congenital or acquired weakness of the vessel wall media, resulting ina
localized dilatation or outpouching. Complications include thrombus formation,
thromboembolism, and compression of nearby structures. Rupture or dissection
may cause sudden death.
aneurysms are due to weakening of the media secondary to ather-oma
formation, and typically occur in the abdominal aorta below the renal arteries.
They are associated with hypertension. Half of aortic aneurysms >6 cm in
diameter will rupture within 10 years. Those >5 cm are treated surgically.
aneurysms involve the ascending aorta in tertiary syphilis (late
stage).Syphilitic (luetic) aortitis causes an obliterative endarteritis of the
vasa vasorum, leading to ischemia and smooth-muscle atrophy of the aortic
media. Syphilitic aneu-rysms may dilate the aortic valve ring, causing aortic
Aortic dissecting aneurysm occurs
when blood from the vessel lumen enters an inti-mal tear and dissects through
the layers of the media. The etiology usually involves degeneration (cystic
medial degeneration) of the tunica media. Aortic dissecting aneurysm presents
with severe tearing pain. The dissecting aneurysm may compress and obstruct the
aortic branches (e.g., renal or coronary arteries). Hypertension and Marfan
syndrome are predisposing factors.
Berry aneurysm is
a congenital aneurysm of the circle of Willis.
are small aneurysms commonly seen in hypertension and
aneurysms are aneurysms usually due to bacterial or fungal infections.
(AV) fistulas are a direct communication between a vein and anartery
without an intervening capillary bed. They may be congenital or acquired (e.g.,
trauma). Potential complications include shunting of blood which may lead to
high-output heart failure and risk of rupture and hemorrhage.