CPT Haem Revision Flashcards
What do platelets release on activation?
ADP TXA Serotonin Calcium Change shape = express GpIIb/IIIa
5-HT function
Platelet chemotaxis
Release by active platlets
TXA/ADP function
Activates other platelets
Platelet diameter
1-4 micrometer
Platelet lifespan
8-14 days
Primary Haemostasis
Injury to vessel wall Vasoconstriction Exposed collagen VWF binds to collagen VWF binds to platelets via Gp1b Platelet activation = express GpIIb/IIIa Fibrinogen binds to these receptors Further platelets bind to fibrinogen
Bernard Soulier Syndrome
Lack of Gp1b
Glanzmanns syndrome
Lack of GpIIb/IIIa
Treatment for Bernard Soulier and Glanzmanns
Platelets or novoseven (recombinant factor VIIa) or transxamic acid
VWD types
Mild = mild to moderate deficiency Moderate = present but defective Severe = absent
VWD Inheritance
Autosomal inheritance
VWD Treatment
DDAVP if mild
Tranexamic acid
VWF containing concentrate
Intrinsic Pathway
12->12a converts 11->11a converts 9->9a.
9-> 9a requires XIa and calcium
9a converts 10-> 10a with calcium and 8
Extrinsic Pathway
TF(3) converts VII -> VIIa
VIIa converts 10-> 10a
Function of 10a
With 5 and calcium converts prothrombin into thrombin
Thrombin converts fibrinogen into fibrin
Factor 13a helps fibrin form stable clot
13a comes from thrombin producing 13
APTT
Intrinsic = 12,11,9 with 8 = 10
PT
Extrinsic = TF + 7 = 10
Bleeding Time
Platelet Function
3-10 mins
Thrombin Time
Common Pathway
Severe haemophillia treatment
Factor VIII Prophylactic
Mild and moderate Haemophillia treatment
DDAVP for mild haemolphillia A
Factor concentrate
What holds plasminogen in its state
Alpha 2 antiplasmin
What converts plasminogen -> plasmin?
tissue plasminogen activator
Released by endothelial cells
Antithrombin inhibits what?
Thrombin VII IX Xa XI
Examples of a SERPIN
Antithrombin
serpin protease inhibitor
Increased anti-thrombin activity
Heparin
5-10,000 fold
Stops clot
Protein S
Co-factor of protein C
Protein C and S
Inactivate Va and VIIIa
Increased Protein C activity
Thrombomodulin
20,000
Consanguinity
Increases incidence of rare bleeding disorders 10-20 x
Prothrombin Deficiency
XI, VII, V, X, II
Factor XI deficiency
Jewish
Avoid transexamic acid
Tx = factor conc
Factor VII deficiency
Low dose recomb fVIIa
15-30ug/kg
Levels rise in pregnancy mild don’t need replacement
Factor V deficiency
Check plasma VIII levels
Tx = FFP plasma solvent detergent = octaplas
Factor V and VIII
ERGIC = abnormality of cellular transport
Tx - VIII, DDAVP, plasma
Fibrinogen Deficiency
Umbilical cord bleeding
Pregnancy abrupt miscarriage, abruption, PPH
Tx = fibrinogen replacement, aim >1 during pregnancy, aim >2 for delivery
Factor II
Vitamin K dependent factor
Tx = plasma, PTCC
Factor X deficiency
Prophylaxis = PTCC, plasma
Factor XIII deficiency
- bleeding from birth
- prolonged umbilical stump bleeding
- Tx = cryo or plasma
Vitamin K Dependent Factor Deficiency
II, VII, IX, X
PTCC
Plasma
Check vitamin c as neonate = haemorrhagic disease of newborn
