Week 2 - Pathophysiology of Thrombosis and Embolism Flashcards
Which factors are the body’s vascular system governed by?
- pressure gradient from arterial to venous
- resistance
- viscocity
- compliance of vessel (type - muscular, elastic, veins)
What causes turbulence in vessels, forceful and unpredictable flow?
- blockage (thromboembolism, atheroma,)
- change in flow (hyperviscosity),
- external compression (tumour),
- inflammation of vessel wall
What is Virchow’s triad?
3 facrtors that lead to thrombus formation. change in flow, change in constituents or change in vessel wall.
How is a thrombus formed?
you need an endothelial injury, turbulent/static blood flow and hypercoagulability of blood. sticky collagen in wall exposed to platelets, forming thrombus
what are favourable outcomes of a thrombus?
- sometimes resolve themselves.
- typically need thrombolysis,
- sometimes organisation occurs and new vessel forms.
what are unfavourable outcomes of a thrombus?
causes death. propagation may occur - embolism
What are common clinical scenarios of a thrombus?
- DVT,
- ischaemic limb (arterial thrombosis),
- myocardial infarction (thrombus forms on atheromatous plaque)
What is an embolus?
detached intramuscular solid, liquid or gas
What are types of embolus?
thrombus, systemic thromboembolus, venous thromboembolus (DVT origin),
-fat, gas, air, tumours, bone marrow, foreign bodies
When can you get a gas embolus?
decompression sickness from N2. bubbles lodge in capillaries
When can you get an air embolus?
- stab wound,
- central venous line insertion,
- surgery air bubble in circulation
How does an amniotic fluid embolism occur?
during childbirth, keratin and skin cells get into maternal circulation and end up in lungs - reaction. mothers collapse and sometimes die
What are risk factors for DVT and pulmonary embolism?
- anything from virchow’s triad.
- cardiac failure,
- severe trauma/burns (hypercoagulable state),
- nephrotic syndrome
What is rheumatic disease?
disorder of immunity. polyarthritis in large limb joints.
RHD is caused by permanent damage of rheumatic fever
What is pancarditis?
inflammation effecting entire heart - epicardium, myocardium and pericardium. can progress to chronic rheumatic disease.
What can pancarditis lead to?
valvular abnormalities - necrosis of cusps/ chordae tendonae.
Which valve does rheumatic heart disease effect?
mitral valve - rarely others. causes mitral stenosis.
what is rheumatic fever?
presents with strep throat. theres a strong antibody reaction, which interracts with unknown antigens in connective tissue and can lead to heart damage.
What signs do you see in the heart if rheumatic fever is present?
Aschoff bodies
What are 3 forms of valvular heart disease?
- valvular stenosis
- valvular incompetence (failure to prevent blood reflux)
- vegetations (infective/thrombotic nodules on valve affecting mobility)
What are lines of zahn?
alternating lines of white platelets and fibrin, and red blood cells, formed in a thrombus formed BEFORE death. areas of faster flowing blood have more lines of zahn
What are Aschoff bodies?
Nodules of inflammatory cells, macrophages and necrosis active in heart
