Components of blood haemostatic system

Question 1

What are the % of blood?

Answer 1

Plasma 55%
WBC and platelets 1%
RBC 45%

Question 2

Describe the coagulation pathway?

Answer 2

PRIMARY HAEMOSTASIS 30 - 40s
1) Collagen and tissue factor exposed
2) VWF binds collagen
3) platelets adhere to VWF - collagen
4) Platelets activate
SECONDARY HAEMOSTASIS - COAGULATION
5) TF and platelets activate clotting factors to make thrombin
6)Thrombin converts fibrinogen to fibrin clot
7) Stable clot

Question 3

What can go wrong with haemostasis?

Answer 3

Abnormal primary haemostasis - low platelet / VWF - pt will bleed and bruise
Abnormal secondary haemostasis - low clotting factors, pt will bleed into joints and soft tissue

Question 4

What are the consequences of haemostasis failure in the oral cavity?

Answer 4

Oral mucosa is highly vascular
Salvia contains fibrinolytic substances and is rish in bacteria
So cycle of:
Haematoma - infection - wound breakdown - bleeding

Question 5

How does VWF disease appear?

Answer 5

Easy bruising, appears black

Question 6

How does haemophilia A present?

Answer 6

Internal bleeding so soft tissues swell

Question 7

How does heritable platelet disorder present?

Answer 7

Blood looks black

Question 8

How do you identify a pt with abnormal haemostasis?

Answer 8

Clinical evaluation - MH, SH, DH

Lab evaluation - because not all bleeding disorders are caused by abnormal FBC eg platelet function disorder

Question 9

How are bleeding disorders classified?

Answer 9

ACQUIRED:
low platelet number
liver disease
kidney disease
anticoagulant drugs
antiplatelet drugs

HERITABLE:
VWD
Haemophilia (A, B, C)

Question 10

What is VWD?

Answer 10

Von Willibrands disease
Low VWF concentration in plasma
Abnormal primary haemostasis

Question 11

How do we treat VWD?

Answer 11

DDAVP (vasopressin) - acts on receptor on the kidney so pt retains water, and acts on the receptor on the epithelial cells so release any stored VWF
Transexamic acid - reduce clot breakdown

Question 12

What is immune thrombocytopenia?

Answer 12

Immune mediated destruction of platelets due to antibody production
Jaundice, subconjunctival haemorrhage

Question 13

What is liver disease?

Answer 13

Liver makes clotting factors and GF which stimulate platelets so liver disease will mean low production of all coagulation factors and platelets - affecting primary haemostasis
Jaundice, lipids around eyes

Question 14

What treatment is there for AITP (autoimmune thrombocytopenia)?

Answer 14

LONG TERM CONTROL:
immunosuppression with steroids
splenoctomy
TREATMENT OF BLEEDING :
transexamic acid
platelet transfusion
TREATMENT OF BLEEDING IN LIVER DISEASE:
transexamic acid
Vitamin K
fresh frozen plasma

Question 15

What drugs affect haemostasis?

Answer 15

ANTI-THROMBOTICS widely given to prevent arterial and venous thrombosis
ANTI - PLATELETS - inhibit arterial thrombosis
ANTI - COAGULANTS -inhibit venous thrombosis

Question 16

What are antiplatelet drugs?

Answer 16

ASPIRIN / CLOPIDOGREL - inhibit platelet activation
NSAIDS/ SSRI/ STATINS
Antiplatelet effect is only overcome by stopping meds and waiting for new platelets to by made by the marrow

Question 17

What are anticoagulant drugs?

Answer 17

LMWH and UNFRACTIONED HEPARIN (UFH) - inhibit coag factors
Prevent venous thrombosis
Monitor UFH with aPTT
Don’t need to monitor LMWH

Question 18

What is warfarin?

Answer 18

oral anticoagulant
prevents the synthesis of vit K dependant clotting factors (2, 7, 9, 10)
Causes increased PT and aPTT
Dose monitoring required to keep INR between 2-3