Pronunciation: gē-yan[h]′ bă-rā′
Definition: an acute, immune-mediated disorder of peripheral nerves, spinal roots, and cranial nerves, commonly presenting as a rapidly progressive, areflexive, relatively symmetric ascending weakness of the limb, truncal, respiratory, pharyngeal, and facial musculature, with variable sensory and autonomic dysfunction; typically reaches its nadir within 2–3 weeks, followed initially by a plateau period of similar duration, and then subsequently by gradual but complete recovery in most cases. Guillain-Barré syndrome is often preceded by a respiratory or gastrointestinal infection and is associated with albuminocytologic dissociation of the cerebral spinal fluid. Although classically considered pathologically to be an acute, inflammatory demyelinating polyradiculoneuropathy (q.v.), pure axon degeneration forms recently have been recognized.