Guillain-Barré Syndrome is best described as which?

• A. Autoimmune disease causing central nervous system demyelination
• B. Autoimmune disease causing peripheral nervous system demyelination, often triggered by infection
• C. A demyelinating disease of the optic nerve
• D. A motor neuron disease

Answer: (B)

Guillain-Barré Syndrome is an autoimmune process that targets the myelin of peripheral nerves, causing demyelination in the peripheral nervous system. This immune attack disrupts nerve conduction, leading to rapidly progressive weakness that typically starts in the legs and ascends, with areflexia. A common trigger is a recent infection, such as a gastrointestinal or respiratory illness, which can provoke the immune response. Because the damage is to peripheral nerves rather than the brain or spinal cord, central nervous system demyelination and optic nerve involvement are not accurate descriptions, and it is not a motor neuron disease like ALS. So the best description is an autoimmune disease causing peripheral nervous system demyelination, often triggered by infection.