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57 Cards in this Set
- Front
- Back
Breakdown of platelet distrubtion in body
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2/3 circulate
1/3 are stored in the spleen |
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What is the lifespan of platelets?
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7 - 10 days
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What is epistaxis?
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Nose bleed
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Name 6 manifestations of PRIMARY hemostatic defects
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Superficial purpura
Petechiae Epistaxis Mucous membrane bleeding Prolonged IMMEDIATE bleeding "Oozy bruisy" patient |
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How does thromboxane effect platelet aggregation?
What is the role of NSAIDs? |
Thromboxane mediates expression of Gp IIb/IIIa on platelets
NSAIDs inhibit Thromboxane formation from arachidonic acid |
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What is a normal platelet count (range)?
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150 - 450 k
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Ranges of different classifications of thrombocytopenia
(Mild, moderate, etc.) (corresponding #s of platelets) |
Mild - 80-120 k
Moderate - 50-80 k Vigilant - 30-50 k Worry - 20-30 k Crisis - 10-20 k PANIC - <10 k |
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Charactertistics of Wiskott-Aldrich Syndrome
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X-linked inheritance
Small platelets Assoc. w/ immunodeficiency, eczema |
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Characteristics of familial thrombocytopenia w/ AML
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Dominant inheritance
Normal size/dysfunctional platelets Propensity to develop AML |
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Amegakaryocytic thrombocytopenia w/ radio-ulnar synostosis
What are its main characteristics? |
Dominant inheritance
Assoc. w/ hearing loss |
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Charecteristics of thrombocytopenia w/ absent radii (TAR)?
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Recessive inheritance
Skeletal defect - absent radius |
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Characteristics of Bernard Soulier thrombocytopenia
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Autosomal recessive
Large, dysfunctional platelets Deficiency of GP 1b receptor on platelets |
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Characteristics of DiGeorge thrombyctopenia
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Palate T-cell defect
Large platelets Right heart problems |
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Characteristics of vWD 2B
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Dominant inheritance
Platelet clumping on smear Due to vWF structural defect |
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Benign Mediterranean Macrothrombocytopenia
What type of inheritance does it have? |
Dominant
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Characteristics of MYH9-related thrombocytopenia
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Dominant inheritance
Giant platelets Neutrophil inclusions +/- hearing loss, cataract, renal defect |
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Characteristics of Gray platelet syndrome
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Dominant inheritance
Large, pale platelets LACK of alpha granules |
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Characteristics of Amegakaryocytic thrombocytopenia (CAMT)
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Recessive inheritance
Possible stem cell defect |
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Congenital thrombocytopenias w/ autosomal recessive inheritance (3)
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CAMT
TAR Bernard Soulier |
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What is deficient/defective in Glanzmann's thrombastenia?
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Gp IIb/IIIa
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What two "factors" are required for Adhesion?
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von Willebrand factor
Gp Ib |
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How do adhesion and aggregation differ in energy requirements?
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Adhesion - NON-energy requiring
Aggregation - energy requiring |
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What drugs are assoc. w/ drug-induced thrombocytopenia (6)
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Quinidine
Heparin NSAIDs Gold salts Sulfa drugs Dilantin |
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How are WBCs affected in ITP?
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They're not
Normal number & morphology |
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What main change is visible in the BM of ITP?
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Increased megakaryocytes
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How do acute and chronic ITP compare in terms of age group of pts?
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Acute - PRE-adolescent
Chronic - POST-adolescent |
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How do acute and chronic ITP compare in terms of sex predilection?
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Acute - F:M equal
Chronic - F:M is 3:1 |
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Which type of ITP is more often associated w/ infection?
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Acute
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How do acute and chronic ITP compare in terms of typical platelet counts?
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Acute - < 20k
Chronic - 20-80k |
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How do acute and chronic ITP compare in terms of duration?
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Acute - 2-6 weeks
Chronic - years |
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How do acute and chronic ITP compare in terms of resolution?
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Acute - often resolves
Chronic - w/o treatment, resolution unusual |
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Above what platelet count does risk of bleeding drop below 5%?
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> 10k
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How do you treat ITP w/ a platelet ct < 20k?
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Steroids, IVIg, anti-D
NOTE: anti-D is given to Rh- pts. who may receive Rh+ blood |
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How do you treat Asymptomatic ITP w/ platelet ct 20-30k?
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Prednisone
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How do you treat SYMPTOMATIC ITP w/ platelet ct 20-30k?
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Treat as if platelets < 20k
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How do you treat Asymptomatic ITP w/ platelet ct 30-100k?
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Do nothing
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How do you treat ITP w/ platelet ct 30-100k if minor bleeding?
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Prednisone
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How do you treat ITP w/ platelet ct 30-100k if major bleeding?
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Treat as if platelets < 20k
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When is relapse of ITP likely if treated w/ splenectomy?
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In first 6 months
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What are the 3 modalities of drug-induced thrombocytopenia?
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Immune complex deposition (common)
Hapten "penicillin" type Auto-sensitization of platelets |
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What drug is often associated w/ auto-sensitization of platelets?
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Aldomet (methyldopa)
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What are the major differences between HITT Type 1 and 2 (4)?
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---Type 1---
Non-immune, CAN continue heparin, Occurs early, No sequelae ---Type 2--- Immune rxn, Must STOP heparin, Occurs later, DISASTER |
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What type of Ab is induced in HITT Type 2?
What is it targeted against? |
IgG
Heparin-PF4 complex on platelets |
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What is the typical pentad of signs in TTP?
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Low platelet count
Fever Renal failure Neuro deficits Microangiopathic hemolytic anemia (strands of fibrin acoross small vessels) |
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What causes congenital TTP?
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Lack of ADAMSTS13 enzyme
(vWF multimers are not cut, causing clumping of platelets) |
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How is TTP treated?
If not treated, what is the mortality? |
Plasma exchange
(remove Abs and replace ADAMSTS13) 90% fatality |
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What is HUS assoc. w/?
(causative factor) |
E. Coli toxin
|
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How does the renal failure in HUS compare w/ that in TTP?
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It is much more pronounced in HUS
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What symptoms does TTP commonly have that is not seen in HUS?
(differentiating factor?) |
Neuro deficits
|
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Mnemonic for pregnancy associated hemolysis/thrombocytopenia
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HELLP
Hemolysis Elevated Liver enzymes Low Platelets |
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Aggregation requires what two "factors" from platelets?
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Presence of and ability to release granules
Ability to form Gp IIb/IIIa receptor |
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What is the function of the Gp IIb/IIIa receptor?
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Binds fibrinogen
Thus, fibrinogen can link platelets Required for AGGREGATION |
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What is the function of the Gp Ib receptor?
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Binds sub-endothelial vWF
Thus, platelets can adhere to vessel wall Required for ADHESION |
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Pooled platelet concentrate transfusion
How many units per donor? |
Each unit is from an individual donor
SO, if 6 units, 6 donors |
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Pheresis unit
How many units per donor? |
6-8 units come from a single donor
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How long are platelets viable at room temp?
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~5 days
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What "normal" physiological processes can cause thrombocytosis (2)?
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Exercise
Peri-partum state |