Atheroma and Thrombosis Flashcards
What is the word used to describe “degeneration of arterial walls characterised by fibrosis, lipid deposition and inflammation which limits blood circulation and predisposes to thrombosis”
Atherosclerosis
The following vessels are commonly affected by ….
- bifurcations
- abdominal aorta
- popliteal arteries
- carotid vessels
- circle of willis
Atherosclerosis
What are the risk factors of atherosclerois?
1) Age
2) Male
3) Family history
4) Genetic
5) Cholesterol
6) Hypertension
7) smoking
8) Diabetes
What is the first step of atherosclerosis?
Endothelial inhjury
In hyperlipidaemia where does lipid accumulate in the vessel?
-Inner most part of the vessel - the intima
Foam cells
Monocytes will migrate to the intima due to endothelial injury, Ingest the lipid and become foam cells
What is the fatty streak stage of atherosclerosis?
1) accumulation of lipids in intima
2) formation of foam cells
What secretes chemokines to attract monocytes, lymphocytes and smooth muscle cells?
foam cells
What secretes connective tissue?
Smooth muscle cells proliferate and secrete connective tissue
What forms atherosclerotic plaque?
Fat, extracellular material, leukocytes and smooth muscle forms atherosclerotic plaque
Describe the structure of an atheromatous plaque?
1) fibrous cap
2) Necrotic centre
3) media
What is the difference between a clot and thrombus?
CLOT:
- stagnant blood
- enzyme process
- elastic
- adopts shape of vessel
THROMBUS:
- Dependent on platelets
- firm
How do platelets becomes activated?
Platelets bind to collagen exposed by endothelial damage and become activated.
What do platelets secrete?
Alpha Granules:
1) fibrinogen
2) fibronectin
3) PDGF
Dense granules:
-chemotactic chemicals
What is Virchow’s Triad?
Changes in the following lead to thrombus formation and platelet adhesion:
1) Intimal surface of vessel
2) partten of blood flow
3) Blood constituents
Describe how Virchow’s Triad is present in arterial thrombus formation?
1) Plaque rupture changes the intimal surface of the vessels and causes turbulent flow.
2) Hyperlipidaemia - changes blood constituents.
3) Platelets bins and fibrin is produced entrapping RBC
Desrcribe how Virchow’s Triad is present in Venous Thrombus formation?
1) Intimal change : valves
2) Change in blood flow : slows due to immobility
3) change in blood constituents:
- inflammatory mediators (infection)
- factor V leiden (hypercoaguable state)
- Oestrogen
What are thrombi in the heart known as?
Mural thrombi
What are mural thrombi?
Thrombi in the heart which occur over areas of endomyocardial injury. e.g. MI, myocarditis, arrhythmias and cardiomyopathy
What is an embolus?
a mass of material in the vascular system that is able to lodge and block the vessel
What are the risk factors for a venous thromboembolism (VTE) ?
Acquires:
- immobility
- maligancy
- previous VTE
- heart failure
- Oestrogens
- obesity
- pregnancy
- renal disease
- smokers
Genetic:
Thrombotic disorders e.g.
-Factor V Leifden
-Protein S deficiency
What are the clinical effects of a small, medium and large pulmonary embolism?
Small = if multiple can cause pulmonary hypertension
Medium = acute respiratory / cardiac failure
Large = Death
Where does a systemic emboli arise?
1) Heart (during MI or Atrial Fib)
2) arterial circulation (atheroma)
Where do infective emboli arise?
1) Vegetations on infected heart valves
What type of emboli can lead to a mycotic aneurysm?
Infective embolism
What are the different types of embolism?
- pulmonary
- venous thromboembolism
- systemic
- infective
- Gas
- amniotic
- fat
- foreign body
What type of embolism leads to a granulomatous reaction?
foreign body embolism
