Coagulation Flashcards
What are the procoagulant aspects of hemostasis?
- Platelets: adhesion -> activation -> aggregation
2. Coagulation: Activation -> thrombin formation -> fibrin formation, polymerization, stabilization
__________ hemostasis involves the platelet plug, __________ hemostasis involves the fibrin clot.
Primary; secondary
What is the membrane receptor for platelet response?
Glycoproteins 1b
Describe the process of platelet plug formation
vWF binds platelet (via GP 1b) to subendothelial matrix
Platelets release alpha-granules and dense bodies which activate GP IIb/IIIa receptors on other platelets and cause release of ADP
Fibrinogen connects GP IIb/IIIa receptors of each platelet and flattens the platelets
Crosslinking of fibrin monomers is done via factor ______.
XIIIa
_________ starts the coagulation cascade in most cases.
Tissue factor
What are the regulators of primary hemostasis?
- NO
- PGl2
- ADPase
What are the regulators for secondary hemostasis?
- Serine protease inhibitors (antithrombin)
- Protein C (controls Va and VIIIa)
- Fibrinolytic system
What could be a result of protein C or protein S deficiencies?
Hypercoaguability
___________ promotes coagulation by causing resistance to enzymatic inactivation by the Protein C/S complex.
Factor V Leiden mutation
How is the plasminogen activated?
tPA + plasminogen = active plasmin
Prothrombin Time screens for the activity of the __________.
Extrinsic coagulation pathway
Prothrombin time forms the basis of ______.
International Normalized Ratio (INR)
A patient has a PT done and is recorded as a 3 on the INR. What medication might he be on?
Warfarin (anticoagulant)
Longer clot time than normal
Partial thromboplastin time screens for the activity of the ___________.
Intrinsic pathway
Which takes longer to activate (extrinsic or intrinsic)?
Intrinsic
What medication might a patient be on if he is being monitored via PTT?
Heparin
What are some clinical manifestations of a primary hemostasis disorder?
- Mucocutaneous bleeding, petechia
2. Excessive bleeding with trauma
What are some clinical manifestations of secondary hemostasis disorders?
- Soft tissue bleeding
2. Excessive bleeding with trauma
A patient with a prolonged PT and PTT is likely to have a (primary or secondary) hemostasis disorder?
Secondary
A patient arrives with small petechia on the skin. What type of hemostasis disorder might this be?
Platelet (primary)
If a patient has normal bleeding time, PT, and PTT, but experiences excessive bleeding what might you suspect?
Regulatory Hemostasis Disorder
T/F: PT screens for platelets, while PTT screens for Coagulation pathway.
FALSE
Both are for coagulation.
PT = extrinsic
PTT = intrinsic
What is the dominant clinical manifestation of vWD?
Mucocutaneous bleeding
What are the three types of vWD?
Type 1: Quantitative deficiency (partial)
Type 2: Qualitative deficiency
Type 3: Quantitative deficiency (total)
Why would PTT be slightly prolongued with vWD?
Factor VIII is slightly effected because it uses vWF to transport
Hemophilia A is a deficiency in factor _____.
VIII
What are the major laboratory features of hemophilia A?
Prolonged PTT and decreased Factor VIII
What is the major treatment option for Hemophilia A?
Factor VIII concentrates
A young child has spontaneous intracranial bleeding and a high PTT number. What might be the diagnosis?
Hemophilia A
T/F: Hemophilia A is more likely to affect men.
TRue
Hemophilia B involves a deficiency in factor ____.
IX
What is the major treatment option for Hemophilia B?
Factor IX concentrates
T/F: Platelet disorders will show with an increased bleeding time.
TRUE
What is thrombocytopenia?
Having a lack of platelets
T/F: Adults are likely to have acute ITP.
FALSE
Children = Acute Adult = Chronic
Describe the pathophysiology of ITP?
Autoantibodies attack the platelet membrane antigens
How would you treat ITP?
Corticosteroids and intravenous immunoglobulin
ITP may cost someone there ________, while TTP may cost someone there _________.
Spleen; kidney
What are the two major clinical manifestations of DIC?
Bleeding from multiple sites and thromboembolic problems
What is the most imperative early issue with DIC?
Stop the bleeding
What is the sequence of clotting factors activated via the intrinsic pathway?
Factor XII -> Factor XI -> Factor IX
In the extrinsic pathway, tissue factor activates factor ___.
VII
What changes occur through the common pathway of blood clotting?
- Activation of Factor X
- Prothrombin -> thrombin
- Fibrinogen to fibrin molecules
PTT would be measured in patients taking __________. While PT would be measured in patients taking ___________.
Heparin; Caumadin/Warfarin
Thrombocytopenia is a ___________ in platelet count. Thrombocytosis and thrombocythemia denote an ________ in platelet number.
Decrease; increase
Does bleeding time measure for primary or secondary hemostasis?
Primary (platelets)
What are the characteristics of a primary hemostasis disorder?
- Muccocutaneous bleeding or bleeding with trauma
2. Prolonged bleed time and thrombocytopenia
What are characteristics of a secondary hemostasis disorder?
- Soft tissue bleeding and bleeding with trauma
2. Long PT and/or PTT
What molecule acts as a carrier protein for Factor VIII until endothelial damage is seen?
vWF
