snakebite-safety issues

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC INTRODUCTION : A snakebite is an injury caused by a bite from a snake, often resulting in puncture wounds inflicted by the animal's fangs and sometimes resulting in envenomation. Snakes are most likely to bite when they feel threatened, are startled, are provoked, or have no means of escape when cornered. Encountering a snake is always considered dangerous and it is recommended to leave the vicinity. There is no practical way to safely identify any snake species as appearances may vary dramatically.

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC 1 . Snake venoms Composition of venom Snake venoms contain more than 20 different constituents, mainly proteins, including enzymes and polypeptide toxins. The following venom constituents cause important clinical effects: 1.1 Procoagulant enzymes ( Viperidae): that stimulate blood clotting but result in incoagulable blood. Venoms such as Russell’s viper venom contain several different procoagulants which activate different steps of the clotting cascade. The result is formation of fibrin in the blood stream. Most of this is immediately broken down by the body’s own fibrinolytic system. Eventually, and sometimes within 30 minutes of the bite, the levels of clotting factors have been so depleted (“consumption coagulopathy”) that the blood will not clot.

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC 1.2 Haemorrhagins (zinc metalloproteinases) that damage the endothelial lining of blood vessel walls causing spontaneous systemic haemorrhage. 1.3 Cytolytic or necrotic toxins - these digestive hydrolases (proteolytic enzymes and phospholipases A) polypeptide toxins and other factors increase permeability resulting in local swelling. They may also destroy cell membranes and tissues. 1.4 Haemolytic and myolytic phospholipases A2 - these enzymes damage cell membranes, endothelium, skeletal muscle, nerve and red blood cells.

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC 1.5 Pre-synaptic neurotoxins (Elapidae and some Viperidae) - these are phospholipases A2 that damage nerve endings, initially releasing acetylcholine transmitter, then interfering with release. 1.6 Post-synaptic neurotoxins (Elapidae) - these polypeptides compete with acetylcholine for receptors in the neuromuscular junction and lead to curare-like paralysis.

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC 2.0 Quantity of venom injected at a bite This is very variable, depending on the species and size of the snake, the mechanical efficiency of the bite, whether one or two fangs penetrated the skin and whether there were repeated strikes. The snake may be able to control whether or not venom is injected. For whatever reason, a proportion of bites by venomous snakes do not result in the injection of sufficient venom to cause clinical effects. Snakes do not exhaust their store of venom, even after several strikes, and they are no less venomous after eating their prey. Although large snakes tend to inject more venom than smaller specimens of the same species, the venom of smaller, younger vipers may be richer in some dangerous components, such as those affecting haemostasis.

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC 3.0 How common are snake bites in India ? It is difficult to answer this question because many snake bites and even deaths from snake bite are not recorded. One reason is that many snake bite victims are treated not in hospitals but by traditional healers. It estimated 200,000 bites and 15-20,000 snake bite deaths per year, originally made in the last century, are still quoted. No reliable national statistics are available. In 1981, a thousand deaths were reported in Maharashtra State.

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC 4.0 How do snake bites happen? Most snake bites happen when the snake is trodden on, either in the dark or in undergrowth, by someone who is bare-footed or wearing only sandals. The snake may be picked up, unintentionally in a handful of foliage or intentionally by someone who is trying to show off. Some bites occur when the snake (usually a krait) comes in to the home at night in search of its prey (other snakes, lizards, frogs, mice) and someone sleeping on the floor rolls over onto the snake in their sleep. Not all snake bites happen in rural areas. For example, in some large cities, such as Jammu in India, people who sleep in small huts (jhuggies) are frequently bitten by kraits.

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC 5.0 How can snake bites be avoided? Snake bite is an occupational hazard that is very difficult to avoid completely. However, attention to the following recommendations might reduce the number of accidents. Education! Know your local snakes, know the sort of places where they like to live and hide, know at what times of year, at what times of day/night or in what kinds of weather they are most likely to be active. Be specially vigilant about snake bites after rains, during flooding, at harvest time and at night.

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC Try to wear proper shoes or boots and long trousers, especially when walking in the dark or in undergrowth. Use a light (torch, flashlight or lamp) when walking at night. Avoid snakes as far as possible, including snakes performing for snake charmers. Never handle, threaten or attack a snake and never intentionally trap or corner a snake in an enclosed space. If at all possible, try to avoid sleeping on the ground. Keep young children away from areas known to be snake-infested. Avoid or take great care handling dead snakes, or snakes that appear to be dead.

