Aneurysms and Dissections Flashcards
Berry aneurysms result from
congenital weakness of the arterial wall, usually found around the Circle of Willis
Berry aneurysms typically occur in who?
young people - heralded by a basilar headache
Where do aortic aneurysms most commonly occur
in the abdominal aorta between the renal arteries and the iliac bifurcation
Most common cause of aortic aneurysms
severe atherosclerosis, often with associated hypertension
Mycotic abdominal aneurysm
atherosclerotic aneurysms that have been infected by circulating organisms (Salmonella gastroenteritis)
Complications of aortic aneurysms
rupture, thrombosis and embolism
Syphilitic (leutic) involvement of the aortic arch leads to
aneurysm
Syphilitic lesions of the aortic arch consist of
obliterative endarteritis with infiltration of lymphocytes and plasma cells
Resulting ischemic injury of the media with syphilitic lesions of the aortic arch result in
dilation of the aortic arch, with contraction of fibrous scars and wrinkling of the intima known as tree-barking
Enlargement of the aortic root leads to
aortic valve insufficiency and the resulting hypertrophy of the heart is known as cor bovinum
Dissections occur when
when an intima tear leads to collection of blood within the vessel wall
Dissections most commonly occur in who
men aged 40 to 60 with hypertension
Most common cause of death with a dissection
dissection into the abdomen, thorax, or pericardium
Describe the pain from an aortic dissection
intense, tearing, and can be confused with myocardial infarction
Key to prevention and treatment of an aortic dissection
control of hypertension
Other important causes of aneurysms and dissections
genetic connective tissue disease: Marfans and Ehlers-Danlos
Berry aneurysms are sometimes associated with
polycystic kidneys and Ehlers Danlos
Most common spots for a berry aneurysm
Circle of Willis > anterior communicating artery > MCA > junction of carotid and posterior communicating artery
Describe the progression of a berry aneurysm rupture
arterial wall bulges through the muscular wall of the artery, causes subarachnoid hemorrhage
How does a berry aneurysm rupture present
with acute, severe headache and transient loss of consciousness; associated with reactive cerebral vasospasm
Arteriovenous fistula
anomalous connection between artery and vein; may be congenital or secondary to trauma, inflammation
What can arteriovenous fistulas cause
significant left to right shunts, overloading the right side of the heart and causing right heart failure
Monckeberg’s arteriosclerosis
focal calcification of the media: affects small to medium sized arteries; basophilic, amorphous medial deposition in media; no associated inflammation
Types of aneurysms
Berry; abdominal; dissecting; leutic; mycotic
True aneurysm
bounded by generally complete but attenuated arterial wall components
False aneurysm (pseudoaneurysm)
extravascular hematoma that communicates with the intravasular space; usually results from intimal tear
Classic saccular aneurysm
berry aneurysm
Classic fusiform or cylindrical aneurysm
atherosclerotic/cystic medial necrosis/syphilitic
Abdominal aneurysms can give rise to
- rupture into peritoneal cavity/retroperitoneal tissue
- impingement on adjacent structure
- occlusion of a vessel
- embolism
- creation of abdominal mass (simulates tumor)
Thoracic aneurysms can give rise to
- encroachment on mediastinal strucutres
- respiratory difficulties
- difficulty swallowing
- persistent cough (laryngeal nerve)
- pain (erosion of bone)
- cardiac disease
- rupture of aneurysm
Dissecting (false aneurysm associated with intimal tear) usually affects
ascending and proximal aorta with intimal tear within 10 cm of aortic valves
Dissecting (false aneurysms) associated with
hypertension; systemic or localized abnormality of connective tissue such as Marfans, Ehlers-Danlos
Most common cause of death with a dissection
rupture into body cavity
hemopericardium most common
Degenerative changes in the media associated with an aortic dissection
elastic tissue fragmentation and disruption; focal separation of elastic and fibromuscular elements; small cleft-like or cystic spaces with amorphous material; no inflammation
Classic symptoms of an aortic dissection
sudden onset of excruciating pain, usually beginning in the anterior chest, radiating to the back and moving downwards as the dissection progresses; often confused with acute myocardial infarction
Describe the aneurysms produced by atherosclerosis
generally causes cylindrical aneurysms which may rupture
Atherosclerotic aneurysms often positioned where
below the renal arteries and above the bifurcation of the aorta; may affect origins of the renal, superior and inferior mesenteric arteries
Atherosclerotic aneurysms often associated with
dilatations of the iliac arteries
Cystic medial necrosis
characteristic changes include elastic tissue fragmentation and disruption, focal separation of elastic and fibromuscular elements, small cleft-like or cystic spaces with amorphous material; NO INFLAMMATION
Cystic medial necrosis is characteristic of
Marfan’s and other collagen disease (Ehlers-Danlos)
Marfan’s
autosomal dominant disease of connective tissue fibrillin; skeletal, cardiovascular, and ocular manifestations; dilatation and dissection of aortic root; mitral valve prolapse
Syphilis (Leutic aneurysms)
associated with tertiary syphilis; always confined to thoracic aorta (arch)
Cor Bovinum
greatly enlarged heart secondary to aortic valve insufficiency
Characteristics of leutic aneurysms
inflammation of adventitia; obliterative endarteritis of the basa vasorum with infiltrate of lymphocytes and plasma cells; secondary ischemic injury of aortic media with patchy loss of medial elastic fibers and muscle cells; inflammatory scarring of the media; treebarking of the aorta
Treebarking of the aortic intima results from
segmental wrinkling due to scar contraction
Mycotic aneurysm
infection by organisms lodged in aortic wall
Mycotic aneurysms particularly associated with
Salmonella gastroenteritis
