Hemostasis dynamics during coagulopathy resulting from Echis envenomation

This work provides a graphic description of the time course of hemostasis tests results during spontaneous evolution of Echis envenoming and correction of hemostasis disorders with antivenom therapy. The dynamics of fibrinogenemia (g L(-1)), prothrombin time (PT, %), activated partial thromboplastin time (aPTT, patient/normal ratio) and platelet count (Giga L(-1)) were collected from coagulopathic envenomed patients of a 12 years prospective study in Africa. Sixty patients were included. 47 of them (78%) received an antivenom (33 ± 12 ml) and 13 did not. Thirty patients (50%) presented bleeding. Only one patient died. The time for fibrinogen to be more than 1 g L(-1) was 181 ± 116 h (7.5 days) in the spontaneous evolution group versus 40 ± 21 h in the antivenom group (p < 0.0001). The times for reaching a PT above 50% were 140 ± 64 min (5.8 days) versus 25 ± 15 h (p < 0.00001) and for reaching an aPTT less than 1.5 times the normal values, 116 ± 76 h (4.7 days) versus 10 ± 9 h respectively (p < 0.0002). Thrombopenia was not a common feature of Echis envenomation. This study is the first one to provide a chart of the evolution of the hemostatic tests during envenomation caused by Echis bites. The plots enable to estimate that, in Echis envenomation, in the absence of antivenom administration, hemostasis remains severely affected until the 8-10th day of evolution. On the contrary, efficient antivenom against African vipers corrects clotting functions within a few hours.