Aneurysms and dissections Flashcards
aneurysms are
-Aneurysms are dilatations of the aorta due
to weakening of the wall
dissections are
-Dissections (also called dissecting aneurysms)
lead to widening of the vessel as the result
of blood dissecting through the wall of the
vessel
aneurysms most commonly occur
in the abdominal aorta distal to the renal arteries
causes of aneurysms
- atherosclerotic weakening of the wall of the aorta
2.also occur as a result of infection, vasculitis, or structural abnormalities
-syphilis: aneurysms of the ascending (thoracic) aorta
-genetic abnormalities of collagen, elastin: ascending
aorta
how do dissections occur?
as a result of blood passing through a tear in the intima
-dissections split the vascular media and create a false
vascular channel
dissections most commonly occur in
thoracic aorta
dissections are most commonly associated with?
hypertension
death from dissections are caused by?
hemopericardium and cardiac tamponade
what is a true aneurysm?
bounded by generally complete but attenuated arterial wall components
what is a false aneurysm?
- (pseudoaneurysm) – widening due to extravascular hematoma that communicates with the lumen (dissection)
atherosclerosis as a cause of aneurysms
-usually positioned below the renal arteries and above the
bifurcation of the aorta
-often associated with dilatations of the iliac arteries
-may affect origins of the renal, superior, and inferior
mesenteric arteries
-thinning and destruction of media resulting from
ulceration of atherosclerotic areas
-cylindrical aneurysms which may rupture
-increased diameter increases risk; 50% mortality
-risk of rupture for small aneurysm 2%
-develop after 50; much more common in men
-familial (other than atherosclerosis or
hypertension)
consequences of abdominal aneurysms
-rupture - peritoneal cavity or retroperitoneal
tissues
-impingement on an adjacent structure
-occlusion of a vessel be either direct pressure or
mural thrombus
-vertebral branches that supply the spinal cord
-embolism from the atheroma or mural thrombus
-abdominal mass that simulates a tumor
berry aneurysms
congenital weakness of arterial wall (usually CNS)
-outpoouching
-usually sporadic
-sometimes associated with autosomal dominant
(adult form) polycystic kidney disease
-also associated with Ehlers-Danlos syndrome
-most common around circle of Willis
-anterior communicating artery(40%)>middle
cerebral artery (34%)>junction of
carotid/posterior communicating artery (20%)
-bifurcations of cerebral arteries
vasculitic aneurysms
-Kawasaki, Wegener’s, temporal arteritis, Takayasu’s etc
mycotic aneurysms
Salmonella gastoenteritis
thoracic aorta aneurysms
- syphilitic
- genetic tissue disorders – Marfan’s, Ehlers-Danlos, etc.
- bicuspid aortic valve
what is the most common rupture in young adults?
berry aneurysms
- causes subarachnoid hemorrhage
- occurs with acute increases in arterial pressure, as will weight lifting
those with berry aneurysms present with
- acute, severe headache
- transient loss of consciousness
- associated with reactive cerebral vasospasm
consequences of a thoracic aneurysm
-encroachment on mediastinal structures
-respiratory difficulties
-difficulty in swallowing/compression of esophagus
-persistent cough due to irritation of or pressure on the
recurrent laryngeal nerves
-incompetence of aortic valve at aortic root
-rupture of the aneurysm – hemopericardium with
cardiac tamponade
dissections leads to what kind of aneurysm
false aneurysm
-actually a misnomer; most dissections occur without
significant aneurysm
how are the locations of dissections different from aneurysms?
usually affects ascending and proximal aorta with
intimal tear within 10 cm of aortic valve
-associated with hypertension; Marfans, Ehlers-Danlos
-tears are usually transverse or oblique, 1-5 cm long
-produces false channel
where do dissecting intramural hematomas form?
-characteristically between middle and outer
thirds of the media
what is the most common cause of death with dissections?
death is rupture into body cavity (pericardial, pleural, peritoneal)
*hemopericardium is most common cause of death
what are the common manifestations in dissections?
-cardiac tamponade, aortic insufficiency, myocardial infarction
classic symptoms of dissections
-include sudden onset of excruciation pain, usually beginning in the anterior chest, radiating to the back, and moving downwards as the dissection progresses; often
confused with acute myocardial infarction
what do complications depend on with dissections?
level of aorta affected
-proximal lesions more common (and dangerous)
-second type include distal lesions (usually beginning
distal to subclavian artery)
Cystic medial necrosis
-non-specific term for several etiologies
characteristic changes with cystic medial necrosis
-elastic tissue fragmentation and disruption
-focal separation of elastic and fibromuscular elements
-small cleft-like or cystic spaces WITH AMORPHOUS
MATERIAL; INFLAMMATION IS ABSENT
-characteristic of Marfan’s and other collagen diseases
-may be associated with fusiform aneurysms or aortic
dissection
why is cystic medial necrosis an inaccurate name?
necrosis is not present
Marfan’s
-autosomal dominant disease of connective tissue
fibrillin
-skeletal, cardiovascular, and ocular manifestations
-dilatation and dissection of aortic root; mitral
valve prolapse
Ehler’s-Danlos Syndrome
- Heterogeneous group of collagen disorders
- Several subtypes: joint, skin, and vascular phenotypes
extreme phenotypes of Ehler’s-Danlos syndrome
-include “circus” freaks demonstrating joint hypermobility and stretching of skin
* most patients do not demonstrate such extreme
phenotypes; many are missed because doctor’s are
looking for freaks
symptoms of Ehler’s-Danlos syndrome
- involve joints, skin, large blood vessels
- frequent dislocations, joint injuries
- easy bruising, delayed wound healing
- scoliosis, near-sightedness, gum disorders
what causes death in E-D syndrome
- vascular aneurysms (berry aneurysm, thoracic aneurysms), uterine, bladder, or intestinal rupture
- treatment of hypertension essential
- anticipation of complications (childbirth)
Syphilis (Luetic aneurysms)
-associated with tertiary syphilis
-nearly always confined to thoracic aorta; usually
involving the arch
*may involve aortic root with aortic valve insufficiency
*occlusion or narrowing of coronary ostia
Cor Bovinum
greatly enlarged heart secondary to aortic valve insufficiency
pathophysiology in Luetic aneurysms
-inflammation of adventitia; obliterative endarteritis
of the vasa 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
-associated with both aneurysmal dilatation and
dissection
-treebarking of the aortic intima results from
segmental wrinkling due to scar contraction
Arteriovenous fistulas
anomalous connection between artery and vein
-may be congenital or secondary to trauma,
inflammation, etc.
-can cause significant left to right shunts,
overloading the right side of the heart and
causing right heart failure
-can also rupture and cause significant bleeding
(cerebral aneurysm)
-presents as stroke (younger population)
What are the signs of a ruptured berry aneurysm
Headache
Subarachnoid hemorrhage
Blood in CSF
Berry aneurysms are seen with
Marfans
Ehlers danlos
Polycystic kidney disease (autosomal recessive in Kids, dominant in adults)
Berry aneurysms most commonly occur in
Around circle of Willis
Anterior communicating artery> middle cerebral artery>junction of carotid/ posterior communicating artery
Bifurcations of cerebral arteries
