Clinical characteristics of yamakagashi (Rhabdophis tigrinus) bites: a national survey in Japan, 2000–2013

BACKGROUND Yamakagashi (Rhabdophis tigrinus) is a species of pit viper present throughout Russia and Eastern Asia. Although R. tigrinus venom is known to induce life-threatening hemorrhagic symptoms, the clinical characteristics and effective treatment of R. tigrinus bites remain unknown. The present study aimed to clarify these issues. METHODS Records in the Japan Snake Institute between 2000 and 2013 were retrospectively investigated. The following were determined: patient characteristics, coagulation and fibrinolytic system abnormalities, effect of antivenom treatment, and outcomes. RESULTS Nine patients (all males; median age, 38 years) with R. tigrinus bites were identified. On admission, the median levels of fibrinogen and fibrinogen degradation products, and platelet counts were 50 mg/dL, 295 μg/mL, and 107,000/mm(3), respectively. The median (minimum-maximum) disseminated intravascular coagulation (DIC) score defined by the Japanese Association of Acute Medicine was 8 (1-8). Antivenom was administered to seven patients, with a median interval of 35 h between bite and antivenom administration. All patients treated with antivenom survived, and the in-hospital mortality rate was 11%. CONCLUSIONS Patients with R. tigrinus bites presented with DIC of a fibrinolytic phenotype, which can result in life-threatening injury unless appropriate antivenom and DIC treatment are provided.