Approach to a postoperative fever Quiz: Ace Your Exams

A 52-year-old woman with a history of uterine fibroids is admitted on post-op day 3 following a total abdominal hysterectomy. She has been experiencing subjective fevers and lower abdominal pain. She received routine anesthesia and required transfusion of 2 units of packed red blood cells for intraoperative blood loss. A urinary catheter was placed during the procedure and removed, however, due to difficulty voiding, the urinary catheter was replaced and remains in place. She has had two bowel movements since her procedure. She does not have chest pain, difficulty breathing, or a cough. Temperature is 100.8°F (38.2°C), pulse is 102/minute, blood pressure is 136/85 mm Hg, respiratory rate is 18/minute, and oxygen saturation is 97% on room air. On physical examination, she has a normal cardio-pulmonary examination. On abdominal examination, the incision sites appear to be healing well without erythema or purulent drainage. She has normal bowel sounds and her abdomen is soft to palpation. There is suprapubic tenderness to palpation. Which of the following diagnostic studies is most likely to confirm the diagnosis?