Miller Fisher syndrome associated with COVID-19: an up-to-date systematic review

Recently, during the pandemic infection of the novel SARS-CoV-2, some cases of Miller Fisher syndrome (MFS) have been reported. We want to summarize the main features of patients with MFS and COVID-19. A PubMed search was performed on 8 October to identify references reporting cases with MFS associated with COVID-19 from the first report of COVID-19 to 8 October 2020 using the following keywords: “Miller Fisher syndrome” AND “COVID-19” OR “SARS-CoV-2”. A systematic review from the first report of coronavirus disease 2019 (COVID-19) to 8 October 2020 revealed 7 cases with Miller Fisher syndrome (MFS) associated with COVID-19. The 7 cases came from 5 countries but most of these patients were from Europe (85.7%), especially Spain. There are 5 cases of MFS diagnosed after the laboratory confirmation of SARS-CoV-2 infection. The mean onset time of MFS-associated neurological symptoms was 14.75 days after the diagnosis of COVID-19. However, the two remaining cases presented initially with MFS-associated neurological symptoms followed by the diagnosis of COVID-19. The most common symptoms of COVID-19-associated MFS were perioral paresthesias (57.1%), ataxia (57.1%), blurred vision (42.9), ophthalmoplegia (42.9), and generalized areflexia (42.9). However, more cohort and case-control studies are required to establish the epidemiological linkage.