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I've been seeing these snake bite threads here and there. There's a lot of good advice, and a LOT of bad advice. I've compiled information from the threads and written a guideline from a recent lecture our medical school class had on snake bite treatments. I hope it clears some things up and helps educate people on proper treatment.
Background:
Treatment:
OK, now that we have that down, there are additional treatment techniques you can use to slow venom spread. These are used if you absolutely cannot get medical help within 10-12 hours. Note however, that venom has local effects on tissue it contacts, meaning that if you choose this method, studies indicate there is a greater chance in actually losing the limb from great tissue destruction such as compartment syndrome.
Currently, the American Heart Association recommends applying pressure immobilization as described below because of a small chance of delayed systemic effects which can kill you (renal damage, widespread edema, severe hypotension, etc). However, American Board of Toxicology does NOT recommend using this because of the increased likelihood of limb loss.
Finally, things which have been proven to not work in slowing the venom:
And those bordering on idiocracy, unless I have missed a serious clinical trial:
Once at the hospital, you can expect something like this:
The bottom line is, the toxin is a peptide/protein, just like those in your own body. Antivenin is the only thing that will help here: something specifically designed to bind the protein. Running vs walking has not been shown to change outcome, as a fast runner moving the venom faster vs a slower walker not moving the venom seems to have similar clinical courses. Take your time, don't make mistakes, and keep in mind mortality is low. If the length of time to medical treatment is long, consider getting medically evacuated. If that is not an option, consider sacrificing a limb to POSSIBLY avoid the dangerous systemic effects of the toxin.
Good luck to all and stay safe!
Additional Information Contributed by Members
Background:
- Most poisonous snakes in America are pit vipers, noted by triangular heads and pits in front of their eyes. Of these, rattlesnakes make up the majority of bites in the U.S.
- The current death rate for rattlesnake bites is 4-5 per year out of about 4000 - 7000 bites per year.
- Venom is made up of proteins, just like in our body. These proteins destroy tissue, leading to cell dysfunction, death, and necrosis.
- Venom travels through lymphatics, NOT vessels. Thus, spread is slow and persistent.
Treatment:
- Immediately after bite, move away from the snake. Do not attempt to kill it. You may get bit again and get twice the dose, or get truly envenomed after an initial dry bite.
- Assess your ABCs to check for anaphylaxis from the venom.
- Remove all jewelry and items from the effected limb. It will start to swell quickly, and this is your one chance to get them off. If you need to, use a string or floss to wrap a finger and remove a ring.
- If possible, get a picture of the snake from a safe distance. This can help with ID, but in most cases, won't change course of treatment in a hospital.
- Keep limb lowered and immobilize with a sling and splint if available. If bitten on the leg or foot, immobilize the extremity and use a splint or brace. Carry the person out or use two people as support to reduce leg use.
- Seek medical attention as soon as possible. If you are more than 5 -6 hours out from medical attention or show signs of rapid systemic progression, consider sending a runner or calling for heli-vac. For a young child, it is advisable to seek the most rapid medical attention possible!
OK, now that we have that down, there are additional treatment techniques you can use to slow venom spread. These are used if you absolutely cannot get medical help within 10-12 hours. Note however, that venom has local effects on tissue it contacts, meaning that if you choose this method, studies indicate there is a greater chance in actually losing the limb from great tissue destruction such as compartment syndrome.
Currently, the American Heart Association recommends applying pressure immobilization as described below because of a small chance of delayed systemic effects which can kill you (renal damage, widespread edema, severe hypotension, etc). However, American Board of Toxicology does NOT recommend using this because of the increased likelihood of limb loss.
- Assess for radial pulse.
- Apply an Ace bandage starting just above (1/2 inch or so) above the bite wrapping UP the arm or leg. It should be as tight as possible WITHOUT occluding venous or arterial blood flow. This is VERY hard to do. Try your best and err on the loose side, as even mildly obstructed lymphatics if better than free flowing lymphatics.
- Recheck for similar radial pulse as you had prior to wrapping.
- If the limb turns blue or radial pulse is lost, you have occluded venous or arterial supply, respectively. Rewrap looser.
- You WILL have to rewrap several times regardless due to swelling in the limb, which will eventually occlude the veins.
Finally, things which have been proven to not work in slowing the venom:
- Icing the bite
- Using suction methods
- Cutting the wound
- Homemade remedies
And those bordering on idiocracy, unless I have missed a serious clinical trial:
- Electroshock therapy (using a stun gun or taser)
Once at the hospital, you can expect something like this:
- Supportive treatment to avoid hypotension (fluids, etc)
- Antivenin if available. Multiple treatment are needed. Antivenin works by binding the toxin proteins in circulation until they are slowly filtered out of the body/degraded. Antivenin is cleared by the body, so symptoms can relapse as the antivenin is cleared and more toxic proteins are available in the circulation again. Multiple treatments are needed and can last 3-7 days at 3-6 vials/day. One antivenin is currently used to treatment multiple snake types (can bind multiple types of venom).
- Rate of anaphylaxis to the newer antivenin is relatively low compared to the older equine antivenin in use 15 years ago. It currently sits at about 8% - 14%, I believe. Anaphylaxis to the old antivenin approached 30%. They used to have a prednisone drip in one hand and antivenin in the other. Yikes.
- Antivenin has a 40-50% relapse rate because once cleared, the toxic effects of the venom can manifest again. The key is to keep enough antivenin in your system until the venom is mostly cleared by the body, which takes days. Relapses up to two weeks have been reported.
- Because the venom uses lymphatics, raising the arm or limp will help clear the toxin faster (this is why you keep it lowered while on the trail, to avoid faster systemic effects). Once in the hospital, raising the arm and clearing toxin faster can potentially be a good thing. People can go home from the hospital after a week, reach up for a bowl, and start getting toxic effects again as sequestered venom is mobilized.
The bottom line is, the toxin is a peptide/protein, just like those in your own body. Antivenin is the only thing that will help here: something specifically designed to bind the protein. Running vs walking has not been shown to change outcome, as a fast runner moving the venom faster vs a slower walker not moving the venom seems to have similar clinical courses. Take your time, don't make mistakes, and keep in mind mortality is low. If the length of time to medical treatment is long, consider getting medically evacuated. If that is not an option, consider sacrificing a limb to POSSIBLY avoid the dangerous systemic effects of the toxin.
Good luck to all and stay safe!
Additional Information Contributed by Members
Disclaimer: This guide is written as a suggestion only. The posting user and posting forum associated with the user assumes no responsibility for outcomes resulting in deciding to follow these suggestions. Always seek help from a professional in the field of medical toxicology.
