Definition: Congenital or acquired weakness of vessel wall media, resulting in a localized dilation or out pouching. The bulge in the aneurysm may burst and death may occur any time. 1. Atherosclerotic aneurysms: Weakening of media secondary to atheroma formation Occur in the abdominal aorta below the real arteries Associated with hypertension Half of aortic aneurysms > 6cm in diameter will rupture within 10 years 2.Aortic dissecting aneurysms Its due to cystic medial necrosis of tunica media. Blood from the vessel lumen enters the intimal tear and dissects through the layers of media. It presents with severe tearing pain. It may compress and obstruct the aortic the aortic branches (eg- renal or coronary arteries) HTN and Marfan syndrome are predisposing factors. 3. Syphilitic aneurysms: Involves ascending aorta Syphilitic (leutic) aortitis causes an obliterative endarteritis of the vasa vasoram. Leading to ischemia and smooth muscle atrophy of aortic media. May dilate the aortic
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