Miller Fisher Syndrome Associated With COVID-19: A History of Molecular Mimicry and an Up-to-Date Review of the Literature

Miller Fisher syndrome (MFS) was first recognized by Collier in 1932 as a clinical triad of ataxia, areflexia, and ophthalmoplegia. In 1956, three cases with this triad were published by Miller Fisher as a limited variant of Guillian-Barré syndrome (GBS), and the disease started to be called by his name. Since the beginning of the SARS-CoV-2 pandemic, there have been many reports of peripheral and central nervous system involvement. Until December 2022, a total of 24 cases, including four children associated with MFS, had been reported. This current review aimed to present the basic clinical and laboratory characteristics of patients with MFS and coronavirus disease-2019 (COVID-19). Since 2020, cases with different age and gender characteristics have been reported from eight different countries. Most cases were reported from Europe. SARS-CoV-2 infection was confirmed in seven of the cases. The youngest case reported was a 6-year-old boy from Turkey, while the oldest case was a 70-year-old female from Spain. All these reported cases and our past medical knowledge of MFS suggest that molecular mimicry is the main immunological mechanism. Despite all these data, more case reports, cohorts, and case-control studies will be needed to clarify the relationship between MFS and COVID-19.