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81 Cards in this Set
- Front
- Back
Giant platelet syndrome |
BERNARD-SOULIER SYNDROME |
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Heterozygotes – near normal platelets |
BERNARD-SOULIER SYNDROME |
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Rare – autosomal recessive |
BERNARD-SOULIER SYNDROME |
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Aggregation studies – normal aggregation response to ADP, epinephrine, collagen and arachidonic acid |
BERNARD-SOULIER SYNDROME |
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Abnormality cannot be corrected by addition of human plasma or cryoprecipitate
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BERNARD-SOULIER SYNDROME |
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Heterozygous are normal |
GLANZMANN THROMBASTHENIA (GT) |
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Abnormal or deficient in GP IIb/IIIa complex needed for binding fibrinogen, VWF, fibronectin |
GLANZMANN THROMBASTHENIA (GT) |
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Blood smear feature-normal platelet count and morphology. Abnormal tests – bleeding time, in-vitro clot formation. Lack of aggregation with all platelet activating agents
Ristocetin-induced binding of VWF to platelets and platelet agglutination are normal |
GLANZMANN THROMBASTHENIA (GT)
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CBC is normal unless there is another underlying reason |
GLANZMANN THROMBASTHENIA (GT) |
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Clinical features |
GLANZMANN THROMBASTHENIA (GT) |
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Treatment |
GLANZMANN THROMBASTHENIA (GT) |
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Mucocutaneous hemorrhage and hematuria, epistaxis and easy and spontaneous bleeding |
DISORDERS OF PLATELET SECRETION |
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Most common plt secretion disorder |
Storage pool release reaction diseases |
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Storage pool release reaction diseases |
DISORDERS OF PLATELET SECRETION |
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Albinism, Nonalbinism. bleeding is mild limited to easy bruisability |
DENSE GRANULE DEFICIENCIES |
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Autosomal recessive |
Hermansky-Pudlak syndrome |
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Rare autosomal recessive |
Chédiak-Higashi syndrome |
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Hermansky-Pudlak syndrome, Chédiak-Higashi syndrome |
DENSE GRANULE DEFICIENCIES |
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X linked recessive disease characterized by triad of severe eczema, recurrent infections owing to immune deficiency and life threatening thrombocytopenia
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Wiskott Aldrich Syndrome
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Unable to make antipolysaccaride antibodies which results in propensity for pneumococcal sepsis
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Wiskott Aldrich Syndrome |
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Gene codes for 502 amino-acid protein, WASP found exclusively in hematopoetic cells
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Wiskott Aldrich Syndrome |
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Rare autosomal recessive disorder |
Thrombocytopenia with absent radii TAR |
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Alpha granules are storage sites for proteins produced by the megakaryocyte (e.g. platelet-derived growth factor, thrombospondin, and platelet factor 4) or present in plasma and taken up by the platelets and transported to α-granules for storage (e.g. albumin, immunoglobulin G(IgG), and fibrinogen) |
Alpha granule deficiency: Gray Platelet Syndrome
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absence of the α granules |
Gray platelet disorder |
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Electron photomicrographs appear to have no α granules |
alpha granule deficiency |
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Deficient α and δ granules |
Alpha-delta storage pool deficiency |
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Autosomal dominant disorder
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Quebec platelet disorder |
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the pathway is required for mobilization of ionic calcium and initiation of events resulting in release in secretion and aggregation of platelets |
Thromboxane Pathway mechanism |
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inhibits cyclooxygenase an enzyme required in the release of thromboxane A2 |
aspirin and ibuprofen |
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required for storage secretion and platelet aggregation in response to epinephrine, ADP and low concentration of collagen |
Thromboxane A2 |
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Clinical features – lifelong mild bleeding disorder |
Glycoprotein (GP) Ia/IIa integrin deficiency |
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Clinical features – mild bleeding |
Glycoprotein VI (GPVI) deficiencies |
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Drugs that are Inhibitors of |
prostaglandin pathway |
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Inhibitors of Membrane Function |
Thienopyridine derivatives |
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Cause of dysfunction coating of platelet membrane by paraprotein
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Multiple myeloma and Waldenström macroglobulinemia |
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Clinical and laboratory features –surgical bleeding after surgery, thrombocytopenia, severe platelet function defect |
Cardiopulmonary bypass surgery |
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Reduction in clotting proteins, reduction of proteins in the natural anticoagulant pathways, dysfibrinogenemia and excessive fibrinolysis |
Liver disease |
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Bleeding due to platelet dysfunction, concentration of guandinosuccinic acid is higher
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uremia |
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Incidence seen in more than 150 families |
Hereditary afibrinogenemia |
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Associated disorders – hyperlipidemia, diabettis mellitus, peripheral arterial occlusive disease, acute arterial occlusion, MI and stroke |
Hyperaggregable platelets |
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Autosomal dominant. Thin walled blood vessels w/ discontinuous endothelium, inadequate smooth muscle and discontinuous endothelium, inadequate elastin. Telangiectasis – dilated superficial blood vessels that create small focal red lesions . Epistaxis, skin and mucous lesions, Bleeding time normal
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Rendu-Weber-Osler syndrome (Hereditary Hemorrhagic Telangiectasia |
