Miller Fisher syndrome with transient coma: comparison with Bickerstaff brainstem encephalitis.

We herein report a 4-year-old boy with Miller Fisher syndrome (MFS) who presented with transient coma in addition to the typical triad of internal and external ophthalmoplegia, cerebellar ataxia and areflexia after an influenza type B infection. The electroencephalogram findings revealed intermittently generalized slow wave bursts. The cerebrospinal fluid revealed high protein and a lack of any cellular response. The serum anti-GQ1b IgG antibody was elevated in the acute phase and disappeared in the convalescent phase. The transient coma with the triad of MFS in this patient indicated an extended brainstem lesion including a reticular formation, which is also the responsible lesion of Bickerstaff brainstem encephalitis (BBE), but the magnetic resonance imaging repeatedly showed no abnormal finding. Our patient suggested the involvement of central nervous system in addition to the peripheral nerve injury in MFS. He also suggested that MFS and BBE may belong to the same group of disorders as syndrome of ophthalmoplegia, ataxia and areflexia (SOAA).