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56 Cards in this Set
- Front
- Back
What is contained in the dense granules of platelets?
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ADP
ATP Calcium Magnesium serotonin |
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What is contained in the alpha granules of platelets?
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alpha 1 antitrypsin
beta thromboglobulin platelet derived growth factor platelet factor 4 factor V fibronectin fibrinogen HMW kinnogen VWF |
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What granule is absent in gray platelet syndrome?
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alpha granules
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What diseases have deficiency of dense granules?
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Hermansky-Pudiak Syndrome
Chediak-Higashi Syndrome |
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Which receptors are involved in adhesion of platelets to subendothelial vWF/collagen
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GPIb-alpha
GPIa-IIa |
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What test differentiates Glanzmann thrombasthenia from Bernard Soulier syndrome?
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Platelet Aggregation Test
Glanzmann: normal response ONLY to ristocetin Bernard Soulier: normal response to all BUT ristocetin |
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What agonists are used in platelet aggregation tests?
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(It's A RACE to aggregate!)
ADP Ristocetin Arachidonate Collagen Epinephrine |
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What is the defect in Glanzmann Thrombasthenia?
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Deficiency or absense of functional platelet membrane receptor: GPIIb/IIIa
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Platelet count and morphology in Glanzmann Thrombasthenia?
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Normal
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Clinical picture in Glanzmann Thrombasthenia
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Severe mucocutaneous bleeding starting in infancy
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What is the defect in Bernard Soulier Syndrome?
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Abnormal or absent surface receptor for VWF: GPIb/IX/V complex
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Are Bernard-Soulier Syndrome and Glanzmann Thrombasthenia problems of aggregation or adhesion?
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Bernard-Soulier: adhesion
Glanzmann Thrombasthenia: aggregation |
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What is the morphology of platelets in Bernard Soulier?
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decreased number, large platelets, often "bizarre"
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Test to diagnose Fanconi's Anemia
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Increased chromosome breakage in PERIPHERAL blood lymphocytes exposed to DIEPOXYBUTANE (DEB) or MITOMYCIN C.
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What is Evans syndrome?
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Autoimmune hemolytic anemia and immune thrombocytopenia
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Emergency Management of Life Threatening Hemorrhage in ITP
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Large IV push platelet transfusion
30mg/kg IV methylpred IVIG 1g/kg +/- emergency splenectomy |
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What is the defect in ALPS (autoimmune lymphoproliferative syndrome)?
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Abnormality of programmed cell death due to mutations in Fas, Fas ligand or caspase 8/10 genes.
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What are the laboratory features of ALPS?
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cytopenias
HYPERglobulinema increase in CD4-/CD8- T cells increase in IL-10 |
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What is the classic diagnostic pentad of TTP (thombotic thrombocytopenic purpura)?
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microangioapthic hemolytic anemia
thrombocytopenia neurologic findings renal manifestations fever |
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What drugs can induce TTP?
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Ticlopidine
Clopidogrel Cyclosporine |
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What clinical scenerios are associated with TTP?
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Autoimmune Disease - especially SLE
Pregnancy Malignancy Infection |
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What do you see in the smear of a patient with TTP?
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Schistocytes and helmet cells
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In TTP what do you expect LDH, retic count, coagulation studies (PT/PTT/fibrinogen) and Coombs to be?
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LDH and RC are high
Coagulation studies are normal Coombs is negative |
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What is the defect in TTP?
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Decreased vWF cleaving protease activity due to:
deficiency (mutation on chromosome 9q34) or antibody against protease. |
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Where is ADAMTS-13 gene found? what does a mutation in this gene cause?
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chromosome 9q34
TTP (deficiency of vWF cleaving protease) |
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Treatment for TTP
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Immediate initiation of plasmapheresis or plasma exchange
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Management of Kasabach-Merritt Syndrome
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Corticosteroids
Vincristine alpha-interferon embolization antifibrinolytic agents (tranexamic acid/e-aminocaproic acid) |
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What drugs most commonly cause immune thrombocytopenia? (5)
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Heparin
Quinine/quinidine sulfa derivatives gold valproic acid |
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What is the pathophysiology of heparin induced thrombocytopenia?
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IgG antibody reacts with heparin-platelet factor 4 complex
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Timeframe for thrombocytopenia due to HIT?
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Thrombocytopenia develops 5-10 days after initial exposure or within 2 days after previous heparin exposure.
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Pathophysiology of NAIT (neonatal alloimmune thrombocytopenia)
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mother is negative for HPA-1A (PLA1), and father or baby is positive, mother therefore develops antiplatelet antibodies which are passed on to the baby.
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What does the anti-HPA-1A antibody bind to?
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GPIIb/IIIa receptor
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What risks are associated with NAIT?
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10-20% risk of intracranial hemorrhage.
Life threatening bleeding during delivery/neonatal period in 1-5% |
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Prenatal treatment of NAIT
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Measurement of fetal platelet count by PUBS at 22+ weeks
If platelet count < 50 could give: IVIG to mother compatible platelet transfusion to fetus |
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Delivery Postnatal management of NAIT
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? C-section
compatible (usually maternal) platelets immediately following delivery consider IVIG |
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Inflammatory causes of thrombocytosis (4)
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Acute and chronic infection
connective tissue disease malignancy Kawasaki syndrome |
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Six causes of thrombocytosis
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Inflammation
Iron Deficiency Marrow Recovery Sickle Cell Disease Post Splenectomy Young infants (especially premature) |
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treatment of essential thrombocythemia
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aspirin
hydroxyurea anagrelide |
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Treatment for Glanzmann thrombasthenia
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local measures for bleeding
anti-fibrinolytic agents platelet transfusions recombinant Factor VIIa Stem cell transplant |
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Treatment for Bernard Soulier
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local measures
DDAVP fibrinolytic inhibitors platelets transfusions Factor VIIa |
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Hermanshy-Pudiak aka
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oculocutaneous albinisnm
dense granule storage disease |
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mechanism for aspirin
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cyclooxygenase inhibitor
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mechanism of abciximab
tirofiban eptifibatide |
GPIIb/IIIa inhibitors
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mechanism of clopidogrel
ticlopidine |
platelet ADP receptor (P2Y12) antagonist
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mechanism of dipyridamole
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multiple actions on platelets culminating in inhibition of aggregation, adhesion and granule release
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most common transfusion related infection
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Hep B (1/220,000)
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clinical presentation of ALPS
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variable presentation of cytopenias (+/- thrombocytopenia, +/- anemia, +/- intermittent neutropenia etc.
lymphadenopathy HSM |
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management options for ITP
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prednisone 4mg/kg/d
IVIG 1gm/kg x 1 IV anti D 75 microgram/kg (75 better than 50, do not use IV anti D if patient is already anemic) |
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Thrombocytopenia is associated with which type of Von Willebrands disease?
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Type 2B
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mechanism of action common to all treatments ITP
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Inhibition of Fc receptors on macrophages
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What does GPIIb-IIIa bind to?
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fibrinogen, fibronectin, vitronectin, vWF, fibrin
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What are the two most important agonists for platelet activation?
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Thrombin and ADP
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what is a morphologic feature of may-hegglin anomaly?
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dohle bodies in granulocytes
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what are the platelet aggregation study findings in TAR?
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decreased aggregation to epinephrine and collagen.
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what is pseudo von willebrand disease
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defect of GP Ib
increased binding of VWF increased ristocetin aggregation |
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what can congenital amegakaryocytic thrombocytopenia progress to
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aplastic anemia
AML MDS |