Coagulation Disorders Flashcards
Give 3 example’s of types of anti-thrombotic medications?
Injectable anticoagulation
oral antigoagulation
anti-platelet medication
Example of Injectable anticoagulation? (1)
Heparins
Examples of oral anticoagulation? (2)
Coumarin
Non-coumarin
Examples of antiplatelet medications? (3)
aspirin
clopidogrel
new drugs (mainly used in cardiology)
Give 2 types of heparin (injectable drugs) (2)
Unfractionated heparin
low molecular weight heparin
Why and where would unfractionated heparin be required?
In a hospital setting
when rapid control of coagulability is necessary, heparin infusions can be used and can be increased or reduced as is necessary
How is unfractionated heparin given and how long is it active for?
Given by infusion and only active for a few minutes
Specifically, why might unfractionated heparin be required in a hospital setting and why might this type of drug be chosen?
Operations
it allows for rapid control
it has a quick onset and quick end to effect
How does unfractionated heparin work?
it inhibits antithrombin 3, preventing its action
How is low molecular weight heparin administered?
Given by subcutaneous injection once daily
What patients might low molecular weight heparin be specifically useful for ? (include example)
patients who have a short term issue with hyper coagulability
An example would be patients who are immobile in bed or recently recovered from procedure which makes them more prone to a coagulation and deep vein thrombosis (caesarean delivery)
What is a con of low molecular weight heparin?
uncomfortable to deliver
(simple terms) How does low molecular weight heparin work?
It stops low level excess clotting without increasing bleeding risk
What are anticoagulants?
Medicines which help prevent blood clots and interfere with coagulation cascade
What are 5 examples of anticoagulants?
Warfarin
Apixaban
Edoxaban
Rivaroxaban
Dabigatran
What is an antiplatelet drug?
Drugs which interfere with platelet numbers or function
Give 8 examples of antiplatelet drugs
Low dose aspirin
clopidogrel
dipyridamole
prasugrel + aspirin
abciximab
eptifibate + aspirin
ticagrelor
tirofaban
PREVENTION: a key factor for patients who suffer from a coagulation disorder is prevention of oral conditions. Name 5 things which factor towards prevention…
regular dental care
dietary advice
oral hygiene
fluoride supplements
fissure sealant
Which dental procedures are safe and can be carried out with all drugs (5)
hygiene therapy
removable pros
restorative dentistry - including crowns and bridges
endodontics
orthodontic treatment
name 5 dental care procedures which you may with to proceed with caution if a patient suffers from a coagulation disorder…
extractions
minor oral surgery
implants
periodontal surgery
biopsies (sometimes)
Name 5 conditions where blood clots will form too readily on or in the circulation?
atrial fibrillation
deep vein thrombosis
heart valve disease
mechanical heart valves
thrombophilia (blood has increased tendency to form clots)
Name 4 sub groups of anticoagulant medicines?
Coumarins
Indanediones
Direct thrombin inhibitor
Factor Xa inhibitor
2 exampls of coumarins..
Warfarin - cheap
Acenocoumarol (Nicoumalone)
Example of Indanediones (1)
Phenindione
Example of direct thrombin inhibitor (1)
Dabigatran
Give 3 examples of Factor Xa inhibitor? (3)
Apixiban
Rivaroxaban
Edoxaban
Describe Warfarin (5)
- Vitamin K antagonist
- the oldest anticoagulant and has most information
- slow onset over 3 days - initial hypercoagulability due to protein C & S inhibition
- inhibits production of Vit K dependant clotting factors, 2, 7, 9, 10
- delay in onset as existing factor have to be consumed
Why does Warfarin have a slow onset ?
initial hypercoagulability due to protein C & S
Which VitaminK dependant clotting factors does warfarin inhibit the production of?
2,7,9,10
Describe what happens in the initial few days of a patient beginning warfarin therapy?
- Vit K inhibition takes between 2-3 days
- patient beginning warfarin is initially at increased risk of coagulation (due to action of drug)
- another form of anticoagulation is often required during this time (NORMALLY HEPARIN)
- patient usually admitted to hospital for this
What happens if a patients warfarin therapy is temporarily stopped?
