Biology of Hemostasis Quiz
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Questions and Answers

What is the primary function of hemostasis?

  • To initiate platelet plug formation
  • To regulate blood flow in the vessels
  • To prevent coagulation of blood
  • To limit blood loss from an injured vessel (correct)

    • Which of the following is the most potent vasoconstrictor substance released in response to vascular injury?

  • Endothelin
  • Thromboxane A2 (correct)
  • Bradykinin
  • Serotonin

    • What is the role of thrombomodulin in the coagulation cascade?

  • Neutralizes procoagulant serine proteases
  • Activates protein C and inhibits factor V and VIII (correct)
  • Cleaves plasminogen to initiate fibrinolysis
  • Blocks the tissue factor VIIa complex

    • Which protein is responsible for cleaving plasminogen to initiate fibrinolysis?

    <p>Tissue plasminogen activator (tPA)</p> Signup and view all the answers

    What does activated protein C (APC) form a complex with to cleave factors Va and VIIIa?

    <p>Protein S</p> Signup and view all the answers

    Which substance is selective for fibrin-bound plasminogen?

    <p>Tissue plasminogen activator (tPA)</p> Signup and view all the answers

    Which protein neutralizes all procoagulant serine proteases and inhibits the tissue factor VIIa complex?

    <p>Antithrombin III (ATIII)</p> Signup and view all the answers

    What is the primary function of vascular constriction following an injury to a blood vessel?

    <p>To reduce blood loss from the injured vessel</p> Signup and view all the answers

    Which substance forms a complex with thrombin, activates protein C, and inhibits factor V and VIII in the feedback inhibition on the coagulation cascade?

    <p>Thrombomodulin</p> Signup and view all the answers

    What is the primary function of α2-antiplasmin in fibrinolysis?

    <p>To cross-link with fibrin to prevent premature clot lysis</p> Signup and view all the answers

    Which factor deficiency results in hemophilia A and von Willebrand’s disease?

    <p>Factor VIII deficiency</p> Signup and view all the answers

    What is the approximate half-life of factor II, and how much of the normal level is needed for hemostasis?

    <p>Half-life of 72 hours, 25% of the normal level needed for hemostasis</p> Signup and view all the answers

    What is the treatment for factor VII deficiency in case of post-operative bleeding?

    <p>A, B</p> Signup and view all the answers

    Which factor is responsible for removing lysine residues from fibrin that are essential for binding plasminogen?

    <p>Thrombin-activatable-fibrinolysis-inhibitor (TAFI)</p> Signup and view all the answers

    What is the treatment for deficiencies of prothrombin or factor X?

    <p>Prothrombin complex concentrate</p> Signup and view all the answers

    What is the replacement therapy for factor XIII deficiency?

    <p>AOTA</p> Signup and view all the answers

    Which factor deficiency results in hemophilia C?

    <p>Factor XI deficiency</p> Signup and view all the answers

    What is the role of factor XIII in maintaining adequate hemostasis?

    <p>Ensuring the stability of the fibrin clot</p> Signup and view all the answers

    What is the effect of having less than one percent normal activity of factors II or prothrombin, V, and X?

    <p>Significant bleeding</p> Signup and view all the answers

    What is the characteristic feature of heparin-induced thrombocytopenia or HIT?

    <p>Antibodies against platelet factor-4 or PF4</p> Signup and view all the answers

    What is the main pathophysiological mechanism underlying primary immune thrombocytopenia (idiopathic thrombocytopenic purpura - ITP) in adults?

    <p>T-cell mediated platelet destruction</p> Signup and view all the answers

    What is the diagnosis method for heparin-induced thrombocytopenia (HIT)?

    <p>Serotonin release assay</p> Signup and view all the answers

    Which disorder is associated with infection by Escherichia coli O157:H7?

    <p>Hemolytic uremic syndrome (HUS)</p> Signup and view all the answers

    What is the primary treatment for hemolytic uremic syndrome (HUS) associated with E. coli infection?

