HEMORRHAGIC DISORPERS
Normal hemostasis: Hemostasis means control and prevention of bleeding from an
injured blood vessel. It includes a coordinated interaction between 3 main elements at the
site of vascular injury:
1. Vessels.
2. Platelets.
3. Coagulation factors.
1. The vascular factor :
The vessel wall is the first line of defence against blood loss. Local
vasoconstriction is induced by a neurogenic- reflex and is maintained by the
vasoconstrictor substances released by platelets.
2. The platelet • hemostatic activity: '
Platelets play a central role in hemostasis:
a) they stimulate vasoconstriction of the in lured vessels.
b) they torm a primary hemostatic plug to seal small vascular tears. This plug is
formed by platelet adhesion ( sticking of the platelets to the subendothelial. structures)
followed by aggregation (sticking of the platelets to each other).
c) they play an essential role in fibrin clot formation by. the production of platelet
factor 3 (PF 3 ) needed in blood clot formation.
d) they induce fibrin clot retraction
3. The coagulation factors and fibrin clot formation
Fibrin clot formation depends on the presence or ionised calcium, blood platelets,
and the coagulation factors. Clot formation through 3 phases:
A) Phase I: Activation of factor X mediated by the intrinsic or extrinsic systems.
B) Phase II: Conversion of Prothrombin to active thrombin.
C) Phase III: Formation of the fibrin clot from fibrinogen.
, Factor Name Factor Name
I Fibrinogen VIII Antihemophilic globulin
II Prothrombin IX Christmas factor
III Tromboplastin X Stuart Prower factor
IV Calcium XI Plasma thromboplastin
V Labile factor antecedent
VI Not assigned XII Hageman -factor
VII Stable factor XIII Fibrin stabilising factor
Blood coagulation and terminology of coagulation factors.
Classification of the hemorrhagic disorders:
I. Bleeding Disorders (Purpura)
A) Due to Platelets disorders:
1) Dicreased Number (Thrombocytopenia ):
a) Hereditary thrombocytopenia: e.g. congenital aplastic anemia
b) Acquired thrombocytopenia:
- Idiopathitc thrombocytopenic purpura (ITP).
- Secondary: e.g. acquired aplastic anemia,
leukemia,
hipersplenism
2) Defective plateler function:
a) Hereditary
b)Acquired: a.g. after aspirin, uremia and malignancies as
Leukemia
B) Due to Vascular disorders:
1) Hereditary: e.g. hemorrhagic telangiectasia.
2) Acquired :
a) Nutritional deficiency: scurvy
b) Allergic: anaphylactoid purpura (Henoch-Schonlein’s)
c) Septicemia: Meiringococcemia
d) Whooping cough.
II. Coagulation disorders:
a) Hereditary: e.g. Hemophilia
b) Acquired: e.g. DIC, liver disease, Hemorrhagic disease of the
newborn.
The commonest platelet disorder is ITP, and the commonest coagulation disorders
are DIC, and Hemophilia
Normal hemostasis: Hemostasis means control and prevention of bleeding from an
injured blood vessel. It includes a coordinated interaction between 3 main elements at the
site of vascular injury:
1. Vessels.
2. Platelets.
3. Coagulation factors.
1. The vascular factor :
The vessel wall is the first line of defence against blood loss. Local
vasoconstriction is induced by a neurogenic- reflex and is maintained by the
vasoconstrictor substances released by platelets.
2. The platelet • hemostatic activity: '
Platelets play a central role in hemostasis:
a) they stimulate vasoconstriction of the in lured vessels.
b) they torm a primary hemostatic plug to seal small vascular tears. This plug is
formed by platelet adhesion ( sticking of the platelets to the subendothelial. structures)
followed by aggregation (sticking of the platelets to each other).
c) they play an essential role in fibrin clot formation by. the production of platelet
factor 3 (PF 3 ) needed in blood clot formation.
d) they induce fibrin clot retraction
3. The coagulation factors and fibrin clot formation
Fibrin clot formation depends on the presence or ionised calcium, blood platelets,
and the coagulation factors. Clot formation through 3 phases:
A) Phase I: Activation of factor X mediated by the intrinsic or extrinsic systems.
B) Phase II: Conversion of Prothrombin to active thrombin.
C) Phase III: Formation of the fibrin clot from fibrinogen.
, Factor Name Factor Name
I Fibrinogen VIII Antihemophilic globulin
II Prothrombin IX Christmas factor
III Tromboplastin X Stuart Prower factor
IV Calcium XI Plasma thromboplastin
V Labile factor antecedent
VI Not assigned XII Hageman -factor
VII Stable factor XIII Fibrin stabilising factor
Blood coagulation and terminology of coagulation factors.
Classification of the hemorrhagic disorders:
I. Bleeding Disorders (Purpura)
A) Due to Platelets disorders:
1) Dicreased Number (Thrombocytopenia ):
a) Hereditary thrombocytopenia: e.g. congenital aplastic anemia
b) Acquired thrombocytopenia:
- Idiopathitc thrombocytopenic purpura (ITP).
- Secondary: e.g. acquired aplastic anemia,
leukemia,
hipersplenism
2) Defective plateler function:
a) Hereditary
b)Acquired: a.g. after aspirin, uremia and malignancies as
Leukemia
B) Due to Vascular disorders:
1) Hereditary: e.g. hemorrhagic telangiectasia.
2) Acquired :
a) Nutritional deficiency: scurvy
b) Allergic: anaphylactoid purpura (Henoch-Schonlein’s)
c) Septicemia: Meiringococcemia
d) Whooping cough.
II. Coagulation disorders:
a) Hereditary: e.g. Hemophilia
b) Acquired: e.g. DIC, liver disease, Hemorrhagic disease of the
newborn.
The commonest platelet disorder is ITP, and the commonest coagulation disorders
are DIC, and Hemophilia
