information:filtering, stylistic:style_transfer
Pathophysiology

Aneurysms form for a variety of interacting reasons. Multiple factors, including factors affecting a blood vessel wall and the blood through the vessel, contribute.

The pressure of blood within the expanding aneurysm may also injure the blood vessels supplying the artery itself, further weakening the vessel wall. Without treatment, these aneurysms will ultimately progress and rupture.

Infection. A mycotic aneurysm is an aneurysm that results from an infectious process that involves the arterial wall. A person with a mycotic aneurysm has a bacterial infection in the wall of an artery, resulting in the formation of an aneurysm. One of the causes of mycotic aneurysms is infective endocarditis. The most common locations include arteries in the abdomen, thigh, neck, and arm. A mycotic aneurysm can result in sepsis, or life-threatening bleeding if the aneurysm ruptures. Less than 3% of abdominal aortic aneurysms are mycotic aneurysms.

Syphilis. The third stage of syphilis also manifests as aneurysm of the aorta, which is due to loss of the vasa vasorum in the tunica adventitia.

Copper deficiency. A minority of aneurysms are caused by copper deficiency, which results in a decreased activity of the lysyl oxidase enzyme, affecting elastin, a key component in vessel walls. Copper deficiency results in vessel wall thinning, and thus has been noted as a cause of death in copper-deficient humans, chickens, and turkeys.