Acute cervical motor radiculopathy induced by neck and limb immobilization in a patient with Parkinson disease.

A 68-year-old woman with Parkinson disease (PD) presented with acute monoplegia of her left upper extremity after the neck and limb immobilization for several hours. Her sensory function was normal, and the chest X-ray showed left phrenic nerve palsy. Electrophysiological studies showed multi-segment muscle involvement (C3 to T1) including denervation potentials and reduced interference of motor units in needle electromyography. M wave amplitude in peripheral nerve stimulation was preserved except for the ulnar nerve, suggesting both axonal injury and conduction block at the anterior spinal roots. The patient showed fair recovery in several months, suggesting sufficient reinnervation and recovery of conduction block. Incomplete root avulsion was thought to be the pathomechanism of acute cervical motor radiculopathy.