Sample's Material Flashcards by B Derms

What is the major regulatory enzyme for Thrombopoiesis?

Thrombopoietin

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Where does Thombopoietin come from?

Continually produced by the liver, bone marrow, endothelium ect.

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______ stimulates megakaryocyte production and differentiation

Thrombopoietin

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Thrombopoietin binds to _____ in ciruclation

Platelets

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When _____ numbers decrease there isn’t enough in ciruclation to pick up the thrombopoeitin, leading to increased thrombopoietin free in plasma that ciruclates to the bone marrow and stimulates production of _____

Platelets

Megakaryocytes

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Platelets are part of _____ hemostasis

Primary

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_____ Provides a surface for which secondary hemostasis occurs on

Platelets

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How long does it take to form the primary hemostatic plug?

3-5 minutes

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In the formation of the primary hemostatic plug, platelets adhere to exposed ______

Subendothelium

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Once platelets adhere to subendothelium they undergo ____, leading to a shape change

Activation

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After platelets are activated, they begin to secrete _____

Granules

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After platelets have activated and secreted granules, they _____ to form a platelet plug

Aggregate

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For platelets to adhere to the subendothelium they require ______Factor

Von Willebrand factor

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Von Willebrand factor binds to ____ on the platelet surface and forms a bridge between the platelets and subendothelium

GP1b

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During primary hemostasis, when platelets ____ , they start to undergo shape changes where they grow long extensions and increase their surface area by 3-5%

Activation

*Increase their surface area

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The majority of negatively charged phospholipids are kept on the inside of the platelet, but when the platelet becomes activated they _____ their membrane in order to carry the negative charge on the outside

Flip

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After platelets become activated, what two things are secreted in their granules?

Von Willibrand factor

Calcium

*Von willebrand factor calls more platelets to the site

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During activation platelets secrete _____ which comes and coats the top of the negatively charged platelets, so the platelets become positively charged

Calcium

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Calcium is secreted in platelet granules that coat the platelet with a positive charge which is important for creating the surface for the _____ factors to come down and bind to form fibrin

Coagulation

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Once the granules are stimulated to form platelet aggregation, _____ binds to the platelets and starts bridging the adjacent platelets.

Fibrinogen

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When _____ binds to activated platelets and bridges adjacent platelets is when you get formation of the platelet plug

Fibrinogen

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True/False: Platelet aggregation is a reversible process

False

*Irreversible

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Platelets provide a surface for formation and deposition of ____

Fibrin

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Platelets activate their cytoskeleton to _____ the clot in order to facilitate wound closure and vessel patency

Retract

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What laboratory tests are used to assess platelet concentration?

Blood Smear Hematology analyzers

Spontaneous hemorrhage occurs when platelet numbers decrease below \_\_\_\_\_\_

20,000

What laboratory tests do we use to access platelet morphology?

Blood Smear Hematology Analyzers

Increased MPV suggests increased \_\_\_\_\_\_

Thrombopoiesis

What does the presence of macrothromobocytes suggest?

Increased platelet production

What are the tests used in the clinical setting to evaluate platelet function?

Bleeding tests \*Buccal mucosal bleeding time or cuticle (toenail) bleeding time

What test do we use to access platelet production?

Bone Marrow Aspirate \*see if there are megakaryocytes or megakaryoblasts

In a thrombocytopenic patient, how should healthy bone marrow respond?

Production of Platelet precursors \*Megakaryocytes and Megakaryoblasts

What are the 5 mechanisms of Thrombocytopenia?

Production Destruction Sequestration Loss Consumption

Differential Diagnosis for Thrombocytopenia due to Loss of blood?

