American Board of Internal Medicine (ABIM) Certification Practice Exam

When is duplex ultrasonography indicated in cases of superficial venous thrombophlebitis?

1. If the patient has a history of DVT

2. Presence of swelling in the extremity

3. If symptoms progress or swelling is pronounced

4. If the thrombophlebitis persists for more than 1 week

The correct answer is: If symptoms progress or swelling is pronounced

Duplex ultrasonography is a critical diagnostic tool used to evaluate the status of veins in the setting of superficial venous thrombophlebitis, particularly when symptoms progress or swelling is pronounced. The rationale behind this indication lies in the potential for superficial venous thrombophlebitis to evolve into deep vein thrombosis (DVT), especially in cases where there is a noticeable change or worsening of the patient's clinical condition. When patients present with increasingly significant symptoms or acute swelling, it raises concern about the possibility of the thrombus propagating into deeper venous systems, which could lead to serious complications such as pulmonary embolism. Therefore, performing duplex ultrasonography helps in assessing the venous patency and confirming whether a DVT is present. In circumstances where there is a history of DVT, though there might be an awareness of the patient's risk status, duplex ultrasonography is not necessarily indicated at that moment unless specific symptoms warrant further investigation. Similarly, while the presence of swelling may raise suspicion for underlying issues, it is the progression of symptoms or significant swelling that more directly indicates a need for imaging. Lastly, persistence of symptoms beyond a week may suggest further evaluation, but it is the acute changes in condition that most strongly suggest the