Ch 4 Pathoma - Thrombosis/Embolism

Question 1

Thrombosis

Answer 1

pathologic formation of an intravascular blood clot

Question 2

Lines of Zahn

Answer 2

alternating layers of platelets/fibrin and RBCs characteristic of thrombosis (thrombi are also attached to vessel walls)

Question 3

How can you tell a thrombus from a postmortem clot on autopsy

Answer 3

lines of zahn

Question 4

Virchow’s Triad

Answer 4

disruption in blood flow (turbulent or static), endothelial cell damage, hypercoaguable state

Question 5

3 examples of disruption in normal blood flow

Answer 5

Immobilization, cardiac wall dysfunction (arrhythmia or MI), aneurysm

Question 6

5 ways endothelial cells prevent thrombosis normally

Answer 6

Block exposure to sub endothelial collagen, produce prostacyclin (PGI2) and NO, secrete heparin-like molecules, secrete tPA, secrete thrombomodulin

Question 7

Prostacyclin (PGI2) and NO (ways endothelial cells prevent thrombosis)

Answer 7

vasodilation and inhibition of platelet aggregation

Question 8

Heparin-like molecules (ways endothelial cells prevent thrombosis)

Answer 8

augment antithrombin III (ATIII), which inactivates thrombin and coag factors

Question 9

Tissue plasminogen activator (tPA) (ways endothelial cells prevent thrombosis)

Answer 9

converts plasminogen to plasmin which (1) cleaves fibrin and serum fibrinogen, (2) destroys coagulation factors, (3) blocks platelet aggregation

Question 10

Thrombomodulin (ways endothelial cells prevent thrombosis)

Answer 10

redirects thrombin to activate protein C, which inactivates factors V and VIII

Question 11

3 causes of endothelial damage

Answer 11

atherosclerosis, vasculitis, high levels of homocysteine

Question 12

Two ways to have elevated homocysteine

Answer 12

vitamin B12/folate deficiency and cystathionine beta synthase (CBS) deficiency

Question 13

How Vitamin B12/Folate deficiency –> Homocysteine buildup

Answer 13

folic acid (aka tetrahydrofolate, THF) circulates in serum as methyl-THF –> methyl transfered to cobalamin (B12) –> (THF can participate in synthesis of DNA precursors) –> cobalamin transfers methyl to homocysteine resulting in methionine

Question 14

Cysthationine beta synthase deficiency

Answer 14

cbs converts homocysteine to cystathionine; characterized by vessel thrombosis, mental retardation, lens dislocation, and long slender fingers (also results in homocystinuria)

Question 15

4 genetic causes for hypercoagulability

Answer 15

Protein C or S deficiency, Factor V Leiden, Prothrombin 20210A, ATIII deficiency

Question 16

Protein C or S deficiency

Answer 16

• autosomal dominant
• normally they inactivate factors V and VIII
• increased risk for warfarin skin necrosis

Question 17

Factor V Leiden

Answer 17

mutated form of factor V that lacks the cleavage site for deactivation by proteins C and S
- most common inherited cause of hypercoagulable state

Question 18

ATIII deficiency

Answer 18

• ATIII inactivates thrombin and coagulation factors

Question 19

In ATIII deficiency does PTT rise/fall/stay the same with standard heparin dosing

Answer 19

stays the same (heparin works by binding and activating ATIII) –> give high dose heparin to activate the limited ATIII and coumadin to maintain anticoag state (can stop high dose heparin when you pass skin-necrosis warfarin window)

Question 20

Estrogen induces ______ production of coagulation factors (increased/decreased)

Answer 20

increased (oral contraceptives = increased risk for thrombus)

Question 21

Embolism

Answer 21

intravascular mass that travels and occludes downstream vessels

Question 22

5 types of emboli

Answer 22

thromboembolus, atherosclerotic embolus, fat embolus, gas embolus, amniotic fluid embolus

Question 23

Embolus characterized by presence of cholesterol clefts

Answer 23

atherosclerotic embolus (formed by atherosclerotic plaque that dislodges)

Question 24

Embolus associated with bone fractures

Answer 24

Fat embolus

Question 25

embolus associated with dyspnea and petechiae on skin overlying the chest

Answer 25

fat embolus

Question 26

embolus classically seen in decompression sickness

Answer 26

gas embolus (presents with joint/muscle pain = “bends” and respiratory symptoms = “chokes”

Question 27

Cassion disease

Answer 27

chronic form of gas embolism characterized by multifocal ischemic necrosis of bone

Question 28

Amniotic fluid embolus presentation

Answer 28

Presents with SOB, neurologic symptoms, and DIC (due to the thrombogenic nature of amniotic fluid) - during labor or delivery

Question 29

embolus characterized by squamous cells and keratin debris

Answer 29

amniotic fluid embolus (both are from fetal skin)

Question 30

Pulmonary infarction due to PE presentation (4 symptoms)

Answer 30

SOB, hemoptysis, pleuritic chest pain, pleural effusion

Question 31

Systemic embolism most commonly arise in the ____ _____

Answer 31

left heart

Question 32

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Answer 32

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