What are the hallmark clinical features of Guillain-Barré syndrome?

• A. Chronic fatigue without weakness
• B. Chronic progressive weakness with hyperreflexia
• C. Vision loss with pain on eye movement
• D. Acute, progressive, symmetrical ascending weakness with areflexia after infection

Answer: (D)

The defining feature is an autoimmune attack on peripheral nerves that follows a recent infection and produces weakness that comes on quickly, progresses from the legs upward (ascending), and is accompanied by absent or reduced reflexes. This pattern—acute, symmetric progression of weakness with areflexia after an infectious event—is what clearly distinguishes Guillain-Barré syndrome from other conditions. Sensory symptoms and autonomic changes can occur, but the hallmark remains the rapid, ascending weakness with loss of reflexes starting after an infection.

Other options describe different scenarios: chronic fatigue without weakness doesn’t reflect an acute motor neuropathy; chronic progressive weakness with hyperreflexia suggests a central nervous system or motor neuron process; vision loss with eye movement pain points to optic neuritis or demyelinating diseases like multiple sclerosis.