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Neurological complications of pandemic influenza A H1N1 2009 infection: European case series and review


Neurological manifestations and outcomes of children with the 2009 H1N1 virus infection have been reported in three American series and from smaller cohorts and case reports worldwide. Of the 83 children admitted between April 2009 and March 2010 with H1N1 virus infection to a tertiary children’s hospital in a European setting, five children aged between 2 and 10 years had neurological symptoms. Four patients had seizures and encephalopathy at presentation. One patient presented with ataxia; one developed neuropsychiatric manifestations, and two developed movement disorders during the disease course. Early neuroimaging showed evidence of acute necrotising encephalopathy (ANE) in one case and non-specific white matter changes in another. Initial neuroimaging was normal for the other three, but interval MRI showed increased signal in bilateral periventricular distribution in one and significant cerebral volume loss in the other. Clinical outcomes varied: two recovered fully while three had residual seizures and/or significant cognitive deficits. Conclusion An analysis of our patients along with all reported cases reveal that seizures and encephalopathy were common neurological presentations associated with pandemic 2009 H1N1 influenza virus infection in children requiring hospital admission. Neuroimaging suggestive of ANE, basal ganglia involvement and volume loss appears to be associated with worse neurological outcome.

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We are thankful to Dr. Keith Pohl, Dr. Elaine Hughes, Dr. Jean-Pierre Lin, Dr. Nuria Martinez-Alier, Dr. Claire Lundy, Dr. Tammy Hedderly, Dr. John Jackman, Dr. Artemis Gika and Dr. Karine Lascelles who were all closely involved in the care and management of these patients and for their helpful comments on this manuscript. We would also like to thank Dr. Atta Siddiqui for reviewing all the neuroimaging; Dr. Sushma Goyal for reviewing the electroencephalograms; Dr. Eithne MacMahon and Dr. Emma Aarons for assistance with virology; and Dr. Ruth Ackers for help with the dosing of zanamivir.

Conflicts of interest

The authors declare that they have no conflict of interest.

Author information

Correspondence to Ming Lim.

Additional information

The authors Pinki Surana and Shan Tang contributed equally to this article.

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Surana, P., Tang, S., McDougall, M. et al. Neurological complications of pandemic influenza A H1N1 2009 infection: European case series and review. Eur J Pediatr 170, 1007–1015 (2011). https://doi.org/10.1007/s00431-010-1392-3

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  • Influenza A
  • H1N1
  • Neurologic outcome
  • Encephalopathy
  • Encephalitis
  • Pandemic