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Yr 2 CHHD > Haematology 1A- Haemostatic and Haemorrhagic Disorders > Flashcards

Haematology 1A- Haemostatic and Haemorrhagic Disorders Flashcards

1
Q

What are 3 functions of von Willebrand factor

A

mediates platelet adhesion to damaged epithelium (1°)
mediates platelet aggregation (1°)
stabilises + transport factor VIII (2°)

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2
Q

What is von Willebrand disease

A

deficiency in vWF
most common inherited bleeding disorder
different types + severity

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3
Q

what are 3 ways to manage von Willebrand disease

A
  1. (Mild) Desmopressin -drug (DDAVP) - stimulate release vWF from platelets and from cells lining blood vessels+ factor VIII - Rx
  2. (Severe) vWF replacement using human plasma - rich in vWF + factor VIII - Rx
  3. Anti-fibrinolytic drugs - slow/prevent clot breakdown - oral or IV
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4
Q

4 ways in which vWD is related to dentistry

A
  1. prolonged oozing post extraction + bleeding in muscles/joint
  2. haematological cover before invasive procedure in severe cases
  3. Avoid regional LA (infiltration/ intra-ligamentary safer)
  4. Avoid aspirin/NSAIDs (acetaminophen/co-codamol safer)
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5
Q

what is 1° haemostasis and what are the components associated with 1° haemostasis

A

platelet plug formation via vWF
blood vessels
vWF
platelets

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6
Q

what is 2° haemostasis and what are the components associated with 1° haemostasis

A

coagulation - strengthen clot so doesn’t break
aim to form fibrin meshwork
by 3 paths - extrinsic, intrinsic + common

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7
Q

where are clotting factors manufactured

A

liver

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8
Q

what are Factor VIII and vWF produced

A

endothelial cells of blood vessels

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9
Q

which factors are vitamin K dependant

A

factors II, VII, IX and X

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10
Q

how are clotting factors present in body

A

in circulation as inactive form

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11
Q

how is extrinsic pathway in haemostasis activated

A

tissue factor released on injury to blood vessel

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12
Q

how is intrinsic pathway activated

A

exposure to collagen

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13
Q

what are 3 1° primary haemostatic (bleeding) disorders

A

vascular disorders
von Willebrand disease (also 2°)
platelet disorder - platelet deficiency + platelet dysfunction

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14
Q

what are 2 2° secondary haemostatic (blood coagulation) disorders

A

von Willebrand disease (also 1°)

clotting factor disorders

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15
Q

name the 3 haemostatic congenital disorders and say which haemostasis stage they are

A 
von Willebrand disease (1°/2°)
haemophilia A (2°)
haemophilia B (2°)
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16
Q

name the 4 haemostatic acquired disorders and say which haemostasis stage they are

A

thrombocytopenia (1°)
platelet dysfunction associated with drugs (1°)
anti-platelet therapy (1°)
anticoagulant therapy (2°)

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17
Q

what are 2 primary haemostasis disorders that are also vascular disorders

A

Hereditary Haemorrhagic Telangiectasia
(Osler-Weber-Rendu Syndrome)
von Willebrand Disease (vWD)

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18
Q

what type of condition is
Hereditary Haemorrhagic Telangiectasia
(Osler-Weber-Rendu Syndrome)

A

autosomal dominant hereditary condition

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19
Q

what are the clinical features that can be seen of
Hereditary Haemorrhagic Telangiectasia
(Osler-Weber-Rendu Syndrome)

A 
Telangiectasia (small vascular malformations) + arteriovenous malformations in skin, mucosa + viscera
normally not present until adolescent
recurrent epistaxis (bleed from nose) super common
Fe+ deficiency anaemia can occur -> chronic bleeding of intestinal tract
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20
Q

what are dental aspects can be seen from Hereditary Haemorrhagic Telangiectasia
(Osler-Weber-Rendu Syndrome)

A

bleeding from oral surgery
regional LA - best avoided - risk of deep tissue bleeding
if GA - avoid nasal intubation

