Pathophysiology of Thrombosis and embolism Flashcards
What is meant by laminar blood flow?
-Normal blood flow of blood that moves parallel and
Types of abnormal blood flow
Stasis
-stagnation of flow
Turbulence
-forceful, unpredictable flow
State conditions that may affect blood flow
- thromb embolism
- atheroma
- hyperviscosity, spasm
- external compression
- vasculitis
- vascular steal
State Virchow’s triad
Factors causing thrombosis
- changes in BV wall
- changes in blood constituents
- changes in pattern of blood flow
Describe the pathogenesis of thrombosis
- Endothelial injury
- stasis OR turbulent blood flow
- hypercoagulability of blood
(Virchows triad)
Describe pathogenesis of thrombosis in an athermatous coronary artery
-turbulent blood flow ( fibrin deposition, platelet clumping)
-loss of intimal cells, rupture occurs an collagen is exposed + platelets will adhere
-fibrin meshwork, RBCs will be trapped + alternating bands ( linez of zahn) formed?
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Examples of changes in vessel wall
atheromatous coroanry artery
-hypercholesterolaemia
Changes in blood constituents examples
- hypervisccity
- post traumatic hypercoaguability
Changes in blood flow examples
- stasis ‘’ ecconomy class syndrome ‘’ post op
- turbulence; atheramatous plaque, aortic aneurysm
What is an embolism?
-movement of abnormal material in bloodstream and may block vessels lumen
What is an embolus?
-detached intravascular solid/liquid/gaseous mass
Sources of systemic/arterial thromboembolus
- mural thrombus ; adheres the vessel wall ( associated with MI/ left atrial dilation + atrifal fibrilation)
- aortic aneurtysms
- atheromatous plaques
- valvular vegetations ( venous thrombi - paradocical emboli)
Systemic thromboembolus
- mainly travels to lower limbs, brain + other organs
- can lead to ischaemia, calibre of occluded vessel, collateral circulation + infarction
Types of embolus
- systemic/arterial thromboembolus
- venous thromboembolus
- fat
- gas
- air
- tumour
- trophoblast
- septic material
- amniotic fluid
- bone marrow
- foreign bodies
Venous thromboembolus
- originates from deep venous thromboses ( lower limbs)
- travels to pulmonary arterial circulation
- can cause occlusion of main pulmonary artery, bifurcation( saddle embolus), smaller arteries
- most common form of thromboemmbolic disease
Consequences of pulmonary thromboembolisk
- silent, pulmonary hamorrhage/infaction, right heart failure, sudden death
- if multiple over time > pulmonary hypertension and RVF
Risk factors for DVT and pulmonary thromboembolism
-cardiac failure, severe trauma/burns, post op/post partum, nephrotic sundrome, disseminated malignancy, oral contraceptive, age, bed rest/immbolisation, obesity, PMH
Surgical patients at risk of DVT/pulmonary thromboembolism
recieve prophylacis : TEDS, s/c heparin
When may a fat embolis occur?
- after major fracture
- sundrome of fat embolism: brain, kidneys and skin is affected
When may a gas embolus occur?
- if you have decompression sickness; N2 forms as bubbles which lodges in brain capillaries
- air embolus due to head, neck wounds, surgery + CV lines
Examples of trophoblast and septic material in association with embolus
Trophoblast - pregnant women > lungs
Septic material - infective endocarditis
Why may amniotic fluid, bone marrow + foregin bodies be an embolus?
amniotic fluid - cause of collapse and can cause death in child birth
Bone marrow - fractures; CPR
Forwign bodies - intravascular cannulae tipes, sutures
What is rheumatic fever?
- disease of disordered immunity
- inflammatory changes in heart,joints + has neurological symptoms
- affects children 5-15 years, boys>girls
Presentation of rheumatic fever
- polyarthritiss of large joints + skin rashes + dever
- pancarditis ( inflammation of endocardium, myocardium AND pericardium) and in acute; heart murmurs will be common