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Giant cavernous hemangioma (vascular tumor) |
Hemangioma-Thrombocytopenia (Kasabach-Merritt) syndrome |
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autosomal dominant, recessive or X-linked |
Ehlers-Danlos syndrome |
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anaphylactoid purpura is allergic manifestations (skin rash and edema) when accompanied by transient arthralagia, nephritis, abdominal pain and purpuric skin lesions
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Henoch-Schönlein purpura (Allergic Purpura)
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Autoimmune disease – mediated by immune complexes that contain IgA |
Henoch-Schönlein purpura (Allergic Purpura)
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platelet function inhibited by myeloma proteins. |
PARAPROTEINEIMIA |
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the deposition of abnormal quantities of amyloid in tissues. Amyloid is fibrous protein consisting of rigid, linear, non-branching, aggregated fibrils |
AMYLOIDOSIS |
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more common in elderly men |
SENILE PURPURA |
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Inducing drugs – aspirin, barbituates, diuretics, digoxin, methyldopa |
DRUG-INDUCED VASCULAR PURPURA |
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Miscellaneous causes of vascular purpura |
Dietary insufficiency – lack of vitamin C (ascorbic acid) – scurvy and decreased synthesis of collagen |
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what does warfarin do? |
reduces factor II, VII IX, X, protein C, protein S and protein Z and prolongs PT |
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Specimen collection tubes |
plastic blue stopper with0.105 to 0.109 mol/L buffered sodium citrate anticoagulant |
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Ratio of blood to anticoagulant |
9:1 with 3.2% sodium citrate |
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Rules of collection |
venous whole blood, first tube to be collected or immediately after nonadditive tube, must not be collected after an additive tube as the additive might transfer to the coagulation tube and invalidate the coagulation tests |
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Hemostasis collection errors that require collection of a new specimen |
lipemia, icterus, clot, short draw, hemolysis, prolonged tourniquet application- elevated the concentration of von willebrand factor and factor VIII and shortens the measured time on clot based assays, storage at 1-6C- precipitation of VWF and destruction of PLTs, storage at >25C- factor VIII deterioration |
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Collecting from indwelling catheters |
Collected by special trained personnel |
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needle gauge for 25 mL specimens |
20-21 |
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needle gauge for >25 mL specimens |
19 gauge |
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needle gauge for pediatric use |
23 gauge, negative pressure must be reduced |
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Adjustment for high hematocrits
9:1 blood to anticoagulant is effective for hematocrit of 55% or less. |
C = (13) (100-H) V
C = volume of sodium citrate in milliliters, V = volume of whole blood-sodium citrate solution in milliliters, H- hematocrit in percent |
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EDTA is used for |
factor V Leiden and prothrombin G20210A mutation |
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heparinized anticoagulant is used for |
platelet satelitosis |
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CTAD blue stopper used for |
to halt in vitro plt or coagulation activation 4 specialty testing: plt factor 4, plt surface membrane p- selectin prothrombin activation markers |
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Storage times |
may be held uncentrifuged at 18°-24°C for up to 24 hours |
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Storage times. Activated partial thromboplastin time (APTT) |
centrifuged and supernatant transferred within 1 hour if patient is on unfractionated heparin to prevent shortening of of the PF4. tested within 4 hours |
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Storage requirements |
Whole blood collected in 3.2% sodium citrate held at 18 to 24°C. Chilling destroys platelet activity. Aggregometry must be completed within 3 hours collection. Mix gently check for clots |
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Light-transmittance optical aggregometers use |
rich plasma with platelet count 200,000 to 300,000 /mcL. Sodium citrate plasma used |
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Clot-based plasma testing use |
platelet poor plasma with platelet count less than 10,000/mcL. Sodium citrate-anticoagulated blood is centrifuged at 1500 xg for 15 mins in a centrifuge at 4400xg for 3 mins |
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Can be stored frozen at |
-20°C for 2 weeks or at -70°C for 6 months |
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platelet function tests |
Bleeding time |
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bleeding time |
original test for platelet function now replaced by PFA- 100 or platelet aggregometry |
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Disorders with prolonged bleeding time |
von Willebrand disease |
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Problems with bleeding time test |
inadequate predictive value |
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Platelet adhesion, aggregation, and secretion are assesed by |
platelet aggregometry |
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Process of aggregation requires |
platelet membranes and platelet activation pathways are intact and plasma fibrinogen concentration is normal |
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PRP aggregometry uses |
specialized photometer called a light transmittance aggregometer
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Platelet processes measured –simultaneous measurement of platelet aggregation and secretion of adenosine triphosphate from activated platelet δ granules |
platelet lumiaggregometry |
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platelet agonists, platelet aggregometry |
Thrombin or synthetic thrombin receptor-activating peptide (TRAP) |
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Normal results – normal concentration of functional VWF and platelets possess a functional VWF receptor, GP Ib/V/IX |
Ristocetin-induced aggregation test (RIPA), Platelet aggregometry in VWF disease |
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conditions detected from platelet lumiaggregometry |
Aspirin and Nonsteroidal anti-inflammatory drugs and clopidogrel |
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conditions detected from platelet lumiaggregometry |
Platelet storage pool defects – ATP release in response to thrombin is reduced as in response to ADP, epinephrine, arachidonic acid and collagen |