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56 Cards in this Set

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What is contained in the dense granules of platelets?
ADP
ATP
Calcium
Magnesium
serotonin
What is contained in the alpha granules of platelets?
alpha 1 antitrypsin
beta thromboglobulin
platelet derived growth factor
platelet factor 4
factor V
fibronectin
fibrinogen
HMW kinnogen
VWF
What granule is absent in gray platelet syndrome?
alpha granules
What diseases have deficiency of dense granules?
Hermansky-Pudiak Syndrome
Chediak-Higashi Syndrome
Which receptors are involved in adhesion of platelets to subendothelial vWF/collagen
GPIb-alpha
GPIa-IIa
What test differentiates Glanzmann thrombasthenia from Bernard Soulier syndrome?
Platelet Aggregation Test
Glanzmann: normal response ONLY to ristocetin
Bernard Soulier: normal response to all BUT ristocetin
What agonists are used in platelet aggregation tests?
(It's A RACE to aggregate!)

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