Thrombotic disorders Flashcards
what are the 3 elements of haemostasis?
primary haemostasis. Blood coag, fibrinolysis.
what are the 3 components of primary haemostasis?
vasoconstriction, platelet adhesis, platelet aggregation.
what convert plasminogen to plasmin? (FIBRINOLYSIS)
urokinase, tissue plasminogen activator (tPA), Factor 7. (this allows plasmin to cleave fibrin into fibrinogen and fibrin degredation products.
define thrombus
clot arising in the wrong place
define thromboembolism
movement of clot along a vessel
what makes up virchows triad
stasis (bedrest, travel), hypercoagulability (pregnancy, trauma), vessel damage (artherosclerosis)
what are the effects of arterial thrombus?
white clot of platlets and fibrin, resulting in ischaemia, principally secondary to artherosclerosis
give examples of arterial thromboembolisms.
coronary (mi, unstable angina), cerebrovascular (stroke, TIA), peripheral emobolism (limb ischaemia)
RF’s of Arterial thrombus
age, smoking, sedentary lifestyle, hypertension, dm, obesity, hypercholestrolaemia, af.
Mx
lifestyle mods, tx of rf’s, thrombolysis - antiplatelets and anticoags
what are the effects of venoous thrombus?
Red thrombus of fibrin and red cells, results in back pressure, due to stasis and hypercoagulability.
examples of venous thromboembolism
limb deep vin thrombosis, pulmonary emboilsm.
DVT (STASIS/ HYPERCOAGULABILITY) RF’s…
age, pregnancy, trauma, HRT, COCP, immobility, surgery, obesuty, systemic disease, fhx, cancer.
what systemic diseases may cause VT?
cancer, myeloproliferative neoplasm, ibd, sle, antiphospholipid syndrome.
how is thrombus diagnosed?
WELLS SCORE, GENEVA SCORE, lab testing (D-DIMER), imaging. DOPPLER US (compressible or non-compressible). Vqscan, ctpa,
tx
Anticoagulants - LMWH, Coumarins (warfarin), DOACs
Thrombolysis only in selected cases - Massive PE
give anexample of an inheriteb predisposition to VT
heritable thrombophilia
what is a commmon cause of hereitable thrombophilia (heritable causes of VT)
factor 5 leiden, prothrombin, g20210A, (rarer: protein c defiicency, protein s deficiency, antithrombin deficiency)
what does factor 5 leiden effect?
prothrombin being turned into thrombin
how is protein c produced?
by action of thrombomodulin upon thrombin
when is microvascular thrombus commonly seen?
DIC (disseminated intravascular coagulation)
where do you commonly see DIC?
cancer, burns and septic shock and eclampsia.
what is DIC? What is the pathalogical basis for the condition?
A diffuse systemic coagulation activation - injury triggers the clotting cascade causing systemic microvascular thrombosis. The high consumption of coagulation factors may lead to bleeding but it is usually the end organ damage which leads to high mortality rate.
what causes tissue ischamia?
gangrene and organ failure.
