Introduction to bleeding disorders. Flashcards

1
Q

In haemostatic balance what 2 factors are balance

A

bleeding (anti-coagulant)

clotting (procoagulant)

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2
Q

what is the first step which results in the activation of a haemostatic plug forming

A

disruption to the BV wall

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3
Q

what molecule do platelets adhere to

A

vWF

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4
Q

what molecule does vWF attach to

A

collagen

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5
Q

what molecule does thrombin activate

A

fibrin

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6
Q

where does thromboxane synthesis take place

A

inside the platelet

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7
Q

what is the purpose of thromboxane

A

contacts blood vessels and activates platelets.

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8
Q

2 important receptors found on the plasma membrane of a platelet.

A

IIaIIIA- receptor for fibrinogen= platelet aggregation.

IBIX- receptor for vWF=platelet adhesion

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9
Q

aspirin inhibits cycloxygenase, what is the function of cycloxygenase

A

produce thromboxane.

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10
Q

what molecule does clopidogrel inhibit

A

ADP

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11
Q

what happens in the extrinsic pathway.

A
  1. Tissue factor expressed on injurged cells= damage BV

2. Activates VII-VIIa, this activates X- Xa, this activated prothrombin to thrombin which converts fibrinogen to fibrin.

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12
Q

what happens in the intrinsic pathway

A
  1. XIIa-XIIa, which converts XI-XIa, which converts IX-IXa.

2. activates X- Xa, this activated prothrombin to thrombin which converts fibrinogen to fibrin.

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13
Q

what are the procoagulant molecules.

A

platelets

clotting factors

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14
Q

what are the anticoagulant molecules

A

Protein C
Protein S- co factor protein C.
Anti-thrombin III
Fibrinolytic system- breaks down the clot when it is no longer needed.

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15
Q

what is the fibrinolytic pathway

A

Tissue plasminogen factor (TPA) breakdown plasminogen to plasmin.
Plasmin then converts fibrin into a fibrin degradation product.
This happens on the surface of a clot.
TPA use for clot busting in acute MI.

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16
Q

What are the different types of bleeding disorders

A
congenital
acquired
platelet
vessel wall
coagulation defect
17
Q

What drug can cause abnormal platelet function (Blood thinner)

A

aspirin

18
Q

what condition is caused by abnormal interaction between the vessel wall and platelets

A

von willibrand factor.

19
Q

what are the major difference between platelet and coagulation defects

A

platelet defects- affect skin and mucosal membranes and form petichae and bruising on skin
coagulation defects- affect spreading haematoma and haemoarthrosis, affect retroperrtioneal bleeding which is often recurrent and prolonged.

20
Q

do petichae blache when pressure is applied

A

no.

21
Q

Von Willebrand disease is caused by a deficiency in which molecule

A

platelets

22
Q

what type of genetic disorder is von willebrand factor

A

autosomal dominant.

23
Q

what factor is reduced in von willebrand disease

A

factor 8 (FVIII)

24
Q

which blood group has lower levels of von willebrand factor

A

blood group O

25
Q

what are common consequences of von willebrand disease

A
  • Mucocutaneous bleeding including menorrhagia

* Postoperative and post partum bleeding

26
Q

are there different types of von willebrand factor, in terms of disease.

A

yes there are mild and more severe forms.

27
Q

what is the treatment that is provided for von willebrand factor disease

A

Antifibrinolytics: tranexamic acid (important in mouth bleeds)
DDAVP- releases VWF from stores in endothelial cells.
factor concentrates of VWF
vaccination against hepatitis
COCP (combined oral contraceptive pill) for menorrhagia

28
Q

haemophilllia a is a deficnecy in which factor

A

factor VII

29
Q

haemophillia b is a deficnency in whihc factor

A

factor IX.

30
Q

what type of genetic inherited disorder are the haemophillias

A

x-linked.

31
Q

what is the function of the drug DDAVP

A

release vWF form endothelial cells.

32
Q

are there degrees of severity in haemophilia

A

yes

normal, mild, moderate and severe.

33
Q

what are the different types of bleeds occur in haemophilia

A
spontaneous/post traumatic
joint bleeding- haemarthorosis.
muscle- haemorrhage
soft tissue- mouth bleed and intracranial bleed.
life threatening bleed in the airways.
34
Q

what is acute and chronic haemophilic arthropathy- which is a complication of haemophilia

A

swollen bone deformity

muscle wasting

35
Q

treatment for haemophilia

A
Replacement of missing clotting protein
DDAVP
factor concentrates
antifibrinolytic agents
vaccine for hep A and hep B
36
Q

complications of treatment from haemophilia treatment

A

Infections- Hep A,B,C,G, HIV, paravirus, vCJD.

Inhibitor development (more common in haemophilia A)- patients become resistant to replacement therapy.

37
Q

How is haemophilia managed

A

Haemophilia Centres and Comprehensive care Centres.
Multidisciplinary Approach
Home treatment
Patient Education and Social Support
Physiotherapy
Orthopaedic Advice & Treatment
Treatment & Diagnosis of Liver Disease
Specialised Management for HIV Positive Patients
Genetic Counselling & Parental Diagnosis

38
Q

appropriate investigations if you suspect a bleeding disorder.

A
Full blood count and blood film
Coagulation screen
Mixing studies if abnormal results
Refer to a haematologist if history suspicious
Von Willebrand profile 
platelet function tests
39
Q

what conditions does the bleeding /normal coagulation screen show.

A
	Thrombocytopenia
	Disorder of platelet function
	vWD
	Factor XIII deficiency
	Mild coagulation factor deficiency
	Vascular disorder
	Disorder of fibrinolysis: rare