Pathoma- Arteriosclerosis, Aortic Dissection, Aneurysm Flashcards
What is aortic dissection?
Intimal tear with dissection of blood through media layer of aortic wall
What are the modifiable risk factors for atherosclerosis? (4)
Modifiable risk factors:
1) HTN
2) Hypercholesterolemia (high LDL)
3) Smoking
4) DM
Where does aortic dissection most commonly occur? Why?
Proximal 10 cm of aorta because this is a high stress region, in which there is lots of pressure for the blood to rip through the media.
What are the 4 complications of atherosclerosis?
1) Stenosis of medium sized vessels (that supply end organs) → imapired blood flow and ischemia resulting in: peripheral vascular disease, angina, ischemic bowel disease.
2) Plaque rupture with thombosis → atherosclerotic emoboli
3) Weakening of vessel wall → aneurysm
4) Plaque rupture with thombosis → MI (coronary arterier) and stroke (eg middle cerebral artery)
What are the 2 types of arteriolosclerosis?
Hyaline arteriolosclerosis, Hyperplastic arteriolosclerosis
What is the gross appearance of glomerular scarring?
Shrinkage of kidney with scarring on the surface
In hyaline arteriolosclerosis, what is seen on microscopy and why
Vascular thickening with pink hyaline, which are the proteins that have leaked into the vessel wall
How do Monckeberg Medial Calcific sclerosis present clinically and why
Bc the calcification is nonobstructive, it doesn’t alter lumen caliber and doens’t alter blood flow; as a result, is not clinically significant
Common arteries that are most susceptible to atherosclerosis (4)
Abdominal aorta, coronary artery, popliteal artery, internal carotid artery
What is seen in gross aorta that has thoracic aneurysm and why
Tree bark appearance due to scarring and fibrosis from endarteritis
What are common causes of weakness of media in kids?
Inherited Connective Tissue disorders:
1) Marfan syndrome- defect of fibrillin which affects elastin → weakning of media
2) Ehlers-Danlos syndrome: defective formation of collagen→ weakening of media
What is hyperplastic arteriolosclerosis?
Thickening of vessel wall by hyperplasia of smooth muscle
How does a thrombus form when plaque ruptures?
Plaque ruptures usually at the necks, exposing the necrotic lipid core. This activates coagulation cascade → thrombus formation. This can occlude a vessel leading to infarction of an organ.
What are fatty streaks and when do they appear?
They are flat yellow lesions of intima consisting of lipid-laden macrophages. They arise early in life (present in most teenagers)
How does atherosclerosis lead to weakening of a vessel and aneurysm?
Blood vessel wall components (intima, media, adventitia) need O2 from the blood via diffusion. Formation of atherosclerosis creates a diffusion barrier, weakning the wall, and increasing the risk of ballooning (aneurysm).
Result of hyperplastic arteriolosclerosis and what are two classic findings?
Results in reduced vessel caliber with end-organ ischemia.
2 classic findings:
1) Acute renal failure- due to acute damage due to high blood pressure to kidney
2) Flea bitten appearance of kidney- on surface of kidney, get pinpoint hemorrhages from blowing out of BVs.
What is arteriolosclerosis and what type of vessels (small/medium/large) are affected?
It is the narrowing of small arterioles.
What causes weakness of media layer of aorta in older adults before aortic dissection occurs?
HTN: in proximal 10 cm of aorta, the wall is very thick and therefore O2 cannot diffuse sufficiently to provide I, M, and A all with O2. As a result, there is vasa vasorum that provides the outer half of aortic wall with oxygen. However, in hypertensive patients, there is hyaline arteriolosclerosis of vasa vasorum, decreasing blood flow to the outer 1/2 of aortic wall. This causes atrophy of SM of the medial layer and weakning of media, increaisng the likelihood of a dissection.
What two disease processes cause hyaline arteriolosclerosis and how?
1) Long-standing benign HTN- high blood pressure forces proteins into the vessel wall → hyaline arteriolosclerosis
2) DM- nonenzymatic glycosylation of basement membrane of blood vessel causes BV to become leaky → protein leaks in → hyaline arteriolosclerosis
How is Monckeberg medial calcific sclerosis seen in x-ray/mammography?
It is usually seen on x-ray or mammography as cacification of blood vessels.