There will be a period of hyper-coagulability which can put patient at risk from a pulmonary embolism (stops blood from going to lungs)
If patient experiences a period of hyper-coagulability while temporally stops warfarin therapy- what condition does this put the patient at risk of?
Pulmonary embolism (stops blood from going to the lungs)
How is the response from warfarin measured?
INR (international normalised ratio)
What is is normal result (correct action) from INR and what might a higher result indicate? (include value)
normal 2-3, for correct action
3-4 in prosthetic valves and higher risk of DVT (deep vein thrombosis or pulmonary embolism)
Why is INR an effective way of measuring the effect of warfarin?
allows results from different labs to be comparable
How often should INR be checked?
every 4-8 weeks- more often if unstable
The INR (?) can be upset by drug interactions, why?
Interactions with other drugs can affect the effectiveness of warfarin, which is highly bound to plasma proteins in the blood, by either changing its amount or its anticoagulant effect.
What should all patients undergoing warfarin therapy carry with them?
A recording anticoagulant booklet- will outline normal INR and how often has been checked
Describe the stability of INR?
- Not always well controlled
- 30% of patients outside their target range at any one time
- many food and medicines can interact with warfarin and upset the INR
What do the SDCEP guidelines say regarding patients (on warfarin) undergoing procedures which are likely to cause haemorrhage?
-INR and FBC blood test within 72 hours of treatment (within 24hrs preferred)
- INR between 2 and 3 will usually mean no excessive haemorrhage at time of treatment
When would a dentist ideally carry out treatment for a patient on warfarin?
Early in the day and early in the week ( to allow for any issues of bleeding)
What INR result can you still carry out treatment but proceed with caution?
less than 4
What local haemostatic meeasures can be applied for patients on warfarin?
- cellulose sponge
- sutures
- LA infiltration around socket to reduce blood flow
What must be provided to a patient on warfarin post operatively?
post operative instructions including contact number (out of hours contact number)
Name 2 subheadings of drugs which interact with warfarin (and INR)?
Potentiating drugs
inhibiting drugs
How do potentiating drugs affect the INR?
increase INR
How do inhibiting drugs affect the INR?
Reduce INR
Name 4 potentiating drugs?
- amiodarone
- antibiotics
- alcohol (with liver disease)
- NSAIDS (ibuprofen)
Name 4 inhibiting drugs?
-carbamazepine, barbiturates
- cholestyramine
- griseofulvin
- alcohol (without liver disease)
Name the 3 sub-headings of medications to avoid prescribing for dental patients on warfarin? (and examples )
- aspirin (as an analgesic)
- NSAIDs
- ibuprofen
- diclofenac
- Azole antifungal drugs (can be prescribed but INR must be monitored and in conjunction with patient’s doctor)
- fluconazole
- itraconazole
- miconazole
Name 3 hazards of taking warfarin?
- haemorrhage
- trauma, such as a hip/bone fracture following a fall - could result in serious bleed
- soft tissue injury leading to bleeding into muscles
How can rapid reversal of anticoagulation be achieved in a hospital setting?
vitamin K injection
What does NOAC stand for? (where might people live who find this these particularity attractive)
New Oral Anticoagulants, (patients living in rural or remote areas)
What are the pros of NOACs?
-no need to monitor action (predictable bioavailability)
-rapid onset of action (within an hour of dose)
-short duration of action (effect lost within a day, no need to wait several days compared to warfarin)
NOACS and short treatment length (postpone extractions)??? (unsure)
How to oral anticoagulants work?
by preventing the effect of Factor X
Which oral anticoagulants are taken once daily? (3)
Rivaroxiban
Edoxaban
Dabigatran
Which oral anticoagulant is taken twice daily and why?
Abixaban, it has a very short half life
What is first thing a dentist should do before treating a patient taking NOACs?
Assess bleeding risk of procedure
When might you wish to treat a patient on NOACs?
early in the day
Compare the low and high risk procedure risks for patients taking NOACs?
