thrombosis and embolism Flashcards
what is a thrombus
solid mass of blood formed in the circulatory system
what causes a thrombus (triad of Virchow)
abnormalities in the vessel wall; (endothelial damage)
atheroma, direct injury or inflammation
abnormalities in blood flow; (may be slower and more time to stick)
stagnation or turbulence
abnormalities in blood components; (hypercoaglubility - more clotting factors)
smokers, post part, post op
what are the 2 different types of thrombi and how do they differ
arterial - pale, granular, lines of Zahn and lower cell content due to faster flow in arteries.
venous - soft, deep red and higher cell content.
what are the 5 different outcomes of thrombosis
lysis - fibrinolytic system dissolves clot
propagation- thrombus spreads, stuff keeps joining sue to stagnant flow
organisation - repair process begins. fibroblasts and capillaries begin to grow resulting in further obstruction
recanalisation- blood flow re-established but usually incomplete (1 or more cannals formed in thrombus)
embolism - part of clot breaks off and travels through blood attaching at distant site
effects of arterial thrombosis
ischaemia and infarction by occlusion of artery
effects of venous thrombosis
congestion and oedema. stops arterial flow because equalises arterial pressure. can lead to ischaemia and infarction.
symptoms include pain and ulceration
what is an embolus
blockage of vessel by solid, liquid or gas at site distant from its origin
other rarer types of embolism
air - caused by negative pressure drawing in air. (often after trauma)
amniotic fluid - (happens due to c-sections where amniotic fluid enters via a tear in the amniotic sac)
nitrogen - (can happen to divers after they resurface and undergo rapid compression and air bubbles enter.)
medical equipment
tumour cells
different types of thrombo-emboli
thrombus that has dislodged and travelled to distant site in body
veins->lungs = PULMONARY EMBOLI
heart, via aorta -> renal, mesenteric and other arteries
carotid arteries-> brain
abdominal aorta-> arteries of legs
pre-disposing factors to DVT
immobility post op pregnancy/post part oral contraceptive (especially with high oestrogen) severe burns cardiac failure disseminated cancer
how to prevent/treat DVT
give heparin?
leg compression during surgery- compression acts as muscles to keep the blood flow
treatment;
herapin - activates antithrombin
oral warfarin - interferes with vit K metabolism. dose has to be titrated with patients PT test results.
effects of different types of embolism
massive = reduction in blood flow and can be rapidly fatal
major= patient presents with shortness of breath and blood stained sputum
minor= asymptomatic/shortness of breath
recurrent minor= pulmonary hypertension
what is a fat embolism
happens during a fracture where bone marrow is disrupted and fat gets out into blood flow
general prophylaxis of thrombo-embloic disease
prevent hypercoaglubility or venous stasis by;
elevating legs
compression socks
anticoagulants
how does aspirin work
acts as antithrombogenic
