Lecture 8 2/7/24 Flashcards
What is thrombosis?
-coagulation of blood within the intact cardiovascular system
-pathologic equivalent to physiologic hemostasis
When is the term clot used vs. thrombus?
-clot is at the site of an injury or postmortem
-thrombus is within an intact vessel
What are the characteristics of thrombus morphology?
-firm
-rough and dry
-attached to vessel wall
-pale tan/layered
-can develop Lines of Zahn (alternating RBCs and platelets/fibrin)
What is a chicken fat clot?
-post-mortem occurrence
-plasma separates from rest of blood
-one part of clot is red, other is yellow to tan/white
What causes a chicken fat clot?
-more rapid erythrocyte sedimentation
-typically due to increased circulating cytokines during illness
What are the three components of the Virchow’s triad that lead to thrombus formation?
-endothelial injury
-alterations in normal blood flow
-increased blood coagulability
What can cause an endothelial injury?
-trauma
-parasites
-atherosclerosis (lipid/cholesterol deposition in vessels)
-arteriosclerosis
-inflammation
How does a loss of laminar blood flow contribute to thrombus formation?
allows:
-platelets to contact endothelium
-clotting factors to separate from inhibitors
-activation of endothelial cells
What can lead to alterations in blood flow?
-turbulence
-stasis
What can cause turbulence?
-cardiac dysfunction
-chronic IV catheter
-aneurysm/focal dilated segment of vessel
What are the causes of increased blood coagulability?
-protein loss
-dehydration
-corticosteroids (thicken blood)
-hormones
-neoplasia
-pancreatitis
What are the potential fates for thrombi?
-dissolution
-organization
-recanalization
-propagation
-embolization
What does organization and recanalization of a thrombus entail?
-organization of collagen closes off a vessel
-recanalization is the blood vessel tunneling through the collagen
-recanalization is associated with increased turbulence
In which direction do thrombi grow/propagate?
towards the heart
What is embolization?
when a piece of the thrombus breaks off and travels to a distant site
What is an infarct?
a region of ischemic necrosis due to obstruction of blood flow
What is an arterial infarct?
decreased blood flow into the area
What is a venous infarct?
decreased blood flow out of the area
Which organs are resistant to infarcts, and why?
-lungs and liver
-have a dual blood supply
How does a thromboembolus differ from an embolus?
-thromboembolus is a type of embolus
-embolus can be any intravascular material carried by the bloodstream to a distant site
What is a saddle thromboembolus?
thromboembolus that occurs where the vessels branch
What are the characteristics of disseminated intravascular coagulation?
-widespread microthrombi
-consumption of platelets and coagulation factors
-results in spontaneous hemorrhage
What are the characteristics of hemorrhage in DIC?
-petechial and ecchymotic
-may be widespread or localized
How does DIC manifest clinically?
-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
Which primary conditions can lead to DIC as a secondary condition?
-heat stroke/hyperthermia
-pancreatitis
-massive tissue injury
-sepsis
-allergic/toxic reaction
-neoplasia
