clotting disorders

Question 1

intrinsic vs extrinsic coagulation pathways

Answer 1

intrinsic: PTT. due to exposure to negatively charged foreign substances.
extrinsic: PT. induced by tissue factor exposed at site of injury

Question 2

Which clotting factors are NOT synthesized by the liver?

Answer 2

vWF and factor VIII (8)

Question 3

What clotting factors may be reduced or deficient in von willebrand disease?

Answer 3

vWF and maybe factor VIII

Question 4

What are the labs seen in von Willebrand disease?

Answer 4

increased PTT (due to potentially reduced VIII), increased bleading time, decr factor VIII antigen, decr vWF, decr. ristocetin cofactor activity

Question 5

How is minor bleeding treated in von Willebrand disease?

Answer 5

desmopressin. this is also useful for mild hemophilia A

Question 6

What factors are decreased in vitamin K deficiency?

Answer 6

II, VII, IX, X

Question 7

What is the difference btw hemophilia A and hemophilia B?

Answer 7

hemophilia A is deficient factor VIII
hemophilia B is deficient factor IX
usually no significant bleeds for either unless pt has

Question 8

What are the labs seen in hemophilia?

Answer 8

incr. PTT, normal PT, normal bleeding ti,e, decr factor VIII or IX

Question 9

What is the pathophysiology behind DIC?

Answer 9

widespread abnormal coagulation from sepsis, trauma, neoplasm, or pregnancy. intial clots form becasue of extensive activation of the clotting cascade by endothelial tissue factor released during bacteremia, which then causes deficient clotting factor and abnormal bleeds

Question 10

What are the key labs in DIC?

Answer 10

low platelets, incr PT, incr PTT, decr. fibrinogen, increased fibrin split products, incr D-dimer, decr hct with schistocytes and few platelets on blood smear

Question 11

What are the 5 signs of TTP-HUS?

Answer 11

AKI, low platelets, hemolytic anemia (and maybe neuro deficits and fever)

Question 12

What is ITP and how is it treated?

Answer 12

autoimmune B cell directed production of antiplatelet antibodies in which platelets are often

Question 13

What is HIT?

Answer 13

IgG abs agains heprain bound to platelet factor 4. the PF4-heparin-platelet complex activates platelets
often see sudden decrease in platelet level, positive serotonin release assay. may treat with direct thrombin inhibitors for thrombi (argatroban)

Question 14

What are causes of impaired platelet production?

Answer 14

drugs, infection, aplastic anemia, folate/vit B12 deficienc, alcohol, cirrhosis