Lecture 8 2/7/24

Question 1

What is thrombosis?

Answer 1

-coagulation of blood within the intact cardiovascular system
-pathologic equivalent to physiologic hemostasis

Question 2

When is the term clot used vs. thrombus?

Answer 2

-clot is at the site of an injury or postmortem
-thrombus is within an intact vessel

Question 3

What are the characteristics of thrombus morphology?

Answer 3

-firm
-rough and dry
-attached to vessel wall
-pale tan/layered
-can develop Lines of Zahn (alternating RBCs and platelets/fibrin)

Question 4

What is a chicken fat clot?

Answer 4

-post-mortem occurrence
-plasma separates from rest of blood
-one part of clot is red, other is yellow to tan/white

Question 5

What causes a chicken fat clot?

Answer 5

-more rapid erythrocyte sedimentation
-typically due to increased circulating cytokines during illness

Question 6

What are the three components of the Virchow’s triad that lead to thrombus formation?

Answer 6

-endothelial injury
-alterations in normal blood flow
-increased blood coagulability

Question 7

What can cause an endothelial injury?

Answer 7

-trauma
-parasites
-atherosclerosis (lipid/cholesterol deposition in vessels)
-arteriosclerosis
-inflammation

Question 8

How does a loss of laminar blood flow contribute to thrombus formation?

Answer 8

allows:
-platelets to contact endothelium
-clotting factors to separate from inhibitors
-activation of endothelial cells

Question 9

What can lead to alterations in blood flow?

Answer 9

-turbulence
-stasis

Question 10

What can cause turbulence?

Answer 10

-cardiac dysfunction
-chronic IV catheter
-aneurysm/focal dilated segment of vessel

Question 11

What are the causes of increased blood coagulability?

Answer 11

-protein loss
-dehydration
-corticosteroids (thicken blood)
-hormones
-neoplasia
-pancreatitis

Question 12

What are the potential fates for thrombi?

Answer 12

-dissolution
-organization
-recanalization
-propagation
-embolization

Question 13

What does organization and recanalization of a thrombus entail?

Answer 13

-organization of collagen closes off a vessel
-recanalization is the blood vessel tunneling through the collagen
-recanalization is associated with increased turbulence

Question 14

In which direction do thrombi grow/propagate?

Answer 14

towards the heart

Question 15

What is embolization?

Answer 15

when a piece of the thrombus breaks off and travels to a distant site

Question 16

What is an infarct?

Answer 16

a region of ischemic necrosis due to obstruction of blood flow

Question 17

What is an arterial infarct?

Answer 17

decreased blood flow into the area

Question 18

What is a venous infarct?

Answer 18

decreased blood flow out of the area

Question 19

Which organs are resistant to infarcts, and why?

Answer 19

-lungs and liver
-have a dual blood supply

Question 20

How does a thromboembolus differ from an embolus?

Answer 20

-thromboembolus is a type of embolus
-embolus can be any intravascular material carried by the bloodstream to a distant site

Question 21

What is a saddle thromboembolus?

Answer 21

thromboembolus that occurs where the vessels branch

Question 22

What are the characteristics of disseminated intravascular coagulation?

Answer 22

-widespread microthrombi
-consumption of platelets and coagulation factors
-results in spontaneous hemorrhage

Question 23

What are the characteristics of hemorrhage in DIC?

Answer 23

-petechial and ecchymotic
-may be widespread or localized

Question 24

How does DIC manifest clinically?

Answer 24

-excessive activation of coagulation leads to abnormal clotting profile
-microthrombi form
-consumption of platelets and coagulation factors leads to spontaneous bleeding
-eventually leads to multiple organ failure and death

Question 25

Which primary conditions can lead to DIC as a secondary condition?

Answer 25

-heat stroke/hyperthermia
-pancreatitis
-massive tissue injury
-sepsis
-allergic/toxic reaction
-neoplasia