Severe coagulopathy after a massasauga rattlesnake bite

The anti-myotoxic effects and mechanisms of Sinonatrix annularis serum and a novel plasma metalloproteinase inhibitor towards Deinagkistrodon acutus envenomation

Non-venomous snakes commonly evolve natural resistance to venom to escape predators. Sinonatrix annularis serum has been shown to inhibit Deinagkistrodon acutus venom-induced hemorrhage and upregulation of serum CK, CK-MB, LDH, AST and ALT levels. Using TMT-labeled proteomics analysis, 168 proteins were found to be altered significantly in the envenomed gastrocnemius muscle and categorized into pathways such as complement and coagulation cascades, leukocyte transendothelial migration, and JAK/STAT signaling. These alterations were mitigated by S. annularis serum. Subsequently, a novel metalloproteinase inhibitor, SaMPI, was isolated from S. annularis serum by two-step chromatography. It showed strong antidotal effects against D. acutus envenomation, including inhibition of subcutaneous bleeding caused by crude venom and DaMP (a metalloproteinase derived from D. acutus) activity in a 1:1 ratio. Histology and immunoblotting analyses demonstrated that SaMPI mitigated myonecrosis, reduced neutrophil infiltration and local inflammatory factor release, and retarded JAK/STAT and MAPK signaling activation. Analysis of the SaMPI gene cloned by 5'-RACE revealed a shared sequence identity of 58-79% with other SVMP inhibitors. These findings demonstrate the protective effects of SaMPI and indicate its potential value as a candidate for viper bite adjuvant therapy.

In cold blood: Observational descriptive review of Eastern Massasauga rattlesnake bites reported to a single poison center over time

The Eastern Massasauga rattlesnake (Sistrurus catenatus catenatus) is a pit viper indigenous to the Great Lakes region and the only venomous snake native to Michigan. It is small-to-medium, thick-bodied with dark brown, bow-tie shaped blotches. Its behavior is described as reclusive and docile and it prefers damp habitats. The venom of the Eastern Massasauga is primarily cytotoxic and hemotoxic. Previous literature describes severe coagulopathies following Eastern Massasauga envenomings, with some resulting in death. The objective of this study was to characterize Eastern Massasauga envenomings in humans reported to the Michigan Poison & Drug Information Center from 2003 to 2020, including a description of clinical manifestations, incidence and characterization of coagulopathies, and medical outcome severities. This was a retrospective review of Eastern Massasauga snakebites reported to our state poison center over time. Coagulopathies were classified according to previous toxicological snakebite literature. The degree of envenoming was scored using an institutional guideline, representing a modified version of validated snakebite severity score system. Our longitudinal review demonstrated Eastern Massasauga bites led to clinically significant toxicity, including persistent, recurrent, and late coagulopathies, though with low incidence of bleeding events. Cases typically resolved with use of antivenom. This, to our knowledge, is the largest descriptive case series characterizing Eastern Massasauga snakebites.

Caring for patients with venomous Crotalinae snakebites

Venomous snakebites are surprisingly common in the US. This article provides an overview of what to do when a patient has been bitten by a North American pit viper, a venomous subset of indigenous snakes.