3. Miller Fisher Syndromesis a rare, acquired nerve disease that is a geographically variable variant of GBS observed in about 1% to 5% of all GBS cases in Western countries yet up to 19% and 25% in Taiwan and Japan respectively.
Aetiology: The Guillain-Barre syndrome (GBS) and its variants are considered post-infectious, immune-mediated neuropathies. Evidence from animal models suggests a key role of molecular mimicry. In Campylobacter jejuni gastrointestinal infections, a lipooligosaccharide present in the outer membrane of the bacteria is similar to gangliosides that are components of the peripheral nerves. Therefore, an immune response triggered to fight infection can lead to a cross-reaction on host nerves.
Many infections have been linked with GBS. The most common are gastrointestinal or respiratory illnesses. Up to 70% of patients have reported an antecedent illness in the 1 to 6 weeks before the presentation of GBS. During the Zika virus outbreak, many GBS cases were described and the results of this study indicate GBS pathophysiologic mechanisms that may be more common after Zika infection. Case reports detail many other possible etiologies linked to GBS including medications and surgeries
In 1976, flu vaccination against the influenza A/H1N1 antigen led to a well-documented, increased incidence of cases of GBS; however, further surveillance data of flu vaccinations in subsequent years have described only one additional case of GBS for every 1 million vaccines. Subsequent studies estimate that developing GBS after a flu infection is up to 7 times more likely than developing GBS after a vaccination.