2 - bleeding disorders

Question 1

what are 3 components of primary haemostasis that can go wrong and cause bleeding disorder?

Answer 1

1. vascular (collagen problem making weak vessel walls)
2. platelet problem - either not enough or not working properly
3. von willebrand factor deficiency

Question 2

what are causes of vascular abnormalities? (cause of primary haemostasis bleeding disorders)

Answer 2

vascular abnormalities = collagen deficiency
1. hereditary like ehlers danlos, marfan’s etc
2. acquired like henoch schonlein purpura vasculitis (vasculitis in kids after virus)

Question 3

what are causes of thrombocytopenia? (cause of primary haemostasis bleeding disorders)

Answer 3

thrombocytopenia = low platelets

1. hereditary (rare)
2. acquired from either production problem (marrow problem) or destroying too many platelets through immune thrombocytopenic purpura ITP (autoimmune), coagulopathy (use up platelets), hypersplenism

Question 4

what are causes platelets to not work? (which causes primary haemostasis bleeding)

Answer 4

• hereditary = rare
• acquired = renal failure or drugs (aspirin & NSAIDS)

Question 5

what are causes of von willebrand factor deficiency? (cause of primary haemostasis bleeding disorders)

Answer 5

1. can be acquired but rare
2. hereditary = common autosomal dominant bleeding disorder, get variable severity

Question 6

what are causes of multiple clotting factor deficiencies which is a cause secondary haemostasis bleeding disorders?

Answer 6

multiple clotting factor deficiencies (acquired) - by liver failure meaning clotting factors not made, by vitamin K deficiency meaning not functional clotting factors, complex coagulopathy like disseminated intravascular coagulation where clotting factors used up

Question 7

what is haemophilia?

Answer 7

= x-linked hereditary disorder (affects men). get prolonged bleeding recurring episodically at 1 or a few sites on each occasion (often joints & some muscles bleed)

it causes single clotting factor deficiency meaning secondary haemostasis bleeding. get varied severity - if severe then loads of bleeding like recurrent haemarthroses, recurrent soft tissue bleeds & bleeding after dental extractions & surgeries

Question 8

which secondary haemostasis test will be prolonged in haemophilia? what is haemophilia A&B ?

Answer 8

normal prothrombin time but prolonged activated partial thromboplastin (aptt)

because both types of haemophilia are in clotting factors on aptt side
haemophilia A = factor VIII deficiency
haemophilia B = factor IX deficiency

Question 9

why is vitamin K relevant in secondary haemostasis?

Answer 9

clotting factors II (prothrombin), VII, IX and X are carboxylated by vit K = basically is essential for their function

Question 10

what are causes of vitamin K deficiency?

Answer 10

• poor diet deficiency
• malabsorption (absorbed in upper intestine & requires bile salts to be absorbed)
• obstructive jaundice (bile not their to help absorb)
• vit K antagonist (warfarin = blocks vitK)
• haemorrhagic disease of newborn

Question 11

what is disseminated intravascular coagulation?

Answer 11

= excessive & inappropriate activation of haemostatic system (it causes multiple clotting factor deficiency causing bleeding)

• you basicullary make microvascular thrombus & use up clotting factors

Question 12

what are causes of disseminated intravascular coagulation? treatment?

Answer 12

causes = sepsis, obstetric emergency, malignancy, hypovolaemic shock

treat underlying cause and replace blood

Question 13

if problem with
a) tissue factor or factor VII
b) VIII and IX
what screening test for fibrin clot formation is prolonged?

Answer 13

a) problem of tissue factor or VII = prolonged prothrombin time

b) problem of VIII and IX = prolonged activated partial thromboplastin time

problem with all = both prolonged

tf + VII = extrinsic pathway
VIII + IX = intrinsic pathway