Which statement describes Guillain-Barre Syndrome's cause?

• A. It is a vitamin deficiency disorder
• B. It is caused by direct bacterial invasion of nerves
• C. It is a metabolic disease
• D. It is caused by the immune system attacking the nerves

Answer: (D)

Guillain-Barré syndrome is caused by an autoimmune process in which the body's immune system mistakenly targets the peripheral nerves, leading to inflammation and demyelination. This immune confrontation disrupts nerve signaling and causes the rapid, progressive weakness seen in GBS. It often follows an infection, but the root issue is immune-mediated nerve damage, not a vitamin deficiency, direct bacterial invasion of nerves, or a metabolic disorder. Understanding this helps explain why symptoms progress from the legs upward and why management focuses on supportive care and monitoring for respiratory involvement, rather than correcting a nutritional or infectious cause.