Guillain-Barré syndrome. Another cause of the "floppy infant"

We report a 4 1/2-month-old female infant with subacute onset of hypotonia. Symmetrical weakness, association with a viral illness, high CSF protein level, diminished nerve conduction velocities, and a prompt recovery were compatible with the diagnosis of Guillain-Barré syndrome. The possibility that this disorder may occur in young infants with weakness should be considered.