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Flashcards in Acquired Bleeding Disorders Deck (25):
1

Name 6 acquired bleeding disorders

Vit K deficiency
Massive transfusion syndrome
DIC
Iatrogenic
Acquired inhibitors

2

How do you determine if a bleeding disorder is due to an inhibitor or a deficiency?

If APTT is prolonged, repeat with 50:50 mix patient to normal plasma. Deficiency= significant correction, inhibitor=no correction

3

In which aquired bleeding disorder is the TT the longest?

DIC

4

Why does liver disease result in clotting disorders?

Clotting factors are synthesised in the liver

5

Why does massive transfusion result in bleeding disorders?

Dilution of clotting factors

6

In which bleeding disorders is the thrombin time increased?

DIC and heparin overuse

7

In which bleeding disorders is the platelet concentration decreased?

Liver disease
DIC
Massive transfusion

8

What are the vitamin K dependent clotting factors?

2,7,9,10

9

How does vit. K usually work?

Acts as a cofactor in a modification step after the synthesis of the clotting factors- vit K reductase works to reduce vit k epoxidase back to its active form- vit k (red)

10

How does warfarin work?

Inhibits the recycling of vitamin K i.e. blocks the synthesis of vit k reductase

11

4 causes of vitamin K deficiency

Obstructive jaundice (bile salts can't reach the gut, fat and subsequently vit. k can't be absorbed)
Prolonged nutritional deficiency
Broad spectrum antibiotics
Neonates (1-7 days) 'haemorrhagic disease of the newborn

12

What is the cause of haemorrhagic disease of the newborn?

Vit K deficiency at birth

13

What is the monitoring blood test for warfarin and what is the normal range?

International normalised ratio INR (PT)

14

How does heparin work?

Activates antithrombin III which results in an increased rate of inactivation of thrombin and factor Xa

15

How does fondaparinux work?

Acts against factor Xa

16

What is the monitoring blood test for fondaparinux?

It does not require monitoring

17

How does aspirin work?

Irreversible Cox 1 and cox 2 (mainly) inhibitor which blocks the synthesis of thromboxane which is a procoagulant in primary haemostasis

18

Causes of bleeding disorders in liver disease

Thrombocytopenia (splenic congestion)
Platelet dysfunction
Low plasma concentration of all factors, apart from factor 8
Less fibrin
Excessive plasmin
Impaired vit. K absorption- reduced synthesis of vit K dependent facotrs

19

What is the definition of massive transfusion

Transfusion of a volume equal to the patient's total blood volume in less than 24hrs or 50% in less than 3 hrs.

20

Causes of bleeding in massive transfusion

Dilutional depletion of platelets and coagulation factors (5, 8 and fibrinogen)
DIC

21

Causes of DIC

Infections
Malignancy
Obstetic complications

22

Lab tests in DIC

thrombocytopenia
PT prolonged
D-dimer (fibrin degredation product) increased

23

Complications of DIC

tissue damage caused by thrombosis- necrosis and further activation of coagulation and fibrinolysis
Purpura, ecchymoses, GI bleeding
Renal function impaired due to microvascular thrombosis
Acute respiratory distress syndrome, adrenal necrosis, chock and thromboembolism

24

What affects warfarin metabolism in the liver

Erythromycin/antibiotics slow down metabolism of warfarin- over anti-coagulation

25

What is the treatment for over anti-coagulation by warfarin

Vitamin K