Hump nosed pit viper envenoming in Coastal Karnataka- unravelling the centuries of deadly camouflage

BackgroundThe Hump-nosed pit viper is a recognized but neglected medically significant species causing morbidity and mortality, with non-availability of a specific antivenom. There are many gaps in our understanding of its envenomation, including burden, clinical syndrome, complications and management. MethodologyThe study is a retrospective sub analysis of the Prospective VENOMS registry and hospital records of Hump Nosed Pit Viper envenomation from a single tertiary care center in coastal Karnataka from May 2018 to March 2024. Epidemiology, syndrome, complications and treatment strategies have been described. A linear mixed model analysis was conducted to study the effect of different therapeutic interventions in combating venom induced consumptive coagulopathy (VICC) Principal FindingsOf 46 cases, 24 patients had VICC. The most common complications were AKI (21.7%), TMA (10.9%) and stroke (4.4%). Anaphylaxis to ASV (23.9%) was the most common therapeutic complication. Therapeutic interventions included ASV, administration of blood products and therapeutic plasma exchange along with supportive care. The linear mixed model revealed that administration of blood products (p=<0.001) had the strongest influence on the INR value, however, often resulting in a transient decline in INR value. ASV (p=0.052) caused only marginally significant change in INR. The role of TPE could not be statistically inferred, however, individual cases with severe VICC improved without complications, therefore it required further study but can be considered in critical cases. Conclusions/SignificanceThis study describes the syndrome of hump-nosed pit viper envenomation, while highlighting the urgent need for a species-specific antivenom, recommends treatment strategies that can be used in the interim. Additionally, geo-spatial mapping draws attention to hotspots and the hypothesis that HNPV in coastal Karnataka have regionally distinct toxicity trends. Author SummaryIndia is often known as the snakebite capital of the world, with recent literature suggesting that not all death and disability is attributable to the "Big four" and highlighting regionally significant species of snake. In the Western Ghat region of India, envenomation by the Hump-nosed pit viper is increasingly being reported. In coastal Karnataka, it has been reported as the second most common cause of envenomation following the Russells Viper, causing systemic envenomation and death. However, little is known about why envenomation is common in this region, is it increasing, how to diagnose envenomation, its clinical syndrome, the anticipated complications, and most importantly, an effective treatment strategy. This study reports envenomation in 46 patients, resulting in 3 deaths, and 24 patients developing derangement in coagulation parameters.