Review Question - QID 215138

A 76-year-old man presents to the emergency room complaining of lower back pain that started this afternoon and has gotten persistently worse. It is neither improved nor worsened with movement. His past medical history is notable for hypertension, hyperlipidemia, and type 2 diabetes mellitus. His medications include lisinopril, atorvastatin, and metformin. He has not had surgery in the past. He smokes 1 pack of cigarettes per day and has done so for the past 25 years. He denies drinking alcohol or using intravenous drugs. On initial exam, his temperature is 36.8°C (98.2°F), blood pressure is 115/75 mmHg, pulse is 105/min, respirations are 18/min, and oxygen saturation is 96% on room air. However, on repeat exam 15 minutes later, his blood pressure is noted to be 90/65 mmHg and pulse is now 126/min. Which of the following diagnoses is most likely in this patient?