Thrombosis and Embolisms

Question 1

what is thrombosis

Answer 1

formation of a solid mass of blood within the circulatory system

Question 2

why does thrombosis occur

Answer 2

• due to abnormalities of the vessel wall
• abnormalities of blood flow
• abnormalities of blood components

Question 3

what abnormalities of vessel walls can cause thrombosis

Answer 3

• atheroma (degeneration of artery wall by accumulation of fatty deposits and scar tissue with constricts lumen)
• direct injury
• inflamation

Question 4

what abnormalities of blood flow can cause thrombosis

Answer 4

• stagnation

- turbulence

Question 5

what abnormalities of blood components can cause thrombosis

Answer 5

• smokers (sticky blood)
• post-partum
• post-op

Question 6

what is the appearance of arterial thrombi

Answer 6

• pale (low RBC content)
• granular
• lines of Zahn (due to areas with a lower cell content)

Question 7

what is the appearance of venous thrombi

Answer 7

• soft
• gelatinous
• deep red (higher cell content)

Question 8

what are the outcomes of thrombosis

Answer 8

• lysis
• propagation
• organisation
• recanalisation
• embolism

Question 9

what is lysis of a thrombosis

Answer 9

• complete dissolution caused by the ibrinolytic system and so blod flow is re-estblished
• most likely with small thrombi

Question 10

what is propagation of a thrombosis

Answer 10

the spread of thrombosis either distally in arteries or proximally in veins
caused by the stagnation above/below the thrombosis giving abnormal flow

Question 11

what is organisation of thrombosis

Answer 11

reparative process where fibroblasts and capillaries grow to replace thrombus however the lumen remains obstructed

Question 12

what is recanalisation of a thrombus

Answer 12

• where blood flow is re-estabhlised after being cut off by the thrombus by allowing blood flow though much smaller channels

Question 13

what is an embolism

Answer 13

• 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

Question 14

what are the effects of an arterial thrombosis

Answer 14

• ischaemia
• infarct
  (depends if collateral circulation is available)

Question 15

what are the effects of a venous thrombosis

Answer 15

• 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

Question 16

what types of embolism are there

Answer 16

thrombo-embolism 
air
nitrogen
medical equipment
tumour cells

Question 17

where do embolisms from venous thrombi end up

Answer 17

in the lungs (pulmonary emboli)

Question 18

where do embolisms from arterial thrombi end up

Answer 18

they pass through the heart and then can pass anywhere

Question 19

what are some predisposing factors for DVT

Answer 19

• immobile
• post-operative
• burns
• cardiac failure
• pregnancy

Question 20

how can DVT be prevented

Answer 20

• stockings with graduating pressure assist compression of veins preventing stagnation
• Flowtron boots inflate to mimic calf pump

Question 21

how is DVT treated

Answer 21

• IV heparin type drugs

- oral warfarin

Question 22

what are the affects of a pulmonary embolism

Answer 22

massive = (60& reduction bloodflow) fatal
major = short of breath, cough and blood in sputum 
minor = asymptomatic or short of breath

Question 23

what do recurrent minor PEs lead to

Answer 23

pulmonary hypertension

Question 24

what causes fat embolism

Answer 24

fracture of long bone releasing bone marrow which can block vessels