Anomalies and Aneurysms Flashcards
What is an AVM?
atrioventricular abnormality
- connection between arteries and veins w/o capillaries
- typically pulsatile mass
Cause:
- congenital
- arterial aneurysm rupture into adjacent vein
- surgically generated -> hemodialysis or chemotherapy
What is a complication of AVMs?
w/ large or multiple -> shunt blood -> high-output cardiac failure
What is a berry aneurysm?
dilation in an artery due to defect in tunica media
What are risk factors for berry aneurysms?
- HTN
- smoking
Genetic:
- polycystic kideny disease
- Marfan syndrome
- Ehlers Danlos syndrome
Where do berry aneurysms most commonly occur?
branch points of Circle of Willis:
-particularly junction of anterior cerebral A. and anterior communicating A.
What is complication of berry aneurysms?
most common cause of subarachnoid hemorrhage -> “worst headache of my life”
What is a mycotic aneurysm?
dilation of an artery due to an infection in the wall
Causes:
- septic emboli
- infection in adjacent tissue
- circulating bacteria
What is fibromuscular dysplasia?
focal, irregular thickening of arteries with intervening normal segments -> beads on a string
Where does fibromuscular dysplasia most commonly occur and what is an associated complication?
renal arteries most common -> renovascular HTN
-50% have epigastric abdominal bruit
What is the difference between a true aneurysm, false aneurysm, and arterial dissection?
True aneurysm:
-muscular wall is intact but thinned -> dilation of vessel
False aneurysm:
-defect through muscular wall -> extravascular hematoma (dilation)
Dissection:
-defect in tunica intima -> blood accumulates within muscular wall -> causes further seperation between layer
What is Marfan syndrome?
defect in fibrillin gene (FBN1)
fibrillin normally sequesters TGF-β:
Marfan -> increased free TGF-β -> increased metalloprotease activity -> fragmentation of elastin
How does Marfan syndrome present?
- tall, thin build
- long arms
- long fingers
- pectus excavatum
What complications occur with Marfan syndrome?
- lens dislocation
- aortic aneurysm/dissection
- mitral valve prolapse
What is Ehlers-Danlos syndrome?
various mutations affecting collagen synthesis
How does Elhers-Danlos syndrome present?
- fragile, hyperextensible skin
- hypermobile joints
- poor wound healing
What complications occur with Ehlers-Danlos syndrome?
- mitral valve prolapse
- rupture of cornea, colon, or arteries
How does tertiary syphilis present?
Gumma - granulomatous lesions
Cardiovascular:
- aortitis -> aortic aneurysm (“tree bark appearance”)
- aortic valve regurgitation
Neurosyphilis:
What is the primary risk factor of throacic aortic aneurysm?
What are other risk factors?
- HTN
- smoking
Other:
- age
- tertiary syphilis
- connective tissue disorders (Marfan/Elhers-Danlos)
- aortic valve defects
- giant cell/Takayasu arteritis
How do thoracic aortic aneurysms present?
typically asymptomatic
symptoms, if present, related to compression of surrounding structures:
- dyspnea
- dysphagia
- cough (recurrent laryngeal nerve)
- upper back pain
What are the primary risk factor of abdominal aortic aneurysm?
-atherosclerosis
-smoking
Other:
-age
Where are throacic aortic aneurysms most commonly seen?
-ascending aorta
How do abdominal aortic aneurysms present?
Most are asymptomatic and discovered via exam or incidentally on radiology:
- pusatile abdominal mass
- abdominal bruit
If symptomatic
-low back pain (severe and acute when ruptured)
What subtypes of AAA are not related to atherosclerosis?
Inflammatory AAA:
- lymphoplasmacytic and macrophage (giant cells) infiltration
- can be treated with corticosteroids
IgG4 AAA:
- subtype of inflammatory AAA with high IgG4
- similar lymphoplasmacytic infiltration
- can be treated with corticosteroids
Mycotic AAA:
-caused by infection of tissue surrounding aorta causing weaking of its walls
Where are abdominal aortic aneurysms most commonly seen?
-below renal arteries, above aoritc bifurcation
How are AAAs treated?
Less than 5cm and <1cm of growth/yr:
- conserative treatment
- monitor with US, frequency increases with size
Greater than 5cm OR greater than 1cm of growth/yr:
-surgery (stenting)
What are the major risk factors of aortic disection?
- HTN
- trauma (particularly deceleration injuries)
Other:
-connective tissue disorders (Marfan/Ehlers-Danlos)
How does aortic dissection present?
Triad:
- “tearing” thoracic pain
- pulse abnormalities (absent or >20mmHg difference)
-mediastinal widening on XR
Where is aortic dissection most commonly seen?
ascending aorta (proximal to brachiocephalic A.)
greatest risk factor is high blood pressure so area of highest pressure -> highest risk
