American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the recommended follow-up for an abdominal aortic aneurysm between 4.5 to 5.4 cm?

1. Ultrasonography every 3 months

2. Repeat ultrasonography in 1 year

3. Immediate CT scan

4. Elective surgery

The correct answer is: Repeat ultrasonography in 1 year

For an abdominal aortic aneurysm (AAA) that measures between 4.5 to 5.4 cm, the standard recommended follow-up is indeed to perform repeat ultrasonography in 1 year. This interval is aligned with guidelines that suggest monitoring smaller aneurysms less frequently to avoid unnecessary interventions while still ensuring that any significant changes in size are detected in a timely manner. Ultrasonography is the preferred method for monitoring due to its non-invasive nature, cost-effectiveness, and ability to provide accurate measurements of the aneurysm size. An annual follow-up allows for adequate observation of potential growth rates, as most AAA in this size range do not require immediate surgical intervention unless they reach a certain threshold of expansion or present symptoms. Other options such as more frequent ultrasound scans or immediate imaging studies like CT are not routinely necessary for patients in this size category unless there are other concerning clinical findings or risk factors that suggest a higher likelihood of rapid aneurysm expansion or other complications. Elective surgery is typically reserved for aneurysms larger than 5.5 cm or those that are symptomatic, meaning it would not be appropriate for a patient with an AAA in the 4.5 to 5.4 cm range.