THERE ARE NO NEUROPHYSIOLOGIC FEATURES CHARACTERISTIC OF AXONAL GUILLAIN-BARRE-SYNDROME

Classical views hold Guillain-Barre Syndrome (GBS) as a primary inflam matory-demyelinating neuropathy in which secondary axonal degeneration may occur, particularly when inflammatory lesions are severe. Feasby and colleagues proposed that primary axonal degeneration can also caus e GBS characterized by inexcitable motor nerves and poor outcome. This hypothesis rests largely on the results of a single autopsy in which no inflammation or demyelination were found. Using an illustrative cas e report confirming earlier studies, we point out that inexcitable mot or nerves (or low amplitude compound muscle action potentials [CMAPs]) are of ambiguous significance and may reflect distal demyelination, c ausing conduction block between distal stimulation sites and target mu scles, a pattern not uncommon in GBS. Recovery from such lesions may o ccur within weeks with restoration of CMAP amplitudes. The recognition of a yet unproven axonal variant of GBS cannot be based solely on doc umentation of inexcitable motor nerves in the context of rapidly devel oping weakness, (C) 1994 John Wiley & Sons, Inc.