The association between the neutrophil lymphocyte ratio and local edema after viper snake envenomation in South Korea.

The role of the inflammatory process in the pathogenesis of local edema-related envenomation has not been explored with endemic venomous snakebites in Korea. Gloydius species are responsible for most snakebites in South Korea. In this study we aimed to investigate whether the neutrophil-lymphocyte ratio is relevant to snake envenomation-induced local edema in South Korea. This retrospective study divided 126 patients into two groups according to local edema severity at presentation. Logistic regression models were used to investigate the association between the neutrophil-lymphocyte ratio and local edema. Sixty-one (48.4%) patients had grade 2 or higher local edema at presentation despite 21 of them being given antivenom before presentation. During hospitalization, local edema progressed in 61 patients 48 (11.5-48) hours after presentation, and 54 patients demonstrated grade 3 or higher local edema. A higher neutrophil-lymphocyte ratio at presentation after adjustment for factors related to envenomation and antivenom administration and factors influencing the neutrophil-lymphocyte ratio were associated with both a higher grade of local edema at presentation and a higher peak local edema grade during hospitalization. The delta neutrophil-lymphocyte ratio during the first 24 h after presentation was related to the local edema progression after presentation. The neutrophil-lymphocyte ratio at presentation is associated with the severity of local edema-related envenomation. Furthermore, the change in the neutrophil-lymphocyte ratio during the first 24 h is related to the risk of local edema progression. Further clinical and experimental research aimed at investigating the role of inflammation on the pathogenesis of local edema should be conducted. This study may suggest the introduction of short-term anti-inflammatory agents considering the failure of antivenom to curb local edema.