weakens the blood vessel wall while repeated trauma of blood flowing through the vessels contributes to the degeneration of the vessel wall. hypertensive injury compounds the degeneration and accelerates the expansion of the aneurysm. This expansion of the wall leads to increased tension. The pressure of the blood within the expanding aneurysm injures the blood vessels supplying the wall of the artery further weakening the arterial wall. Without treatment, these aneurysms progress to rupture.
Mycotic aneurysm is due to a bacterial infection that involves the arterial wall. The common locations are the abdomen, thigh arm, and neck. The complications are rupture or sepsis. Less than 3% of the abdominal aortic aneurysms are mycotic.
In its 3rd stage can manifest as aneurysm of the aorta which is due to loss of the vasa vasorum in the tunica adventitia.
Though this is very rare it is due to reduced activity of the lysyl oxidase enzyme affecting elastin which is a key component in the arterial wall. It leads to thinning of the arterial wall and thus aneurysm formation.