Hemorrhage

Two differential diagnoses for Thrombocytopenia due to Consumption of platelets

DIC Vasculitis- ex. Ehrlichia and FIP

Differential Diagnosis for Thrombocytopenia due to Destruction

Immune-mediated Thrombocytopenia

Differntial Diagnoses for Thrombocytopenia due to Decreased Production

Bone Marrow Hypoplasia Neoplasia- ex. Leukemia

Differential Diagnosis for Thrombocytopenia due to Sequestration

Splenomegaly Splenic Torsion Splenic neoplasia

Thrombocytopenia due to ______ is the only one that causes severe thrombocytopenia

Destruction \*Immune mediated thrombocytopenia

What are the two major mechanisms for Thrombocytosis?

Increased production Increased distribution in plasma

What 4 diseases may cause reactive thrombocytosis?

Chronic inflammatory disease Iron deficiency anemia Chronic hemorrhage IMHA

What 3 situations may cause reactive thrombocytosis?

Rebound from thrombocytopenia Post-splenectomy Excitement and exercise- splenic contraction

What mechanism is involved in Von Willebrands disease?

Decreased platelet adhesion \*Defects in the adhesion molecule that binds platelets during initiation of platelet plug- platelets float away and platelet plug is not formed

Von Willebrand is a carrier for Factor \_\_\_\_

VIII

True/False: In Von Willebrands disease the CBC will show a normal platelet count

True

In Von Willebrand disease, there will be a ____ bleeding time

Prolonged

What test would you run to confirm Von Willebrand disease?

Analyze Plasma for Von Willebrand Factor

What is the platelet associated bleeding pattern for Von Willebrand disease?

Prolonged Bleeding

What are the 4 Vitamin K dependent factors?

II, VII, IX, X \*KNOW THIS

What are the major blood systems in the dog?

Dog Erythrocyte Antigen (DEA) Dal blood system

What are the two common DEA blood types in dogs?

DEA 1.1 DEA 1.2 \*45% of population is DEA 1.1

What are the most antigenic blood types in the dog?

DEA 1.1 DEA 1.2

Do dogs have naturally occuring isoantibodies?

No \*1st exposure stimulates antibody production

What blood type is not always expressed in Dalmations?

Dal \*Ubituitous in all dogs except some dalmations lack the Dal antigen

What are the major blood systems in the cat?

The AB group system The Mik system

Do cats have naturally occuring isoantibodies?

Yes \*All cats have naturally occuring alloantibodies

True/False: You shoud blood type all cats prior to transfusion

True

What Feline Blood type is associated with strong isoantibodies?

Type A \*Strong natural isoantibodies against type A. Do not give type A blood to a type B cat

True/False: It is okay to give type A blood to a type B cat

False \*cat will die due to strong antibodies against type A blood

True/False: You can give type B blood to a Type A cat without having a major reaction

True \*weak antibodies against type B blood

What are the 2 most antigenic blood types in the horse?

Aa and Qa \*implicated in neonatal isoerythrolysis

In a Major crossmatch, what is tested in the recipient and the donor?

Recipient- serum Donor- Red Blood cells

Identifies antibodies against RBC antigens in the plasma of the recipient or donor

Crossmatching

When interpreting a crossmatch you should look for what two things?

Hemolysis Agglutination

Whe performing a crossmatch, if there is agglutination it is a ____ crossmatch

Positive

No agglutination or hemolysis means you have a ____ crossmatch

Negative

If crossmatching comes back negative, due to no agglutination or hemolysis, the recipient is ____ to have a transfusion reaction from the donors Red blood cells

Not likely

In a crossmatch if agglutination or hemolysis are detected it is a _____ crossmatch

Positive

If a crossmatch comes back positive with agglutiation or hemolysis, the recipient is ____ for a transfusion reaction

at risk \*DO NOT TRANSFUSE

When a mare develops antibodies against the red blood cell antigens of her foal due to mating with a sire that has genes for offending red blood cell antigens

Equine Neonatal Isoerythrolysis

True/False: In neonatal isoerythrolysis the foal is born healthy but can become sick after ingestion of the mares colostrum

True

In what disease do foals ingest mares colostrum and absorb antibodies against their red blood cell antigens

Equine Neonatal Isoerythrolysis

Transfusion reaction that leads to mild extravascular hemolysis that occurs up to 3 weeks post-transfusion

Delayed hemolytic immune mediated reaction

Why might you get coagulopathy in a patient with liver disease?

