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113 Cards in this Set
- Front
- Back
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What are the 3 steps of platelet aggregation?
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Adhesion
Activation Aggregation |
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What is involved in platelet activation?
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Causes bone marrow to stimulate more platelet growth, causes vasoconstriction, starts coagulation cascade
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What is at the end of the coagulation cascade (that we need to know?)
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Factor 10 - Prothrombin - Fibrinogen - Fibrin monomer
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If a patient bleeds excessively upon injury, what kind of problem does that indicate?
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Platelet problem
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If a patient bleeds excessively hours after injury, what kind of problem does that indicate?
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Coagulation factor problem
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What breaks up fibrin monomers?
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Plasmin
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What test measures the fibrinolytic system, and can only be positive if there is a clot somewhere?
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D-Dimer
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What is the normal platelet count range?
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150,000-450,000
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When is the mean platelet volume increased?
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In disorders with rapid platelet turnover
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What is the normal range bleeding time?
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3-9 minutes
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What is the bleeding time test a measure of?
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The efficiency of the vascular and platelet phases of clotting
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What does the bleeding time test screen for?
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inherited disorders of platelet function
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What is the normal prothrombin time range?
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13-17 seconds
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What does the prothrombin time test measure?
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Extrinsic & common pathways
Coagulation factors V, VII, X, prothrombin & fibrinogen. |
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What medication does the prothrombin time test monitor?
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Coumadin (INR)
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What does the partial thromboplastin time test screen for?
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Coagulation disorders
Monitors heparin therapy |
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What is the normal time range for the partial thromboplastin time test?
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25-36 seconds
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What does the partial thromboplastin time test measure?
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Intrinsic & common pathway
Coag factors prekallikrein, HMW kininogen, XII, XI, IX and VIII in the intrinsic pathway X, V, prothrombin, and fibrinogen in the common pathway. |
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What is the normal range of fibrinogen?
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150-350 mg/dl
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What is the normal range of fibrinogen degradation products?
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0-5
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When would fibrinogen degradation products be increased?
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In DIC or fibrinogenolysis
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Protein S and C are dependent on which vitamin?
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Vitamin K
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What is the function of protein S?
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Mediates the anticoagulant activity of activated protein C
Inhibits factor Xa activity |
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What affects the level of protein S?
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Use of oral anticoagulants
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What is the function of protein C?
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inactivates factors Va and VIIIa to inhibit coagulation - when activated by thrombin - thrombomodulin complex
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What affects the level of protein C?
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Vitamin K deficiency
Oral anticoagulants |
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What is the normal range for the thrombin time test?
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15-18 seconds
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What does the thrombin time test measure?
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Fibrinogen conversion to fibrin
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What would be an abnormal thrombin time test measure based on fibrinogen levels?
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fibrinogen levels below 70-100 mg/dl
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When is the thrombin time greatly prolonged?
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In the presence of heparin
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When is D-Dimer formed?
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when thrombin initiates the conversion of fibrinogen to fibrin and activates factor XIII.
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What is the D-Dimer test specific for?
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fibrinogen degradation products
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What does the D-Dimer test?
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Fibrinolysis
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When would the D-Dimer be elevated?
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DIC
PE |
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When should you order a D-Dimer for a PE?
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Only if you have a low probability of PE
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What does DIC stand for?
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Disseminated Intravascular Coagulation
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What is the only test that works for monitoring low molecular weight heparin?
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Anti-Xa Heparin Assay
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What are the brand names of low molecular weight heparin?
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Lovenox
Fragmin |
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Are petechiae characteristic in coagulation or platelet disorders?
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Platelet
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Are deep hematomas characteristic in coagulation or platelet disorders?
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Coagulation
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Are superficial ecchymoses common in coagulation or platelet disorders?
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Both.
Common in coagulation: large and solitary Characteristic in platelet: small and multiple |
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Is hemarthrosis characteristic in coagulation or platelet disorders?
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Coagulation
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Is delayed bleeding common in coagulation or platelet disorders?
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Coagulation
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Is bleeding from superficial cuts persistent in coagulation or platelet disorders?
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Platelet
(minimal in coagulation) |
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Which disorder is more common in males, coagulation or platelet?
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Coagulation
80-90% inherited disease appear in males |
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Which disorder is more common in females, coagulation or platelet?
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Platelet
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Which disorder usually has a positive family history, coagulation or platelet?
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Coagulation
(platelet - rare except for vW/D) |
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What disorder is X-linked recessive?
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Hemophilia A & B
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What factor is deficient in hemophilia A?
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factor VIII
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What factor is deficient in hemophilia B?
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factor IX
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Which disease is the "Christmas tree" disease?
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Hemophilia B
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Hemophilia A and B look the same on physical exam - True or False?
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True
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Which lab is elevated in Hemophilia A?
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PTT
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What is the treatment for hemophilia A?
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factor VIII concentrates
FFP, cryoprecipitates EACA with or without DDAVP |
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What is a possible complication of giving fresh frozen plasma?
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pulmonary edema
elevated blood pressure |
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Which hemophilia is more common?
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Hemophilia A
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Which lab is elevated in hemophilia B?
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PTT
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What is the treatment for hemophilia B?
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Factor IX concentrate
FFP cryoprecipitates |
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What produces von Willebrand's factor?
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endothelial cells
platelets |
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Which factor does von Willebrand's factor protect?
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factor VIII
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What is the most common congenital bleeding disorder?
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von Willebrand's disease
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Is von Willebrand's a coagulation or platelet problem?
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platelet
(problem with platelet adhesion) |
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Genetically, what kind of pattern is von Willebrand's disease?
