Clinical Reasoning: A 35-Year-Old Man Presenting With Chronic Left Foot Drop and Right Hand Weakness.

A 35-year-old man presented with an 8-year history of left foot drop and a 5-year history of right hand weakness without sensory involvement. He underwent nerve conduction studies, imaging, and serologic testing. Treatment led to dramatic improvement, although continual maintenance treatment was required. In this case report, we outline the clinical presentation and reasoning at each step, which led to diagnosis and management of a treatable neuromuscular disorder.