Severe and prolonged hypofibrinogenemia following Protobothrops cornutus snake bite: A case report from Vietnam

We report a clinical case of severe and prolonged hypofibrinogenemia caused by envenomation from Protobothrops cornutus, an pit viper species found mainly in Vietnam and parts of southern China. A 60-year-old woman was bitten while hiking in Cuc Phuong national forest of Ninh Binh province, Vietnam. Although WHO guidelines discourage antivenom administration for minor coagulation abnormalities, in this case, the decision was made due to a fibrinogen level <1.0 g/l and the patient's risk factors, including age (60 years) and untreated arterial hypertension, increasing the risk of spontaneous cerebral hemorrhage. Her fibrinogen level progressively dropped from 1.5 g/l to a nadir of 0.24 g/l at 112 hours post-bite, despite administration of 60 vials of monovalent Trimeresurus albolabris antivenom (produced by the Institute of Vaccines and Medical Biologicals (IVAC), Nha Trang, Vietnam, and distributed by Vabiotech). A temporary increase to 1.13 g/l was observed after infusion of 400 ml of cryoprecipitate, but hypofibrinogenemia relapsed thereafter and only stabilized after 181 hours after Protobothrops cornutus bite. This clinical case highlights the distinctive coagulopathy caused by Protobothrops cornutus envenomation with severe and prolonged hypofibrinogenemia despite the use of large doses of monovalent Trimeresurus albolabris antivenom (which was not specific to P. cornutus) and cryoprecipitate while liver and kidney functions, creatine kinase (CK) levels, remained within normal limits, indicating that the venom primarily affected the coagulation system without causing damage to other major organs.