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Chapter 15
Hemostasis and thrombosis
Platelet structure
Platelets are anucleate fragments of megakaryocyte cytoplasm that support and amplify hemostasis. The major structural elements directly contributing to hemostasis are (i) plasma (surface) membrane proteins and phospholipids and (ii) secretory granules (Table 15-1). Other platelet components involved in shape change and metabolism indirectly support hemostasis.
Plasma membrane
The platelet plasma membrane provides a highly reactive surface on which hemostatic reactions are localized by a number of receptors that bind adhesive proteins and components of the coagulation and fibrinolytic systems. The ligands include proteins of the subendothelial matrix, plasma proteins, and endogenous platelet proteins Platelet granules Platelet function and coagulation reactions Coagulation cascade Role of inhibitors in hemostasis Tissue factor pathway inhibitor Protein C–protein S pathway Heparin–antithrombin The fibrinolytic system as a regulator of hemostasis
Approach to the bleeding patient
History and clinical examination Laboratory evaluation Platelet function tests Hemostasis
Platelet disorders: thrombocytopenias
Idiopathic thrombocytopenic purpura Diagnosis Management Initial management of children Initial management of adults Management of children and adults with chronic refractory ITP Emergency treatment Management of women during pregnancy and of their newborn infants Gestational thrombocytopenia Thrombocytopenia with infection Thrombocytopenia in the critically ill Drug-induced thrombocytopenia (other than heparin) Heparin-induced thrombocytopenia Inherited thrombocytopenia Thrombotic thrombocytopenic purpura and hemolytic uremic syndrome Pathogenesis Clinical presentations of TTP–HUS syndromes Congenital Children Adults Diagnosis Management
Disorders of platelet function
Inherited disorders Glanzmann thrombasthenia Bernard–Soulier syndrome Acquired disorders Drugs, foods, and spices Chronic renal failure von Willebrand disease Testing for vWD Type 1 vWD Type 2 vWD Type 2A vWD Type 2B vWD Type 2M vWD Type 2N vWD Type 3 vWD Treatment of vWD Pseudo-vWD Acquired vWD
Coagulation disorders
Hemophilia A (factor VIII deficiency) Hemophilia B (factor IX deficiency) Treatment Carrier testing for hemophilia Inhibitors of factor activity in patients with hemophilia Acquired inhibitors of factor VIII in patients without hemophilia Hereditary factor XI deficiency Other forms of hemophilia Disseminated intravascular coagulation Treatment Liver disease Vitamin K deficiency Venous thromboembolic disease Evaluation of patients with venous thrombosis Diagnosis of venous thromboembolism Diagnosis of PE Hypercoagulable states due to inherited or acquired conditions APC resistance/factor V Leiden Prothrombin 20210 mutation Antithrombin deficiency Protein C deficiency Protein S deficiency Antiphospholipid antibodies Hyperhomocysteinemia Other rare inherited causes of thrombophilia Acquired diseases predisposing to thrombosis Thrombophilia testing: reconsidering its utility Postphlebitic syndrome Therapy for thrombotic disorders
Specific antithrombotic agents
Unfractionated heparin Low-molecular-weight heparins Warfarin Newer antithrombotic agents Direct thrombin inhibitors Factor Xa inhibitors Inhibitors of the factor VIIa–tissue factor pathway Activated protein C Soluble thrombomodulin
Thrombolytic agents
Indications for thrombolytic therapy Choice of thrombolytic agents Streptokinase Tissue plasminogen activator Single-chain urokinase-type plasminogen activator Staphylokinase Laboratory monitoring Complications of thrombolytic therapy Glycoprotein IIb/IIIa inhibitors Inferior vena caval filters | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||