A patient with acute purely motor polyneuropathy with positive GD1a ganglioside antibodies who presented with paresis in combination with hyperreflexia is reported. Neurophysiological tests revealed features compatible with acute motor axonal neuropathy. Therapy with intravenous immunoglobulin led to rapid clinical improvement. However, at the time when signs of active denervation appeared on electromyographic testing, the patient developed bilateral papillitis. The pathogenesis of pure motor Guillain-Barré syndrome with hyperreflexia and papillitis is discussed.