Envenomation Basics

General First Aid

• Ensure your own safety before approaching to provide help
• Administer Basic Life Support if required
• Provide reassurance to the victim and avoid unnecessary movement
• Apply Pressure Immobilisation bandage if snake or Funnel Web Spider envenomation is suspected
• Do not apply a tight tourniquet
• Do not wash the wound
• Do not suck or cut the wound
• Seek expert medical attention as soon as possible
• Where possible take medical assistance to the victim

Pressure Immobilisation

This very important two-stage first aid intervention has been proven to have a significant effect on reducing absorption of Australian snake, marine and spider venoms into the blood stream. This will delay envenomation until expert medical care is available.

The technique is based on the knowledge that many Australian snake, marine and spider venoms do not enter the blood stream immediately but rather they are absorbed into the lymphatic system first before entering the blood. The aim is to prevent transport of the venom through the lymphatic system preventing it from entering the blood stream.

The pressure immobilisation technique may be used for

• All Australian snakes
• Funnel Web spiders and Mouse spiders
• Blue Ringed Octopus
• Cone Shells

Pressure
A bandage is applied over the affected limb. It should commence initially over the area of the bite site and then be extended to enclose the entire limb. If no formal bandages are available, torn strips of clothing can be used as an alternative. A compression bandage cannot be applied to the trunk

The bandage should be applied with the same firmness used to bandage a sprained ankle. The bandage should not be too tight that it interferes with blood flow in and out of the limb. To avoid unnecessary limb movement, the bandaging may be applied over clothing rather than taking the clothing off

Correctly applied, the compression bandage may be left in place for many hours without any threat to limb circulation. It must not be removed until the victim is in a location with expert medical care and availability of the appropriate antivenom.

Immobilisation
Once a compression bandage is applied, the limb should be splinted to prevent unnecessary movement that may encourage “muscle pump” spread of venom through the lymphatics.

Any unnecessary movement should be avoided (ie envenomation victims should be stretchered to safety rather than walk to safety)

Serum Sickness

Following administration of antivenom containing large volumes of foreign (horse or rabbit) immunoglobulin, victims of envenomation may develop serum sickness.

Symptoms include

• fever (high temperature)
• rash
• joint aches and pains
• fatigue (feeling tired and weak)

The symptoms typically occur between 4-10 days following administration of antivenom and may persist for up to two weeks.

Symptoms of serum sickness can be reduced by prescription of corticosteroid (Prednisolone) by a doctor. If multiple doses of antivenom are required to treat envenomation, corticosteroid maybe prescribed by the doctor at the time of discharge from hospital as a precaution.