Bleeding Disorders Flashcards
(27 cards)
What can cause failure of platelet plug formation? (primary haemostasis)
vascular disease
von willebrand disease
platelets - decreased number or reduced function
What can cause decreased function of platelets?
acquired:
drugs e.g. aspirin, NSAIDs
renal failure
hereditary: v rare
Why does renal failure cause reduced platelet function?
build up of toxins interfere with platelet function
What is thrombocytopenia?
decreased number of platelets
What can cause thrombocytopenia?
hereditary
acquired:
increased destruction - hypersplenism e.g. liver disease, coagulopathy e.g. DIC, autoimmune e.g. ITP
decreased production e.g. marrow failure
What are some causes of vascular disease resulting in failure of platelet plug?
hereditary e.g. Marfans
acquired e.g. old age, steroids, scurvy, vasculitis
What causes von willebrand deficiency?
usually hereditary - VWF deficiency
- autosomal dominant
- variable severity
What pattern of bleeding do you see with failure of platelet plug formation?
primary haemostasis bleeding pattern
- mucosal bleeding
- purpura
- menorrhagia
What can cause failure of fibrin clot formation?
multiple clotting factor deficiencies
single clotting factor deficiencies e.g. haemophilia
What can cause multiple clotting factor deficiencies?
liver failure
vitamin K deficiency or warfarin therapy
DIC
What can cause vitamin K deficiency?
warfarin therapy
malabsorption
poor dietary intake
obstructive jaundice (as you need bile salts for absorption)
What is DIC?
disseminated intravascular coagulation
excessive and inappropriate activation of the haemostatic system
What can cause DIC?
sepsis
hypovolaemic shock
obstetric emergencies
Why do obstetric emergencies cause DIC?
placenta rich in TF
infarcts activate haemostasis dramatically
Why is there end organ failure in DIC?
microvascular thrombus formation
then more damage results in more activation of coagulation, resulting in more thrombus etc etc
How is DIC treated?
treat underlying cause
platelet and plasma transfusion
fibrinogen replacement
Why are FDPs/D Dimers increased in DIC?
as there is also excess fibrinolysis
Why does vitamin K deficiency cause multiple clotting factor deficiencies?
factors II, VII, IX and X are all carboxylated by vit K
Why does liver failure cause multiple clotting factor deficiency?
as clotting factors are synthesised in the liver
What is haemophilia?
x linked hereditary disorder resulting in single clotting factor deficiencies
What are the PT and APTT results in haemophilia?
normal PT
prolonged APTT
What is the bleeding pattern in haemophilia?
secondary haemostasis
bleeding from medium to large vessels
What clotting factor is deficient in haemophilia A?
factor VIII
What clotting factor is deficient in haemophilia B?
factor IX
