Haematology
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What is hyperaemia?
Active inflammation of an area to move inflammatory molecules and cells to an injured site
What is the lifespan of a platelet?
7-10days
What does endothelium produce to prevent clotting at trest?
NO and prostacyclin
What does the plt attach to on endothelial injury?
Type II collagen via GPIV
What happens when platlet binds col 2 with GPIV?
They activate then adhere more via the vWF receptor. The GPiBIX is important for more sticking. They change shape, and they become negatively charged. Plts then aggregate and form a a plug.
What class of molecule are the proteins of the clotting cascade?
Serine proteases
What coagulation factors are Vit K dependent for post-translational activation?
II, VII, IX, X, protein C and S`
How is haemophilia A inherited?
X linked
What factor is affected by haemophilia A?
Factor VIII deficiency
How would Haemophilia A pts present?
Almost all men (x - linked) Family history Joint bleeding as a baby Bruising very easily Long APTT (VIII part of the intrinisc pathway)
How is severe haemophilia A treated?
Replacement of factor VIII recurrentyl. Unfortunatley, it’s halflife is only 8-12hrs, so needs to be given every day or two.
What is the role of vWF?
Mediates attachment of platelets to ECM, but also stabilises factor VIII and increases its half life.
How is vWD inherited?
Well there are 3 types. Classical type I is AD. The others are AR.
How do you treat vWD?
With desmopressin - causes more production and release of vWF from platelets. Blood donor derivaed VIII has bound vWF (the recombinant stuff does not).
What is the most common cause of thrombocytopoenia due destruction?
Viral (CMV, EBV, HIV) Drugs (qunine) Autoimmune (SLE) Sepsis/DIC Lymphoproliferative disorders Idiopathic thrombocytopoenia Post-transfusional purpura TTP, HELP, HUS
What are the named disorders of platelet function?
Bernard-soulier syndrome vWD Glanzmanns disease
What drugs cause platelet dysfunction?
Aspirin Clopidogrel NSAIDs Penicillins Cephalosporins Herparin Ethanol
Who should be investigated for thrombophilia?
Less than 45 Recurrent events Spontaneous DVT Proven family history Thrombosis in an unusual site Life threatening/catastrophic clot
What tests are in a thrombophilia screen?
Factor V leidien (35-40%) Protein C deficiency 5-8% Protein S definiciency 5-8% ATIII 2-3% APLS 2-3% Plasminogen <1% Fibrinogen <1%
What happens if you treat somone with protein C deficiency with warfarin?
Warfarin induced skin necrosis
What are the 3 antiphopholipid anthipodies?
What is unique about APLS compared with other thrombophilia syndromes?
It predisposes to arterial clotting not just venous clotting. This is why it can lead to stroke at a young age and loss of pregnancy.
What is the half life of unfractionated heparin?
6hrs
What is the reversal agent for heparin?
Protamine