thrombophilia and acquired anticoagulation Flashcards
(80 cards)
1
Q
what is thrombophilia
A
- increased risk of clots developing
- clot too much
- often an acquired condition superimposed on a genetic condition
- opposite of haemophilia
2
Q
how can thrombophilia be life threatening
A
- if the clot breaks off and passes through the body it can cause an embolism and block important arteries/veins
3
Q
what are the inherited syndromes of thrombophilia
A
- protein S deficiency
- protein C deficiency
- factor V Leiden
- antithrombin III deficiency
4
Q
what do the inherited syndromes of thrombophilia have
A
- slightly higher levels of clotting factors
- don’t always know the reason why there are higher clotting factors though
5
Q
what are the causes of acquired thrombophilia
A
- antiphospholipid syndrome
- oral contraceptives
- surgery
- trauma
- cancer
- pregnancy
- immobilisation
6
Q
how can surgery cause thrombophilia
A
- patients are often immobile after surgery so there is less circulation and surgeries generally make the body clot more by having more clotting factors
7
Q
how can trauma cause thrombophilia
A
- body goes into an exaggerated repair mode
8
Q
how can cancer cause thrombophilia
A
- can get DVT and then pulmonary embolism can be caused
9
Q
what are the platelet abnormalities
A
- thrombocytopenia
- thrombocyhtemia
- qualitative disorders
10
Q
what is thrombocytopenia
A
- reduced platelet numbers
11
Q
what are qualitative disorders of platelets
A
- normal platelet number but abnormal function
12
Q
what is thrombocythenia
A
- increased platelet number s
- something bad is going on
13
Q
can platelets function be tested
A
- no, there is no way to test platelet function
14
Q
what are the causes of thrombocytopenia
A
- idiopathic
- drug related = penicillin, alcohol, heparin
- secondary to lymphoproliferative disorders
15
Q
can dental treatment continue on patients with thrombocytopenia
A
- yes, only if the platelet count is >50x10^9
16
Q
what are the inherited causes of qualitative disorders of platelets
A
- Bernard Soulier syndrome
- Hermansky Pudlak
- Glansmann’s thromboasthenia
17
Q
what are the causes of acquired qualitative disorders of platelets
A
- cirrhosis
- drugs
- alcohol
- cardiopulmonary bypass = have platelets that don’t work well then things may bleed longer than usual
18
Q
what is a dangerous level of thrombocythemia platelet count
A
- if platelets are only slightly higher than usual then can treat patient normally
- if platelet count is around 600-700 then this can lead to disease
19
Q
is thrombocythemia a common disease
A
- no
20
Q
what medication are patients with thrombocythenia usually on
A
- aspirin to prevent clot formation
- need to be aware of this when giving dental treatment
21
Q
what are the common causes of liver disease
A
- alcohol
- hepatitis
- drug induced
22
Q
what is the normal value of haemoglobin
A
- male = 13-18
- female = 11.5-16.5
23
Q
what is the normal value of platelets
A
- 150-400 x10 ^9/litre
24
Q
what is the normal PT levels
A
- 13-18 seconds
25
what is the normal APTT time
- 33-48 seconds
26
what is the normal TT time
- 9-12 seconds
27
what is INR
- ratio of patients PT against a normal person's
| - if normal then the ratio should be 1
28
what are the haematological changes in liver disease
- haemoglobin = little change
- platelets = decrease
- PT = increase
- APTT = increase
- TT = increase
- when treating a patient with liver disease, these are all things to be aware of
29
what is the effect on dental surgery if the patient is in the mild stage of liver disease
- blood results often are normal, so normal precautions apply
- broadly speaking, can treat as normal
30
what is the effect on dental surgery if the patient is in the moderate stage of liver disease
- often only one parameter abnormal and platelet count >100
- no problem with treatment
- local measures following extraction
31
what is the effect on dental treatment if the patient is in the severe stage of liver disease
- all blood results are abnormal
- problems with haemostasis
- extraction must be carried out in conjunction with haematologist = patient will probably have abnormal platelets and INR and so then need to talk with specialist for what to do
32
what are patients with severe liver disease given
- fresh frozen plasma
| - plasma without blood cells, only all the normal clothing factors in it from an individual donor
33
what is drug induced coagulopathy
- anti-thrombotic medication
34
what drugs are physician instigated clotting changes
- oral anticoagulatns
- heparins
- anti platelet medication = given by tablet
35
how is heparin given
- given by injection
- can use this as a short term treatment as by the time that the others are given then patient will be released from the hospital
36
what are indications for anticoagulation needed
- atrial fibrillation = don't want to give an injection so give tablets which cause blood less likely to clot
- deep venous thrombosis
- heart valve disease
- mechanical heart valves
- thrombophilia
37
what are the available oral anticoagulants
- coumarins
- direct factor Xa inhibitors
- direct thrombin inhibitors
38
what is a coumarin
- warfarin
- main one
- can cause death if you poison someone with warfarin
39
what is an direct factor Xa inhibitor
- rivaroxaban
40
what is a direct antithrombin inhibitor
- dabigatran
41
where did warfarin get its name for
- Wisconsin Alumni Research Foundation coumaRIN
42
where did warfarin come from
- developed from spoiled sweet clover which cause epizootic of haemorrhage disease in Wisconsin cattle
- drought caused poor corn harvest, but sweet clover would grow so was used as cattle feed
- disease was first recognised in 1920, dicoumarol extracted in 1940
- warfarin became a major anticoagulant
43
why is warfarin the most used drug for anticoagulation
- because it is cheap
| - the process to put a patient on warfarin is not cheap but the drug itself is cheap
44