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21
Q

what are 4 clinical features that can be seen from von Willebrand Disease

A

can be present as 1° or 2° haemostasis or both

  1. bruising, epistaxis
  2. prolonged bleed during surgical/dental procedures
  3. GI bleeding + menorrhagia (long periods) frequent
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22
Q

what type of disorder is Bernard - Soulier disorder

A

1° haemostasis

hereditary platelet disorder - deficiency

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23
Q

What are the main causes of platelet disorders - deficiency

A 
megakaryocyte suppression
bone marrow failure
splenomegaly ( sequestration of platelets)
hereditary 
increased destruction of platelets
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24
Q

how does megakaryocyte suppression cause platelet deficiency causing platelet disorder

A

caused by:
chemotherapeutic agents
viruses - parvovirus infection, mumps, HIV

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25
Q

what can platelet disorders ( deficiency) can bone marrow failure cause

A

aplastic anaemia
leukaemia
lymphoma
metastases

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26
Q

how does increased platelet destruction cause platelet deficiency causing platelet disorder

A

autoimmune - Idiopathic thrombocytopenic purpura
drugs - Cytotoxic drugs
diseases - Disseminated intravascular coagulation, SLE (lupus?), Malaria

27
Q

what are main 2 causes of platelet dysfunction

A

anti-platelet drugs

vWD

28
Q

Name the 4 anti-platelet drugs that cause platelet dysfunction

A

Aspirin
NSAIDs (act on platelet until drug leaves system, 48hrs)
Clopidogrel, prasugrel
Dipyridamole
other drugs act irreversibly + permanent on platelet lifespan (7-10 days)

29
Q

what are 3 main clinical features of platelet dysfunction disorder

A

easy bleeding + bruising
petechiae
purpura
ecchymosis

30
Q

what are dental aspects can be seen from platelet deficiency disorders

A

Patients suspected thrombocytopenia - Investigate
platelet count (PC) - requesting full blood count (FBC)
prior dental treatment
• Refer to GP/haematologist for further management
• Risk of spontaneous bleeding, PC ˂ 20,000/mm3

31
Q

what are dental aspects can be seen from platelet dysfunction disorders

A

minor dental procedures - continue medication
treat with no interrupting antiplatelet medication
no stop medication unless consult with GP
limit initial treatment area
if there is post extraction bleed - use local homeostatic agents for control

32
Q

what are 2 homeostatic agents used to control post extraction bleeding from platelet dysfunction disorders

A

compressive packing

sutures, absorbed homeostatic agents (oxidised cellulose)

33
Q

what are 3 2° haemostatic hereditary disorders

A

haemophilia A
haemophilia B
vWD

34
Q

how can 2° haemostatic acquired disorders occur

A

if patient going through anticoagulant therapy

35
Q

what are 3 anticoagulant therapies that can cause acquired disorders to occur

A

warfarin therapy
heparin therapy
novel/non-vitamin K oral anticoagulant (NOAC) therapy

36
Q

what are 3 ways which 2° haemostatic disorders can occur

A

hereditary
acquired
disease conditions

37
Q

what are 3 disease conditions that can cause 2° haemostatic disorders

A 
liver disease (inc obstructive jaundice)
disseminated intravascular coagulation
malabsorption syndromes
38
Q

what is haemophilia A caused by

A

factor VIII deficiency has a

39
Q

what is haemophilia B caused by

A

factor IX deficiency

40
Q

who is affected by haemophilia

A

x linked disorders only males

females carrier

41
Q

what clinical features can be seen from mild haemophilia patients

A

minimal bleeding usually associated with surgery

42
Q

what clinical features can be seen from moderate haemophilia patients

A

bleed after minor injury + requires urgent attention

43
Q

what clinical features can be seen from severe haemophilia patients

A

bleed very often with or without provocation

44
Q

what clinical features can be seen from haemophilia a+b patients

A

haemorrhage appears stop immediately after injury but intractable oozing follows
-> bleeding in deep tissues (joints, muscles)

45
Q

what are 2 main ways to manage haemophilia

A

diagnosis

treatment

46
Q

what are 3 main ways of diagnosing haemophilia

A

positive fam history
clinical presentation
investigation - clotting factor assyas

