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Management of snake and spider bites
Information on snake and spider bites is available 24 hours a day from the NSW Poisons Information Centre on 131 126.
Note that this page is not intended as a comprehensive guide to the management and treatment of snake and spider bites but rather as a general guide.
Some facts about snakes and spiders
Venomous snake and spider bites are uncommon but may be life-threatening and difficult to treat.
- Bites from venomous snakes and spiders can occur without venom injection. Between 20 and 80 per cent of people bitten develop no symptoms and do not require antivenom.
- Almost all snake bites occur on limbs. Those especially at risk from snakebite include snake-fanciers, very young children in snake-prevalent areas, and young males.
- Envenomation by Australian snakes causes neurotoxicity (progressive paralysis) and haemotoxicity (coagulopathy). Myolysis and renal damage may also occur. The proportions of these effects varies between different snake species. Local effects are usually minor or absent.
- A wide variety of venomous snakes reside in NSW. Only the death adder and the red-bellied black snake are correctly identified by most people.
Selecting the correct antivenom for snake bite
To select the correct antivenom:
- the snake must be identified by a recognised professional herpetologist
OR
- the snake of origin of the venom must be identified via an unequivocal positive result with the CSL Venom Detection Kit on a swab from the bite site or from urine. The test should be done by a laboratory-trained person. Note that a positive bite-site test, without clinical or laboratory evidence of envenomation, does not automatically imply the need for giving antivenom.
OR
- there is accurate local knowledge of the types of venomous snakes occurring in the area. This may, for instance, permit the use of two specific antivenoms to cover all possibilities, which would be less expensive and possibly safer than the use of polyvalent antivenom.
Spiders
On the east coast of NSW, any bite from a large black or dark-coloured spider must be considered potentially dangerous. You need to be an expert to distinguish funnelweb spiders (Atrax or Hadronyche) from non-venomous types of spiders. On the other hand, the redback spider is widely known and recognised as a venomous spider. Effective antivenoms are available for both funnelweb and redback envenomation.
First aid
First aid recommendations for envenomation are to firmly apply a compression bandage around the bite site then around the whole limb and immobilise the limb with a splint. This delays systemic venom absorption.
If you don't have enough material to cover the whole limb, a broad tourniquet applied firmly to the limb without disturbing the distal pulses is better than nothing—as long as the person is totally immobilsed.
If the snake envenomation is severe, the victim will become progressively more unwell without appropriate treatment. On the other hand, funnelweb envenomation is often more dramatic, sometimes leading to a critical state in less than an hour.
Hospital treatment
Hospital personnel do the following:
- If the snake has not been expertly identified, cut away part of the compression bandage and test the bite site and urine with the CSL Venom Detection Kit.
- When the antivenom becomes available, remove the first aid measures.
- Arrange baseline tests, including clotting studies.
- Give antivenom if the victim has clinical or laboratory evidence of significant envenomation. The decision on when to treat may be difficult and often warrants discussion with a clinician with experience of the problem. The correct dose of antivenom is whatever is required to reverse paralysis and coagulopathy. This may be one or several units. The choice of antivenom follows the principles in step 3 above. Antivenoms are heterogenic immunoglobulins and anaphylaxis is always a potential hazard. Have adrenaline 1:1000 drawn up and ready for use. Always read the antivenom package literature before giving the antivenom.
- Maintain respiration and circulation and use other supportive measures as appropriate.
- Contact the NSW Poisons Information Centre on 131 126 if you need telephone advice. If necessary, appropriate consultants will discuss management directly with you.
Where can I get more information?
Have a look at the following websites:
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