Fisher syndrome in childhood.

Three children, age 2, 7, and 12, developed Fisher syndrome: inability to walk because of ataxia, complete areflexia, and ophthalmoplegia. Ptosis was prominent in all the children, but the pupillary response to light was affected only in one child. Limb weakness was never present, and sensation normal. One patient was obtunded for several days. Two had prodromal upper respiratory tract illnesses, and the third patient was bitten by an insect 2 days before her symptoms began. Cerebrospinal fluid (CSF) protein content was moderately increased in all patients, but only one child's CSF had a pleocytosis. CSF gamma globulin levels were normal. In the acute phase, F waves and H responses were absent in two cases but returned to normal with clinical recovery. All three patients had marked electroencephalographic (EEG) abnormalities that later improved. The EEG pattern suggested a brainstem disorder. These findings plus the obtundation, gaze paralysis, and ataxia indicate that in Fisher syndrome there is parenchymal involvement of the central nervous system with or without nerve root involvement.