circulation II Flashcards
causes of thrombosis
virchow’s triad:
1 - injury to vessel wall
2 - increased coagulability
3 - decreased flow
hemostasis
- normal
- blood maintained clot free
- hemorrhage stopped by sealing vessels after rupture
thrombosis
- pathological
- inappropriate clotting in living person
- clot formation on uninjured endothelium or occlusion of vessels after minor injury
thrombus
coagula that forms inside blood vessels or heart chambers
clot
coagula outside of blood vessels or in vessels after death
pathogenesis of thrombosis - endothelial injury
1 - injury/loss to endothelial cells 2 - inflammation 3 - anatomic alterations - plaques 4 - trauma/surgery 5 - endothelial dysfunction
pathogenesis of thrombosis - abnormal blood flow
- non-laminar - brings platelets closer to wall, does not dilute clotting factors or bring enough anti-clotting factor
- decreased blood flow - patients confined to bed, dilated atria or vessels, venous thrombosis
- turbulence - endothelial injury and dysfunction
pathogenesis of thrombosis - hypercoagulability
1 - primary (genetic)
common: factor V (G1691A), prothrombin (G20210A), (C677T) mutations, or increased factors VIII, IX, XI, or fibrinogen
rare: protein C or S, or antithrombin III deficiency
2 - secondary (acquired) - cardiac failure, tissue damage, oral contraceptives, hyperestrogenic state, disseminated cancer, increased platelets, lifestyle
heparin-induced thrombocytopenia (HIT)
unfractionated heparin induces formation of antibodies against heparin-platelet factor 4
anti phospholipid antibody syndrome
- antibodies bind ot plasma proteins causing endothelial damage, hypercoagulant state
ventricular mural thrombosis
- caused by injury to endocardium or decreased flow following MI
vegetations
- thrombosis of heart valves
- endothelial injury from bacteria, antibodies, trauma
venous thrombosis - phlebothrombosis
- stasis of blood in uninflamed veins
- deep veins in calf, popliteal fossa
- firmly anchored head, loosely anchored tail
- can lead to embolism, edema
venous thrombosis - thrombophlebitis
- thrombosis in inflamed veins
- can be sterile due to trauma or septic due to bacteria
thrombosis of microcirculation - DIC
- disseminated intravascular coagulation
- fibrin thrombi consume platelets and coagulation proteins which leads to bleeding disorder
outcomes of thrombosis (4)
1 - lysis (dissolution)
2 - organization in connective tissue
3 - propagation towards heart
4 - embolization
five most frequent types of embolisms
1 - pulmonary thromboembolism 2 - systemic embolism 3 - fat embolism 4 - air embolism 5 - amniotic fluid embolism
embolus
- intravascular mass that is detached and carried
- can be part of thrombus, fat, cholesterol, gas, part of a tumor, bone marrow, foreign body, amniotic fluid
pulmonary thromboembolism
- most common embolism (95%)
systemic thromboembolism
- origin 80% in left side heart, large part mural thrombi
- rest from aortic aneurisms, plaques, vegetations
- lodge - 75% lower extremities, 10% brain
fat embolism
- origin - fractures of long bones, trauma of fat tissue, burns
- usually silent
- fat embolism syndrome in severe cases with pulmonary insufficiency, neurologic symptoms, anemia, thrombocytopenia, petechiae
air embolism
- obstetric procedures, chest trauma, decompression sickness
- bends - gas bubbles out of solution to form gas emboli
- treatment - high pressure with slow decompression
caisson disease
- chronic decompression syndrome
- focal necrosis (femur, humerus, tibia)
amniotic fluid embolism
- infusion of amniotic fluid into maternal circulation via tear in the placenta or rupture of uterine veins during labor or immediately postpartum