    <p>Plasma exchange</p> Signup and view all the answers

    What is the recommended treatment for acquired hypofibrinogenemia if the patient is experiencing severe purpura fulminans?

    <p>Fibrinogen concentrates</p> Signup and view all the answers

    What is the recommended initial treatment for acquired hypofibrinogenemia if there is active bleeding?

    <p>Fresh frozen plasma</p> Signup and view all the answers

    What is the classic triad of symptoms seen in thrombotic thrombocytopenic purpura or TTP?

    <p>Thrombocytopenia, microangiopathic hemolytic anemia, and renal &amp; neurologic signs</p> Signup and view all the answers

    What is the characteristic feature of idiopathic thrombocytopenic purpura (ITP) in children?

    <p>Short-lived with history of viral illness</p> Signup and view all the answers

    What is the most common underlying condition required for the diagnosis of acquired hypofibrinogenemia?

    <p>Organ injury such as severe pancreatitis</p> Signup and view all the answers

    Which of the following can act as potent thromboplastins in acquired hypofibrinogenemia?

    <p>Bone marrow</p> Signup and view all the answers

    What is the effect of ε-aminocaproic acid and tranexamic acid on primary fibrinolysis?

    <p>They inhibit the release of urokinase</p> Signup and view all the answers

    Which etiology is associated with acquired hypofibrinogenemia and involves the release of urokinase during surgical manipulation or extracorporeal bypass?

    <p>Primary fibrinolysis</p> Signup and view all the answers

    In acquired hypofibrinogenemia, which diagnostic parameter is expected to be elevated?

    <p>Fibrin degradation products</p> Signup and view all the answers

    Which of the following is a potential cause of acquired hypofibrinogenemia that involves the presence of large aneurysms?

    <p>Large aneurysms</p> Signup and view all the answers

    What is the mainstay therapy for reducing hypersplenism in patients with coagulopathy of liver disease?

    <p>Splenectomy</p> Signup and view all the answers

    Which condition is characterized by shock and tissue injury as key initiators, leading to systemic activation of anticoagulant and fibrinolytic pathways?

    <p>Acute coagulopathy of trauma (ACoT)</p> Signup and view all the answers

    What is the current term used for coagulopathy associated with trauma?

    <p>Trauma-induced coagulopathy</p> Signup and view all the answers

    Which diagnostic test is frequently performed to provide a better assessment of bleeding risks compared to standard tests of hemostasis in patients with liver disease?

    <p>Thromboelastography (TEG)</p> Signup and view all the answers

    What is the treatment that forms a complex with thrombin, activates protein C, and inhibits factor V and VIII in the feedback inhibition on the coagulation cascade?

    <p>Fresh frozen plasma</p> Signup and view all the answers

    What are the most common coagulation abnormalities associated with liver dysfunction?

    <p>Prolongation of prothrombin time and reduced production of thrombopoietin</p> Signup and view all the answers

    What is the management approach for polycythemia to reduce red blood cells, spontaneous thrombosis, and spontaneous hemorrhage?

    <p>Hydroxyurea</p> Signup and view all the answers

    What is the primary method for reducing hypersplenism in patients with coagulopathy of liver disease?

    <p>Splenectomy or splenic embolization</p> Signup and view all the answers

    What is the recommended treatment for reducing bleeding risks compared to standard tests of hemostasis in patients with liver disease?

    <p>Thromboelastography (TEG)</p> Signup and view all the answers

    Which therapy is used as the mainstay therapy for polycythemia?

    <p>Phlebotomy</p> Signup and view all the answers

    What is the hallmark feature of antiphospholipid syndrome (APLS)?

    <p>Presence of lupus anticoagulant and anticardiolipin antibodies</p> Signup and view all the answers

    Which newer anticoagulant has no method for detecting the degree of anticoagulation and no reversal agent?

    <p>Dabigatran</p> Signup and view all the answers

    In which scenario may surgical treatment be undertaken without full reversal of the anticoagulant?

