Clinical Reasoning: A 68-Year-Old Man With Progressive Numbness, Vertigo, and Cognitive Decline.

A 68-year-old man presented with subacute progressive numbness in his lower extremities and vertigo. Concurrently, he developed behavioral and cognitive changes. Initial examination demonstrated mild distal symmetric weakness in the lower extremities, allodynia in the feet, decreased proprioception at the ankles, and absent reflexes in the lower extremities.