Author Topic: "Doc K's Snakebite Facts & First Aid"  (Read 10620 times)

Offline DeltaEchoVictor

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"Doc K's Snakebite Facts & First Aid"
« on: April 09, 2010, 05:08:32 AM »
I've copy & pasted the info from THIS thread.  It's good info & if you spend any time outside at all you should take a few moments to familiarize yourself with the various types of snakes you're likely to eventually encounter.

Thanks to Doc K for compiling this info for us.  

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I wanted to share my thoughts on snakebites.  
This is the cliffnotes version of a recent lecture I gave on the subject.

Most of this is geared toward a North American audience; however the concepts can be applied to most places in the world.

I have been bitten 20+ times by snakes.  Almost all of them were before I was 12 years old (I was 8 when I was first bit by a ringneck snake in South Florida – it didn’t draw blood, so I don’t really count that one.  ;D ).  Fortunately, I have never been bitten by venomous snake.  In reality, I should never have been bitten by any of those snakes.  

Snakes (except in very, very rare circumstances) want to be left alone.  They will sneak away if given the chance.  If you provoke them, they will bite.  If they are venomous, you can die.  With that said, just because it is venomous doesn’t mean it has to die.  Most people don’t kill every bee they see just because it has the ability to sting you.  Snakes have a vital role in the ecosystem.  Please don’t kill them because you don’t understand their importance or how to avoid getting bitten. – okay off my soapbox now.  ;)



SNAKE FACTS
Over 120 species of snakes in North America. (Only 20 species are venomous.)
300 of over 2,700 species worldwide are venomous.

About 45,000 snakebites occur annually in the U.S. (About 8,000 of these bites are from venomous snakes (10-50% are dry bites – meaning that the venomous snake chooses not to inject venom with the bite)).
300,000 – 400,000 venomous snakebites occur yearly worldwide.

About 12 fatalities yearly from snake envenomations in the U.S.
30,000 – 110,000 deaths worldwide from envenomations.

Mortality is less than 3% if envenomated in the U.S. without treatment.
Mortality is less a third of 1% in the U.S. if antivenom is given.
This is drastically different in other parts of the world.



SNAKEBITE FACTS
Most snakebite victims are males (>70%).
Most victims are between 10 and 27 years of age.

Highest group for non-venomous bites: 10-14 year old males.
Highest group for venomous bites: 19-27 year old males.

98% of snakebites are on extremities (most on hands and arms – MEANING: The person who was bitten was messing with the snake!).

Most bites occur between April and September.

>45% occur at victim’s home or yard.
~4% occur while victim was fishing or golfing.

Alcohol intake is a factor in many envenomations.



VENOMS
Can basically be broken down into two types:
Hemotoxic – Intense Pain at bite, Spreading edema (swelling) at bite, Ecchymosis (bruising)
Neurotoxic – Minimal Pain at bite, Numbness, Neurological symptoms, Breathing failure



SEVERITY OF THE SNAKEBITE
Extremely variable.  Depends on:
Species of snake
Size of snake
Location of bite
Volume of venom injected
Age of victim
Size of victim
Health of victim



SNAKEBITES:  WHAT NOT TO DO
Tourniquets – proven to do more damage than good.
Wound Incisions (Cut and Suck) – great for movies, bad in real life
Negative Pressure Venom Extractors (e.g. Sawyer extractor) – recent good studies have shown this to be ineffective (and potentially cause minor harm)
Ice – doesn’t help
Electric Shock – great for the people watching  ;D , but does no good to the victim
Alcohol – topical or ingested… no benefit
Aspirin – can make bleeding worse
Lymphatic bands – (if you even know what this is…) may be used in the future with certain snakebites.  The Australians are doing a lot of research on this currently



SNAKEBITES: WHAT SHOULD I DO?
(MOST IMPORTANT – know the snakes in your area.  As Jack would say, “Be situationally aware!”  If you can identify the snake as non-venomous, then you do not need to hurry to the ER.)
Basic First Aid
Minimize Activity
Remove tight clothing or jewelry in anticipation of swelling
Use pen to mark and time border of swelling
Maintain extremity in neutral position
Do not capture or kill snake.
Do not handle snake if you do not heed above advice (The New England Journal of Medicine published a review of cases where people were bitten by dead venomous snakes… they have a muscle bite reflex!)
Try to take a photo of snake to aid in identification
Call 911 or get the person to the hospital


The rest of the information in this lecture was geared to ER and Hospital care where antivenom and laboratory testing is available.  



