Flashcards in Components of blood haemostatic system Deck (18)
What are the % of blood?
WBC and platelets 1%
Describe the coagulation pathway?
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
What can go wrong with haemostasis?
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
What are the consequences of haemostasis failure in the oral cavity?
Oral mucosa is highly vascular
Salvia contains fibrinolytic substances and is rish in bacteria
So cycle of:
Haematoma - infection - wound breakdown - bleeding
How does VWF disease appear?
Easy bruising, appears black
How does haemophilia A present?
Internal bleeding so soft tissues swell
How does heritable platelet disorder present?
Blood looks black
How do you identify a pt with abnormal haemostasis?
Clinical evaluation - MH, SH, DH
Lab evaluation - because not all bleeding disorders are caused by abnormal FBC eg platelet function disorder
How are bleeding disorders classified?
low platelet number
Haemophilia (A, B, C)
What is VWD?
Von Willibrands disease
Low VWF concentration in plasma
Abnormal primary haemostasis
How do we treat VWD?
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
What is immune thrombocytopenia?
Immune mediated destruction of platelets due to antibody production
Jaundice, subconjunctival haemorrhage
What is liver disease?
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
What treatment is there for AITP (autoimmune thrombocytopenia)?
LONG TERM CONTROL:
immunosuppression with steroids
TREATMENT OF BLEEDING :
TREATMENT OF BLEEDING IN LIVER DISEASE:
fresh frozen plasma
What drugs affect haemostasis?
ANTI-THROMBOTICS widely given to prevent arterial and venous thrombosis
ANTI - PLATELETS - inhibit arterial thrombosis
ANTI - COAGULANTS -inhibit venous thrombosis
What are antiplatelet drugs?
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
What are anticoagulant drugs?
LMWH and UNFRACTIONED HEPARIN (UFH) - inhibit coag factors
Prevent venous thrombosis
Monitor UFH with aPTT
Don't need to monitor LMWH