Coagulation // Unit 5 Flashcards by Serah Carbon

What composes hemostasis?

vascular system
platelet
coagulation
fibrinolysis

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What are the systems involved in hemostasis?

primary & secondary

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What is the primary system activated by?

Small vessel damage (controls vasoconstriction/platelet function)

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What is the secondary system activated by?

major trauma, surgery or hemorrhage

controls coagulation proteins & enzymatic rxns

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What is coagulation?

a series of proteins that go through a series of enzymatic rxns to form fibrin

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What is the life span of PLTs?

7-10 days

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What is the cell that drops off PLTs at the site of injury?

megakaryocyte through endomitosis

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What are the 3 phases of PLT function?

adhesion
amplification
aggregation

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In the adhesion phase, what are the PLTs adhering to? What is required?

collagen, vMF & Gp1b

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What makes up the vessel wall?

collagen
elastic fibers
smooth muscles

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What occurs during amplification?

more PLTs are recruited to aggregate

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What enforces aggregation of PLTs?

Thromboxane A2

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What coagulation factor isn’t produced in the liver?

VIII

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What factors make up the extrinsic pathway? Does is have a faster or slower response?

III & VII

faster

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What factors make up the intrinsic pathway?

XII, XI, IX, VIII

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Hemophilia A is a factor ___ deficiency?

VIII

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What factor is a substrate for thrombin & a precursor of fibrin?

Factor I, fibrinogen

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What factor is the fibrin stabilizing factor?

Factor XIII

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What factor activates factor VII?

Factor III

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Hemophilia B is a factor ____ deficiency?

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Deficiency of factor ___ may cause prolonged aPTT

XII

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What factor accelerates the transformation of prothrombin to thrombin?

factor V

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What are the contact factors?

HMWK
Pre-K
XII
XI

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What pathway forms the fibrin clot?

the common pathway

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What do PT & aPTT measure?

PT- extrinsic pathway | aPTT- intrinsic pathway

What type of bleeding is seen in a decreased PLT count?

gingival bleeding epistaxis extensive bruising petechiae

What causes an altered distribution of platelets?

enlarged spleen

What coagulation process is vitamin K dependent?

Prothrombin group

Which drugs can cause thrombocytopenia?

quinines NSAIDs Sulfonamides Diuretics

Where can closed bleeding occur?

``` soft tissue genitourinary gastrointestinal bleeding in muscles bleeding in bones, joints & skull ```

What is unique about the factor VIII molecule?

largest protein in the coagulation complex not exclusively synthesized by the liver forms complex w/ vMF for transportation genetically controlled by X-chromosome

What are some symptoms of an individual with Hemophilia A & B?

``` bleeding in... GI tract kidneys gums muscles joints umbilical cord circumcisional hemarthrosis ```

What are the lab results of a person with Hemophilia A & B?

normal bleeding time normal PT increased APTT

How was Hemophilia A treated back in the day? What was the issue with this?

whole blood transfusion | 80-90% of pts contracted HIV

What is the issue with treating Hemophilia A & B?

patients run the risk of developing inhibitors or antibodies to their infusion products

In clotting factor disorders in both bleeding and no bleeding, what are the factors?

bleeding- XIII, X, VII, V, II | no bleeding- contact activation factors (XI, XII, HMWK, Pre-K)

Describe Factor XIII clotting disorder

normal PT & PTT tested with 5M urea test issues/bleeding w/ pregnancy

Describe factor II, V, VII & X clotting disorders

prolonged PT & APTT rare autosomal recessive treated with prothrombin complex concentrates

What are causes of Vitamin K deficiency?

antibiotic therapy nutritional deficit biliary obstruction malabsorption syndrome

If Vitamin K is depleted, what will show in lab results?

Increased PT & APTT

What is the role of fibrinogen in the coagulation & fibrinolytic system?

gets converted to fibrin (fibrinopeptides A & B) by thrombin and is the onset of a solid clot & is broken down by the fibrinolytic system

Name some acquired disorders of fibrinogen...

``` minor increases: inflammation pregnancy stress diabetes oral contraceptives ``` major increases: hepatitis atherosclerosis decreases: acute liver disease acute renal disease DIC

Name the 3 types of inherited fibrinogen disorders & their values

afibrinogenemia <10 hypofibrinogenemia 20-100 dysfibrinogenemia (qualitative)

Describe Afibrinogenemia

autosomal recessive increased PT, PTT, TT & reptilase time long bleeding time abnormal PLT aggregation

Describe hypofibrinogenemia

heterozygous form of afibrinogenemia autosomal recessive mild spontaneous bleeding severe postop bleeding

Describe dysfibrinogenemia

autosomal dominant inherited homo or hetero most lab findings are abnormal inc PT, PTT, TT & RT

What is the role of thrombin in the coagulation system?

PLT release reaction PLT aggregation activation of factor V & VIII activation of Protein C

What is the role of thrombin in the fibrinolytic system?

negative feedback by converting plasminogen to plasmin which breaks down fibrin

When is thrombin & tPA generated?

during injury to endothelial cells

What are the activators of the fibrinolytic system?

``` tPA factor XIIa kallikrein HMWK Urokinase ```

What are products or fibrinolysis called? What are their labels?

``` fibrin splint/degradation products X Y D E D-dimers ```

Which inhibitor prevents plasmin from binding to fibrin & is the most important inhibitor of the fibrinolytic system?

alpha-2 antiplasmin

What are events that can trigger DIC?

``` infections tissue injury malignancy heat stroke GI disorders OB complications snake bites ```

What may develop in patients with DIC?

microangiopathic hemolytic anemia due to microthrombi

Describe the two types of thrombosis...

arterial thrombi- PLTs. RBCs & WBCs | venous thrombi- fibrin & WBCs

What factors does antithrombin neutralize?

mostly IIa | IXa, Xa, XIa, XIIa

What are the inherited risk factors for thrombosis?

``` AT deficiency Protein C deficiency Protein S deficiency Factor V Lieden Prothrombin Mutation ```

What are the two forms of protein S & their %'s?

free 40% | C4b bound 60%

What are the differences between the two types of type II qualitative protein S disorders?

IIa - reduced free protein with normal total protein | IIb - both free & total protein are normal

What are the most common acquired risk factors for thrombosis?

LA/Antiphospholipid syndrome | HIT

What are the specimen requirements for coagulation testing?

3.2% sodium citrate 9:1 dilution spin @ 3000 rpm for 5 min Hct >60% need to be drawn differently

Which drug inhibits the formation of thromboxane A2?

aspirin, antiplatelet drug

What is special about coumadin?

long term anticoagulant | inhibits vitamin K dependent coagulation factors (II, VII, IX, X)

Coagulation // Unit 5 Flashcards

(63 cards)