Review Question - QID 216542

A 60-year-old woman presents to the emergency department with back pain after gardening. Her pain is 7/10 in severity, non-radiating, and not relieved by rest. She has never experienced this pain in the past and denies fever, night sweats, unintentional weight loss, and bowel or bladder incontinence. She has hypertension for which she takes hydrochlorothiazide and had a recent asthma flare requiring a prednisone taper. She does not drink alcohol or smoke. Her temperature is 98.6°F (37.0°C), blood pressure is 120/80 mmHg, pulse is 90/min, and respirations are 18/min. Physical exam reveals an uncomfortable middle-aged woman in no acute distress. There is no tenderness to palpation of the spinous processes. Flexion of the hip with the knee extended while the patient is supine does not elicit any pain, nor does forced dorsiflexion of the foot at terminal hip extension. She has 5/5 strength to hip flexion, extension, abduction, and adduction; knee flexion and extension; and ankle dorsiflexion and plantarflexion bilaterally. Bilateral patellar and Achilles reflexes are 2+. Serum laboratory results are as follows:

Hemoglobin: 12.0 g/dL
Creatinine: 1.1 mg/dL
Ca2+: 10.6 mg/dL

Which of the following is the most likely diagnosis?