A 73-year-old man with a history of hypertension, coronary artery disease, and chronic obstructive pulmonary disease (COPD) presents with 6 weeks of interscapular back pain with 2 days of vague gait unsteadiness and 1 day of trouble emptying his bladder. He denies any preceding fevers, infections, or trauma. On examination, he has normal vital signs and normal strength, sensation, and reflexes in his upper extremities. He has mild 4+/5 weakness in bilateral hip flexion, knee flexion, and ankle dorsiflexion; mildly decreased sensation to all modalities with a sensory level at T9; intact rectal tone; increased patellar and ankle reflexes with extensor plantar responses; and a wide-based, spastic gait. Which of the following is the most likely underlying cause of his symptoms?
A. epidural neoplastic metastasis
B. idiopathic transverse myelitis
C. osteomyelitis
D. ruptured disc with herniation
E. spinal dural arteriovenous fistula
