Guillain-Barre syndrome is most likely due to what type of mechanism?

• A. Multiple sclerosis
• B. Guillain-Barre syndrome
• C. Myasthenia gravis
• D. Lyme disease

Answer: (B)

Guillain-Barré syndrome is an autoimmune attack on the peripheral nervous system that follows an infection. The immune response generates antibodies (and T-cell activity) that cross-react with components of peripheral nerve myelin or axolemma due to molecular mimicry, triggering inflammation and demyelination (with possible axonal damage) of the peripheral nerves. This immune-mediated process produces the rapid, ascending weakness with areflexia that characterizes the syndrome, and nerve testing typically shows demyelinating patterns. This mechanism is different from central nervous system demyelination (as in multiple sclerosis), a neuromuscular junction disorder (as in myasthenia gravis), or an infectious cause like Lyme disease.