    <p>When the patient is on heparin with an aPTT less than 1.5 times the control</p> Signup and view all the answers

    What is the recommended reversal agent for heparin?

    <p>Protamine sulfate</p> Signup and view all the answers

    Which condition requires holding heparin infusion for four to six hours before a procedure and restarting it within 12 to 24 hours after the procedure?

    <p>Mechanical heart valves</p> Signup and view all the answers

    What is the primary method for reducing hypersplenism in patients with coagulopathy of liver disease?

    <p>Splenectomy</p> Signup and view all the answers

    Which substance should be discontinued several days before an operation as part of the reversal strategy for coumarin-derivative anticoagulants?

    <p>Vitamin K</p> Signup and view all the answers

    What is the effect of ε-aminocaproic acid and tranexamic acid on primary fibrinolysis?

    <p>Inhibit primary fibrinolysis</p> Signup and view all the answers

    Which factor deficiency results in hemophilia A and von Willebrand’s disease?

    <pre><code>extit{Factor VIII} </code></pre> Signup and view all the answers

    What is the characteristic feature of idiopathic thrombocytopenic purpura (ITP) in children?

    <p>Decreased platelet count</p> Signup and view all the answers

    What is the shelf life of platelet concentrates?

    <p>140 hours</p> Signup and view all the answers

    What is the recommended hemoglobin level for autologous transfusion during elective procedures?

    <p>Exceeds 11 grams per deciliter</p> Signup and view all the answers

    What is the therapeutic level of platelets per microliter?

    <p>50,000 - 100,000</p> Signup and view all the answers

    What is the product of choice to prevent febrile non-hemolytic transfusion reactions and cytomegalovirus transmission?

    <p>Red blood cells and frozen red blood cells</p> Signup and view all the answers

    What is the effect of leukocyte-reduced red blood cells?

    <p>Prevents fever and rigors</p> Signup and view all the answers

    What is the primary function of tranexamic acid?

    <p>Inhibiting plasminogen activation and plasmin activity by binding to lysine binding site</p> Signup and view all the answers

    In which surgical settings is tranexamic acid used to decrease bleeding and the need for blood transfusions?

    <p>Coronary artery bypass grafting</p> Signup and view all the answers

    When is the greatest benefit achieved when administering tranexamic acid after trauma?

    <p>Between one to three hours after trauma</p> Signup and view all the answers

    What is the reduced risk of death due to bleeding associated with tranexamic acid?

    <p>21 percent</p> Signup and view all the answers

    What are the adverse events associated with prolonged use of tranexamic acid?

    <p>Visual disturbances and thromboembolic events</p> Signup and view all the answers

    What is the primary focus of the damage control resuscitation (DCR) strategy?

    <p>Halting and preventing the lethal triad of coagulopathy, acidosis, and hypothermia</p> Signup and view all the answers

    What does the term 'permissive hypotension' refer to in the context of resuscitation?

    <p>Allowing blood pressure to remain lower than normal levels</p> Signup and view all the answers

    What is the recommended volume replacement for symptomatic patients who have lost up to 20 percent of their total blood volume?

    <p>Crystalloid or colloid solutions</p> Signup and view all the answers

    What is the primary aim of administering four to six units of red blood cells within four to six hours of admission under the damage control resuscitation (DCR) strategy?

    <p>Early correction of anemia and coagulopathy</p> Signup and view all the answers

    Which factors in the coagulation cascade are measured by activated partial thromboplastin clotting time?

    <p>Factors I, II, and V</p> Signup and view all the answers

    What is the main purpose of releasing and administering predefined blood products in ratios similar to those of whole blood, as part of the damage control resuscitation (DCR) strategy?

    <p>Early correction of anemia and coagulopathy</p> Signup and view all the answers

    What is the therapeutic target range for the activated partial thromboplastin clotting time?

    <p>1.5 to 2.5 times the control value</p> Signup and view all the answers

    What is the primary aim of conducting the Ivy bleeding time test?

