Snake Bites


NEBOSH are now focusing hard on using more new questions in their exam papers to try to ensure that students learn the syllabus instead of just memorising set answers to frequently asked questions. This is because they want to ensure that students actually understand the topics and are able to analyse and discuss the issues involved. One of the new questions in the recent IDIP Unit B paper was about precautions to prevent being bitten by snakes and the first aid procedures to follow in the event of a snake bite.  Most of the answers submitted showed that despite this being a part of the current syllabus, it is an area that students were not prepared for and did not know much about.

There’s an excellent paper available on the Internet published by the World Health Organisation (WHO), but it’s quite long (162 pages) and not for the squeamish. It’s mainly for the South East Asia region, but the principles it discusses would apply anywhere in the world. It’s been written for the medical community and health workers and has photos of most of the common dangerous snakes, and of some quite horrifying physical effects from snake bites. It also tells you quite a lot about the scale of the problem and the potential treatments. One of the main points to learn is that anti-venom is not something that you would carry around with you in a first aid kit. Anti-venom is different for each species of snake and needs to be administered in a hospital.

shutterstock_106286333

I think that most people’s knowledge of treating snake bites comes from old Hollywood films, where the hero cuts into the wound from the bite and sucks out the venom before binding it up tightly. This used to be the recommended treatment, even as recently as the 1980’s. I have a definitive text on Sri Lankan snakes written by an eminent authority at that time which was still claiming this was a common treatment procedure. Today, however, this is not part of our medical practice; these techniques are all now forbidden. Current first aid practice tells us not to cut into the wound as that spreads the poison and introduces new infections. Do not try to suck out the poison as it will be ineffective, except at poisoning yourself as well. Do not bind up the area or apply a tourniquet as the reaction to the venom will make the affected area swell up, and binding will restrict blood flow leading to possible gangrene or loss of the limb. Do keep the victim calm, inactive and get them to hospital as quickly as possible. Identify the type of snake, if possible, so that the right kind of anti-venom can be administered if needed at the hospital.

Many snake bites do not result in poisoning. At the hospital the medical staff will wait for symptoms to appear before administering treatments because of the risks it involves. Only around 25% of people that are bitten will require special treatment in the hospital.

Snake anti-venom is expensive and is produced from venom milked from live snakes. So the anti-venom has to be matched to the type of snake that made the bite. In some countries, polyvalent anti-venoms are available which can be used against several different species. In India, for example, there is a 4 species polyvalent anti-venom. The venom taken from live snakes is diluted and injected into horses or sheep which produce anti-bodies to counter it. These antibodies are collected from the animals and used to make the anti-venom. This then has to be administered to the patient slowly over 1 hour using an intra-venous drip. Because the anti-bodies have come from an alien species there is a high risk of anaphylactic shock, so medical staff need to be ready to inject adrenaline to counter this. There are some species of snakes for which there is currently no approved anti-venom available (such as coral snakes in the USA).

Snake bites are quite a significant health issue, WHO estimate that there are over 5 million snake bites per year with 125,000 fatalities worldwide. Exact numbers are difficult to calculate as many cases are not reported to the authorities, and are treated by local traditional healers with the outcomes unknown.

World Health Organisation

apps.searo.who.int/PDS_DOCS/B4508.pdf

WebMD

http://www.webmd.com/first-aid/snakebite-treatment


Kim Batten