Review Question - QID 214535

A 65-year-old man presents to the clinic with complaints of pain and numbness in both of his hands. He reports decreased sensation and tingling in both of his hands that began about 2 months ago. The pain is described as an intermittent burning sensation that is worse at night. He denies any fevers, chills, loss of bowel or urinary control, lightheadedness, or focal weakness. His medical history is significant for diabetes, hypertension, and a herniated C7 disc secondary to a motor vehicle accident 3 years ago. Family history is noncontributory. He endorses a 15 pack-year smoking history and IV drug use. A physical examination demonstrates decreased sensation to pinprick to his bilateral hands, arms, and shoulders. What is the most likely explanation for this patient’s symptoms?