    <p>To evaluate platelet and vascular dysfunction</p> Signup and view all the answers

    What is the approximate upper limit of normal bleeding time with the Ivy test?

    <p>7 minutes</p> Signup and view all the answers

    Which type of agents may significantly impair hemostatic function?

    <p>Antiplatelet agents</p> Signup and view all the answers

    Apart from known medications, what other factors should be considered if abnormalities in coagulation studies are observed?

    <p>Congenital abnormalities of coagulation</p> Signup and view all the answers

    Which type of heparins may mildly elevate the activated partial thromboplastin clotting time?

    <p>Low-molecular weight heparins</p> Signup and view all the answers

    What is the recommended platelet count to prevent spontaneous hemorrhage?

    <p>Below 20,000 platelets per microliter</p> Signup and view all the answers

    In which surgical procedures are platelet transfusions still recommended despite a lack of evidence supporting their use?

    <p>Ophthalmologic and neurosurgical procedures</p> Signup and view all the answers

    What does the prothrombin time measure the function of?

    <p>Factors I, II, V, VII, and X</p> Signup and view all the answers

    At what platelet count are platelet transfusions still recommended in ophthalmologic and neurosurgical procedures?

    <p>Less than 100,000 platelets per microliter</p> Signup and view all the answers

    At what platelet count is a risk of thrombotic complications present?

    <p>Greater than 1,000,000 platelets per microliter</p> Signup and view all the answers

    What laboratory test is recommended as the method of choice for reporting prothrombin time values?

    <p>International normalized ratio</p> Signup and view all the answers

    What is the primary aim of administering corticosteroids if bleeding follows transfusion by five or six days?

    <p>To reduce fibrinolysis</p> Signup and view all the answers

    What is the normal range for platelet count per microliter?

    <p>150,000 to 400,000</p> Signup and view all the answers

    In the context of excessive intraoperative or post-operative bleeding, what can cause consumptive coagulopathy?

    <p>Fibrinolysis</p> Signup and view all the answers

    What is an uncommon cause of thrombocytopenia and associated bleeding after transfusion?

    <p>Transfusion purpura</p> Signup and view all the answers

    In the context of massive transfusion, what can cause hypothermia and dilutional coagulopathy?

    <p>Corticosteroids</p> Signup and view all the answers

    Study Notes

    Coagulopathy Management

    • In patients with active bleeding, initiate fresh frozen plasma, cryoprecipitate, and fibrinogen concentrates, as well as platelet concentrates.

    Fibrinolysis and Antifibrinolytic Agents

    • Urokinase is released during surgical manipulation or extracorporeal bypass and can be treated with antifibrinolytic agents, such as ε-aminocaproic acid and tranexamic acid.

    Myeloproliferative Diseases

    • Treatment for myeloproliferative diseases includes low-dose aspirin, thrombosis phlebotomy, and hydroxyurea.

    Coagulation Factors and Liver Disease

    • Vitamin K-dependent factors include II (prothrombin), VII, IX, and X.
    • Fibrinogen, Factor V, Factor VIII, and Factors XI, XII, and XIII are also involved in coagulation.
    • Antithrombin III, plasminogen, protein C, and protein S are relevant to coagulation regulation.
    • Liver disease is associated with increased bleeding risk, thrombotic risk, thrombocytopenia, and impaired humoral coagulation function.
    • Prothrombin time and international normalized ratio (INR) are commonly prolonged in liver dysfunction.

    Diagnostics and Management

    • Thrombin Activation and TAFI are diagnostic markers.
    • Management of coagulopathy involves treating underlying liver disease and addressing bleeding and thrombotic risks.

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    Description

    Test your knowledge of the biological process of hemostasis, which functions to limit blood loss from an injured vessel by orchestrating vascular constriction, platelet plug formation, fibrin formation, and fibrinolysis. This quiz covers the physiological events, such as vascular constriction and feedback inhibition.

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