Platelet Disorders TEST ONLY.docx

Platelet Disorders Ultrastructures Granulomere (3 types) Alpha Delta Lambda Hyalomere Lighter staining peripheral zone Maintains platelet’s discoid shape Hemostasis Platelet plug occurs in the primary stage Fibrin integrates to form blood clot, in secondary stage Bleeding Disorders Defects...

Platelet Disorders Ultrastructures Granulomere (3 types) Alpha Delta Lambda Hyalomere Lighter staining peripheral zone Maintains platelet’s discoid shape Hemostasis Platelet plug occurs in the primary stage Fibrin integrates to form blood clot, in secondary stage Bleeding Disorders Defects of: Primary hemostasis (platelets, vessels) Secondary hemostasis (coagulation cascade and regulation) Physical Exam Petechiae primary hemostasis Hematoma/hemarthrosis clotted blood within the tissues in secondary hemostasis Bleeding Disorders Assc with Vascular Abnormalities Scurvy, Ehlers-Danlos: Microvascular bleeding due to collagen defects (dental abnormality) Perivascular amyloidosis: weakens vessel walls Thrombocytopenia Grades: Mild: 100,000-150,000 Mod: 50,000-99,000 Severe: <50,000 Surgical bleeding: <50,000 Spontaneous bleeding <10,000 Immune Thrombocytopenia Most common autoimmune disorders Autoantibodies attack megakaryocytes Autoantibodies attack platelets Platelet GP IIb/IIIa complex Ib/IX 2 clinical types: Acute: children Chronic: adult women Acute Immune Thrombocytopenia Exclusively in children Autoantibody production due to exposure of cryptangiens or pseudoantigens Reduced platelet count Megakaryocytes hyperplasia in bone marrow Chronic Immune Thromobocytopenia Common in women Autoantibodies against platelet GPIIb/IIIa or GPIb/IX Reduced platelet count Bone marrow may contain normal-to-increased number of megakaryocytes Hematopoiesis present in spleen causing splenomegaly Heparin-Induced Thrombocytopenia Complication of heparin therapy 2 types: Type I: Presents within the first 2 days after exposure to heparin Types II: Presents 4-10 days after exposure to heparin (time doubles) HIV Assc Thrombocytopenia: ineffective platelet production and/or increased peripheral destruction Thrombotic Thrombocytopenic Purpura (TTP) Thromboses in small vessels Low platelet count Clinical presentation: Microthrombi in affected organs Different from Hemolytic Uremic syndrome Etiology: Deficiency of Metalloprotease ADAMTS13 Infection of E Coli Infection of Shigella Pathologic: RBC fragmentation containing microangiopathic hemolytic process. (Similar to acute immune TCP) Megakaryocytic hyperplasia in bone marrow (Similar to acute immune TCP) Hyaline thrombi in glomerulus and small arterioles Lab Studies Schistocytosis ADAMTS13 activity testing Treatment: Platelet transfusion contraindicated Know patient’s history: Infection Drug Family history Transfusion of platelet Thrombocytosis: occurs in Neoplastic (myeloproliferative disease) Bleeding Disorders related to defective platelet functions Inherited or acquired Three large categories Defects of adhesion Defects of aggregation Disorders of platelet secretion