If this were Post-TEOTWAWKI
- Pray the victim survives.
- Provide fluids if the victim’s blood pressure gets too low.  IV is best, but rectal can work as well.
- It could take hours to days for the effects of the venom to resolve.
- The victim may be in extreme pain - treat with tylenol or narcotics.  Avoid aspirin, ibuprofen, naproxyn, or other non-steroidal anti-inflammatory medications that may make bleeding issues worse.
- The victim may bleed from many parts of their body.  Fluids can help keep blood pressure normal.
- Watch for infection of a finger, toe, hand, or foot if the venom caused extensive tissue damage.  Don't pop blisters if they form.
- The victim may likely have residual effects from the venom - like partial paralysis of a hand or foot, and it may be permanent.
- In the severe case of a person unable to breathe (due to swelling or paralysis):  if you knew what you were doing and could handle it for a long time, you may need to intubate and breath for the patient until the venom effects wear off.   This would be a last ditch effort of desperation.


Moral of the story… don’t get bitten.

Hope this helps,
Doc K

Offline DeltaEchoVictor

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Re: "Doc K's Snakebite Facts & First Aid"
« Reply #1 on: April 09, 2010, 05:09:47 AM »
Why would you not, if you can do it without endangering yourself, kill the snake?  Not out of revenge or anger but rather so you can provide a positive identification of the type to the hospital/first responder? 

In the United States, we have about 20 venomous snakes (I say about, because there are some closely related snakes that scientists are deciding if they are sub-species of one snake or two distict species... way too complicated to get into cladograms and the such).
It's easiest if we group them into 4 types (check the links for pics as well):
1) Rattlesnakes - Crotalus and Sistrurus species
2) Water Moccasins (AKA Cottonmouths) - Agkistrodon piscivorous
3) Copperheads - Agkistrodon contortrix
4) Coral Snakes - Micrurus and Micruroide species


If you are bitten by #4, a type of Coral Snake... well, there is no antivenom available anymore for this neurotoxic snake (except in a few locations, and it is going to expire at the end of 2010).  Drug companies say it is not cost effective, and they may be right from a strictly economic standpoint.  There has only been one death in the last 20 years from a coral snake in the U.S.  It was in central Florida, and the vicitm did not seek medical attention.  You really have to try hard to get bitten by a coral snake.  They have small heads, mouths, fangs, and their fangs do not flip open like the Pit Vipers (#1,2,3 above).  On top of that, they are brightly colored Red, Black, and Yellow (although the yellow can sometimes be so pale it looks white).

Now I will insert a comment about identifying Coral Snakes.  There is an old rhyme that is often told about the order of colors to identify a venomous coral snake or a non-venomous mimic (like the Scarlet King Snake - which I was biiten by myself): 
"Red touches Yellow- kills a fellow; Red touches Black - venom lack (or friend of Jack)"

PLEASE NOTE:  This rhyme only works if you are NORTH of Mexico City.  South of Mexico City there are a BUNCH of deadly Coral Snakes with completely different color patterns: black-yellow-black-yellow; orange-black-yellow-black; red-black-white-red; gray-black-red-gray, etc.)


If you are bitten by #1 - identification is easy.  It has a rattle.  Babies may not have a rattle, but that is okay - you'll see in a minute.
If you are bitten by #2 - identification is also pretty easy.  Cottonmouths have... well, big, white, cotton-looking mouths when they open up wide - which they do all the time when they are mad.  Babies have bright colored tails.
If you are bitten by #3 - identification is harder, but not too hard.  Babies have bright colored tails.

So, if you are bitten by #1, #2, or #3, the antivenom is the same for these hemotoxic snakes.  It is FabAV (sold as CroFab).  It is a polyvalent antivenom (made up of multiple venoms).  The snakes included were the Eastern Diamondback Rattlesnake (the deadliest snake in the U.S. - most deaths caused), the Western Diamondback Rattlesnake (very common), the Mojave Rattlesnake (the deadliest poison of rattlesnakes in the U.S.), and the Cottonmouth (the Copperhead's venom is so closely related to the Cottonmouth that the antivenom can be used for both).


CASE SCENARIOS

CASE ONE
A 23 year old female is bit by a snake on her Left ankle.  She didn't see the snake.  They were camping and the victim was bit on her way to the outhouse in the dark - forgot her flashlight.  The group quickly drives her to the hospital.  She has two puncture wounds on her left ankle.  No swelling.  She is scared, but doesn't have any other symptoms.  The proper guidelines are to clean the wound and watch her for 6-8 hrs to see if she develops symptoms.  She doesn't develop any symptoms after 7 hrs and is sent home.  This could have been a non-venomous snake or a dry bite from a venomous snake.