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC Avoid having rubble, rubbish, termite mounds or domestic animals close to human dwellings, as all of these attract snakes. Frequently check houses for snakes and, if possible, avoid types of house construction that will provide snakes with hiding places

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC 6.0 Local symptoms and signs in the bitten part fang marks local pain local bleeding bruising lymphangitis lymph node enlargement inflammation (swelling, redness, heat) blistering local infection, abscess formation necrosis

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC 7.0 Management of snake bite Stages involved in management of snake bite First aid treatment Transport to hospital Rapid clinical assessment and resuscitation Detailed clinical assessment and species diagnosis Investigations/laboratory tests Antivenom treatment Observation of the response to antivenom: decision about the need for further dose(s) of antivenom

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC Supportive/ancillary treatment Treatment of the bitten part Rehabilitation Treatment of chronic complications 7.1 First aid treatment First aid treatment is carried out immediately or very soon after the bite, before the patient reaches a dispensary or hospital. It can be performed by the snake bite victim himself/herself or by anyone else who is present.

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC 7.2 Aims of first aid attempt to retard systemic absorption of venom preserve life and prevent complications before the patient can receive medical care (at a dispensary or hospital) control distressing or dangerous early symptoms of envenoming arrange the transport of the patient to a place where they can receive medical care Above all, do no harm!

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC Local people may have great confidence in traditional (herbal) treatments, but they must not be allowed to delay medical treatment or to do harm. Most traditional first aid methods should be discouraged: They do more harm than good ! 7.3 Recommended first aid methods Reassure the victim who may be very anxious Immobilize the bitten limb with a splint or sling (any movement or muscular contraction increases absorption of venom into the bloodstream and lymphatics) Consider pressure-immobilisation (Fig ) for some elapid bites

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC Protect the patient (and others, including yourself) from further bites. While identifying the species is desirable in certain regions, do not risk further bites or delay proper medical treatment by attempting to capture or kill the snake. If the snake has not already fled, carefully remove the victim from the immediate area. Make sure to keep the bitten limb in a functional position and below the victim's heart level so as to minimize blood returning to the heart and other organs of the body. Do not give the patient anything to eat or drink. This is especially important with consumable alcohol, a known vasodilator which will speed up the absorption of venom. Do not administer stimulants or pain medications to the victim, unless specifically directed to do so by a physician.

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC Avoid any interference with the bite wound as this may introduce infection,increase absorption of the venom and increase local bleeding As far as the snake is concerned – do not attempt to kill it as this may be dangerous. However, if the snake has already been killed, it should be taken to the dispensary or hospital with the patient in case it can be identified. However, do not handle the snake with your bare hands as even a severed head can bite!

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC 7.4 The special danger of rapidly developing paralytic envenoming after bites by some elapid snakes: use of pressure-immobilisation Bites by cobras, king cobras, kraits or sea snakes may lead, on rare occasions, to the rapid development of life-threatening respiratory paralysis. This paralysis might be delayed by slowing down the absorption of venom from the site of the bite. The following technique is currently recommended: Ideally, an elasticated, stretchy, crepe bandage, approximately 10 cm wide and at least 4.5 metres long should be used. If that it not available, any long strips of material can be used. The bandage is bound firmly around the entire bitten limb, starting distally around the fingers or toes and moving proximally, to include a rigid splint.

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC The bandage is bound as tightly as for a sprained ankle, but not so tightly that the peripheral pulse (radial, posterior tibial, dorsalis pedis) is occluded or that a finger cannot easily be slipped between its layers.

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC Pressure immobilisation is recommended for bites by neurotoxic elapid snakes, including sea snakes but should not be used for viper bites because of the danger of increasing the local effects of the necrotic venom. Ideally, compression bandages should not be released until the patient is under medical care in hospital, resuscitation facilities are available and antivenom treatment has been started . Release of a tight tourniquet or compression bandage may result in the dramatic development of severe systemic envenoming.

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC 7.5 Transport to hospital The patient must be transported to a place where they can receive medical care (dispensary or hospital) as quickly, but as safely and comfortably as possible. Any movement, but especially movement of the bitten limb, must be reduced to an absolute minimum to avoid increasing the systemic absorption of venom. Any muscular contraction will increase this spread of venom from the site of the bite.

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Source :WHO compiled By K Krishnamurthy ,Asst.Safety Officer-ARDC THANK YOU