A 58-year-old woman presents to the ambulatory clinic complaining of a swollen and painful right calf that started two days ago. She is currently receiving chemotherapy for active ovarian cancer and reports spending most of the past week in bed due to profound fatigue. Vital signs include a temperature of 37.1°C (98.8°F), blood pressure of 128/82 mmHg, heart rate of 88/min, and respiratory rate of 14/min. Physical examination reveals pitting edema extending to the right knee, mild erythema, and localized tenderness along the popliteal vein. The right calf circumference is measured to be 4.5 cm larger than the left calf. Which of the following is the most appropriate next step in evaluating this patient's condition?
- Compression ultrasonography of the right lower extremityAnswer
- BSerum D-dimer assay
- CComputed tomography venography of the lower extremities
- DCatheter-directed contrast venography
- EMagnetic resonance venography of the right leg
Answer
Compression ultrasonography of the right lower extremity
The correct answer is compression ultrasonography of the right lower extremity. This patient presents with multiple high-risk features for deep vein thrombosis (DVT), including active cancer, recent bedridden status, localized tenderness, and significant unilateral calf swelling. These clinical features result in a high Wells score, indicating a high pretest probability for DVT. According to evidence-based diagnostic sequencing guidelines, the most appropriate initial diagnostic step for a patient with a high pretest probability is a non-invasive venous compression ultrasonography.
Step-by-Step Solution
Key Concept
In patients with a high pretest probability for deep vein thrombosis (DVT) based on the Wells criteria, the correct next diagnostic step is compression ultrasonography, bypassing the D-dimer assay.