Haematological system

Question 1

Anticoagulation: What is thrombosis?

Answer 1

Inappropriate blood coagulation within a vessel is called thrombosis

Question 2

Anticoagulation: What is appropriate blood coagulation?

Answer 2

when blood escapes from a vessel (failure of this results in bleeding)

Question 3

Anticoagulation: What are the two types of coagulation?

Answer 3

In the arterial circulation:
high pressure system
platelet rich

In the venous circulation:
low pressure system
fibrin rich

Question 4

Anticoagulation: How is arterial thrombosis treated?

Answer 4

Antiplatelet

Question 5

Anticoagulation: How is venous thrombosis treated?

Answer 5

Anticoagulant

Question 6

Anticoagulation: What are 3 common anti platelet drugs? How do they work? What is the lifetime of the drug? What is the dose?

Answer 6

Aspirin
Inhibits cyclo-oxygenase (platelet enzyme) irreversibly
Act for lifetime of platelet ie 7-10 days
Dose 75-300mg per day

Clopidogrel
Blocks ADP receptor (on platelet surface) irreversibly
Acts for lifetime of platelet ie 7-10 days
Dose 75mg per day

Prasugrel
Blocks ADP receptor irreversibly
Acts for lifetime of platelet ie 7-10days
More rapid and consistent inhibition than clopidogrel

Question 7

Anticoagulation: What type of medication does not have to be stopped before dental procedures?

Answer 7

Antiplatelet

Question 8

Anticoagulation: What are the common anticoagulants and via what route are they taken?

Answer 8

Intravenous
Unfractionated heparin

Subcutaneous
Low molecular weight heparins eg enoxaparin, tinzaparin, dalteparin

Oral
Warfarin, dabigatran, rivaroxaban, apixaban, edoxaban

Question 9

Anticoagulation: What does heparin bind to?

Answer 9

Antithrombin which increases the activity of antithrombin

it’s an indirect thrombin inhibitor as it enhances the activity of antithrombin

Question 10

Anticoagulation: How is heparin given in hospital and monitored?

Answer 10

continuous infusion

APTT test - aim for ratio 1.8-2.8

Question 11

Anticoagulation: What is low molecular weight heparin and how is it given? What is it used for?

Answer 11

Smaller molecule made from unfractionated heparin
Given subcutaneously
Renally  excreted
Given once daily. Weight adjusted dosing
No monitoring necessary

Used for treatment and prophylaxis
In Sheffield – Dalteparin is used

Question 12

Anticoagulation: When is low molecular weight heparin stopped and started after dental treatment?

Answer 12

For dental work give last dose 24 hours before dental surgery
Next dose 4 hours after dental surgery

Question 13

Anticoagulation: What does warfarin inhibit?

Answer 13

factors II, VII, IX, X - 2, 7, 9, 10 (vitamin K dependent)

protein C and protein S

Question 14

Anticoagulation: Where is warfarin metabolised?

Answer 14

the liver via cytochrome P450

Question 15

Anticoagulation: When do the effects of warfarin start and continue after being stopped?

Answer 15

Peak effect 3-4 days after starting, and effect still present 4-5 days after stopping
ie slow on and slow off action

Question 16

Anticoagulation: What drug may reduce warfarin binding to albumin?

Answer 16

phenytoin

Question 17

Anticoagulation: What drug may inhibit hepatic microsomal degradation of warfarin?

Answer 17

Erythromycin - strong interaction, stays in blood stream longer - cerebral bleed

Question 18

Anticoagulation: What drug may accelerate hepatic microsomal degradation of warfarin?

Answer 18

Carbamazepine

Question 19

Anticoagulation: How is warfarin monitored?

Answer 19

The test to do is the INR (International Normalised Ratio)
Dose of warfarin based on the INR
Frequency of monitoring depends on the stability of the patient’s INR
eg can be 1 per week up to 1 every 8 weeks.
INR must be measured before surgery or invasive procedures
Can be measured using
a near patient testing device
Uses a drop of blood, similar
to blood glucose measurement

Question 20

Anticoagulation: What is the anticoagulation target for treatment of DVT/PE (6 months) or AF?

Answer 20

2.0-3.0

Question 21

Anticoagulation: What is the anticoagulation target for treatment of recurrent DVT/PE on warfarin life long and mechanical heart valves?

Answer 21

3.0-4.5

Question 22

Anticoagulation: What are the side effects of warfarin?

Answer 22

Bleeding
Annual risk 	   
3% any bleeding
1% serious / life-threatening 
0.3% death due to bleeding

Skin necrosis (only at start of treatment)

Embryopathy (if used in first trimester of pregnancy

Question 23

Anticoagulation: How is warfarin reversed?

Answer 23

Stop Warfarin
takes 2-3 days

Give vitamin K (iv,sc,o)
with iv preparation 80% correction in 6hrs

OR Give Fresh Frozen Plasma (FFP)
need large volume, only partial correction

or GIVE Clotting Factor Concentrate
Containing factors II, VII, IX, X
complete correction in 10minutes

Question 24

Anticoagulation: What warnings are given to patients on warfarin?