CASE TWO
A 55 year old male is bit in the Right big toe while walking his little yippee dog after dark.  He didn't see the snake.  He has his wife drive him to the ER because his toe is swelling and hurts.  He has one single puncture wound on the outside of his toe.  His foot is swollen to the ankle, and his whole toe is dark purple.  The doc correctly deduces this is a hemotoxic snake bite (base on the area it could be a rattlesnake, copperhead, or cottonmouth).  He gets IV's, fluids, and antivenom.  He stays the night in the hospital.

CASE THREE
A 19 year old male college student is brought to the ER by his friends.  He says his face feels numb.  He smells of alcohol.  His friends finally admit that they found a small brightly colored snake and were playing with it.  The victim was letting it wrap over his face for a picture when it bit him on the nose.  He didn't think anything of it - barely any blood, pinpricks in fact.  No pain.  But about 15 minutes later his face started to get numb and he had trouble speaking.  The ER doc correctly deduces this is a neurotoxic snakebite from a Coral Snake.  No antivenom is available.  He is placed in the ICU with anesthesia standing by just in case he looses the ability to breathe.  Fortunately he does not.  He is discharged after a few days.


Hope this helps,
Doc K


Offline DeltaEchoVictor

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Re: "Doc K's Snakebite Facts & First Aid"
« Reply #2 on: April 09, 2010, 05:11:06 AM »
Is their blood pressure becoming low due to the swelling? Or does the venom cause increased bleeding?

Bleeding can contribute.  A lot of it is shock... there are many components to venom and there are different degrees of vasodilatory effects (blood vessels relaxing) that cause the blood to want to pool in the extremities and the blood pressure drops.

How does rectal fluid administration work?

I'm going to do another post on this one, but... short answer is any tube that can be conected to a bag of fluid can be inserted into the rectum a few inches.  Connect the bag to the other and hold it above the person to gravity feed the fluid.  The colon's job is to absorb fluids out of our stool (we diarrhea when that stops working well).  There you have it... enough to be dangerous!  ;D

Why are lymph bands no longer in favor?

They concentrate the venom in one location.  If you are bitten by a hemotoxic snake that has a low death rate in the U.S. (usually you have a less than 1 in 20 chance of dying with NO medicat treatment vs. let's say the Saw-Scaled Viper in the Middle East with a 1 in 3 chance of dying) you want to spread that venom all over the body.  If it stays concentrated in the hand for instance, then WAY more damage will be done to that hand - you may loose digits or the entire hand.

In comparison (and this is what the Australians (mainly) are doing research on) the neurotoxic snakes have a higher lethality and shorter window for treatment.  So if you can keep the venom isolated, you may be able to stall the venom effects of decreased breathing and cardiac activity.

If a person is bitten by a hemotoxic snake and there is no medical attention available, what can you do beyond IV fluids? Would you perform some type of escharotomy-style procedure on the swollen limb or something to prevent compartment syndrome?

Escharotomy is mainly if you have a big burn, and it's sister procedure, Fasciotomy, used to be used a lot for bad snakebites.  It has gone way out of favor due to antivenoms.  They are just not needed.  However, I would consider it if you knew how to measure compartment pressures and knew enough of surgery not to cut nerves and major blood vessels and how to keep large open wounds from becoming infected and knew how to close everything back up the right way... basically, this is where I pray we never get to this point.

Doc K

Offline DeltaEchoVictor

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Re: "Doc K's Snakebite Facts & First Aid"
« Reply #3 on: April 09, 2010, 05:12:33 AM »
Question: does activated carbon or its homemade equivalent have any potential of helping or hurting in the case of a venomous snake bite? I have heard of it being applied both as a topical paste and internally.

Activated charcoal is used mainly (almost exclusively) as an oral absorber (well, actually adsorber) of toxins, poisons, etc.  You need to be able to expose the wet toxin to the charcoal to "soak up" the bad stuff.  The charcoal needs to physically touch the poison for it to work.This is why it works well in accidental or purposeful poisonings.  The poison is sitting is a big bag of fluid and the added charcoal just soaks it up. 

Since we do not drink snake venom (usually, that is  ;) ), there is no benefit to taking it orally after a snakebite.  Venom doesn't migrate and accumulate in the stomach fluid or anywhere along the intestinal tract.

Topical activated charcoal is only good (potentially) for open wounds.  Remember, activated charcoal has to physically touch the venom to soak it up.  Snakebites are puncture wounds by nature.  There is no way to get the activated charcoal to the venom.  Let's say you even tried to cut open the punture wounds (REALLY not recommended), you will still not get to the venom.  Venom doesn't just sit there in a puddle under the surface of the skin.  It gets absorbed into the tissues of the body. 

