1. HEMOSTASis
Nada Mohamed Ahmed ,
MD, MT (ASCP)i

2. Contents
Normal hemostasis
Primary hemostasis disorders

3. Haima + Stasis
Prevent blood loss

4. Maintains blood flow
Prevents bleeding

5. HEMOSTASIS Definition - Heme = blood - stasis = to halt
It is the process of forming clots in the wall of damaged blood vessels & preventing blood loss while maintaining blood in a fluid state with in the vascular system.
Spontaneous arrest of bleeding by physiological process.

6. Formation of Platelet Plug Formation of blood clot
Stages of Hemostasis
Vascular Constriction
Formation of Platelet Plug
Formation of blood clot
Fibrinolysis

7. stages of primary hemostasis
Platelet Adhesion
Platelet Activation
Platelet Aggregation

8. platelet adhesion

9. Platelet activation : platelet release action

10. Platelet aggregation

11. Secondary hemostasis “Cascade of reactions” by Macfarlane, R.G.,1967
It states that ‘inactive’ enzymes are activated, and the ‘activated’ enzymes in turn activates other inactive enzymes until final step is reached.

12. Clotting Factors Factor I Fibrinogen Factor II Prothrombin Factor III
Thromboplastin
Factor IV
Calcium
Factor V
Labile factor, or proaccelerin
Factor VI
Non – existent
Factor VII
Stable factor or proconvertin
Factor VIII
Antihaemophilic factor / globulin A
Factor IX
Christmas factor or Antihaemophilic factor B
Factor X
Stuart – Prower factor
Factor XI
Plasma thromboplastin antecedent or Antihaemophilic factor C
Factor XII
Hageman factor or Contact factor
Factor XIII
Fibrin stabilizing factor or Laki – Lorand factor

13. Intrinsic Pathway

14. Conversion of Prothrombin to Thrombin & Fibrin Polymerization

15. Extrinsic Pathway

17. why blood does not clot in circulation ?
Endothelial surface factor
-smoothness
-layer of glycocalyx
-Negatively charged
Velocity of circulation
Natural anticoagulants
Activation of Fibrinolytic system
Liver removes activated clotting factors

18. FIBINOLYSIS

19. Haemostatic (Bleeding) Disorders
Disease conditions characterized by excessive bleeding tendency due to defect in the haemostatic system, caused by:
Vascular defects
Platelet defects
Coagulation defects
Excessive fibrinolysis

20. Acquired Platelet Disorders Congenital Thrombocytopenia
(low platelet count) Thrombocytopathy
(Abnormal Platelet function)
Decreased production.
Excessive destruction.
Sequestration in the spleen.
Acquired
Drugs: Asprin
Uremia
Myeloproliferative disorders
Multiple myeloma
SLE
Congenital
Glanzman’s disease
Bernard Soluier’s
Storage granules defect

21. Thrombocytopenia caused by decreased platelet production
Congenital: Thrombocytopenia Aplastic anemia
Acquired: States of Bone Marrow Failure:
Aplastic Anemia
Viral Infections
Nutritional Deficiencies
Chemotherapy & Radiation Therapy
Infiltration of Abnormal Cells
Leukemia. ,Metastatic Cancer.

22. Thrombocytopenia Excessive platelet destruction: Causes are :
.1- Drug induced thrombocytopenias.
2-Post-Transfusion (within 5 to 14 days)
2-Autoimmune Hemolytic Anemia/thrombocytopenia.

23. Thrombocytopathies
(Abnormal Platelet Function)
Inherited Qualitative Platelet Disorders may be due to abnormalities of
platelet membrane glycoproteins,
- Glanzmann Thrombastenia, abnormal GPIIb/IIIa
– Bernard-Soulier Syndrome, abnormal GPIb, GPIX and GPV
2. platelet granules,
These may occur due to absence of granules in platelets, storage pool disorder (characterized by disturbed platelet aggregation to collagen.

24. Acquired Disorders of Platelet Function (Cont…)
Drugs:
Best example is ASPIRIN which is the MOST COMMON cause of acquired platelet function disorder.
Aspirin irreversibly affect the cyclo-oxygenase enzyme. The effect last 4-7 days and it takes about 10 days before the platelets are replaced.
Presents as elevated bleeding time but purpura is unusual.

25. Diagnosis
Platelet count
Bleeding time
Specific Tests

26. Platelet Count 50,000 - 100,000 Mild Thrombocytopenia
NORMAL , ,000 CELLS/MM3
< 100, Thrombocytopenia
50, ,000 Mild Thrombocytopenia
< 50, Sever Thrombocytopenia

27. Provides assessment of platelet count and function
Bleeding Time
Provides assessment of platelet count and function
Normal value
2-8 minutes

28. Specific Tests Tests for specific Platelet Functions.
Platelet aggregation test.
Test for platelet secretion.
Clot retraction test.

29. Clot Retraction Release of fibrin stabilizing factor
Contractile protein of platelets