[An adult Guillain-Barré syndrome patient with enhancement of anterior roots on spinal MRI and severe radicular pain relieved by intravenous methylprednisolone pulse therapy: A case report]. 
A 37-year-old man was admitted to our hospital because of progressive abnormal gait and severe pain in the low back and lower extremities, more severe on the right side, especially in his right posterior thigh.  The pain appeared one week after he suffered from slight fever and diarrhea.  On admission, a neurological examination revealed mild distal weakness of the all extremities and loss of Achilles tendon reflex, associated with positive Lasègue sign.  However, sensation was intact except for slightly impaired vibratory sensation on the trunk.  An electrophysiological study showed diminished amplitude of compound muscle action potential and loss of F-wave of the posterior tibial nerves.  Finding of cerebrospinal fluid was normal at the time of admission, although 12 days later albuminocytologic dissociation was found.  Cervical and lumbar magnetic resonance images showed gadolinium enhancement of the anterior nerve roots and the cauda equina, more prominent on the right side, correlating with the prominent side of the patient's leg pain.  Because of neurological features, electrophysiological abnormalities and CSF findings, we diagnosed his illness as Guillain-Barré syndrome (GBS) characterized by severe back and leg pain.  The character of pain was deep and aching, suggesting myalgic pain caused by the affected anterior roots.  A short course high-dose intravenous immunoglobulin (IVIg) therapy was not effective against the radicular pain although minimal improvement of limb weakness occurred.  Non-steroidal anti-inflammatory drugs and carbamazepine were unsuccessful for pain relief.  Thereafter, intravenous methylprednisolone (IVMP) pulse therapy was introduced.  On the day IVMP pulse therapy started, severe radicular pain began to decrease and became gradually milder without any marked effect on the other symptoms and signs of GBS.Moderate to severe pain is a common and early symptom of GBS and requires aggressive treatment.  IVMP pulse therapy may be one of treatments for refractory and intolerable pain of GBS.