Hematology Lecture PDF

Hematology Lecture 8 5March 2023 Platelets disorders by Abdulfatah Albakkosh Introduction: • Platelets are produced in the bone marrow by fragmentation of the cytoplasm of megakaryocytes, one of the largest cells in the body Hematology Lecture 8 5March 2023 Quantitative Platelet Disorders Pri...

Hematology Lecture 8 5March 2023 Platelets disorders by Abdulfatah Albakkosh Introduction: • Platelets are produced in the bone marrow by fragmentation of the cytoplasm of megakaryocytes, one of the largest cells in the body Hematology Lecture 8 5March 2023 Quantitative Platelet Disorders Primary thrombocytosis • Uncontrolled, malignant proliferation of platelets, not in response to thrombopoietin; can be caused by essential thrombocythemia, polycythemia Vera, and chronic myelocytic leukemia. • b. Platelet counts can be >1000 X 10 /L. • c. Associated with either hemorrhagic or thrombotic complications. Quantitative Platelet Disorders Secondary (reactive) thrombocytosis • It is characterized by increased platelet production, usually in response to thrombopoietin. Platelet count is elevated, but usually < 1000 X 10 /L. • Can result from: ☺ Chronic and acute inflammatory disease ☺ Iron deficiency ☺ Rapid blood regeneration ☺ Splenectomy Hematology Lecture 8 5March 2023 Thrombocytopenia • Platelet count is below 100 x 10 /L • Abnormal bleeding associated with thrombocytopenia or • abnormal platelet function is characterized by spontaneous skin purpura and mucosal hemorrhage and prolonged bleeding after trauma. Common Platelet Disorders Thrombocytopenia Decreased production • Aplastic anemia ( Drugs , Virus ,etc.) • Tumor Increased destruction • • • • Immune thrombocytopenia (ITP) Throbotic thrombocytopenic purpura (TTP) Disseminated intravascular coagulation (DIC) Hypersplenism Qualitative Defect • • • • • Von Willebrand disease Bernard-Soulier syndrome Glanzmann thrombasthenia Drugs (Aspirin) Uremia Hematology Lecture 8 5March 2023 Disorders of platelet function A- hereditary • 1- deficiency of membrane GPIIb (Glanzmann's disease) • 2- deficiency of GPIb (Bernard-Soulier syndrome) • 3- absence of (α. granules or dense granules ). Disorders of platelet function B-Acquired platelets disorders 1-Antiplatelet drugs: Aspirin therapy is the most common cause of impaired platelet function. 2-Hyperglobulinaemia associated with multiple myeloma. 3-Myeloproliferative Disorders as CML 4-uremia in renal failure Hematology Lecture 8 5March 2023 Inherited Coagulation Disorders Haemophilia A • The prevalence is 30-100 per million population. • Hemophilia A (classic hemophilia) is an X-linked recessive condition resulting from a deficiency of factor VIII. Clinically, hemophilia A predominately affects males. Inherited Coagulation Disorders Haemophilia A • Symptoms vary depending on the degree of deficiency. • Newborns may develop bleeding at the time of circumcision. • Other problems include spontaneous hemorrhage into joints (hemarthrosis), easy bruising and hematoma formation after minor trauma, and severe prolonged bleeding after surgery or lacerations Hematology Lecture 8 5March 2023 Inherited Coagulation Disorders Haemophilia A • Laboratory studies typically show normal platelet count and normal bleeding time, normal PT, and prolonged PTT. • Treatment is factor VIII concentrate. Inherited Coagulation Disorders Hemophilia B (Christmas disease) • is an X-linked recessive condition resulting from a deficiency of factor IX that is clinically identical to hemophilia A. • Treatment is recombinant factor IX. Hematology Lecture 8 5March 2023 Inherited Coagulation Disorders • Von Willebrand disease • is an autosomal dominant bleeding disorder characterized by a deficiency or qualitative defect in von Willebrand factor • vWF is normally produced by endothelial cells and megakaryocytes. Clinical features include spontaneous bleeding from mucous membranes, prolonged bleeding from wounds, and menorrhagia in young females. Hemarthrosis is uncommon. Inherited Coagulation Disorders • Von Willebrand disease • Lab studies show normal platelet count, a prolonged bleeding time, normal PT, and often prolonged PTT. Abnormal platelet response to ristocetin (adhesion defect) is an important diagnostic test. Hematology Lecture 8 5March 2023 Inherited Coagulation Disorders • Von Willebrand disease • Treatment for mild classic cases (type I) is desmopressin (an antidiuretic hormone analog), which releases vWF from Weibel-Palade bodies of endothelial cells. Inherited Coagulation Disorders Acquired coagulopathies • include vitamin K deficiency (decreased synthesis of factors II, VII, IX, X, and protein C & S) and liver disease (decreased synthesis of virtually all clotting factors). Hematology Lecture 8 5March 2023 Inherited Coagulation Disorders Disseminated intravascular coagulation (DIC) • obstetric complications can cause DIC because the placental tissue factor activates clotting. • Gram-negative sepsis can cause DIC because tumor necrosis factor activates clotting. • Microorganisms (especially meningococcus and rickettsiae) Inherited Coagulation Disorders Disseminated intravascular coagulation (DIC) • Adenocarcinomas (mucin activates clotting) • DIC causes widespread microthrombi with the consumption of platelets and clotting factors, causing hemorrhage. • Laboratory studies show decreased platelet count, prolonged PT/PTT, decreased fibrinogen, and elevated fibrin split products (D.dimers). Treat the underlying disorder. 5March 2023 Falsely low platelet counts a) Platelet satellitosis: Platelets can adhere to neutrophils when exposed to EDTA. Redraw in sodium citrate to correct; multiply obtained platelet count by 1.1 to correct for dilution factor in sodium citrate tube. b) EDTA-dependent platelet agglutinins: Platelets can adhere to each other when exposed to EDTA. Correction of the problem is the same as for platelet satellitosis.. Hematology Lecture 8