Acquired bleeding and anticoagulants Flashcards
What is thrombophilia?
- Increased risk of clots developing
- Often an acquired condition superimposed on a genetic condition
- Usually possible to find a cause for the clot
What are possible inherited causes of thrombophilia? (4 points)
- Protein C deficiency
- Protein S deficiency
- Factor V Leiden
- Antithrombin III deficiency
What are acquired causes of thrombophilia? (7 points)
- Antiphospholipid syndrome
- Oral contraceptives
- Surgery
- Trauma
- Cancer
- Pregnancy
- Immobilisation
What is thrombocytopenia?
- Reduced platelet numbers
What is a qualitative disorder?
- Normal platelet number but abnormal function
What is thrombocythemia?
Increased platelet numbers
What are the possible causes of thrombocytopenia? (3 points)
- Idiopathic
- Drug related (alcohol, penicillin’s, Heparin)
- Secondary to lymphoproliferative disorder
Dental treatment can proceed safely providing the platelet count is what?
> 50*10^9
Are inherited qualitative disorders common or rare?
Rare
What are examples of acquired qualitative disorders? (4 points)
- Cirrhosis
- Drugs
- Alcohol
- Cardiopulmonary bypass (tend to have platelets that don’t work well)
Is thrombocythemia common or uncommon?
Uncommon disease
What medication are patients with thrombocythemia usually on to prevent clot formation?
Usually on aspirin
What are common causes of liver disease? (3 points)
- Alcohol
- Hepatitis
- Drug indiced
What is the value of a normal INR?
- 1
What is the haematological change in haemoglobin in liver disease?
Little change
What is the haematological change in platelets in liver disease?
Decrease
What is the haematological change in PT in liver disease?
Increase
What is the haematological change in APPT in liver disease?
Increase
What is the haematological change in TT in liver disease?
Increase
What does PT mean?
Prothrombin time
What does APTT stand for?
- Activated Partial Thromboplastin Time
What effect does mild stage liver disease have on dental surgery?
- Blood results often normal so normal precautions apply
What effect does moderate stage liver disease have on dental surgery? (3 points)
- Often only one parameter abnormal and platelet count >100
- No problem with treatment
- Local measures following extraction
What effect does severe stage liver disease have on dental surgery? (3 points)
- All blood results abnormal
- Problems with haemostasis
- Extractions MUST be carried out in conjunction with haematologist
What are 3 examples of anti-thrombotic medication?
- Oral anticoagulation (swallow - not injection)
- Heparins (injection)
- Antiplatelet medication (by mouth)
What are possible indications for anticoagulation? (5 points)
- Atrial fibrillation
- Deep vein thrombosis
- Heart valve disease
- Mechanical heart valves
- Thrombophilia
What are 3 subtypes of oral anticoagulants?
- Coumarins
- Direct Factor Xa inhibitors
- Direct Thrombin Inhibitors
What is an example of a coumarin (type of oral anticoagulant)?
- Warfarin
What are 2 examples of direct factor Xa inhibitors (type of oral anticoagulant)?
- Rivaroxaban
- Apixaban
What is an example of a direct thrombin inhibitor (type of oral anticoagulant)?
- Dabigatran
Give 3 examples of new oral anticoagulants?
- Rivaroxiban
- Apixiban
- Dabigatran
Why are new oral anticoagulants increasing used over warfarin?
- They are ‘safer’ and ‘cheaper’ alternative
- No monitoring needed routinely
What is the daily dose of warfarin?
1-15mg
What is the response of warfarin measured by?
- Measured using the INR
When should the INR be checked for someone on warfarin?
Every 4-8 weeks
What are examples of potentiating drugs when combined with warfarin? (4 points)
- Aminodarone
- Antibiotics
- Alcohol (with liver disease)
- NSAID’s
What are examples of inhibiting drugs when combined with warfarin? (4 points)
- Carbamazepine, barbiturates
- Cholestyramine
- Griseofulvin
- Alcohol (without liver disease)
What are examples of medicines you should use with caution when a patient is on Warfarin? (3 points)
- Aspirin (as an analgesic)
- Most antibiotics (amoxycillin least likely to cause problems)
- Azole antifungal drugs (fluconazole, itraconazole)
What should you assume with warfarin?
- Assume all drugs interact with warfarin
- Always seek advice from GP if you are prescribing
- INR check needed in 24-48hrs
What is the INR (international normalised ratio)?
- INR= Patient PT/ mean normal PT
What is the target INR for patients with mechanical heart valves?
3.0-4.0
What is the target INR for patients with recurrent VTE while adequately anticoagulated?
3.0-4.0
What is the target INR for patients with atrial fibrillation?
2.0-3.0
What is the INR range that you roughly want a patient to be in?
2.0-4.0
What is a common risk of being on warfarin?
- HAEMORRHAGE RISK
- 1% per annum risk of serious bleed (needing hospitalization/transfusion)
- 25% of these are fatal
What are common risks of adjusting a patients INR? (4 points)
- Fatal thromboembolic events
- Non-fatal thromboembolic events
- Rebound hypercoagulable st ate
- Restarting warfarin makes coagulation more likely
What are examples of dental treatments where the INR must be checked? (4 points)
- Extractions
- Minor oral surgery
- Periodontal surgery
- Biopsies
What are examples of dental treatments where the INR is not checked? (4 points)
- PRosthodontics
- Conservation
- Endodontics
- Hygiene phase therapy
What are the SDCEP guidelines in relation to giving injections on a patient on warfarin? (3 points)
- Use a LA containing a vaso-constrictor
- Where possible use an infiltration, intraligamentary or mental nerve injection
- If there is no alternative an inferior alveolar nerve block is used the injection should be administered slowly using an aspirating technique
When should you treat a patient on warfarin?
- In the morning, early in the week
When must the INR of a patient on warfarin be checked prior to dental treatment?
- Must be checked in the 48 hours prior to treatment but should be as near as possible to the time of treatment
What must the INR of a patient on warfarin be so dental treatment can proceed?
must be <4.0
When extracting teeth on a patient on warfarin. How many teeth should you remove at a time?
- No more then three roots
What are local measures to aid haemostasis of a patient on warfarin after having dental treatment? (4 points)
- LA infiltration
- Oxidised cellulose
- Sutures
- Pressure
What are good post operative instructions to give to a patient on warfarin after being given dental treatment?
- Must include emergency contact details
How are unfractionated heparins administered?
- Given by IV infusion in hospital
- Very short half life so very controllable
How are low molecular weight heparins administered?
- Given by subcutaneous injection by the patient at home
- Dose weight related - no monitoring
What are examples of drugs available as antiplatelet medication? (4 points)
- Low dose aspirin (75mg daily)
- Clopidogrel
- Dipyridamole
- Ticlopidine
If a patient is on an anticoagulant and antiplatelet therapy, what should you do?
- Discuss with a hospital therapist
- Each individual case is slightly different
