Acute flaccid myelitis: Consensus diagnostic criteria is helpful but careful evaluation of disease course is as important.

Abstract

Acute flaccid myelitis (AFM) is a severe neurological syndrome, characterized clinically by an acute flaccid paralysis (AFP) and radiologically by spinal neuroimaging demonstrating grey-matter predominant lesions [ [1] Murphy O.C. Messacar K. Benson L. Bove R. Carpenter J.L. Crawford T. et al. Acute flaccid myelitis: cause, diagnosis, and management. Lancet. 2021 Jan 23; 397: 334-346 Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar ]. AFM was first introduced as a diagnostic entity after the surge of cases in California and Colorado between 2012 and 2014, although the syndrome has been well recognised prior and sometimes reported in other guises such as transverse myelitis (TM) plus [ [2] Absoud M. Greenberg B.M. Lim M. Lotze T. Thomas T. Deiva K. Pediatric transverse myelitis. Neurology. 2016 Aug 30; 87: S46-S52 Crossref PubMed Scopus (64) Google Scholar ]. In the United States (US), a biennial outbreak was subsequently observed with cases almost doubling at the last peak in 2018 (see Fig.1) [ [3] Acute flaccid myelitis cases and outbreaks. https://www.cdc.gov/acute-flaccid-myelitis/cases-in-us.htmlDate accessed: May 1, 2023 Google Scholar ]. There was a lag before cases were seen in Europe with the last surge being reported in the United Kingdom. Although the anticipated surge in 2020 did not occur, the relaxing of social-distancing measures implemented during the COVID-19 pandemic has seen enterovirus infections rates increasing again, the harbinger of AFM outbreaks.