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Autosomal dominant
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Where does bleeding usually occur in von Willebrand's disease?
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Mucous membranes
GI, nasal, sinus, vaginal |
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What is the most common type of von Willebrand's disease?
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Type 1 (80%)
partial deficiency bleeding time may be normal |
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What is the most severe type of von Willebrand's disease?
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Type 3
usually diagnosed in childhood |
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What labs are prolonged in von Willebrand's disease?
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Bleeding time
PTT (due to decreased factor VIII) |
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What is the treatment for von Willebrand's disease?
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vWF concentrates
Cryoprecipitate if vWF concentrates not available DDAVP (stimulates release of vWF) |
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What is the acquired hypercoagulability state?
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Antiphospholipid syndrome
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Factor V Leiden, Protein S & C deficiencies, and antithrombin III deficiency are examples of what?
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Inherited hypercoagulability states
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Factor V Leiden is resistant to inactivation by what?
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activated protein C
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What are the results of Factor V Leiden?
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increased factor Va and increased thrombin formation
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What is the treatment for protein S & C deficiency?
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Heparin then coumadin
Pregnancy - use low molecular weight heparin |
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If heparin has little/no effect on anticoagulation, what should you suspect?
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Antithrombin III deficiency
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What syndrome should you suspect in a young patient with an MI, CVA, recurrent thrombotic events, or recurrent pregnancy losses?
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Antiphospholipid syndrome
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What disease is found in 15-30% of patients with antiphospholipid syndrome?
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Lupus (SLE)
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What is the pathogenesis of antiphospholipid syndrome?
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Activation of endothelial cells, oxidant mediated injury of the vascular endothelium, interferes with natural anticoagulants
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What are the 2 laboratory criteria for antiphospholipid syndrome?
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Anticardiolipin antibody
Lupus anticoagulant antibodies |
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If a woman has 3 or more unexplained spontaneous abortions before 10 weeks, what syndrome should you suspect?
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Antiphospholipid syndrome
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What is the treatment for antiphospholipid syndrome?
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Eliminate predisposing factors
Aspirin prophylaxis Prevention of further thromboses: Coumadin INR > 2.0 Heparin |
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What does aspirin do to a platelet?
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Makes it nonfunctioning for the life of the platelet (7 days)
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What is DIC a result of?
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Always secondary to another condition
Result of excess formation of thrombin and plasmin |
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What disorder is bleeding and clotting at the same time?
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DIC
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What labs are decreased in DIC?
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Platelet count, fibrinogen
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What labs are increased in DIC?
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PT, aPTT, FDP, D-Dimer positive
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What other disease can produce results similar to DIC?
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Liver disease
(but D-Dimer will be negative) |
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What is the treatment for DIC?
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Treat underlying cause
If you give FFP, must give heparin ATIII, cryoprecipitate, platelets |
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What does TTP stand for?
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Thrombotic Thrombocytopenia Purpura
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What does ITP stand for?
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Immune Thrombocytopenia Purpura
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What is TTP characterized by?
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hyaline platelet thrombi in terminal arterioles and capillaries
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What syndrome in children is the same as TTP?
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HUS
Hemolytic uremic syndrome (mainly involves the kidney) |
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What are the signs/symptoms of TTP?
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Thrombocytopenia
Microangiopathic hemolytic anemia Fever Neurologic signs Mild renal insufficiency (creatinine 2) |
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What abnormality of red cells is found in microangiopathic hemolytic anemia?
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Schistocytes
(red cell fragments) |
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What is the treatment for TTP?
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plasma exchange
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ITP is most prevalent in what group?
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Females ages 20s & 30s
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What is ITP associated with in children?
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Recent viral infection
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What are the signs/symptoms of ITP?
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petechiae, purpura, gingival bleeding, menorrhagia
thrombocytopenia (platelets may be <10,000 |
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Splenomegaly is present in ITP, true or false?
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False
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What is the pathogenesis of ITP?
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platelet sensitization by auto-reactive antibodies - react to glycoprotein IIb/IIIa complex
Increased amounts of platelet associated IgG Shortened survival of macrophages |
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What in the bone marrow is increased in ITP?
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Megakaryocytes
Large platelets in blood |
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What is the treatment for ITP?
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Prednisone
Splenectomy Danazol High dose IV immunoglobulin If the above fails: N-plate (thromboplastin) |
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What percentage of patients with heparin induced thrombocytopenia will have a thromboembolic event?
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50-66%
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What is the pathogenesis of HIT?
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patient produces antibodies (IgG) against the complex formed by heparin and platelet factor 4
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What is the treatment for HIT?
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Stop the heparin
Argatroban or hirudin (direct thrombin inhibitors) |
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What is the mechanism of action for heparin?
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Catalyzes ATIII inactivation of serine proteases
Allows for increased levels of activated factors in the blood |
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What is the half life of heparin?
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1-2 hours
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What is used to treat a heparin overdose?
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Stop the heparin
Protamine sulfate |
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What are the advantages of low-molecular weight heparin?
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MOA same
Half life longer No lab monitoring needed Fewer side effects |
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What is the MOA of Coumadin?
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Antagonist of Vitamin K
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What drugs/substances have a negative interaction with Coumadin?
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NSAIDS
Green tea Antibiotics/antifungals Barbiturates Ethanol Phenytoin Salicylates Vitamin K |
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When does the maximum effect of coumadin take place?
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48 hours after dosage
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The loading dose of coumadin should never be more than _____ mg.
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10
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What is a coumadin overdose treated with?
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Vitamin K
FFP |
