American Board of Internal Medicine (ABIM) Certification Practice Exam

In patients with an asymptomatic intracranial aneurysm in the posterior circulation, surgery is indicated when:

1. the aneurysm is smaller than 5 mm

2. the aneurysm shows rapid growth to greater than 7 mm in size

3. the patient is younger than 55 years

4. there are no clinical signs

The correct answer is: the aneurysm shows rapid growth to greater than 7 mm in size

Surgery for an asymptomatic intracranial aneurysm in the posterior circulation is indicated when the aneurysm shows rapid growth to greater than 7 mm in size. This is because an increase in the size of the aneurysm, especially beyond the 7 mm threshold, significantly raises the risk of rupture and associated complications. The characteristics of intracranial aneurysms indicate that larger aneurysms pose a greater risk of hemorrhage; hence, monitoring their size and growth is crucial in management decisions. Rapid enlargement can indicate a change in the structural integrity of the aneurysm wall or an increased hemodynamic stress, which may warrant surgical intervention to prevent a potentially catastrophic rupture. Other factors, such as the patient's age or the lack of clinical signs, do not solely determine the need for surgery; they are taken into account alongside the aneurysm's size and growth patterns. An aneurysm smaller than 5 mm usually has a very low risk of rupture and typically does not require surgical intervention unless there is significant growth or additional risk factors present. When there's no clinical indication or if the aneurysm is stable and small, conservative management may be appropriate. Therefore, the reasoning behind surgical intervention correlates primarily with the observed growth pattern rather than static characteristics or