LOW risk procedure:
no NOAC change
pros and restorative for example
HIGHER risk procedure:
miss/delay morning dose
When a patient is taking apixaban what might be the best thing to do if getting a tooth extracted?
miss morning dose and carry out extraction first thing in the morning
True or False: For a patient on twice daily NOAC they should take the first dose after treatment
FALSE, skip first and take second dose
When should a patient on once daily NOAC take their dose?
Immediately after treatment
What must be avoided for patients with inherited coagulation defects ?
Inferior Dental Block
Describe sensible treatment planning for patients on NOAC?
Describe sensible treatment planning for patients on NOAC?
IDB if needed
local haemostatic measures
do extraction and beginning of day beginning of week
keep for at least 20 mins post extraction to assess bleeding
Which dental antibiotics are NOAC not safe with
Macrolides-
erythromycin and clarithromycin
Are NOACS safe with antifungals?
Yes, topical, fluconazole
Are NOACS safe with LA?
yes
Are NOACs safe with antivirals ?
Yes
Are NOACs safe with NSAIDS?
No, they will prolong action and inhibit platelets
Name 3 anti-platelet medicines which are included in standard therapy
Low dose aspirin (75mg)
Clopidogrel
Dipyridamole
Name 5 anti-platelet medicines which are included in advanced cardiac therapy?
Prasugrel + Aspirin
Abciximab
eptifibate + aspirin
ticagrelor
tirofaban
What affect to antiplatelet drugs have in clinical practice?
inhibit platelet aggregation
inhibit thrombus formation in the arterial circulation
(often used in compination)
may be slight increase in post extraction bleeding
How should you treat a patient on aspirin therapy alone?
- treat without interrupting medication
local haemostatic measures
consider limiting initial treatment area
How should you treat a patient on Non-aspirin single therapy & dual therapy WITH aspirin?
do not interrupt treatment
expect prolonged bleeding (limit initial area)
local haemostasis essential
What should you do if two antiplatelet drugs are taken in combination WITHOUT aspirin?
- discuss with doctor (stop one of the drugs 7 days prior to surgery)
-if this is not possible refer to hospital unit
What else should you issue a patient who is on anti-platelet drugs
local measures to aid haemostasis (tranexamic mouthwash?/ AVOID NSAID analgesics??)
good post operative instruction which must include emergency contact details
Which dental prescribed drugs can interact with antiplatelet medicines?
-AVOID NSAIDs, may reduce the effect of aspirin to prevent cardiac events
-erythromycin/fluconazole may reduce efficacy of clopidogrel
- clarithromycin may INCREASE the effect of ticagrelor
-carbamazepine/omeprazole may reduce efficacy???
What 3 things might an inherited bleeding disorder affect?
- coagulation cascade
- platelets
- a combined deficiency
How does an inherited bleeding disorder affect the coagulation cascade?
A reduction in one or more of the coagulation factors or control proteins
What is the word for too little clot formed?
Haemophilia
What is the word for too much clot formed?
Thrombophilia
How does an inherited bleeding disorder affect platelets?
- number of platelets which are present in the circulation
- function of platelets which are being produced
Name 4 disorders which reduce coagulation factors?
- factor VIII deficiency
- Factor IX deficiency
- von willebrand’s disease
- factor XI deficiency
What is Factor VIII deficiency also known as ?
haemophilia/ haemophilia A
What is Factor IX deficiency also known as ?
Christmas disease/ haemophilia B
Describe von willebrand’s disease?
- reduced factor VIII level
- reduced platelet aggregation (function)
What is Factor XI deficiency also known as ? (and which population is it most common in)
haemophilia C/ common in the ashkenazy jew population
What is one of the main causes for a patient to have Haemophilia A & B
Inheritance- sex-linked recessive disease
How can haemophilia A & B be inherited ?
- defective gene on the X chromosome
- males are affected and females are carriers
- MALES won’t have spare X chromosome to
produce normal quantities of the protein.
FEMALES will have one X affected and one X
normal.
