Miller fisher syndrome with positive anti-GQ1b/GT1a antibodies associated with COVID-19 infection: A case report.

Background: Miller fisher syndrome (MFS) is a variant of Guillain-Barré syndrome, an acute immune-mediated peripheral neuropathy that is often secondary to viral infections. Anti-ganglioside antibodies play crucial roles in the development of MFS. The positive rate of ganglioside antibodies is exceptionally high in MFS patients, particularly for anti-GQ1b antibodies. However, the presence of other ganglioside antibodies does not exclude MFS.

Case summary: We present a 56-year-old female patient who suddenly developed right blepharoptosis and progressively worsening vision in both eyes. There were flu symptoms prior to onset, and a coronavirus disease 2019 test was positive. On physical examination, the patient exhibited bilateral extraocular muscle paralysis, weakened reflexes in both limbs, and impaired coordination. The cerebrospinal fluid examination results showed no obvious abnormalities. Bilateral peroneal nerve F-waves were not extracted. Serum anti-GD1b IgG and anti-GT1a IgG antibodies were positive. The patient received intravenous methylprednisolone (1000 mg/day), with the dosage gradually decreased. Additionally, intravenous high-dose immunoglobulin treatment was administered for 5 days (0.4 g/kg/day) from day 2 to day 6 of hospitalization. The patient's symptoms improved after treatment with immunoglobulins and hormones.

Conclusion: Positive ganglioside antibodies may be used as supporting evidence for the diagnosis; however, the diagnosis of MFS is more reliant on clinical symptoms.