Major predisposing factors:
(1) hereditary defect in connective tissue resulting in weakness of the aortic wall (these may be manifested as a myxoid degeneration of the aortic medial layer)
(2) aortic aneurysm, with weakening of the aortic wall and abnormal mural pressures
Hereditary disorders of connective tissue include:
(1) Marfan's syndrome (affecting the fibrillin gene)
(2) Ehler-Danlos syndrome (affecting collagen type III)
(3) MASS phenotype
(4) Shprintzen-Goldberg syndrome
(5) other familial disorders
Disorders associated with aortic aneurysm:
(1) atherosclerosis (high blood pressure, smoking, hyperlipidemia)
(2) stimulant drug abuse (cocaine, amphetamine, etc)
(3) autoimmune vasculitis
(3a) Takayasu's arteritis
(3b) giant cell arteritis
(3c) Behcet's disease
(3d) rheumatoid aortitis
(3e) Ormond's disease (retroperitoneal fibrosis)
(4) infectious vasculitis (syphilis, salmonellosis, brucellosis, Staphylococcus aureus, fungal, etc)
(5) iatrogenic (angioplasty, cardiac catheterization, surgery)
(6) trauma (with high-speed impact)
Some of these risk factors are preventable or treatable while others are not.
