Envenomation by Trimeresurus stejnegeri stejnegeri: clinical manifestations, treatment and associated factors for wound necrosis

Abstract Background: Trimeresurus stejnegeri stejnegeri bite induces tissue swelling, pain, thrombocytopenia, rhabdomyolysis, and acute renal failure. However, the incidence of coagulopathy, factors associated with wound necrosis, and the appropriate management of this condition have not been well characterized yet. Materials: This study included patients bitten by T. s. stejnegeri that were admitted to the study hospitals from 2001 to 2016. Patient characteristics, laboratory data, and management approaches were compared in victims with and without wound necrosis. Results: A total of 185 patients were evaluated: three patients (1.6%) were asymptomatic; whereas tissue swelling and pain, local ecchymosis, wound necrosis, coagulopathy, thrombocytopenia, rhabdomyolysis, and renal impairment were present in 182, 53, 13, 15, 10, 1, and 3 patients, respectively. One patient died from coagulopathy and hemorrhagic shock. Antivenom was administered to all envenomed patients at a median time of 1.8 h after the bite. The median total dose of antivenom was five vials. Chi-square analysis showed that bitten fingers, using cold packs during first aid, presence of bullae or blisters, lymphangitis or lymphadenitis, local numbness and suspected infection to be significantly associated with wound necrosis. After adjustment using a multivariate logistic regression model, only cold packs as first aid, bulla or blister formation, and wound infection remained significant. Conclusions: The main effects of T. s. stejnegeri envenomation are tissue swelling, pain, and local ecchymosis. We do not recommend the use of cold packs during first aid to reduce wound pain, as this may be a risk factor for wound necrosis. In addition, patients with bulla or blister formation should be carefully examined for subsequent wound necrosis. Antiplatelet use may worsen systemic bleeding. No severe rhabdomyolysis or renal failure was observed in this large case series, we therefore considered that they were not prominent effects of T. s. stejnegeri bite.研究背景：竹叶青指名亚种（Trimeresurus stejnegeri stejnegeri）咬伤可引发组织肿胀、疼痛、血小板减少症（thrombocytopenia）、横纹肌溶解症（rhabdomyolysis）及急性肾衰竭（acute renal failure）。但目前针对该类咬伤后凝血功能障碍（coagulopathy）的发生率、伤口坏死（wound necrosis）相关危险因素及适宜诊疗方案，尚未得到充分明确与系统表征。 研究对象与方法：本研究纳入2001年至2016年间就诊于合作研究医院的竹叶青指名亚种咬伤患者。对比分析伴伤口坏死与未伴伤口坏死患者的临床特征、实验室检测结果及诊疗方案。 研究结果：本研究共评估185例患者，其中3例（1.6%）无明显症状；其余患者中，182例出现组织肿胀与疼痛，53例出现局部瘀斑（ecchymosis），13例出现伤口坏死，15例出现凝血功能障碍，10例出现血小板减少症，1例出现横纹肌溶解症，3例出现肾功能损害。1例患者因凝血功能障碍及失血性休克死亡。所有中毒患者均接受了抗蛇毒血清（antivenom）治疗，给药中位时间为咬伤后1.8小时，中位总给药剂量为5瓶。卡方检验结果显示，咬伤部位为手指、急救时使用冷敷、出现大疱或水疱（bullae or blisters）、合并淋巴管炎（lymphangitis）或淋巴结炎（lymphadenitis）、局部麻木及疑似感染，均与伤口坏死存在显著相关性。经多因素logistic回归（multivariate logistic regression）校正后，仅急救时使用冷敷、大疱或水疱形成及伤口感染仍为独立危险因素。 研究结论：竹叶青指名亚种蛇咬伤的主要临床表现为组织肿胀、疼痛及局部瘀斑。不建议在急救时使用冷敷以缓解伤口疼痛，因其可能为伤口坏死的危险因素。此外，对于出现大疱或水疱的患者，需密切监测其后续是否发生伤口坏死。抗血小板药物可能加重全身出血风险。本大样本病例系列未观察到严重横纹肌溶解症或急性肾衰竭病例，因此认为此类症状并非竹叶青指名亚种咬伤的显著临床表现。