Back Pain on Eliquis: Seen in the ED

History of present illness. A 72-year-old woman presents to the hospital for low back pain that started tonight during dinner without any injury or heavy lifting. The pain does radiate a little to her left leg and is worse when she moves but she denies any abdominal pain, leg weakness, numbness, fever, trouble using the toilet, or other complaints. She has never had this pain in the past. Among multiple medical problems she has osteoporosis and paroxysmal atrial fibrillation for which she is prescribed apixaban (Eliquis).

Vital signs and physical examination. Her vital signs are normal. She is in mild to moderate distress and grimaces when she has to sit up or move in bed. Her abdomen is benign, but she does have bilateral CVA tenderness as well as spinal percussion tenderness in the upper lumbar and lower thoracic area. The rest of the exam is normal including leg strength.

Initial diagnostic testing: An MRI of the spine is performed assess for nerve root compression with special concern for a possible spinal epidural hematoma (image).

What is the most likely diagnosis?