How is etiology of aneurysms?

Conditions that cause degradation or abnormal production of structural components of aortic wall [elastic/collagen]. Inflammation, oxidative stress, proteolysis, wall stress, mediated by B and T cells, macrophages, cytokines, MMPs. Etiologies (degenerative aging [cigarettes, hyperTG ,HTN], chronic aortic dissection, aortitis, infective, trauma, genetic [Marfan's, Loeyz, Ehler, Turners, Familial, Bicuspid aortic valve] Acute aortic syndrome (aortic dissection, intramural hematoma, atherosclerotic ulcer) Aortitis (vasculitis, rheumatic, infective [syphilis, TB, fungus]) Familial (20% of pt) Trauma (penetrating and non-penetrating chest trauma mostly descending aorta beyond insertion of ligamentum arteriosum) Weakening of wall by chronic aortic dissection.