What does the severity of Haemophilia A & B depend on?
the amount of clotting factor produced
what does iu stand for?
international unit
What is a ‘normal’ iu?
1iu
(Severe Haemophilia A & B) What is the % of activity and international unit/ml?
less than 2% activity
<0.02 iu/ml
(Moderate Haemophilia A & B) What is the % of activity and international unit/ml?
2-9% activity
0.02-0.09 iu/ml
(Mild Haemophilia A & B) What is the % of activity and international unit/ml?
10-40% activity
0.1-0.4 iu/ml
(Carriers- Haemophilia A & B) What is the % of activity and international unit/ml?
More than 50% activity
<0.5 iu/ml
Describe the management of Haemophilia A in severe & moderate cases…
- require the use of recombinant factor VIII
—produced in a laboratory under controlled circumstances
What drug to the majority of mild&carriers Haemophilia A patients respond to?
DDAVP, Desmopressin
Does Desmopressin have an effect on the coagulation cascade?
NO
How does DDAVP work to stop bleeding in mild & moderate Haemophilia A patients?
many patients with factor VIII will have a lot of the protein bound to the vascular wall and DDAVP displaces this from the binding on the wall into the circulation
- temporarily boosting the amount of factor VIII present within the circulation
How many times can DDAVP be used?
only a few times- factor VIII has all been displaces
When might DDAVP be useful again?
if patient given time to reacquire the protein on the vascular surface
In very mild cases- what might be a better way of managing Haemophilia A?
oral tranexamic acid (helps blood to clot)
- much same effect as increasing levels of factor VIII in the blood
What does DDAVP stand for?
Desmopressin
How does DDAVP work?
releases factor VIII that has been bound to endothelial cells giving a temporary boost to factor VII levels and clotting ability
How does tranexamic acid work?
inhibitor of fibrinolysis
- keeps any clot that is formed
How is Haemophilia B managed in severe and moderate cases?
require the use of recombinant factor IX
- factor IX not bound to vascular surface therefore DDAPV is no use
How is haemophilia managed in mild and carriers cases?
require the use of recombinant factor IX
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Which factor is reduced in von willebrand’s disease?
reduction in factor VIII levels
How is von willebrands disease passed down from parents to child? (a________ d_______)
autosomal dominant
- not transmitted by the X chromosome
True/False: both sexes are equally affected by von willebrands disease
True
How does Von Willebrans’s disease work?
Defective vW factor on platelets interacts badly with factor VIII so poor clot activation by platelets
Type 1 vW disease, describe…
common
dominant
mild
type 2 vW disease, describe…
common
dominant
mild
type 3 vW disease, describe…
Not as common
recessive
severe
How are severe & moderate cases of Von Willebrand’s disease managed?
DDAVP is enough for most
boosts factor VIII levels
from protein bound to endothelial surface
How are mild & carriers cases of vW disease managed?
mild cases may only require oral tranexamic acid
Who should you consult with regards to a patients management of vW disease?
a patient’s haematologist
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What are some other rarer bleeding disorders?
- inherited defects of other factors in the coagulation pathway
- inherited defect of either the number or function of the platelets
Which procedures (for patients with bleeding disorders) can be carried out in primary care?
non-bleeding procedures
What does the degree of bleeding risk depend on?
Baseline factor activity
- higher factor activity gives lower risk
What must be incorporated into the patient treatment plan?
- location of treatment (hospital or primary care)
- medical treatment needed before or after treatment
In severe and moderate haemophilia cases how is dental care affected?
- majority of treatment in the dental treatment unit attached to the haemophilia centre
- pros and other no-risk treatments can be in primary care
In mild and carriers haemophilia cases how is dental care affected?
- treatment shared by the GDP/PDS depending upon procedure and LA needs
- patient reviewed at the haemophilia centre dental unit every two years
Name 5 bleeding risk dental procedures which require special care…
- administeration of LA
- extractions
- minor oral surgery
- periodontal surgery
- biopsies
Name 3 LA’s which are safe in patients with haemophilia?
