Coagulation Disorders

Question 1

What are steps up until platelet aggregation?

Answer 1

Vascular injury exposes subendothelial matrix proteins (collagen). Plasma vWF anchor to collagen
Adhesion: Platelets adhere to immobilized vWF by the GPIb/V/IX, also adhere to collagen by GPVI and integrin α2β1
Activation: Interactions between platelet surface receptors (e.g. GPIbα, integrins) and their ligands leads to activation, release ADP and TXA2 which activate and recruit circulating platelets.
Aggregation: The fibrinogen receptor (GPIIb/IIIa or GPαIIbβ3) is activated, binds fibrinogen, which bridges adjacent platelets forming a platelet plug.

Question 2

tenase intrinsic path

Answer 2

IX + VIII

Question 3

extrinsic path utilizes…

Answer 3

trauma and tissue factor to activate VII

Question 4

what activates factor 10?

Answer 4

tenase and factor 7, they activate prothrombin (II) via X and V

Question 5

What are natural anti coagulants?

Answer 5

Tissue Factor Pathway Inhibitor (TFPI), Anti-thrombin /Heparin Cofactor II/Heparin which Inactivates (IX, X, XI and XII)
Protein C/Protein S/Thrombomodulin which Inactivates Va & VIIIa, activates plasminogen
Plasminogen - Cleaves Fibrin

Question 6

What are some inherited defects of platelets?

Answer 6

secretion defects, recruitment defects - lack of ADP receptor, cohesion defects - aB integrn deficiency, Adhesion defects - lack vWF, lack GP

Question 7

X link recessive, deficient VIII

Answer 7

Haemophilia A

Question 8

X link recessive, deficient IX

Answer 8

Haemophilia B

Question 9

autosomal dominant/recessive, deficient XI

Answer 9

Haemophilia C

Question 10

What are treatments for VwF deficiency?

Answer 10

Desmopressin: synthetic analog of vasopressin that elevates FVIII and vWF plasma concentrations

vWF/FVIII concentrate for – Type 2B

Anti-fibrinolytic therapy, i.e. Amino-caproic Acid or Amicar

Topical agents (usually for oral mucosal bleeding)

Recombinant Factor VIIa

Question 11

What does PT/PTT mix studies do?

Answer 11

PT looks to see is VII, X, V, II, or fibrinogen are deficient. PTT looks to see if XII,XI, IX, VIII, X, V, II, fibrinogen are deficient

Question 12

What activates plasminogen?

Answer 12

Factor XI, XII, kalikrein, tPA

Question 13

Predisposition to form blood clots in the presence of acquired and/or inherited traits that result in hypercoagulability

Answer 13

thrombophilia

Question 14

What does protein C do?

Answer 14

activates protein S which inactivates factors VIII, V

Question 15

Antithrombin inhibits…

Answer 15

Xa, IIA, VII, IX, XI, XII

Question 16

renders factor V (both the activated and inactive forms) insensitive to the actions of activated protein C (aPC), a natural anticoagulant

Answer 16

Factor V Leiden

Question 17

Autosomal Dominant single-point gain of function mutation. Results in increased activity of plasma prothrombin

Answer 17

Prothrombin G20210

Question 18

Systemic autoimmune disorder characterized by:
- Combination of arterial and/or venous thrombosis
- Pregnancy morbidity
- presence of lupus anticoagulant

Answer 18

antiphospholipid syndrome