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Hemostatic process. 1- Vascular Consrriction. 2- Platelet plug formation. 3- Fibrin formation ( Coagulation ). 4- Fibrinolysis. Platelet Function. 1- Adhesion 2- Release Reaction 3- Agreggation 4- Retraction. platelet function:
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Hemostatic process 1- Vascular Consrriction 2- Platelet plug formation 3- Fibrin formation ( Coagulation ) 4- Fibrinolysis
Platelet Function 1- Adhesion 2- Release Reaction 3- Agreggation 4- Retraction
platelet function: 1- Adhesion — the deposition of platelets on the . subendothelial matrix 2 - Aggregation — platelet-platelet cohesion 3- Secretion — the release of platelet granule proteins 4- Procoagulant activity — the enhancementof thrombingeneration
Platelet secretion : Platelets secrete a variety of substances from their granules upon cell stimulation: 1- ADP and serotonin. 2- Fibronectin and thrombospondin.3-Fibrinogen is released from platelet alpha granules.4-Thromboxane A2, a prostaglandin metabolite, promotesvasoconstrictionand furtherplatelet aggregation.5-Growth factors, such as platelet-derived growth factor (PDGF), have potent mitogenic effect on smooth muscle cells. The release of PDGF
Platelet defects 1- Quantity Platelet disorders : Thrombocytopenia ( ITP) Thrombocytosis 2- Quality Platelet disorders: Acquired (drugs) Congenital
Causes of Thrombocytopenia 1 1- Decreased production: -Congenital - Acquired: Marrow hypoplasia Marrow replecement Megaloblastic anemia Specific Platelet suppression by drugs Occasional viral infection
Increased destruction of platelets 2 1-Immune thrombocytopenia Idiopathic viral infection Associated with drugs Isoimmune noanatal thrombocytopenia Post transfusion purpura 2-Microangiopathic platelet destruction Disseminated intravascular coagulation Hemolotic Uremic syndrome Thrombotic thrombocytopenic purpura 3-Severe sepsis 4-Massive transfusions
Acquired defects in platelet function 1- Myeloprolifrative disorders: Essential Thrombocthemia Chronic Myelogenous leukemia Agnogenic myeloid metaplasia 2-Uremia 3- Acute L. & MDS 4- Dysproteinemias 5-Cardiopulmonary bypass 6- Acquired Von Willebrand disease 7- Anti platelet antibodies 8- Liver disease 9- Drugs and other agents
Immunologic thrombocytopenia • Drug-induced • True ITP • Systemic lupus erythematousus • Lymphoprolifrative disease • HIV-1 associated • Post –Transfusion • Sarcoidosis • Solid Tymors • Mononucleosis • Immunodeficiency • Post marrow Transplant
Non –immunologic Thrombocytopenia 1- Disseminated intravascular coagulation 2- Bacterial septicemia 3- TTP- HUS 4- Ethanol-induced 5- Massive blood loss 6- Hereditary condition
Cause of Thrombocytopenia: 1 1- Decrease Marrow production: Marrow failure: AA. Marrow infiltration :leukemia , Myelidysplasia, Fibrosis…. Marrow depression: Iradiation,Chemotherapy Selective BM depression:ethanol, drags induced Nutritional deficiency: megaloblastic anemia. Hereditary causes: Fanconi”s anemia congenital megacariocytic hypoplasia.
Cause of Thrombocytopenia: 2 2- Increased destruction of platelets: Immune: ITP , SLE , CLL , NHL, CVD. Drud-induced: Heparin,Gold, Quinidine, Penicillins, cimetidine, digoxin. Infection : HIV , Other Viruses , Malaria. Post Transfusion purpura. Neonatal purpura (isoimmune). Non-immune: DIC , TTP , UHS , Congenital / acquired heart disease, Cardiopulmonary bypass , Kasabach-Merritt syndrome. Hereditary causes: Fanconi”s anemia congenital megacariocytic hypoplasia.
Causes of reactive thrombocytosis: -Hemorrage - Surgery - Trauma - Iron deficiency anemia - Splenoctomy - Infection - Malignant disease - Inflamatory disease
Lab studies in Thrombocytopenia P.B.S. and Hemogram Bone marrow Examination Antinuclear antibody HIV antibody , Blood culture Fibrinogen degradation products ( FDP ) PT & PTT & Fibrinogen Serum protein electrophoresis Liver, Spleen and retroperitoneal Ultrasound Abdomino-pelvic CT scan Renal function tests
Drugs Affecting Platelet Strong Inhibitors Moderate Inhibitors Weak Inhibitors Alcohol Hitroglycerin Nitroprusside Aspirin Abciximab (anti gpIIb/IIIa) Ticlopidine (anti ADP) NSAFD Antibiotics Penicillins cepholosporins nitrofurantoin Dextran Fibrinolytics Heparin Hetastrach
Arachidonic acid metabolism and the effect of ASA P Phospholipids Phospholipase A Arachidonic acid ASA Cyclooxygenase Prostaglandine endoperoxide Prostacycline Thromboxane Inhibition of aggregation Promotion of aggregation