Bushviper wrote:An occlusive tourniquet can also cause the muscles in the limb to die off if it is left on for an extended period of time.
This is exactly the reason why the use of tourniquets are no longer advocated for the lay public. An arterial tourniquet by definition cuts off all oxygenated blood flow into the limb and will cause the tissue to die off if left in situ for sufficient time.
Death following an intravenous envenomation could still be considered as a death due to the direct effects of the venom as opposed to the indirect effects (as would be the case with anaphylaxis). One of the cases I mentioned was certainly an intravenous bite - both fangs penetrated the popliteal vein (that's the big one that runs behind your knee). Statistically, the chance of this happening (ie both fangs penetrating a major blood vessel) would probably be akin to winning the combined national lotteries of the UK, France, Germany and South Africa on the day of your wedding to the Queen of Sheba - while enduring a snowstorm in hell!
Statistics however, are of little comfort to the victim.
Intravenous bites have, to my knowledge, been documented in Bitis arietans, Naja annulifera, Dendroaspis polylepis and Cotalus adamanteus. I am sure there are others as well. Intravenous bite are extremely rare though - most snakebites, including those from many viperids, result in subcutaneous injection of venom.
Anaphylaxis to snake venom is a subject that has only been researched in detail comparatively recently. Those most at risk are people who are repetitively exposed to large quantities of aerosolized venoms - people who regularly work with spitting cobras as well as people milking snakes regularly and venom researchers. The risk of developing a sensitivity to snake venoms due to one or two previous bites, while possible, is negligible. I still have, somewhere at home, slides of a life-threatening bite from Crotaphopeltis hotamboeia (due to anaphylaxis).
Armata makes some very good points. I have mentioned in another post the danger of underestimating bites from the small arboreal vipers. It is my contention that ANY venomous snake has the potential to cause a life-threatening reaction and should be treated as such.
As I said earlier in this thread, very few doctors have the requisite specialist knowledge to treat a serious snakebite. The biggest problem with a doctor taking medical advice from a non-medically qualified person (even though that person may have the requisite specialized knowledge) is that of liability. In such a situation, the doctor will be held legally and ethically accountable for any and all treatment given. As an example, were you as a lay person to advise the doctor treating your friend for snakebite that he needed to administer antivenom (ie you have just prescribed a drug) and the patient developed an anaphylactic reaction to the antivenom and subsequently died, you would be completely off the hook. Should the victim's family decide to register a malpractice complaint or civil claim against the doctor, that doctor would be wholly accountable.
This example perhaps, illustrates the need to have a properly referenced protocol with recognized subject matter experts as contacts -ie Prof Muller, who is head of the department of Toxicology at the University of Stellenbosch would certainly (objectively) qualify as a recognized subject matter expert. My buddy from down the road who has been breeding snakes for 20 years and has been bitten 5 time this year already, would not!
Your point about the treating doctor being ambivalent when the victim is completely sure of the identification of the snake is valid. So too is your point about diplomacy. If you present to the emergency room with a professional looking, properly referenced protocol and a diplomatic demeanour your are far more likely to have the doctor take your input seriously than would be the case were you to storm into the hospital proclaiming yourself as THE snakebite expert while loudly instructing everyone to get out of your way. To reiterate my advice to Swazi, the gold standard would be to set up a meeting with the hospital emergency department and staff involved to discuss your bite protocol before you needed to use it.
Armata, I am sure that between yourself and Prof Muller you will certainly produce a good emergency protocol. I look forward to seeing this, and also to the outcomes of the conference in November.
Just to end off, with regard to your point about not taking a live snake to hospital, several years ago a friend of mine who was crewing the Flight for Life helicopter in Jhb was called out for a snakebite (it turned out to be a rinkhals). On scene she scooped the dead snake into a bag and flew it to Baragwanath Hospital with the patient for identification. When she handed over to the emergency room staff that it was a rinkhals bite, she was asked how she knew this. She promptly upended the bag and dumped the now very much alive rinkhals into the crowded emergency room! (if you've ever been there you will know what I mean about crowded) It took several hours to find and recapture the snake again!
If ignorance is bliss, there must be a lot of happy people out there...