Teaching Video NeuroImage: Unraveling the Enigma of Ocular Flutter in Anti-GD1b and Anti-GT1a Rhombencephalitis

A 45-year-old man with worsening limb numbness and dizziness was found to have ocular flutter (Video) during a hospital examination.Initial tests including serum studies, brain MRI, and electromyography were normal.CSF opening pressure was normal, but CSF IgM, IgG, and IgA were elevated and protein levels were 1.02 g/L (0.15-0.45 g/L) without pleocytosis, suggestive of albuminocytologic dissociation.The differential diagnosis, therefore, included Guillain-Barr syndrome, or autoimmune brainstem encephalitis or cerebellitis, prompting tests for specific autoimmune antibodies such as anti-MOG, anti-GFAP, anti-AQP4, and those related to paraneoplastic syndromes and cerebellitis.These findings, along with positive anti-GD1b IgM and anti-GT1a IgM antibodies, supported Bickerstaff encephalitis, particularly given the absence of infection or vaccination history.Antiganglioside antibodies have been linked to ocular flutter but are not traditionally associated with Bickerstaff encephalitis. 1 The patient received intravenous immunoglobulin and dexamethasone.After treatment, his dizziness, limb numbness, and ocular flutter notably improved.