[Unilateral dilated light-unresponsive pupil in Guillain Barré syndrome]

We report a case of Guillain Barré syndrome presenting with a unilateral internal ophthalmoplegia and unilateral minor sensory impairment, followed by respiratory failure, missing reflexes, tetraparesis and bilateral facial weakness. All symptoms responded to immunoglobulin. The diagnosis was confirmed by cerebrospinal fluid analysis and electroneurography. This case was especially unusual because the pupil abnormality was unilateral and appeared prior to motor impairment.