D007251:Influenza, Human / Q000150:complications* / Q000821:virology; D009422:Nervous System Diseases / Q000453:epidemiology / Q000209:etiology*
chemical_list: D007252:Influenza Vaccines