![]() ![]() Most guidelines are based on clinical grading systems that rely on the clinician's ability to evaluate the clinical manifestations evident in the patient. The recommendations on which our own institutions treatment protocol is based were developed in 2005 and are largely derived from the knowledge and experience of a single surgeon. Guidelines have been developed to assist doctors to treat patients with snakebite. In addition, coagulopathy may not be identified until the patient manifests with lethal haemorrhaging. Cytotoxic swelling may progress insidiously, as may the effects of systemic toxicity, resulting in shock. The severity of envenomation may not be initially appreciated by admitting doctors. This process of establishing severity is highly subjective and is included in guidelines for snakebite management in SA. In the absence of objective criteria, the presumed severity of a bite is typically dependent on the attending doctor's own experience and clinical judgement. In the case of cytotoxic bites, the severity of injury is critically dependent on the body part bitten and the depth at which the venom is injected. The potency of venom varies with the species of snake and in larger snakes the volume of expelled venom is usually higher. Defence bites that are designed to fend off danger may in some cases deliver less or no venom, resulting in a dry bite. Snakes will utilise their venom differently depending on the situation, controlling the volume injected and the fang contact time with their prey. The severity of a snakebite is highly variable and dependent on numerous factors. Rarely, the boomslang (Dispholidus typus), a colubrid with a haemorrhagic venom, can cause potentially fatal bleeding. The black mamba (Dendroaspis polylepis) and various cobra (Naja) species are elapids possessing potent neurotoxic venom and muscle weakness. Prevalent species include the Mozambique spitting cobra (Naja mossambica) and puff adder (Bitis arietans), an elapid and viperid respectively, both of which have a potent cytotoxic venom. ![]() Snake species and density vary across the regions of SA. There are some 38 venomous snake species in South Africa (SA), of which approximately half are dangerous to humans. Until our severity score has been validated (or modified) for use across SA, we propose to name it the Zululand Severity Score a true SA Severity Score may follow. Its value is greatest when used in those patients who fall in the mild to moderate clinical category. Our results show that the identified score is a useful adjunct to clinical assessment in managing snakebite. The positive predictive value and negative predictive value were 81.8% and 65.2%, respectively.ĬONCLUSION. Testing of the score on the validation cohort produced a specificity of 96.6% and a sensitivity of 22.5%. Each risk predictor was assigned a score of 1 receiver operating characteristic curve analysis returned a value of >4 out of 6 as the optimal cut-off for prediction of an ATI (area under the curve 0.804 95% confidence interval 0.758 - 0.84). Six risk predictors for ATI were identified from the development cohort: age 7 hours (OR 4.63), white cell count >10 x 10 9/L (OR 3.15), platelets 1.2 (OR 2.25). Of 879 snakebite admissions, 146 in the development cohort and 40 of 100 in the development validation cohort reached the primary endpoint of an ATI. The score was then tested prospectively for accuracy in a new validation cohort consisting of 100 patients admitted for snakebite to our unit from 1 December 2014 to 31 March 2015. These factors were then used to develop a standard scoring system. Factors predictive of ATI and the optimal cut-off score for predicting an ATI were identified. The development cohort consisted of 879 patients with snakebite who presented to the Ngwelezane Hospital Emergency Department from December 2008 to December 2013. The primary outcome was an active treatment intervention (ATI) defined as antivenom treatment or any surgical procedure. We studied all snakebite admissions to a regional hospital in KwaZulu-Natal, SA. To develop and validate a scoring system for managing snakebites in South Africa (SA). IIIMB BCh, FRCP, PhD School of Clinical Medicine, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa IIPhD School of Public Health, College of Health Sciences, University of KwaZu lu-Nata l, Durban, South Africa IMB BCh, FCEM, MPhil School of Clinical Medicine, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa Classifying snakebite in South Africa: Validating a scoring system ![]()
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