what is the history of warfarin
1950s - life-long treatment on all
1960s - out of favour except short term DVT
1970s - INR established
1980s and 90s - clinical trials demonstrated efficacy in atrial fibrillation
45
why must warfarin patients be monitored
- some patients need monitored more than others
| - if you change warfarin doss, then you change the metabolism of the patient and so the INR is also changed
46
what are some examples of new oral anticoagulants (NOAC)
- rivaroxaban
- apixaban
- dabigatran
47
why are NOAC being used
- they are increasingly being used as 'safer' and 'cheaper' alternatives to warfarin
- no monitoring is needed routinely
- although more expensive as a drug they are cheaper for the NHS
- they are very predictable on their bioavailability = apixaban is always 50% whereas warfarin bioavailable can change
48
why is NOAC cheaper than warfarin
- if put someone on warfarin, then they need to be out into hospital to do so and then they need put on heparin for the first 3 days then need monitored for the first few weeks
- costs the NHS a lots
- this is not needed with NOAC
49
what are NOAC used for
- short term treatment
50
what is the daily dose of warfarin
- 1-15mg
| - can vary a lot
51
what is the response to warfarin measured in
- INR
- should be checked every 4-8 weeks
- all patients should carry an anticoagulant booklet
52
what are some potentiating drugs that interact with warfarin (cause blood to become thinner)
- all drugs will interact with warfarin
- amiodrone
- antibiotics
- alcohol = with liver disease
- NSAID's
53
what are some inhibiting drugs that can interact with warfarin (cause warfarin to not work as well)
- carbamazepine, barbiturates
- cholestyramine
- griseofulvin
- alcohol = without liver disease
54
what medication must be used with caution with warfarin
- aspirin = as an analgesic
- most antibiotics = amoxycillin is least likely to cause problems
- anole anti fungal drugs = fluconazole, itraconazole
55
when must the INR be checked after starting a new medication is on warfarin
- 24-48 hours after starting a new medication
| - always seeks advice from GP if you are prescribing something to a patient on warfarin
56
how is INR calculate
- patient prothrombin time/ mean normal prothrombin time
57
what does INR give
- ISI
| - international sensitivity index
58
what is the target INR
- mechanical heart valves = 3-4
- recurrent VTE while adequately anti coagulated = 3-4
- other causes = 2-3
- want to adjust warfarin so that the INR is between 2 and 4 most of the time
59
what are the risks of warfarin
- haemorrhage
- 1% per annum risk of a serious bleed = needing hospitalisation/transfusion (25% of these are fatal)
- if you get any trauma it will be much worse if on warfarin
60
what are the risks of adjusting INR
- fatal thromboembolic events
- non-fatal thromboembolic events
- rebound hyper coagulable state = restarting warfarin makes coagulation more likely
61
how does warfarin work
- inhibiting vitamin K clotting factors
- using warfarin stops the function of vitamin K
- when you stop using warfarin then clotting factors start to work again but then it is difficult to get warfarin back under control again
62
what is the SDCEP guidance for what treatment INR must be checked for
- extractions
- minor oral surgery
- periodontal surgery
- biopsies
63
what is the SDCEP guidance for when INR does not need to be checked for treatment
- prosthodontics
- conservation
- endodontics
- hygiene phase therapy = can get some bleeding but not too bad that it will cause an issue
64
what type of LA must you use for patient with coagulation disorders
- LA with vasoconstrictor
65
what types of injection should you give according to SDCEP
- infiltration, intraligamentary or mental nerve injection
| - can give an IV nerve block for thrombophilia unlike haemophilia
66
how should the injection be administered if having to inferior alveolar nerve bloc
- slowly using an aspirating technique
67
when should you treat patients with coagulation disorders
- treat in the morning and early in the week
| - treat early in the week so if there is any issues then patient can come back during the week
68
when should INR be checked before treatment
- should be checked 48 hours prior to treatment but should be as near as possible to the time of treatment
69
what INR value means treatment can proceed
- if INR <4
70
how many teeth can be extracted according to SDCEP from a patient with coagulation issues
- 3 teeth = but means 3 roots
| - can't extract anymore than 3 roots at a time
71
what are local measures to aid homeostasis
- LA infiltration, oxidised cellulose, sutures, pressure
72
what must good post-operative instruction include
- emergency contact details
73
what are unfactioned heparins
- given by IV infusion in hospital = need to check APPT
- have a very short half life so are very controllable
- patient in hospital will have a drip stand with a pump
74
what are low molecule weight heparins
- given by subcutaneous injection by the patient at home
| - dose weight related = no monitoring required
75
are heparins used often
- not commonly used in community
76
what are available anti platelet medication
- low dose aspirin = 75mg daily
- clopidogrel
- dipyridamole
- ticlopidine
77
what are the guideline for single agent anti platelet medication
- delayed haemostasis by adequate haemostasis
78
what are the guideline for dual agent anti platelet medication
- usually aspirin and clopidogrel
- is STENT = discuss with cardiologist
- otherwise = stop one of the drugs 7 days prior to surgery, discuss with doctor
79
how long is a platelets half life
- 7 days
80
what must you do for patients on both anticoagulant and anti platelet therapy
- need to discuss with a hospital specialist
- if you upset antiplatelet drug, then you will upset the warfarin metabolism and INR (warfarin is complicated)
- NOAC and anti platelet drugs are less complicated then warfarin