47
Q

what are 3 main ways of treating haemophilia

A
  1. increase production of factor VIII -> desmopressin
  2. replacement therapy for specific clotting factor
  3. inhibit fibrinolysis by antifibrinolytic agents
48
Q

what 2 places is replacement therapy for specific clotting factor taken from for treating haemophilia

A

clotting factor concentrate from plasma

commercial produced recombinant factor

49
Q

what are 2 antifibrinolytic agents used to inhibit fibrinolysis to treat haemophilia

A

tranexamic acid

EACA ( epsilon amino caproic adic)

50
Q

what are 6 dental aspects to be considered for haemophilic patients

A
  1. preventative dentistry - minimise surgical intervention -> serious bleed
  2. close co-op with their haematologist
  3. sig risk of haemorrhage after surgery or LA
  4. ensure adequate clotting factors (VIII/IX) levels
  5. post operative -> look signs haematoma forming (swelling)
  6. trauma to head + neck -> prophylactic factor VIII replacing is essential
51
Q

if patient has thrombosis , then they will be on anticoagulant therapy. What are 8 common indications of it

A
  1. atrial fibrillation
  2. cardiac valvular disease
  3. mech prosthetic heart valves
  4. ischaemic heart disease (recent myocardial infarction)
  5. deep venous thrombosis
  6. pulmonary embolism
  7. renal dialysis
  8. transient ischaemic attacks or strokes
52
Q

what are examples of anticoagulant medication

A

warfarin
heparin
NOACs ( non vitamin K oral anticoags)

53
Q

what does warfarin do and how is it used

A

inhibits vit K dependant clotting factors II, VII, IX, X
oral
it has narrow therapeutic range - frequent monitor + dose adjustment
sensitive to other drugs
INR/prothrombin time

54
Q

what are dental aspects to consider for patients taking warafrin

A

preventative dentistry - minimal surg intervene

measure INR within 24hrs of surgery

55
Q

what are 4 drugs that warfarin can interact with + should avoid prescribing

A

metronidazole
macrolides
azole antifungals
aspirin/NSAIDs

56
Q

what are 2 ways to minimise risk of warfarin interacting with other drugs

A

avoid concurrent use of 2 medications

alternative drugs

57
Q

what does heparin do

A 
anti coagulant drug
inhibits clotting factors II, X
short lived effect
2 types: standard + low mole weight
monitored by APTT
58
Q

when is IV heparin given + when is LMWH (under skin) heparin given

A

IV - immediate manage of acute thromboembolic events

LMWH - non-hospital ambulatory patients

59
Q

what are 4 types of NOACs

A 
Dabigatran - inhibit factor IIa
helps convesion of thrombin-> active thrombin (strengthen clot)
apixaban - inhibit factor Xa
edoxaban - inhibit factor Xa
rivaroxaban - inhibit factor Xa
60
Q

What are advs of NOACS

A

more predicatble lvls of anticoags
no routine montoring
wide TR + easer to manage
effective + safer

61
Q

what are indications of giving NOACs

A

stroke prevention in AF (atrial fibrillation) patients

Thromboembolic disease

62
Q

what is time of action of NOACS

A

rapid onset action, 2-4hrs

relatively short half lives (5-13hrs)

63
Q

key homeostatic investigations that help diagnose + treat haemostatic disorder

A

• Full blood count- platelet count
• Bleeding time- platelet defects
• Prothrombin time (PT)/ international normalised ratio
(INR)- extrinsic pathway and warfarin therapy
 PT- (10-12 secs)
 INR- universal test (Patient’s PT/Control PT) (0.9-1.2)
 INR therapeutic range for patients on warfarin (2-3)
• Activated partial thromboplastin time (aPTT)- Intrinsic
pathway (30-40secs) and heparin therapy
 aPTT therapeutic range for patients on heparin (1.5-2.5)

64
Q

what to remember in patients with bleeding disorders

A

Obtains a comprehensive medical history
 Perform a thorough clinical examination
 Request appropriate special investigations
 Consult with haematologist and/or physician
 Refer where necessary to hospital for dental care

Yr 2 CHHD (4 decks)

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