Bleeding dysfunctions Flashcards
How does heparin work?
Binds to antithrombin 3 and inactivates factor X
What condition can heparin induce?
Heparin-induced-thrombocytopenia (HIT)
What is Heparin-induced-thrombocytopenia?
Decrease in number of blood platelets (thrombocytopenia) and increased risk of thrombosis. Can lead to DVT, PE or stroke.
How does aspirin work as an antiplatelet?
COX inhibitor, decreased prostaglandins, therefore decreased synthesis of thromboxane 2. Platelets become less sticky so decreased platelet aggregation and decreased vasoconstriction.
How does clopidogrel work?
Taken orally in inactive form.
Liver converts into active form.
Metabolite selectively inhibits P2Y12 receptor (ADP receptors) on surface of platelets.
Reduced response of ADP inhibits platelet activation and prevents release of substance that promote aggregation.
How does the thrombolytic alteplase work?
Alteplase (aka tissue plasminogen activator) often used in emergency situations.
Binds to fibrin in blood clot.
Promotes conversion of plasminogen to plasmin.
Plasmin then breaks down fibrin into smaller fragment and dissolves clot.
What are 3 inherited bleeding dysfunction conditions?
Haemophilia A
Haemophilia B
Von Willebrand disease
Haemophilia is an _-_____ conditions that mainly affects males
X-linked
Haemophilia A is a deficiency of…
clotting factor 8, crucial in clotting cascade
True or false: haemophilia A is more common than haemophilia B?
True
What are symptoms of haemophilia?
Spontaneous bleeds
Hemarthrosis (bleeding in joint space)
Bruising easily
Epistaxis (nosebleed)
How do you diagnose haemophilia?
Normal Pt with increased APTT (only intrinsic pathway affected)
Decreased factor 8 assay
How do you treat haemophilia type A?
IV factor 8 and desmopressin (releases f8 stored in vessel walls)
Haemophilia B is a deficiency of…
clotting factor IX
