A 36-Year-Old Man Comes to the Emergency Department with Severe

A 36-year-old man comes to the emergency department with severe pain in his left leg.  He is a carpenter and recalls that he had a small puncture wound from a wood splinter yesterday in his workshop.  The patient washed the wound and applied a small adhesive bandage.  This morning, he experienced severe pain in his left thigh and calf, and the pain has worsened since.  He has no other medical problems and takes no medications regularly.  His temperature is 39.4 C (103 F) , blood pressure is 90/60 mm Hg, heart rate is 96/min, and respirations are 16/min.  Physical examination of his left lower extremity shows slight erythema and swelling of the thigh and calf with severe tenderness to palpation.  Two blisters are present on the posterior aspect of his proximal calf. While in the emergency department, the patient complains of increasing pain despite intravenous narcotic administration.  His blood pressure decreases to 70/50 mm Hg despite 2 L intravenous fluids.  Vasopressors are initiated.  His creatine phosphokinase level is 7,400 IU/L (normal 60-174 IU/L) and lactic acid level is 3.2 mmol/L (normal 0.7-1.8 mmol/L) .  Blood cultures are pending.  Which of the following is the most appropriate next step in management of this patient?

A) Antibiotics and intensive care unit admission
B) Antibiotics and urgent surgical debridement
C) CT scan of the left lower extremity
D) Urgent surgical debridement
E) X-ray of the left lower extremity