Vitamin K deficiency/coumadin therapy

• Vitamin K deficiency leads to decreased synthesis of factors II, VII, IX, and X, and protein C

• Coumarin therapy inhibits synthesis of vitamin K-dependant procoagulant factors and protein C (physiologic inhibitor of activated factors V and VIII)

• Both PT and aPTT may be prolonged, but PT is more sensitive and is used to monitor coumarin therapy (PT should be 1.5-2.5 X > normal)

• In people with a protein C deficiency, coumarin therapy can lead to thrombotic skin necrosis (especially on the breast and penis) if they aren’t heparinized first

• O/D of coumarin-like anticoagulants can lead to bleeding complications (no shit?)

• Liver disease will look like coumarin/vitamin K deficiency, but there will also be low factor V, and there may also be production of functionally abnormal fibrinogen (dysfibrinogenemia) and a platelet defect (acquired storage pool d/o); the bleeding tendency may be further aggravated by activation of fibrinolysis

Category: Medical Subject Notes , Pathology Notes