Answer 24

No IM injections
No aspirin, NSAID without consultation
No contact sports – otherwise normal activities
Moderate alcohol intake is not harmful but excessive alcohol intake (binging) is
Significant changes in diet should be reported
Consult doctor or pharmacist before any new medication including over-the-counter drugs

Question 25

Anticoagulation: When is it safe to perform an extraction on a patient taking warfarin?

Answer 25

iNR has to be less than 4.0 All patients must have INR within 24hr of extraction (in stable patients 72h will be OK) Near patient testing devices give accurate results but must have documented good quality control

Question 26

Anticoagulation: What are some new DOACs?

Answer 26

Rivaroxaban, Apixaban, Edoxaban (Xa inhibitors) Dabigatran (Thrombin inhibitor) - AF very common All licensed for thromboprophylaxis after hip and knee surgery May replace low molecular weight heparin for general thromboprophylaxis Also licensed in treatment of thrombosis and atrial fibrillation

Question 27

Anticoagulation: What are DOACs used for?

Answer 27

For prevention and treatment of thrombosis | Aiming to replace warfarin

Question 28

Anticoagulation: What are the advantages of DOACs over warfarin?

Answer 28

``` Standard oral doses, not weight based No monitoring No alcohol or food interactions Fewer drug interactions No major adverse events other than bleeding Half life 6-15 hours ```

Question 29

Anticoagulation: What are the disadvantages of DOACs over warfarin?

Answer 29

Dabigatran mainly renally excreted No antidote (exc for dabigatran) More expensive than warfarin

Question 30

Anticoagulation: What are the guidelines for dental surgery and DOACs? and how is the dose of the DOAC changed if an extraction is needed?

Answer 30

Use local anaesthetic with vasoconstrictor unless contraindicated Use infiltration or intraligamentary injection if possible If inferior alveolar nerve block is used, the injection should be administered slowly using an aspirating technique If patient is on short term oral anticoagulant treatment, if possible delay the dental work until discontinuation of anticoagulation If dental extraction or dental surgery is required on oral anticoagulants: Do not take the anticoagulant on the morning of the dental work. Restart 4 hours post procedure

Question 31

Lymphoid and myeloid disorders: What is acute myeloid leukaemia?

Answer 31

proliferation of primitive precursor cells usually only found in the bone marrow proliferation without differentiation replaces normal bone marrow cells leads to anaemia: palor and lethargy neutropenia: infections (no normal white cells) thrombocytopenia: bleeding (fewer megakaryocytic) bone pain due to marrow infiltration

Question 32

Lymphoid and myeloid disorders: What are the 4 types of leukaemia?

Answer 32

ALL AML CLL CML

Question 33

Lymphoid and myeloid disorders: What is acute lymphoblastic leukaemia? What is the treatment?

Answer 33

malignant proliferation of lymphoblasts in bone marrow mainly children 85% cured esp girls age 1-10 low WBC, certain morphology poor prognosis in adults treatment: induction chemotherapy, consolidation chemo and or craniospinal irradiation maintenance chemo bone marrow transplantation if relapsed

Question 34

Lymphoid and myeloid disorders: What is acute myeloid leukaemia?

Answer 34

can diagnose via gums? malignant proliferation of myeloblasts in bone marrow poor prognosis in 15-50% 5 year survival .....

Question 35

Lymphoid and myeloid disorders: What is chronic lymphatic leukaemia?

Answer 35

proliferation of mature lymphocytes usually B cells most common affects elderly over 65

Question 36

Lymphoid and myeloid disorders: What is chronic myeloid leukaemia?

Answer 36

High white cell count and spenomegaly

Question 37

Lymphoid and myeloid disorders: What is myelodysplasia?

Answer 37

premalignant condition of haemopoietic precursors happens with increasing frequency as age increases

Question 38

Lymphoid and myeloid disorders: What are the two types of lymphoma?

Answer 38

Non hodgkin Hodgkin's

Question 39

Lymphoid and myeloid disorders: What are the two types of non Hodgkin lymphoma?

Answer 39

low grade - gradual onset - incurable about 10 year survival high grade - rapid progression - potentially curable with chemo, radio, transplantation

Question 40

Lymphoid and myeloid disorders: What is polycythaemia?

Answer 40

Increase in circulating red cell concentration

Question 41

Lymphoid and myeloid disorders: What is multiple myeloma?

Answer 41

Malignant proliferation of plasma cells int he bone marrow myeloma has monoclonal Ig in blood in and urine

Question 42

Lymphoid and myeloid disorders: how is myeloma treated?

Answer 42

diagnosis - blood and urine tests.. treatment chemo ...

Question 43

Oral manifestations:

Answer 43

neutropenic ulcer in aplastic anaemia