Cardion L20 22 Atherosclerosis Flashcards Preview

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Flashcards in Cardion L20 22 Atherosclerosis Deck (30):
1

Atherosclerosis Definition

A disease of the arterial intima in which there is an accumulation of lipid debris with an associated inflammatory reaction.

There is focal asymmetric narrowing of vessels as the result of the build up of intimal athermanous plaque.

The process develops very slowly, over a period of 30-40 years, with progressive occlusion of the arterial vessels.

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Tunica media

External elastic membrane
Smooth muscle

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Tunica media

Internal elastic membrane
Lamina propria (smooth muscle and connective tissue)

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Arteriosclerosis definition

Arteriosclerosis describes the inevitable thickening of arterial walls with aging. This occurs in all populations and is not in itself pathological.

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Arteriosclerosis leading to pathological states.

Hypertension, as a result of reduction in the luminal diameter of the vessels and thus reduction of the internal volume of the circulation.

Ischemia, as a result of progressive reduction in blood flow.

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Atherosclerosis pathological lesions:

Fatty Streak
Fibrous Plaque
Complicated Fibrous plaque

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Fatty Streaks

Collection of lipid laden macrophages lying in the intima of the vessel.

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There is no what in fatty streaks

Free fat or evidence of an inflammatory reaction.

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Lesions found from

Infancy in the aortic intima and their presence is not related to nutritional status.

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Fibrous Plaque: Definition

The essential lesion of atherosclerosis. It is a nodular thickening of the arterial intima

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Fibrous Plaque: Composed of

A core of free fat (85% cholesterol and cholesterol ester; 15% triglyceride).

Proliferated mesenchymal cells (smooth muscle cells and macrophages)

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Fibrous Plaque: Defining factor

An area of fibrous scar at the base of the plaque
Abundant intercellular matrix (Proteoglycan)

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Fibrous Plaque: Complications of fibrous plaque:

Surface thrombosis
Intraplaque haemorrhage

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Fibrous Plaque: Surface thrombosis

Loss of surface endothelium leading to thrombosis. This may be a source of embolus or, alternatively, the thrombotic material may be incorporated into the plaque an thus increase its size.

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Fibrous Plaque: Intraplaque haemorrhage

Intraplaque haemorrhage may cause sudden increase in size of the plaque. Such haemorrhage arises from rupture of new vessels in the base of the plaque which originates in the inflammatory response to the free fat of the plaque.

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3. Four major sites: of atheroma

a. Carotid arteries → bifurcation
b. Coronary arteries → origin
c. Abdominal aorta → renal arteries and bifurcation
d. Deep femoral arteries → entering deep soft tissue

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atheroma description

1. Atheromatous lesions do not form uniformly throughout the circulation.
2. Disease is focal and lesions are located at specific sites.

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Endothelial Injury: causes

1. Cholesterol
2. Inflammatory mediators
3. Smoking
4. Infection
5. Toxins – endotoxins
6. Mechanical stress
7. Neoplasia

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Atheroma conseqeunces

Gradual Vascular Occlusion
Sudden Vascular occlusion
Haemorrhage

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Gradual Vascular Occlusion

Cerebral Ischaemia
Myocardial Ischaemia
Renal Ischaemia
Peripheral (limb) Ischemia

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Sudden Vascular occlusion

Thrombosis
Embolism


Myocardial infarction
Cerebral Infarction
Renal infarction

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Haemorrhage

Rupture of Aortic Aneurysm
Rupture of cerebral aneurysm

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Gradual Vascular Occlusion:

Cerebral ischemia
Cardiac ischemia
Renal ischemia
Peripheral (limb) ischemia

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Cerebral ischemia

Chronic ischemia damage leading to progressive cerebral atrophy and dementia.

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Cardiac ischemia

Reduction in coronary artery perfusion leads to a syndrome of pain (angina pectoris) with increase cardiac output i.e. exercise

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Renal ischemia

Reduction in renal blood flow will compromise renal function (reduced glomerular filtration) and will cause hypertension.

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Peripheral (limb) ischemia

Reduction of peripheral perfusion leads to pain on exercise (intermittent claudication) and eventually peripheral gangrene

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Sudden vascular occlusion → caused by

thrombosis or embolism causing acute ischemia and infarction

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Acute Haemorrhage: over a long period

→ atheromatous plaques leads to atrophy of the medial tissues and weakness of the wall.

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Acute Haemorrhage:

1. Catastrophic haemorrhage in atheromatous disease is the result of rupture of an aneurysm.
2. An aneurysm is a pathologically dilated vessel. There are a large number of causes of aneurysm of which one is atheroma.

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