Decreased synthesis of coagulation factors Production of dysfuntional factors \*Leads to a tendency for BLEEDING

Syndrome caused by continued activation of coagulation and fibrinolysis

DIC \*disseminated intravascular coagulation

Syndrome that results in thrombosis of the microvasculature and depletion of coagulation factors leading to bleeding

DIC

How does the coagulation panel appear during the consumptive phase of DIC?

thrombocytopenia prolonged PT and PTT Increased FDP \*also decreased anti-thrombin and fibrinogen

The consumptive phase of DIC leads to \_\_\_\_\_

Bleeding

Phase of DIC that leads to thrombosis and organ dysfunction

Hypercoagulable

What type of bleeding patterns do you expect with DIC?

Petechia, Ecchymosis, GI bleeding \*Massive bleeding

DIC is caused by exposure of \_\_\_\_\_

Tissue factor

What type of bleeding pattern do you expect with Warfarin toxicosis?

Bleeding into thoracic cavity Bleeding into Joint cavities Bleeding into the brain

How does the coagulation panel appear for Warfarin?

normal platelet count Prolonged PT and PTT

What 2 tests are used to access fibrinolytic activity?

Fibrin Degradation products D-dimer

What are the two tests to access the intrinsic/common pathway? Which one is more sensitive

Activated Partial thromboplastin Time Activated Clotting time \*Activated Partial Thromboplastin Time is more sensitive

What test is used to access the extrinsic/ common pathway?

Prothrombin Time

What test requires 70% deficiency of factor VII before prolongation is detected?

Prothrombin Time \*Extrinsic pathway

If the Prothrombin Time is prolonged, in the extrinsic pathway test, there is a _____ deficiency

Factor VII

What intrinsic pathway test requires 95% deficiency of the factor beore prolongation is detected

Activated Clotting Time \*Factor has to practially be wiped out

What two intrinsic pathway tests measure the time for fibrin clot formation?

Activated Partial Thromboplastin Time Activated Clotting Time

What is the significance of a prolonged time with the Intrinsic pathway tests?

Deficiency of an Intrinsic or common pathway factor \*Could be any factor

How do you collect a sample for a coagulation test?

Clean Stick \*avoid collection from heparinized catheter

What tube do you use for collection of a sample for coagulation tests?

Sodium Citrate tube

When do you get falsely decreased platelet concentrations on the analyzer?

Clumping Too big (macrothrombocytes)

Expression of which cofactor initiates coagulation?

Tissue Factor (Factor III)

What is the key factor that promotes amplification of secondary hemostasis?

Thrombin

During amplification, what four factors does Thrombin affect?

Va, VII, VIIIa, XI

What three factors contribute to coagulation efficiency?

Calcium Factor V Platelet Membrane

What coagulation factor has the shortest half life?

VII

Prior to ____ of a liver, you should screen for coagulation abnormalities

Biopsy

What are the 2 differentials for severe thrombocytopenia?

Immune mediated thrombocytopenia DIC

How would you differentiate between DIC and Immune mediated thrombocytopenia on a CBC?

Immune mediated thrombocytopenia will have a lower platelet count

In Warfarin toxicosis, Warfarin inhibits _____ epoxide reductase

Vitamin K \*Warfarin inhibits the synthesis of Vitamin K. Vitamin K is needed for the blood to clot, therefore warfarin toxicosis leads to uncontrolled bleeding

What cofactor is required for antithrombin to inactivate thrombin?

Heparin

What are the two major end-products for fibrinolysis?

Fibrin Degradation products D-dimers