platelets (adhesion and...
TRANSCRIPT
HAEMOSTASIS(VIRCHOW’S TRIAD)(VIRCHOW’S TRIAD)
Blood vessel (vasoconstriction)Blood vessel (vasoconstriction)Platelets (adhesion and aggregation)
C l ti d Fib i l iCoagulation and Fibrinolysis
Prof. Dr. Herman Hariman, Ph.D (U.K), SpPK (KH)Prof. Dr. Adi Koesoema Aman, SpPK (KH)
HAEMORRHAGICHAEMORRHAGIC SCREENING TEST
A Global test that may predict what happened with thepp
Blood vessel (vasoconstriction)( )Platelets (adhesion and aggregation)
Coagulation and FibrinolysisCoagulation and Fibrinolysis
Tourniquet TestC ill f iliCapillary-fragility-test
• Hess test (commonly used): pressure isHess test (commonly used): pressure is put midway between systole and diastole for 5 minutes Reading is done 5 minutesfor 5 minutes. Reading is done 5 minutes after the release of the cuff
• Rumple Leed (X): the same pressure as• Rumple Leed (X): the same pressure as above but for 15 minutes and reading is done straight away after the release of thedone straight away after the release of the cuff
InterpretationInterpretation
• (+): small red dots difficult to be seen(+): small red dots difficult to be seen• (++): bigger dots and easily seen
( ) t l il b t l it• (+++): not only easily seen but also quite prominent and sometimes confluent
• (++++): true bruising
Bleeding TimeBleeding Time
• As a global test to measure roughlyAs a global test to measure roughly• Platelet’s function
Pl t l t’ b• Platelet’s number
First blood drop is wipedN t bl d i ti d ff b filt 30Next, blood is tipped off by filter paper every 30 sec
Normal is less than 5 min
Bleeding TimeBleeding Time
• As a global test to measure roughlyAs a global test to measure roughly• Platelet’s function
Pl t l t’ b• Platelet’s number
Platelet Aggregation● Platelet adhesion is mediated by vWF. This activates platelets
causing release of TxA2
● During activation, a receptor for fibrinogen becomes exposed onthe platelet membrane.
●Activated platelets release by ADP, Epinephrin, serotonin:
Fibrinogen ADP/ATPvWF Serotonin dense core granulesvWF SerotoninFactor V Ca2+
Factor VIIIPl t l t d i d th f t (PDGF) t h liα
-gra
nule
s dense core granules
Platelet derived growth factor (PDGF) ~ promotes healingPlatelet factor IV – prevents formation of active thrombin
inhibitor from heparin and anti-thrombin III.
α
AGGREGATION OF PLATELETAGGREGATION OF PLATELET
IS MEASURED AFTER ADDING
THE PLATELET AGONISTS
SUH AS
ATPEPINEPHRINSEROTONINRISTOCETIN
Basic Principle ofpvon Willebrand’s Factor Test
• FUNCTIONAL TEST• Ristocetin co-factor assay dg Plt aggregometer
• ANTIGEN TEST (immunoassay)• Radioimmunoassay (RIA)• Enzyme-linked immunoassay (ELISA)
Basic Principle ofBasic Principle ofFibrinogen test
• Among other coagulation factors, Fibrinogen has no enzymatic activity and hence there is no functional test but only detection of protein
Intrinsic pathway
XIIa
TF
Extrinsic PathwayXIa
ProthrombinVIIa
TF
IXa
XaVa
VIIIaV
VIII
Fibrinogen FibrinThrombin Soft clot
gXIIIa
FibrinHard clot
FIBRINOGEN ASSAYSFIBRINOGEN ASSAYS
• Radial immunodifussionRadial immunodifussion• Clauss method (pure clotting-based)• Blomback and Blomback (+thrombin –Ca++)Blomback and Blomback (+thrombin Ca++)
soluble and unstabilized. The tyrosine content is measured after adding urea.g
• Ratnoff and Menzies: Fibrinogen is clotted into Fibrin in glass beads, washed and bolied +NaOH, tyrosine measured with Fiolin Calcateu-Phenol reagent
I t i i th E t i i thIntrinsic pathway Extrinsic pathway
Final Common pathwayFinal Common pathwayX, V,
Prothrombin Thrombin
Fibrinogen Fibrin
I t i i th E t i i thIntrinsic pathway Extrinsic pathway
Final Common pathwayFinal Common pathwayX, V,
Prothrombin Thrombin
Fibrinogen Fibrin
Prothrombin Time (PT)
I t i i th E t i i thIntrinsic pathway Extrinsic pathway
Final Common pathwayFinal Common pathwayX, V,
Prothrombin Thrombin
Fibrinogen Fibrin
Activated Partial Thromboplastin Time (APTT)
I t i i th E t i i thIntrinsic pathway Extrinsic pathway
Final Common pathwayFinal Common pathwayX, V,
Prothrombin Thrombin
Fibrinogen Fibrin
Thrombin Time (T.T)
BASIC HAEMORRHAGIC SCREENING TEST
MEASURES ROUGHLYMEASURES ROUGHLY• Full Blood Count• Torniquet test• Bleeding timeBleeding time• Prothrombin time
A ti t d ti l th b l ti ti• Activated partial thromboplastin time• Thrombin time