prolonged bleeding

Question 1

What is haemostasis

Answer 1

The control of bleeding in health

Question 2

What is prolonged bleeding defined as in the contact of dentistry

Answer 2

Bleeding which:

1. Continues beyond 12 hours
2. Causes the patient to call or return to the dental practitioner or A&E
3. Results in the development of a large haematoma or ecchymosis within the oral soft tissues
4. Requires a blood transfusion

Question 3

How do we classify the aetiology of disordered haemostasis

Answer 3

1. Congenital cause

2. Acquired cause

Question 4

Which classification of aetiology of disordered bleeding is more commonly seen in dentistry

Answer 4

Acquired disorders

Question 5

What can the abnormality responsible for disordered haemostasis be

Answer 5

1. Quantitive (amount)

2. Qualitative (abnormality)

Question 6

What can be affected in quantitative abnormalities of bleeding

Answer 6

1. Reduced amounts of factor VIII (haemophilia A)

2. Reduced number fo platelets (thrombocytopenia)

Question 7

What can be affected in Qualitative abnormalities of bleeding

Answer 7

Platelets with abnormal function

Question 8

What is haemophilia A

Answer 8

Reduced amounts of factor VIII

Question 9

What can congenital causes of prolonged bleeding be due to

Answer 9

Abnormalities of

1. Soluble Coagulation Factors:
2. Platelets
3. Blood vessels

Question 10

Give examples of disorders that can result in abnormalities of soluble coagulation factors

Answer 10

1. Haemophilia A
2. Haemophilia B
3. Von Willebrand’s disease

Question 11

Name the condition that results in congenital reduction in factor VIII

Answer 11

Haemophilia A

Question 12

What Is haemophilia B

Answer 12

congenital reduction in factor IX

Question 13

What is von Willebrand’s disease

Answer 13

Congenital reduction on von Willebrand’s factor

Question 14

Give an example of a disorder that can result in abnormalities of blood vessels

Answer 14

Hereditary Haemorrhagic Telangiectasia

Question 15

What can acquired causes of prolonged bleeding be due to

Answer 15

1. Iatrogenic
2. Renal failure
3. Hepatic failure
4. Boen marrow failure

Question 16

Name the most common cause of prolonged bleeding in the UK

Answer 16

Iatrogenic

Question 17

What can result in iatrogenic prolonged bleeding

Answer 17

Anti-platelet drugs and warfarin

Question 18

What is renal failure associated with

Answer 18

impaired platelet function and prolonged bleeding.

Question 19

Name the 2 mechanism which can contribute to disordered haemostasis in liver function

Answer 19

1. Reduced synthesis of soluble clotting factors and hepatic failure
2. Obstructive jaundice

Question 20

What can happen in obstructive jaundice

Answer 20

Absorption of vitamin K is impaired

Question 21

Why is vitamin K important

Answer 21

Needed for the synthesis of clotting factors II, VII, IX, X

Question 22

Where are platelets formed

Answer 22

In the bone marrow

Question 23

What can bone marrow failure result in

Answer 23

Reduced production of functional platelets

Question 24

Other than platelets what else is formed in the bone marrow

Answer 24

Erythrocytes

Question 25

What are erythrocytes

Answer 25

Red blood cells

Question 26

What can bone marrow failure be caused by

Answer 26

1. Leukaemia 2. Therapeutic drugs 3. Renal failure 4. Alcohol abuse

Question 27

How can we measure disordered haemostasis

Answer 27

1. Prothrombin time 2. International normalised ratio 3. Activated partial Thromboplastin time 4. Bleeding time

Question 28

How do we measure prothrombin time

Answer 28

By taking a venous damper of blood

Question 29

What is the value of the prothrombin time determined by

Answer 29

The activity of clotting factor VII

Question 30

How is the international normalised ratio calculated

Answer 30

(prothrombin time of patient)/ (mean thrombin time of healthy patient)

