In this article, we will discuss the Pathogenesis of Brain Aneurysms. So, let’s get started.
Pathogenesis
The most common mechanism of aneurysms formation is thus a combination of several causes, starting with a congenital defect in the media at the bifurcation of cerebral vessels. These weak spots are present at branching of these vessels. Hemodynamic stress in the form of local turbulence of blood at this site causes hyperplasia and splitting of internal elastic lamina. This combination of a congenital defect with acquired loss of elastic membrane under the effect of blood pressure may predispose to outpouching of the fragmented elastica leading to saccular aneurysm formation which produces clinical features due to its rupture at the weakest spot. Aneurysms >7mm in diameter and those located at the top of basilar artery and at the origin of posterior communicating artery are at greater risk of rupture.
Sites of aneurysms
- Anterior communicating artery (30.1%)
- Middle cerebral artery (20%)
- Internal carotid artery (7.5%)
- Posterior communicating artery (25.1%)
- Posterior inferior cerebellar artery (4.12%)
- Basilator tip (7%)
- Others (6.1%)