How do you treat a snakebite in the wilderness?

Travellers have an exaggerated fear of snakes. In general snakes move swiftly to avoid humans and are rarely seen. Some species of snakes, especially the adder family prefer to remain hidden and are the commonest snake involved in bites on travellers. The local population tend to come into contact with different species as the result of farming activities and children playing. On expedition when either working or travelling in environments where snakes are likely to be living, team members should be encouraged to wear boots and even trousers, never collect firewood or dislodge stones and logs with bare hands. Never put one's hand into burrows or holes. If working from a field base, maintain hygiene, as food attracts vermin, which will attract snakes.

When snakes strike they do not always inject venom into their prey (aprox 50%). However it is virtually impossible to distinguish between a bite in which venom has and has not been injected, in the early stages. And hence both must be treated in the same way. A useful early sign of envenomation can be seen if 10mls of blood is withdrawn and left in a glass vial for 20min, if it does not coagulate it indicates systemic envenomation, and confirms the need for treatment. Envenomation causes local swelling, bleeding, bruising, lymphangitis, blistering, necrosis and infection. Snake venom acts in several very distinct ways depending on the species, for example cobras and mambas inject a neurotoxin, (however some have haemolytic qualities) which as the name suggests acts on neurotransmitters and can result in quite rapid paralysis. Other snakes have a variety of myotoxins, cardiotoxins and haemotoxins. Descending paralysis starts with ptosis (droopy eyes) and external ophthalmoplegia, (loss of eye movement) progressing to respiratory failure. Occasionally snakes spray their venom into victim's eyes, causing painful chemical conjunctivitis and the risk of corneal ulceration, anterior uveitis and secondary infection. The eyes should be irrigated immediately with water.

Treating Snakebites

1. Calm the victim.
2. Wash the wound by pouring water over the wound, attempting to wash away any venom
3. Dress with sterile dressing, being careful not to expose any cuts on your own hands to the lesions as venom may still be present.
4. Apply a compression dressing along the length of the limb starting distally and proceeding proximally, apply a splint at the same time unless the snake is known, and does not cause paralysis.
5. Immobilise the limb and if possible elevate to minimise venom spread.
6. Give simple analgesia, not aspirin.
7. Transport to hospital.

Do not attempt to capture the snake; if still present it will only bite again. Several devices are currently available on the market for vacuum extracting the venom from bites. There is no evidence that these are effective and it may well be that their only function is to increase blood flow into the region thus increasing the spread of the venom. The use of antivenom should usually be reserved for hospital use, as it has a substantial risk of anaphylaxis, it is also difficult in the third world to obtain specific antivenom as production is varied and many countries import their antivenom from other counties and hence have varied effectiveness. Local advice is imperative.

When arriving in hospital
Do not allow the compression dressing to be removed until antivenom has been given. A window can be cut to allow visualisation of the bite area.