Question 31

What is the INR number in health

Answer 31

1.0

Question 32

What does a high iNR number mean

Answer 32

Greater: 1. Degree of anticoagulation 2. Risk of adverse side effects

Question 33

What is a therapeutic INR typically between

Answer 33

2.0-4.0

Question 34

Why do we calculate the activated partial thromboplastin time

Answer 34

For the assessment of heparin anticoagulation

Question 35

What is bleeding time a measurement of

Answer 35

Platelet function

Question 36

What are the consequences of prolonged bleeding

Answer 36

1. Acute haemorrhage | 2. Chronic haemorrhage

Question 37

What is chronic haemorrhage a MAJOR cause of in the UK

Answer 37

Anaemia

Question 38

How can we manage patients suffering with prolonged bleeding

Answer 38

A good HISTORY

Question 39

What do we want to fund out when taking a history

Answer 39

Identification of known and unknown problems

Question 40

How is haemostasis usual achieved

Answer 40

1. Vascular spasms 2. Platelets plug formation 3. Blood coagulation 4. Growth of fibrous tissue in the Hole in the vessel

Question 41

What is platelet plug formation activated by

Answer 41

Tissue damage which exposes sub endothelial collagen

Question 42

How is the Platelet plug formed

Answer 42

1. Platelets activated as a result of tissue damage 2. Enhanced Platelet adhesion and aggregation 3. Enhanced activation of factor X

Question 43

When are antiplatelet drugs prescribed

Answer 43

Fore Treatment or prevention of further cardiovascular disease

Question 44

Give examples of Antiplatelet Drugs

Answer 44

1. Aspirin | 2. clopidogrel

Question 45

How does aspirin work

Answer 45

It binds irreversibly to platelets | It inactivated the COX-1 enzyme

Question 46

what is the importance of the COX-1 enzyme

Answer 46

is needed for thromboxane A2 mediated aggregation

Question 47

How does clopidogrel work

Answer 47

by binding to the P2Y12 receptor irreversibly and preventing Adenosine Di Phosphate (ADP) mediated aggregation

Question 48

When are platelets renewed

Answer 48

Every 10 days

Question 49

Over which age is aspirin prescribed

Answer 49

Over the age of 16

Question 50

Why is aspirin not given to children under 16 years

Answer 50

because of the risk of Reye’s Syndrome

Question 51

what is reyes síndrome

Answer 51

(rare condition which can cause potentially fatal swelling of the liver and the brain

Question 52

State the normal platelet level in venous blood

Answer 52

150,000 - 450,000/ml

Question 53

when are platelets levels reduced

Answer 53

1. leukaemias, 2. some anaemias, 3. pregnancy, 4. chronic alcohol abuse, 5. medication 6. Idiopathic Thromobocytopenia

Question 54

What is purpura

Answer 54

Teram used to describe a rash of tiny bruises

Question 55

What is eechymosis

Answer 55

refers to larger bruises

Question 56

A count of how many platelets is safe to carry on dental treatment

Answer 56

Over 80,000/ml

Question 57

What are the indications for the prescription of warfarin

Answer 57

1. Atrial fibrilaion 2. Previous recurrent DVT or PE 3. Heart valve replacement

Question 58

What is warfarin

Answer 58

A vitamin K dependent clotting factor agonist

Question 59

How does paraffin work

Answer 59

It works at the level of the activation fo the clotting cascade leading to diminished clot formation

Question 60

What do patients on warfarin usually carry

Answer 60

A yellow book

Question 61

What does the yellow book warfarin patients carry record

Answer 61

Carries records of their iNR

Question 62

Give examples of drugs that can potentiate warfarin

Answer 62

MICONAZOLE FLUCONAZOLE METRONIDAZOLE ERYTHROMYCIN

Question 63

What do drugs that potentiate warfarin do

Answer 63

Increase risk of haemorrhage

Question 64

Give examples of drugs that can reduce the effect warfarin

Answer 64

CARBAMAZEPINE

Question 65

Name some herbal medicines and food stuff that can interfere with warfarin metabolism

Answer 65

1. Ginseng 2. St Johns Wort 3. Green tea (rich in vit K) 4. Liver 5. Broccoli 6. Brussel sprouts 7. High oxalate greens like spinach, 8. Alcohol 9. coriander and cabbage 10. Grapefruit 11. Pomegranate juice 12. Cranberry juice