30th April 2024

A 22-year-old woman presents with severe pain and swelling in her left lower leg following a fall while skiing.

A 22-year-old woman presents with severe pain and swelling in her left lower leg following a fall while skiing. She reports that the pain is disproportionate to the injury and worsens when stretching her leg muscles. On examination, the leg is tense and pale, and her pulses are weak. Passive stretch of the muscles increases pain.

Investigations:

Haemoglobin: 142 g/L (115–155)

White cell count: 8.3 × 10⁹/L (4.0–11.0)

Platelets: 242 × 10⁹/L (150–400)

CRP: 3 mg/L (<5)

Serum creatine kinase: 620 IU/L (25–200)

Which is the most appropriate next investigation to confirm the diagnosis?