Secondary Hemostasis Flashcards
Expression of which cofactors initiates coagulation?
Tissue factor (III)
Which coagulation factor drives amplification?
Thrombin (IIa)
What are the 4 VitK dependent coagulation factors?
2, 7, 10, 9.. coagulation time!
What factor increases antithrombin activity?
Heparin
Increase activity by 1000x
Where is heparin found in the body?
Expressed on endothelial cells and circulates in the plasma
If you have a protein losing enteropathy, are you hypo or hyper -coagulable?
Hypercoaguable –> loss of antithrombin
What are the two major end products of fibrinolysis ?
Fibrin degradation products (FDP)
D-dimers
When are fibrin degradation products and D-dimers increased??
When there is increased clotting—> increased clot breakdown
What is responsible for clot degradation
Plasmin
To run coagulation tests, how should blood be collected?
“Clean stick”
Avoid taking blood from heparinized catheter
Blood for coagulation tests should be collected in ??
Sodium citrate tube (blue top) –> calcium chelator
What two tests can be used to measure the intrinsic pathway?
Activated partial prothrombin time (PPT)
Activated clotting time (ACT)
What test is more sensitive for measuring the intrinsic pathway of coagulation?
Activated prothrombin time (70% factor deficiency to produce result)
–>ACT requires a 95% deficiency to produce a result
What test can be used to measure the extrinsic pathway?
Prothrombin time (PT)
What test is good to detect a vitamin k deficiency due to the short half life of its coagulation factors
PT -> extrinsic pathway (factor VII)
If you have a prolonged PT, what are your two differentials?
Factor VII deficiency
Common pathway deficiency
If you have a prolonged PTT, but a normal PT, what can you infer from these results?
Deficiency in factors 12, 11, 9, or 8 (intrinsic pathway)
If you have a normal PPT and and prolonged PT, what can you infer from these results?
Deficiency in factor VII
If PTT is prolonged and PT is prolonged, what can you infer?
Deficiency in factors of the common pathway
If there is an increase in FDP or D-dimers, what is the cause?
Increased fibrinolysis
Severe internal hemorrhage
Decreased FDP clearance by the liver
What toxin is commonly associated with vitK deficiency
Warfarin
What bleeding pattern do you expect in an animal with vitK deficiency?
Increase bleeding
- anemia, weakness
- hypovolemia
- dyspnea
- lameness
- neurological
RBC: anemic (regenerative) PLT: normal MPV: normal PTT/ACT: prolonged PT: prolonged
Vitamin K coagulopathy
What are common causes of DIC?
Induction of tissue factor -sepsis, tissue necrosis, neoplasia
Endothelial damage - exposed collagen
Proteolytic enzyme -snake venom or pancreatitis
What are the two phases of DIC?
Hypercoaguable phase (thrombosis and ischemic necrosis)
Consumptive phase (bleed)
What phase of DIC results in bleeding?
Consumptive phase
What bleeding pattern is seen in DIC?
Mucosal due to PLT consumption
Hemorrhage due to factor consumption
What is the cardinal change seen in DIC?
Thrombocytopenia
Thrombocytopenia
Prolonged PTT/PT
Increased FDP and D-dimers
Decreased antithrombin
Hemorrhagic anemia
Schistocytes
What dis?
DIC
Why are coagulopathies associated with liver disease?
Decreased production of coagulation factors
and/or
Production of dysfunctional platelets
What is the classic presentation of an inherited factor deficiency?
Young animal with bleeding disorder
What are the three most common inherited factor deficiencies?
Hemophilia A
Hemophilia B
Factor XII (Hageman’s disease )
What common inherited factor deficiencies are associated with bleeding
Hemophilia A: VII
Hemophilia B: IX
PLT: normal
BMMT: normal
PTT/ACT: prolonged
PT: normal
Inherited factor deficiency
