Thrombosis and Embolisms Flashcards
what is thrombosis
formation of a solid mass of blood within the circulatory system
why does thrombosis occur
- due to abnormalities of the vessel wall
- abnormalities of blood flow
- abnormalities of blood components
what abnormalities of vessel walls can cause thrombosis
- atheroma (degeneration of artery wall by accumulation of fatty deposits and scar tissue with constricts lumen)
- direct injury
- inflamation
what abnormalities of blood flow can cause thrombosis
- stagnation
- turbulence
what abnormalities of blood components can cause thrombosis
- smokers (sticky blood)
- post-partum
- post-op
what is the appearance of arterial thrombi
- pale (low RBC content)
- granular
- lines of Zahn (due to areas with a lower cell content)
what is the appearance of venous thrombi
- soft
- gelatinous
- deep red (higher cell content)
what are the outcomes of thrombosis
- lysis
- propagation
- organisation
- recanalisation
- embolism
what is lysis of a thrombosis
- complete dissolution caused by the ibrinolytic system and so blod flow is re-estblished
- most likely with small thrombi
what is propagation of a thrombosis
the spread of thrombosis either distally in arteries or proximally in veins
caused by the stagnation above/below the thrombosis giving abnormal flow
what is organisation of thrombosis
reparative process where fibroblasts and capillaries grow to replace thrombus however the lumen remains obstructed
what is recanalisation of a thrombus
- where blood flow is re-estabhlised after being cut off by the thrombus by allowing blood flow though much smaller channels
what is an embolism
- when part of the thrombus breaks of and travels in the blood stream
- blockage of a blood vessel by solid, liquid or gas at a site away from its origin
what are the effects of an arterial thrombosis
- ischaemia
- infarct
(depends if collateral circulation is available)
what are the effects of a venous thrombosis
- congestion which increases hydrostatic pressure to cause oedema
- ischaemia and infarction as the increased fluid pressure will equal arterial pressure so less nutrients etc will move out
what types of embolism are there
thrombo-embolism air nitrogen medical equipment tumour cells
where do embolisms from venous thrombi end up
in the lungs (pulmonary emboli)
where do embolisms from arterial thrombi end up
they pass through the heart and then can pass anywhere
what are some predisposing factors for DVT
- immobile
- post-operative
- burns
- cardiac failure
- pregnancy
how can DVT be prevented
- stockings with graduating pressure assist compression of veins preventing stagnation
- Flowtron boots inflate to mimic calf pump
how is DVT treated
- IV heparin type drugs
- oral warfarin
what are the affects of a pulmonary embolism
massive = (60& reduction bloodflow) fatal major = short of breath, cough and blood in sputum minor = asymptomatic or short of breath
what do recurrent minor PEs lead to
pulmonary hypertension
what causes fat embolism
fracture of long bone releasing bone marrow which can block vessels