- Buccal Infiltration
- Intraligamentary injections
- intra-papillary injections
Name 3 LA’s which are dangerous to use in patients with haemophilia?
- inferior alveolar nerve block
- lingual infiltration
- posterior superior nerve block
How to manage carrying out an extraction in a patient with haemophilia?
- appropriate cover from haemophilia unit
-needs planned in advance - very hard to get ‘on-demand’ care organised
- comprehensive post-operative instructions including contact number for haemophilia unit
Difference between observing (severe & moderate) and (mild & carriers) patients after receiving an extraction or surgery?
Severe & Moderate:
- patients should be observed overnight following surgery
Mild & Carriers:
- patients must be observed for 2-3 hours after surgery
For patients diagnosed as mild or carriers of haemophilia, where must extractions and surgery be carried out?
Refer to Hospital
For patients diagnosed as mild or carriers of haemophilia, where must restorative dentistry be carried out?
- Pros and treatment without LA is General Dental
- LA: buccal infiltration, intra-papillary and intraligamentary can all be treated in a general dental practice.
-LA: inferior dental block and lingual infiltration should be refered to hospital
For patients diagnosed as severe and moderate cases of haemophilia, where must they be treated?
- dentate patients must receive treatment in hospital or by arrangement with haemophilia unit
- an edentulous patient can receive treatment in a GDP
What is the most important aspect of care for patients with medical issues?
Prevention
Name 5 things which aid prevention of dental issues?
- dietary advice
- oral hygiene
- fluoride supplements
- regular dental care
- fissue sealant where appropriate
What is thrombophilia ? (simple terms)
an increased risk of clots developing
Describe Thombophilia ? (detailed- 4 marks)
- increased risk of clots developing
- clot formation is greater than clot breakdown ability
- excessive stable clot formed inappropriately in the circulation
- inhibitors of coagulation cascade are in a reduced amount therefore more clot is formed than normal
Why might a patient be diagnosed with Thromophilia?
often an acquired condition superimposed on a genetic tendency
can present any point in life
What can the clot embolising result in? (include names of conditions)
-it can lead to blockage of major blood vessels in the heart and/or lungs
- pulmonary thromboembolism
- life threatening in many cases
Name the 2 subheadings of thombophilia inherited syndromes?
Inherited hyper-coagulation
acquired hyper-coagulation
Name 4 causes? of inherited hyper-coagulability?
Protein C deficiency
Protein S deficiency
Factor V Leiden
Antithrombin III deficiency
Name 7 causes of acquired hyper-coagulation?
- antiphospholipid syndrome (lupus anticoagulants)
- oral contraceptives
- surgery
- trauma
- cancer
- preganncy
-immobilisation
Name 3 platelet disorders which increase bleeding?
- reduced platelet numbers : thrombocytopenia
- normal platelet number but abnormal function: qualitative disroders
- increases platelet numbers: thrombocythemia: high platelet count but the platelets do not work
What values of platelet count can dental treatment proceed safely ? (primary care & hospital)
???
What is thrombocytopenia?
Low numbers of normal platelets
Does a patient with thrombocytopenia usually function normally?
YES
What are some of the things which are believed to have been able to cause this reduction in platelet count?
- idiopathic (unknown cause)
- drug related: alcohol, penicillin based drugs, heparin
- secondary to lymphoproliferative disorder - leukaemia or myelodysplasia
What is Lymphoproliferative disorder?
bone marrow producing excessive number of white cells or red cells it may not have enough capacity to produce adequate number of platelets
What is the term for high numbers of (often poor) functioning platelets ?
Thombocythemia
Describe Thrombocythemia?
- increased number of platelets
- uncommon disease
- usually on aspirin to prevent clot formation (aspirin each day)
With regards to patients who have a normal platelet count but abnormal function, is this common to be inherited? (name 3 conditions which can cause this )
No, it is rare.
- bernard soulier syndrome
-hermansky pudlak
-glanzmann’s thrombasthenia
What may have caused a patients to acquire normal platelet count but abnormal function?
- cirrhosis
- drugs
- alcohol
- following patients treatment on cardiopulmonary
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