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

Abstract

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.

A rare neurological complication of COVID-19: Pediatric Miller Fisher Syndrome. A case report

“…Prior to the COVID-19 pandemic, the global incidence of Guillain-Barré Syndrome (GBS) was approximately 1-2 cases per 100,000 people, and the manifestation variant of Miller-Fisher Syndrome (MFS) accounted for only 5% of GBS cases [4,6]. A systematic review conducted on nervous system involvement triggered by SARS CoV-2 shows 25 cases of MFS associated with COVID-19 in adults, and four cases in children [7].…”

“…In our patient apart from anti-GQ1b antibodies the classic clinical symptoms and CSF changes were present. The absence of anti-GQ1b antibodies considers the case of MFS to be atypical as the majority of MFS cases (85-90%) are known to have positive anti-GQ1b antibodies particularly in variants with ophthalmoplegia [4,22]. However, despite being positive in majority of the patients with MFS absence of antiGQ1b antibodies does not rule out the diagnosis [23].…”

“…Additional diagnostic methods that bolster suspicion of GBS include electromyography (EMG) and magnetic resonance imaging (MRI), along with the identification of anti-GQ1b antibodies. However, despite the fact that anti-GQ1b antibodies are positive in the majority of GBS patients (up to 90%), their absence does not exclude the diagnosis [4,5]. We herein report a retrospective case of Miller Fisher syndrome development in a 5-month-old infant subsequent to SARS CoV-2 infection.…”

Blood biomarkers in acute ischemic stroke: The prognostic value of neutrophil-to-lymphocyte ratio and mean platelet volume

“…Similar to peripheral molecular mimicry mechanisms, microglial activation may also be altered during ischemic stroke processes. 23 Increased astroglia and oligodendrocyte reactivity may reduce potential regenerative mechanisms of plasticity patterns, such as axonal growth, synaptic remodeling, remyelination, cortical remodeling, and reattachment of neural networks to healthy intact tissue. Attenuation of the pro-inflammatory effects and strengthening of the anti-inflammatory effects after stroke may guide our future treatment strategies.…”