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.