Defibrination during warfarin therapy in a man with protein C deficiency.
A 57 year old man presented with apparently spontaneous lower extremity deep vein thrombosis and pulmonary embolism. He was treated in conventional fashion with intravenous heparin and oral warfarin. After 4 daily doses of warfarin the prothrombin and proconvertin (P+P) time was within therapeutic range, and heparin was stopped. Over the next six hours complete defibrination occurred, associated with severe bleeding complications. Functional protein C measured after normalization of routine coagulation tests averaged 40% of normal, and was only 3.5% of normal immediately prior to the episode of defibrination. We conclude that the very low functional protein C levels seen immediately prior to defibrination were caused by a combination of pre-existent protein C deficiency and warfarin therapy, and directly predisposed to defibrination once heparin was stopped, despite "therapeutic" warfarin anticoagulation. Exacerbation of intravascular coagulation should be considered a potential prothrombotic effect of warfarin therapy in protein C deficient individuals.
D000347:Afibrinogenemia / Q000209:etiology*; D004211:Disseminated Intravascular Coagulation / Q000150:complications / Q000188:drug therapy; D006023:Glycoproteins / Q000172:deficiency*; D006493:Heparin / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D011486:Protein C; D011655:Pulmonary Embolism / Q000188:drug therapy / Q000209:etiology; D013924:Thrombophlebitis / Q000188:drug therapy / Q000209:etiology; D014859:Warfarin / Q000009:adverse effects* / Q000627:therapeutic use
D006023:Glycoproteins; D011486:Protein C; D014859:Warfarin; D006493:Heparin