Bleeding disorders Flashcards
4 steps in stopping bleeding
- promary hemostasis - platelets and VWF
- secondary - coagulation cascade
- generate thrombin
- form fibrin clot - clot stabilization
- factor 13 and thrombin activator - healing
what is center of cascade and rate limiting step
factor 10
what is common pathway
10+5> 2 (prothrombin (2) becomes thrombin (2a)> fibrinogen to fibrin (clot)
what is path of extrinsic
7+tissue factor to activate 10
what is intrinsic pathway
HMWK and prekallikrein>12>11>9+8>10
what are contact factors
- prekallikrein
- HMWK
- Factor 12
NOT needed to control bleeding
what are 2 tests and what do they test?
- protrombin time (INR) - extrinsic and common
2. activated partial thromboplastin time (PTT) - int and extrinsic
what is INR and what is is designed for
standardized PT
- measure for warfarin
2 general types of coagulation factors
- non-enzymatic types
- 5, 8, and TF - zymogens
- 2,7,9,10 - all K dependend
where are most factors made and 4 exeptions
liver
- tissue plasminoggen activator (tPA)
- VWF
- thrombomodulin
- 8 is made in liver but also endothelium
what is factor with shortest half life
7, then 5+8
where does coag occur
on membranes with expose phospholipids
- not resting cells
what is 1 inherited disorder of primary hemostasis
von willbrand disease
what is 2 inherited disorder of secondary hemostasis
- hemophilia
2. 11 def.
what is 3 acquired disorder of primary hemostasis
- drugs!
- thrombocytopenia
- uremia
what is 4 acquired disorder of secondary hemostasis
- DRUGs
- liver dis
- DIC
- vit K def
what is best predictor of bleeding disorder
bleeding Hx