[Guillain-Barré syndrome associated with anti-GQ1b antibody--nosological relationship between Fisher's syndrome and Guillain-Barré syndrome].

A 15-year-old man developed diplopia, ataxic gait and bulbar palsy. Two days after the onset of neurological symptoms, neurological examination revealed external ophthalmoplegia, cerebellar ataxia, and areflexia. Muscle weakness in the areas innervated by cranial nerves and in the four limbs, and glove and stocking type sensory impairment were also observed. On the 13th hospital day, CSF protein was elevated with normal cellularity. Serum IgM anti-GQ1b antibody was increased, which decreased concurrently with the clinical improvement. Recent studies have revealed the frequent presence of serum anti-GQ1b antibody in Fisher's syndrome. Therefore, this patient showed Fisher's syndrome at the beginning, then evolved to Guillain-Barré syndrome associated with anti-GQ1b antibody, which would support close association between Fisher's syndrome and Guillain-Barré syndrome.