Applied Physiology and Pathophysiology of Thromboembolic Disorders Flashcards
what are the Direct thrombin inhibitors
Dabi, argatroban, bilvilruidin, desirudin
what are the Factor Xa inhibitors
Apixaban, Rivaroxaban, edoxaban (enoxaparin does it too)
what are the indirect thrombin inhibitors
heparin, fondaparinux (ATRIXA) , enoxaparin
what are the 1/2 lives of protein C and S
8 hours (C) and 30 hours (S)
How does warfarin affect protein C and S
Warfarin inhibits the body’s own production of protein C and protein S. Therefore, initial treatment with warfarin alone in people with protein C or protein S deficiency may temporarily make clotting worse or precipitate a new clot or a severe skin rash known as skin necrosis
How do protein C and protein S inhibit coagulation?
Activated protein C (APC) together with its cofactor protein S inhibits coagulation by degrading FVIIIa and FVa on the surface of negatively charged phospholipid membranes.
Patient with HIT (caused by LMWH/Heparin) are at elevated risk for
venous/arterial thrombosis
myocardial infarction
skin lesions
all due to development of HIT antibodies
what are the clear signs of HIT?
- platelet count fall > 50% and Platelet nadir >20kg/ul
- clear onset between 5-14 days or platelet fall < 1 day (with prior heparin exposure in the past 30 days)
- new confirmed thrombosis, skin necrosis at heparin injection site, anaphylactoid reaction after IV heparin bolus, adrenal hemorrhage
what is Immune thrombocytopenia
platelets become coated with autoantibodies to platelet membrane antigens, resulting in splenic sequestration and phagocytosis by mononuclear macrophages (shortens lifespan of platelets) decrease number of platelets
What is secondary ITP
what immune thrombocytoenia does but it is assoicated with another condition like (HIV, HCV, SLE, CLL)
The condition caused by severely reduced activity of the von Willebrand factor cleaving protease ADAMTS13. (characterized by arteriolar platelet rich thrombi, kidney dsyfunction, thrombocytopenia) is known as what?
Thrombotic thrombocytopenia purpura
Can arterial flow cause platelet or fibrin based clots?
Platelet based (associatedw with atherscelerotic plaque, cause by turbulent blood flow that can damage arterial endothelium and activate platelets to initiate coagulation, can cause ischemia, infarction)
Venous flow is static and can cause _____ base clots
fibrin (emobolus like can morel likely to detach and travel)
what are the STRONG risk factors for VTE
- Hip/knee replacement/major surgery, SCR or major trauma (>10)
What are the moderate risk factors for VTE
arthroscopic knee, central venous lines, chemotherapy, congestive heart or respiratory failure, hormone replacement therapy, malignancy, OC therapy, paralytic stroke, pregnancy/postpardum, previous VTE, thrombophilia
what are the lowest risk factors for VTE
bed rest greater than 3 days immobility due to sitting old age laparoscopic surgery, obestiy pregnancy and varicose veints