Term
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Definition
| Vessel wall damage, altered blood flow/stasis and increased blood coagulability |
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Term
| How does antithrombin inhibit coagulation? |
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Definition
Inhibits F10a and thrombin (2a)by binding with them making them inactive.
Heparin potentiates its action. |
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Term
| How does protein C/S system inhibit coagulation? |
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Definition
Functions as a negative feedback system, Increased thrombin=increased protein C/S system.
Thrombin+thrombomodulin= protein C activation= protein S activation.
Protein C- inactivates F8a&5a inhibiting intrinsic pathway, inactivates tissue plasminogen activator inhibitor (t-PAI).
Protein S- Potentiates protein C's action. |
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Term
| Describe an arterial thrombi |
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Definition
| 'white clots' mainly platelets and some fibrin. Usually a result of atherosclerosis. Antiplatelets most effective treatment. |
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Term
| Describe a venous thrombi |
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Definition
| 'red clots' mainly fibrin and RBC. Usually a result of stasis and hypercoagulability. Anticoagulants most effective treatment. |
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Term
| Describe factor 5 leiden. |
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Definition
| Autosomal dominant 5% caucasians. Structural change to F5, therefore cannnot be inactivated by protein C. Increased risk of VTE/PE and miscarriage/stillbirth/pre-eclampsia. Diagnosed with positive APTT |
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Term
| Describe anti-phospholipid syndrome |
|
Definition
Antibodies attack endothelium membrane and trigger clotting. Primary- no associated symptoms, Secondary- as a result of other conditions e.g SLE.
Diagnosis- Vascular thrombosis or preganacy complications PLUS anticardiolipin antobodies or lupus anticoagulant.
Risks- VTE/PE, miscarriage, stillbirth pre-eclampsia, CVA, MI. |
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Term
| What are the signs and risks of a DVT? |
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Definition
Signs- Swollen limb, pitting oedema, vein tenderness.
Risks- CA, immobility, pregnancy, previous VTE. |
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Term
| How do you investigate a suspected DVT? |
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Definition
Wells scoring system.
Low score: D-Dimer Test
High score: USS & Doppler, venography and CT. |
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Term
|
Definition
| Low molecular weight herpains, warfarin, TED stockings, ?IVC filter? |
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Term
|
Definition
Often asymptomatic.
Collapse, chest signs (pain,haemoptysis dyspnoea), hypoxia, DVT signs. |
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Term
| How do you investigate a suspected PE? |
|
Definition
Bloods- D Dimer, ABG
ECG- S1Q3T3, right ventricular strain, new right bundle branch block.
X-Ray- CXR, CT PA or VQ scan, USS of lower limbs |
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Term
|
Definition
| Resus and fluids where needed, anticoagulation (low molecular weight heparin/warfarin), ?thrombolysis? |
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Term
|
Definition
| Coagulation factors, fresh frozen plasma, cryoprecipitate and vitamin K. |
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Term
| What is Vitamin k essential for the activation of? |
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Definition
| F7,9,10 and thrombin (F2) |
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Term
| What are the therapeuitc indications of Vitamin K? |
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Definition
| Warfarin reversal and haemorrhagic disease of the new born |
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Term
| What is the antidote for heparin overdose? |
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Definition
| Protamine, alkaline protein which binds to acidic heparin. |
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Term
| What is Heparins mechanism of action? |
|
Definition
| Made up of a negatively charged chain & pentasaccharide.Antithrombin binds to pentasaccharide and is potentiated by forming this complex. |
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Term
| How does unfractioned heparin work and what monitoring does it require? |
|
Definition
Inactivates F10a & Thrombin - via complex formation with antithrombin
Requires Monitoring – Unpredictable dose response due to low bioavaiability
Binds to plasma/cellular proteins due to long –vely charged chain
Short Half Life – Th. regular doses required |
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Term
| How does low molecular weight heparin work and what monitoring does it require? |
|
Definition
Inactivate F10a only – Th more nuanced anticoagulant effect)
Doesn’t require monitoring – Predictable dose response - bioavailability
Longer Half Life – Th. can be given once daily |
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Term
| What are the main side effects of heparin? |
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Definition
| Osteoporosis, heparin inducde thrombocytopoenia and hyperkalaemia. |
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Term
| What is Warfarin's mechanism of action? |
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Definition
| Inhibits Vitamin K reductase, therefore active vitamin K cannot be produced. This means factors 2,7,9 and 10 cant be activated. |
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Term
| What are the interaction and the antidote for warfarin? |
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Definition
| ABX, NSAIDs, antiepileptics, alcohol, grapefruit and cranberry. |
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Term
| What are 2 contraindications for warfarin use? |
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Definition
Pregnancy- teratogenic
Alcoholism |
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Term
| What are the indications for the use of warfarin and duration of treatment? |
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Definition
1st VTE – 3 months if provoked (e.g. by travel), 6months if unprovoked
2nd/recurrent VTEs – Indefinite treatment |
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Term
| Name 3 anti-platelet therapies? |
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Definition
| Asprin/NSAIDs, clopidogrel/ticlodepine and monoclonal antibodies |
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Term
| How does aspirin/NSAIDs work as an antiplatelet therapy? |
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Definition
| Inhibit COX enzyymes, prevetn production of thromboxane a-2 and therefore reduce platelet aggregation |
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Term
| How do clopidogrel and ticlodepine work as an antiplatelet? |
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Definition
| Inhibit ADP effects on platelets, reduce platelet aggregation. |
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