Snake-bite Envenomation: A Comprehensive Evaluation of Severity, Treatment and Outcome in a tertiary Care South Indian Hospital

摘要

Snake bite is a known cause for increased morbidity and mortality in India. A six year retrospective review of medical records was carried out to study the trends, epidemiology, snakebite severity, treatment, and outcome among 252 patients of snakebite in a tertiary care South Indian hospital. Severity assessment showed an average grade of 3.3 with moderate injury. Hemotoxicity and Cellulitis was the most common complications among unidentified snake bites and cobra bites. An average of 11.9 ± 9.3 vials (N=2994) were administered and 96 (48%) anaphylactic reactions were observed. The mortality rate was 10.7% (n=27) while 78.9%of patients improved with 8.2±8.3 day hospitalization period. Severity scores, complications and outcomes were significantly associated with type of snakes, age distribution and linearly correlated to the time elapsed between snake bite instance and hospitalization. Mortality and morbidity can be minimised by the early interventions following identification of snakes, associated sign, symptoms and severity. Introduction In India, it is estimated that up to 20,000 people die annually from snake bites. Morbidity is also significant and there seems to have been little improvement in reducing the fatalities over the years in spite of now having good supplies of polyvalent anti-snake venom (ASV) available in all population centers. The major reason for high mortality rate (about 5% to 10% of all those reporting bites) is the delay in getting the victim to a well-equipped casualty treatment facility fast enough. Snake bite, an important cause of death in rural patients in developing countries, is a neglected public health problem. Worldwide, of the estimated 5 million people bitten by snakes each year, about 1,25,000 die. 1 More than 2,00,000 cases of snake bite are reported in India each year and 35,000–50,000 of them have turned out to be fatal. Reports from Maharashtra, State in India, disclose that an estimated 10,000 annual venomous snake bites account for 2000 deaths. 2 Romulus Whitaker, pointed out that, the Indian cobra (Naja naja), the common krait (Bungarus caeruleus), the Russell's viper (Daboia russelii) and the sawscaled viper (Echis carinatus) are basically four venomous snakes found in India. He called them the “Big Four” which are mainly responsible for Indian snake bite mortality. 3 The concept of the ‘‘Big Four'‘ restricts sound epidemiological work and the development of effective snake antivenoms. It should be replaced by the model introduced in the 1980s by the World Health Organization, which has not received adequate circulation and implementation. 4The type of snake bite varies from region to region. Wherever one species prevails, the chances of humans coming into their contact is higher, then the bite of that species will be more common. 3 Snake bite is continuing to be a major medical concern in India. World Health Organization survey reports that 1.2–2.4 deaths occur per 100,000 victims with a mortality level of 25,000 per annum. There are many causal factors that contribute to this mortality rate, and many questions remain unanswered. To make more meaningful use of resources such as antivenom, ventilator therapy and renal support systems in patients with snake bite, it is important that the healthcare providers aptly identify those at high risk of potentially fatal complications. Simple demographic and clinical characteristics could be used to help doctors distinguish between high-risk and low-risk patients. To be useful, the predictors like snake bite severity score should be simple, accurate and clinically credible. There has, however, been very little qualitative herpetological work in India, since the 1940s. Limited statistics on mortality and morbidity due to envenomation are available. Such data have recognizable limitations. 4 There are very limited Indian studies which have assessed severity and its role in predicting outcome of snake envenomation. The factors, like time-lags