Exam 3 - Disorders of Secondary Hemostasis

Question 1

what is TF? why is it important?

Answer 1

tissue factor - present on membrane of most cells & is released when trauma occurs activation factor VII - the main activator of coagulation

Question 2

what is the main factor that serves as the activation factor of coagulation?

Answer 2

factor VII

Question 3

what is responsible for the production of factor VIII?

Answer 3

vascular endothelial cells - still requires liver function for activation

Question 4

what factors are included in the intrinsic pathway?

Answer 4

XII, XI, IX, VIII

Question 5

what factors are included in the extrinsic pathway?

Answer 5

VII

Question 6

what factors are included in the common pathway?

Answer 6

X, V, II, I

Question 7

T/F: a single factor must be <30% to cause a prolongation of PT/PTT

Answer 7

true

Question 8

what is the pathogenesis of anticoagulant rodenticide toxicity?

Answer 8

rodenticides inhibit the enzyme that regenerates vitamin K

vitamin K is essential for factors II, VII, IX, & X

Question 9

when do animals develop clinical signs from anticoagulant rodenticide toxicity?

Answer 9

1-4 days

Question 10

how is anticoagulant rodenticide toxicity diagnosed?

Answer 10

based on Pt, PTT, & history of exposure

Question 11

what are some examples of anticoagulant rodenticides?

Answer 11

warfarin, diphacinone, brodifaccoum

Question 11

what are some examples of anticoagulant rodenticides?

Answer 11

warfarin, diphacinone, brodifaccoum

Question 12

what coagulation test is the first to be prolonged in anticoagulant rodenticide toxicity? why?

Answer 12

PT

factor VII has the shortest half-life, so it’s affected first

Question 13

what is the treatment for recent ingestion of anticoagulant rodenticide?

Answer 13

induce vomiting, give activated charcoal, & treat with vitamin k1

Question 14

what are the 7 disorders covered for disorders of secondary hemostasis?

Answer 14

1. vitamin k antagonist rodenticide toxicity
2. vitamin k deficiency
3. liver dysfunction
4. inherited coagulation factor deficiencies
5. disseminated intravascular coagulation
6. drugs
7. snake envenomation

Question 15

what does PT evaluate?

Answer 15

extrinsic & common pathways - factors VII, X, V, II, & I

Question 16

PT may be prolonged due to deficiency/dysfunction of what 2 factors?

Answer 16

VII & X

Question 17

other than factor deficiency/dysfunction, what other conditions can cause a prolonged PT?

Answer 17

liver dysfunction, disseminated intravascular coagulation, heparin administration, or hypofibrinogenemia

Question 18

what does PTT evaluate?

Answer 18

intrinsic & common pathways - factors XII, XI, IX, VIII, X, V, II, & I

Question 19

PTT may be prolonged due to deficiency/dysfunction of what factors?

Answer 19

factors VIII, IX, XII, XI, II, V, X

Question 20

PTT may be prolonged due to deficiency/dysfunction of what factors?

Answer 20

factors VIII, IX, XII, XI, II, V, X

Question 21

other than factor deficiency/dysfunction, what other conditions can cause a prolonged PTT?

Answer 21

heparin therapy, liver dysfunction, hypofibrinogenemia, dysfibrinogenemia, or DIC

Question 22

what does the activated clotting time assess?

Answer 22

intrinsic & common pathways

Question 23

what is hemophilia a?

Answer 23

congenital deficiency of factor VIII that is x-linked, so it’s carried by females & manifested in males

Question 24

what clinical signs are commonly seen in hemophilia a?

Answer 24

severe, spontaneous bleeding, bleeding into joints & skeletal muscle is common, some patients die within a few weeks of life

Question 25

what abnormalities are seen on diagnostic tests for patients with hemophilia a?

Answer 25

prolonged PTT with a normal PT

Question 26

what is the treatment for hemophilia a?

Answer 26

give fresh plasma or cryoprecipitate which contain factor VIII to control bleeding

Question 27

how is hemophilia a diagnosed?

Answer 27

confirmed with specific factor assay

Question 28

what abnormalities are seen on diagnostic tests for patients with hemophilia b?

Answer 28

prolonged PTT with a normal PT

Question 29

what is hemophilia b?

Answer 29

uncommon congenital deficiency of factor IX occurring in dogs & cats

Question 30

what is hageman deficiency?

Answer 30

factor XII deficiency especially common in cats

Question 31

what abnormalities are seen on diagnostic tests for patients with hageman deficiency?

Answer 31

prolonged PTT - but patients don't bleed abnormally

Question 32

factors II, VII, IX, & X are made in the liver but require what for the final step of synthesis?

Answer 32

vitamin K

Question 33

what enzyme is inhibited in anticoagulant rodenticide toxicity?

Answer 33

vitamin K epoxide reductase - responsible for vitamin K regeneration

Question 34

why is vitamin k not given IM or IV?

Answer 34

IM - not given because of hematoma formation IV - avoid due to risk of anaphylaxis or heinz bodies formation

Question 35

what can cause vitamin k deficiency?

Answer 35

severe cholestatic liver disease, severe small intestinal disease

Question 36

how do you treat vitamin k deficiency?

Answer 36

supplement with subcutaneous vitamin K

Question 37

what is DIC?

Answer 37

mixed disorder of primary & secondary hemostasis caused by abnormal activation of the coagulation system & an imbalance between coagulation & fibrinolysis resulting in the formation of thrombi in circulation causing consumption of platelets & coagulation factors

Question 38

what abnormalities are seen on diagnostic tests for patients with DIC?

Answer 38

thrombocytopenia, prolonged PTT and/or PT, normal to low fibrinogen, elevated d-dimers, & decreased antithrombin concentration schistocytes on blood smear

Question 39

what therapy is used for treating DIC?

Answer 39

aimed at treating the underlying cause, halting abnormal coagulation, maintaining organ perfusion, & preventing secondary complications

Question 40

prior to doing a liver biopsy, what is critical to evaluate?

Answer 40

coagulation panel

Question 41

what bleeding disorder is a common congenital coagulopathy of cats? what symptoms do they have?

Answer 41

hageman deficiency - factor XII typically asymptomatic