Guillain-Barré syndrome is an acute inflammatory demyelinating polyneuropathy (AIDP) in which molecular mimicry between microbial antigens and gangliosides on the myelin sheath triggers autoantibody production and complement-mediated destruction of Schwann cells. Demyelination disrupts saltatory conduction in peripheral motor and sensory nerves. The classic presentation is ascending symmetrical weakness with areflexia, progressing over days to weeks. Approximately 30% of patients develop respiratory failure requiring mechanical ventilation. Autonomic dysfunction affects 70% of patients and is the leading cause of death. The nurse performs serial neurological assessments, monitors respiratory function, manages hemodynamic instability, coordinates immunotherapy, and provides comprehensive supportive care.