title: Effect of antivenom therapy of Rhabdophis tigrinus (Yamakagashi snake) bites.
abstract: BACKGROUND
  Rhabdophis tigrinus (Yamakagashi snake) is a rear-fanged colubrid snake present throughout Russia and Asia. Its venom induces life-threatening hemorrhagic symptoms and severe disseminated intravascular coagulation with a fibrinolytic phenotype. R. tigrinus antivenom manufactured by the immunization of horses to neutralize the venom has the risk of adverse events such as anaphylaxis and serum sickness disease. It should be used when benefit is greater than the risk of adverse effects; however, its efficacy has not been well evaluated. Although our previous survey of nine cases demonstrated that seven of all cases treated with antivenom survived, the clinical characteristics and prognosis without antivenom administration remained unclear. We assumed that R. tigrinus antivenom administration overlaps self-recovery with supportive care. We aimed to determine the association between antivenom administration and outcome with further analyzed cases.
  
  
  METHODS
  We retrospectively reviewed the records of the Japan Snake Institute between January 1, 1973 and December 31, 2013. Antivenom and without antivenom groups were compared with regard to baseline demographic features, treatment-related factors, and outcomes.
  
  
  RESULTS
  In total, 34 patients were analyzed (97% male, median age 37.5 years). Twenty-five patients were further examined from our previous study. On admission, the median levels of fibrinogen and fibrinogen degradation products were 35 mg/dL and 200 μg/mL, respectively, and platelet counts were 107,000/mm(3). The median disseminated intravascular coagulation score (defined by the Japanese Association of Acute Medicine) was 5. Antivenom was administered to 19 patients, with a median interval of 32 h between bite and antivenom administration. The in-hospital mortality rate was 12%. In univariate analysis, baseline characteristics and laboratory data were not significantly different between the antivenom and without antivenom groups. Hospital mortality in the antivenom group was significantly better than that in the without antivenom group (0% vs. 26.7%, P = 0.03). Moreover, the number of patients developing renal failure requiring hemodialysis was significantly lower in the antivenom group (5.3% vs. 40.0%, P = 0.03).
  
  
  CONCLUSIONS
  In our small retrospective study, antivenom administration was likely to be effective in the management of R. tigrinus bites. Apparently, further research is required to confirm its efficacy.
authors.affiliation: Emergency Medical Center, Kagawa University Hospital, 1750-1 Ikenobe, Miki Kita, Kagawa 761-0793 Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Hifumi
authors.affiliation: The Japan Snake Institute, Yabutsuka 3318, Ota Gumma, 379-2301 Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sakai
authors.affiliation: Department of Bacteriology II, National Institute of Infectious Disease, Gakuen 4-7-1, Musashimurayama-shi, Tokyo 208-0011 Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yamamoto
authors.affiliation: Department of Internal Medicine, Kaizuka Hospital, Hakosaki 7-7-27, Higashi-ku, Fukuoka 812-0053 Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Murakawa
authors.affiliation: Department of Immunology, National Institute of Infectious Disease, Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640 Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Ato
authors.affiliation: Department of Bacteriology II, National Institute of Infectious Disease, Gakuen 4-7-1, Musashimurayama-shi, Tokyo 208-0011 Japan.
authors.forename: Keigo
authors.initials: K
authors.lastname: Shibayama
authors.affiliation: Division of Critical Care Medicine and Trauma, National Hospital Organization Disaster Medical Center, 3256 Midori-cho, Tachikawa, Tokyo 190-0014 Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kato
authors.affiliation: Division of Critical Care Medicine and Trauma, National Hospital Organization Disaster Medical Center, 3256 Midori-cho, Tachikawa, Tokyo 190-0014 Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Koido
authors.affiliation: Division of Critical Care Medicine and Trauma, Yamanashi Prefectural Central Hospital, 1-1-1 Fujimicho, Kofu, Yamanashi 400-8506 Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Inoue
authors.affiliation: Emergency Medical Center, Kagawa University Hospital, 1750-1 Ikenobe, Miki Kita, Kagawa 761-0793 Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Abe
authors.affiliation: Emergency Medical Center, Kagawa University Hospital, 1750-1 Ikenobe, Miki Kita, Kagawa 761-0793 Japan.
authors.forename: Kenya
authors.initials: K
authors.lastname: Kawakita
authors.affiliation: Emergency Medical Center, Kagawa University Hospital, 1750-1 Ikenobe, Miki Kita, Kagawa 761-0793 Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Hagiike
authors.affiliation: The Chemo-Sero-Therapeutic Research Institute (KAKETSUKEN), 1-6-1 Okubo, Kita-ku, Kumamoto-shi, Kumamoto 860-8568 Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ginnaga
authors.affiliation: Emergency Medical Center, Kagawa University Hospital, 1750-1 Ikenobe, Miki Kita, Kagawa 761-0793 Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kuroda
keywords: Antivenom; Rhabdophis tigrinus; Yamakagashi