Bleeding Disorders

Question 1

what are causes of a failure of platelet plug formation

Answer 1

vascular
platelets
VWF

Question 2

what are examples of vascular abnormalities that can cause problems

Answer 2

Marfan’s Syndrome
- have less collagen in their vessel walls

Vasculitis
- Henoch-Schonlein Purpura

Question 3

what are acquired causes of thrombocytopenia

Answer 3

1. reduced production
   - marrow problem [along with pancytopenia]
2. increased destruction [if there was just a decrease in platelets]

Question 4

what is thrombocytopenia

Answer 4

to few platelets

Question 5

what are causes of platelet destruction

Answer 5

DIC = coag factors would fall too

Immune thrombocytopenic purpura (ITP) [autoimmune]

Hypersplenism = glandular fever, malignancy

Question 6

what is the mechanism of destruction in ITP

Answer 6

antibodies stick to the platelet (IgG) which is then picked up by the spleen and removed

Question 7

what drugs can cause an acquired platelet defect

Answer 7

aspirin

NSAID

Question 8

apart from drugs, what else can cause an acquired platelet defect

Answer 8

renal failure

- urea builds up and effects the platelet function

Question 9

what causes vWF deficiency - acquired

Answer 9

rare;
would be due to an antibody against vWF;
associated with hyperthyroidism

Question 10

what causes vWF deficiency - hereditary

Answer 10

Autosomal dominant

reduction in vWF (more common) or reduced function in vWF (more severe)

Variable severity

Question 11

what are causes of failure of a fibrin clot formation

Answer 11

DIC
Liver disease
[vitamin K deficiency leading to abnormal production of clotting factors]
Haemophilia

Question 12

what tests results would suggest a multiple factor deficiency such as DIC or liver failure

Answer 12

prolonged PT AND APTT

Question 13

where are all clotting factors made

Answer 13

the liver

Question 14

what clotting factors require vitamin K

Answer 14

2 (prothrombin)
7
9
10

Question 15

why do clotting factors need vitamin K

Answer 15

carboxylated by vitamin K = gives them a negative charge

w/out this they would not be attracted by the platelet plug to go to the area

Question 16

what are sources of Vitamin K

Answer 16

diet - leafy green vegs [broccoli, sprouts]

Question 17

where is vitamin K absorbed

Answer 17

upper intestine

Question 18

what is required for vitamin K absorption

Answer 18

bile salts

- any gallstones in the gallbladder can lead to disruption

Question 19

what are causes of Vit K deficiency

Answer 19

Poor dietary intake
Malabsorption
Obstructive jaundice
Vitamin K antagonists (warfarin)
Haemorrhagic disease of the newborn

Question 20

what are babies given to avoid hemorrhagic disease of the newborn

Answer 20

IM Vit K injections

Question 21

what is the definition of Disseminated Intravascular Coagulation (DIC)

Answer 21

Excessive and inappropriate activation of ALL the haemostatic system

Question 22

what happens in DIC

Answer 22

Microvascular thrombus formation caused by platelet and fibrin clots
- causes end organ failure

THEN Clotting factor consumption as the body uses the factors up
- see bruising, purpura and generalised bleeding

Question 23

what causes DIC

Answer 23

mass release of tissue factor

- can be due to sepsis, tumour, obstetric problems, hypocolaemic shock

Question 24

what the lab findings in DIC

Answer 24

Prolonged PT
Prolonged APTT

Very High D-Dimer

Question 25

Tx of DIC

Answer 25

treat the underlying cause

replacement therapy

• platelet transfusion
• plasma transfusions
• fibrinogen replacement

Question 26

what is haemophilia

Answer 26

An X-linked, hereditary, life long disorder in which abnormally prolonged bleeding recurs episodically at one or a few sites on each occasion (called target joints)

Question 27

what does X-linked mean

Answer 27

girls are carriers

boys are affected

Question 28

what are the forms of haemophilia

Answer 28

Haemophilia A

• factor 8 deficiency
• most common

Haemophilia B
- factor 9 deficiency

Question 29

what are common target joints

Answer 29

ankles
knees
elbows

Question 30

what happens in target joins

Answer 30

bleed in, blood sits there, get iron, causing inflammation, new blood vessels form that are v fragile, can bleed again from these, more iron, more damage

untreated can lead arthropathy

Question 31

what is important to remember in haemophilia

Answer 31

no abnormality of primary haemostasis

i.e. something like a paper cut would heal fine

Question 32

what lab results are seen in haemophilia

Answer 32

PT = NORMAL

APTT = markedly PROLONGED

Question 33

what are features of severe haemophilia

Answer 33

Recurrent Haemarthroses (ankle, knees, elbows)

Recurrent soft tissue bleeds

Prolonged bleeding after dental extractions, surgery and invasive procedures