Parkinsonism and neurological manifestations of influenza throughout the 20th and 21st centuries.
OBJECTIVE
Given the recent paper by Jang et al. on "A Highly Pathogenic H5N1 Influenza Virus" which reported a novel animal model of parkinsonism, we aimed to perform a complete historical review of the 20th and 21st century literature on parkinsonism and neurological manifestations of influenza.


METHODS
There were at least twelve major flu pandemics reported in the literature in the 20th and 21st century. Neurological manifestations most prevalent during the pandemics included delirium, encephalitis, ocular abnormalities, amyotrophy, myelopathy, radiculopathy, ataxia and seizures. Very little parkinsonism was reported with the exception of the 1917 cases originally described by von Economo.


CONCLUSIONS
To date there have been surprisingly few cases of neurological issues inclusive of parkinsonism associated with influenza pandemics. Given the recent animal model of H5N1 influenza associated parkinsonism, the medical establishment should be prepared to evaluate for the re-emergence of parkinsonism during future outbreaks.
Henry
Julia
J
University of Florida Movement Disorders Center, Department of Neurology, Gainesville, FL, USA.
Smeyne
Richard J
RJ
Jang
Haeman
H
Miller
Bayard
B
Okun
Michael S
MS
D000818:Animals; D001717:Birds; D016208:Databases, Factual / Q000706:statistics & numerical data; D049669:History, 16th Century; D049672:History, 19th Century; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D005585:Influenza in Birds; D007251:Influenza, Human / Q000150:complications* / Q000453:epidemiology / Q000266:history; D009422:Nervous System Diseases / Q000453:epidemiology / Q000209:etiology* / Q000266:history*; D058873:Pandemics; D020734:Parkinsonian Disorders / Q000453:epidemiology / Q000209:etiology* / Q000266:history*