Hemostasis - Ex 6 Flashcards Preview

724 Clin Path > Hemostasis - Ex 6 > Flashcards

Flashcards in Hemostasis - Ex 6 Deck (28):
1

Factors of Intrinsic Pathway (4)

VIII
IX
XI
XII

2

Factors of Extrinsic Pathway (1)

VII

3

Factors of Common Pathway

X
V
II
I

4

What is the importance of Factor XIII?

Solidifies fibrin clot!

5

Main source of Coag. Factors

LIVER!

*MOs: II, V, VII, X

6

Factor III

aka Tissue Thromboplastin

*Found in fibroblasts, sm muscle cells, and endothelial cells

**Phospholipid & TF = Factor III

7

Vit K dependent Factors

II, VII, IX, X

*Vit K *activates* these factors

8

Main Anticoagulation protein

Antithrombin (70%)

This is the ONLY anticoagulant. protein we measure

9

What does Antithrombin inactivate?

Thrombin
XIIa
XIa
Xa
IXa

10

Glomerulus and Antithrombin

Antithrombin can pass through glomerulus when damaged --> This decreases antithrombin levels --> patient is now more susceptible to Thrombosis

11

Fibrinolysis

Conversion of plasminogen to plasmin by:

Factor XII and tPA

12

Tissue plasminogen activator - therapy

Used clinically for strokes

* tPA will artificially force clot breakdown

13

Fibrinolysis - Simplified

Plasmin breaks down fibrin or fibrinogen into:

1. D-Dimers
**Fibrin only

2. Fibrin(ogen) Degradation Products (FDPs)

14

Thrombocytopenia - Differentials (3)

1. Destruction (most common)
2. Consumption
3. Decreased production

15

Thrombocytopenia

Disorder of primary hemostasis --> see petechia on mucosal surfaces and membranes

16

DIC

Cause of thrombocytopenia - consumption

1. Massive activation of clotting factors
2. Rapid consumption of clotting factors --> leads to bleeding
**Clotting to death and bleeding to death at the same time**

*DIC is a red flag for a severe underlying disorder --> it is never a primary disorder

17

DIC - Causes

*Extensive Tissue Damage
- heat stroke
- pancreatitis
- severe hypoxia

*Endotoxemia/Septicemia

*IMHA

*Neoplasia (procoagulant proteins)

*Vascular disease

18

Easiest way to remember DIC? (Lab Values)

EVERYTHING is abnormal!

19

Liver failure

Liver is source of clotting factors --> damaged liver --> decreased production of factors --> coagulopathy

20

Bile Duct Obstruction

Bile is required to absorb fat --> Via K is fat solute --> without fat, there is a Vit K deficiency that can reduce coagulation factor activity

21

Name 7 Lab Evaluations of Hemostasis

1. Platelet count
2. Bleeding time
3. Activated clotting time (ACT)
4. Activated partial thromboplastin time (APTT)
5. One-stage prothrombin time (OSPT or PT)
6. Fibrinogen (Thrombin Time)
7. von Willebrand factor (vWDF)

22

Platelet count

Estimation from a blood film

Automated

23

Bleeding Time

Cut buccal mucosa and see how long it takes to clot

24

Tests of Intrinsic Pathway

APTT and ACT

25

Tests of Extrinsic Pathway

OSPT (aka PT)

26

Which of the tests uses whole blood?

ACT

*Thrombocytopenia can cause erroneously prolonged clotting times

27

Quantitative Fibrinogen

Measure of fibrinogen

1. Excess thrombin is added to diluted plasma

2. Rate of fibrinogen to fibrin is measured

3. Time to "clot" is indirectly proportional to fibrinogen concentration

28

How do we measure fibrinolysis?

D-Dimers