Pathophysiology of Thrombosis Flashcards
What is normal blood flow?
Laminar (smooth and ordered with cells in the middle)
What are the 2 kinds of abnormal blood flow?
Stasis
Turbulence
What is stasis blood flow?
Stagnation of flow, meaning blood flow slows down or stops
What is turbulence blood flow?
Forceful, unpredictable flow
What could defects in blood flow be due to?
Thromboembolism
Atheroma
Hyperviscocity
Spasm
External compression
Vasculitis
Vascular steal
What are the factors that cause thrombosis known as?
Virchow’s triad
What are the different components of Virchow’s Triad?
Changes in the blood vessel wall
Changes in the blood constituents
Changes in the pattern of blood flow
What is an example of changes in the blood vessel wall as part of Virchow’s triad?
Atheromatous coronary artery
What is an example of changes in blood constituents as part of Virchow’s triad?
Hyperviscocity
Post traumatic hypercoagulability
What is an example of changes in blood flow as part of Virchow’s triad?
Stasis or turbulence
What is thrombosis?
Formation of a solid mass from the constituents of blood within the vascular system during life
What is the formation of a solid mass from the constituents of blood within the vascular system during life called?
Thrombosis
What can a thrombus easily be confused with?
Blood clot - they are two different things
What is the pathogenesis of thrombosis?
1) Turbulent blood flow (fibrin deposition, platelet clumping)
2) Loss of intimal cells, denuded plaque
3) Collagen exposed, platelets adhere
4) Fibrin meshwork, red blood cells trapped
5) Alternating bands (lines of Zahn)
6) Further turbulence and platelet deposition
7) Propagation
8) Consequences
What commonly leads to thrombus?
Hypercholesteroaemia
What is the relationship between atheroma and thrombosis?
Arterial thrombosis is usually laid over an atheroma
What does the consequences of a thrombus depend on?
Site
Extend
Collateral circulation
What are some common clinical scenarioes of thrombosis?
Deep vein thrombosis
Ischaemic limb
Myocardial infarction
What are the potential outcomes of thrombosis?
Resolution
Organisation
Death
Propagation (turns to embolism)
What is an embolism?
Movement of abnormal material in the bloodstream and its impaction in a vessel (blocking the lumen)
What is the movement of abnormal material in the bloodstream and its impaction in a vessel (blocking the lumen) called?
Embolism
What are most emboli?
Dislodged thrombi (thromboembolism)
What do factors causing the embolism depend on?
Type of embolism
What are different types of embolism?
Thrombus
Fat
Gas
Tumour
Trophoblast
Septic material
Amniotic fluid
Bone marrow
Foreign bodies
What are the two different kinds of embolism caused by thrombus?
Systemic/arterial thromboembolism
Venous thromboembolism
Where do aortic embolisms travel to?
Wide variety of sites, lower limbs being most common, could go to the brain
What do consequences of arterial thromboembolism depend on?
Vulnerability of affected tissues to ischaemia
Calibre of occluded vessel
Where do venous thromboembolisms originate from?
Deep venous thrombosis (lower limbs)
Where do venous thromboembolisms travel to?
Pulmonary arterial circulation
What do consequences of venous thromboembolism depend on?
Size of embolus
What could the consequences of venous thromboembolism be?
Silent
Pilmonary haemorrhage/infarction
Right heart failur
Sudden death
What does multiple pulmonary embolism over time lead to?
Pulmonary hypertension and right ventricular failure
What are examples of gas embolism?
Decompression sickness (N2 forms as bubbles which lodge in capillaries)
Air embolus
What is a trophoblast?
Cells forming the outer layer of a blastocyst
What are the cells forming the outer layer of a blastocyst called?
Trophoblast
What is infarction?
Obstruction of the blood supply to an organ causing local death of the tissue
What is obstruction of the blood supply to an organ causing local death to the tissue called?
Infarction
What are some risk factors for deep vein thrombosis and pulmonary embolism?
Cardiac failure
Severe trauma/burns
Post operation
Nephrotic syndrome
Disseminated malignancy
Oral contraceptives
Increasing age
Bed rest/immobilisation
Obesity
Past medical history of deep vein thrombosis
What is used as prophylaxis for surgical patients at risk of deep vein thrombosis?
TEDS
S/C heparin
What is prophylaxis?
Treatment or action to prevent disease
What is treatment or action to prevent disease called?
Prophylaxis
