Haem BB Flashcards
The most important cell in the initiation of normal haemostasis.
endothelial cell
A potent inhibitor of plasmin in the blood.
protein C
tall, easy ruising, pectus excavatum, lax joints and a high-arched palate
Ehlers Danlos syndrome
bleeding time interpretation
If thrombin time is up there is a fibrinogen problem.
If APTT or PT is up there is a coagulation factor dysfunction or deficiency.
If bleeding time is up there is a platelet dysfunction or deficiency.
If D-dimers (fibrin split products) are zero you can rule out DVT.
To diagnose DIC you need low platelets, low fibrinogen, raised APTT and PT, raised D-dimers, schistocytes on blood smear,
and a compatible clinical setting.
Let’s simplify the clotting cascade.
Common pathway - factors I, II, V, X
Extrinsic pathway - factor VII
Intrinsic pathway - factors VIII, IX, XI, XII
Raised PT - problem in common or extrinsic pathway
Raised APTT - problem in common or intrinisc pathway. A deficiency of any factor except VII and XIII can raise the APTT.
Which protein, important in haemostasis, is vitamin K dependent but is not a serine protease?
protein S
Which key clotting factor activates both factors V and VIII, and also activates protein C?
thrombin
A drug that is administered intravenously and has a rapid effect by potentiating the action of antithrombin. Action can be reversed quickly which is of relevance in myocardial infarction patients who may require early invasive treatment (ie PTCA).
unfractionated heparin
Antiplatelet action. Indicated for primary prophylaxis of stroke in a patient experiencing recurrent retinal TIAs (amaurosis fugax). Ineffective for DVT prophylaxis.
aspirin
Antiplatelet action. Licensed for secondary prophylaxis of stroke. More effective than aspirin alone. Cheap.
dipyramidole and modified release aspirin
Dangerous combination with no added efficacy and increased GI bleed.
clopidogrel and aspirin
This drug when given alone initially increases the clotting risk
warfarin
Side effects include cutaneous necrosis
warfarin
The drug most likely to cause thrombocytopaenia with paradoxical thrombosis
unfractionated heparin
Indicated as thrombotic prophylaxis in DIC
deltaparin
Contra-indicated if recent sore throat, if ever used before, or in the presence of proliferative retinopathy.
streptokinase