Finally, activated doesn't "draw out" poisons either... so, a topical activated charcoal (either orally or topically) would just not be helpful in the case of venomous snakebites.

Doc K

Offline DeltaEchoVictor

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Re: "Doc K's Snakebite Facts & First Aid"
« Reply #4 on: April 09, 2010, 05:13:22 AM »
Doc K - Great Post +1, thanks for your time in this post.

One question.

This may be a tertiary problem, if a problem at all. Most of our pit viper venom, as I understand, can cause hemolysis. That make me think of muscle damage thus the possibility of a developing rhabdomyolysis. In a SHTF scenario, would you push fluids in snakebite victims to increase renal output or is this a non-issue ?

Kold

Great question... you must have stayed in a Holiday Inn Express last night.  ;D

I'll get a bit technical for the medical types: 
The main cause of death with hemotoxic venoms is defibrination.  This can last for weeks and can rebound even after antivenom is given (up to three weeks or so... the antivenom has a shorter half-life than the venom does... fortunately, the rebound is greatly reduced compared to the initial defibrination).

The other big problem with hemotoxic venoms is rhabdomyolosis.  This can lead to myoglobinuric renal failure and can also lead to electrolyte abnormalities (hyper/hypokalemia, hypocalcemia, etc.). 

So the short answer is, Yes!  Give them fluids.  If you do not have access to higher level medical care, have them drink plenty (just enough not to make them vomit... but envenomation can cause nausea).  IV and rectal hydration if needed.

Doc K

Offline DeltaEchoVictor

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Re: "Doc K's Snakebite Facts & First Aid"
« Reply #5 on: April 09, 2010, 05:14:18 AM »
I have heard there is some type of shots for dogs so that in case they are bit, they will not need the anti-venom, just a penicillin shot.

You are right.  There is a Rattlesnake Vaccine for dogs (not for humans).  The antibiotic shot is just for prevention, but I don't know if it is really needed.  We don't normally give antibiotics to humans with snakebites, because these wounds don't usually get infected.  But I am not an animal doctor.  It is made from just the Western Diamondback Rattlesnake venom, but it appears to have some good cross-reactivity for most other rattlesnakes and even the Copperhead.  It does not work for the Cottonmouths or Coral Snakes.  Here are a couple of good resources if interested:

http://rattlesnakevaccinefordogs.com/

http://www.rattlesnakevaccinations.com/


Doc K

Offline DeltaEchoVictor

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Re: "Doc K's Snakebite Facts & First Aid"
« Reply #6 on: June 08, 2010, 01:39:04 AM »
So lets say its TEOTWAWKI and my son or daughter or wife or whatnot gets bit by a copperhead or rattler(these two seem to be the most prevelant in my areas), what do I need to do exactly? any kind of kit I can prepare for a snakebite trauma?


#1  Avoid venomous snakes TEOTWAWKI.  Since MOST people in the U.S. who are bit by snakes are messin' with them in the first place, almost all snakebites in the U.S. are provoked.  Don't be that person.

#2  If you, or a loved one, is bitten by a snake, and you will not have access to medical care (not because you are too stubborn or stupid to go to the ER), I would recommend the following (I'll kind of quote myself here a bit from above):

 - Know the snakes in your area.  As Jack would say, “Be situationally aware!”  If you can identify the snake as non-venomous, then you have much less worry about.
 - Stay calm (both patient and victim)
 - Basic First Aid: Clean the wound with lots of clean (i.e. drinkable) water.  Irrigate the wound a whole lot, and you will decrease your chance of an infection.
 - Minimize Activity
 - Remove tight clothing or jewelry in anticipation of swelling
 - Use pen to mark and time border of swelling (useful to monitor swelling progression or improvement)
 - Maintain extremity in neutral position (this just helps to slow the spread of the venom, so you don't get hit with it all at once)
 - Monitor the victim's blood pressure.  If it starts to drop substantially, you are in trouble.   This is a sign of shock (the blood vessels are opening wide and blood is pooling instead of circulating - to be as simple as possible.) Keep their head lower than the rest of their body to keep blood going to the brain.  If you know how to place an IV, it should have been placed as soon as the person got to you.  Now would be the time to give IV fluids through that IV.  If you do not have the ability to give IV fluids, there is not a whole lot more to do other than pray they make it through.  Rectal fluids - yes that is possible -  is too slow of a route for shock, but if I had nothing else, I may try it.  Compression wraps - basically ACE wraps around the legs and arms to keep blood pressure up is also a last ditch effort. 
 - If the victim starts bleeding from the nose, mouth, rectum, vagina, or other orifice, this is also a very bad sign.  It means that their coagulation system has gone haywire from the venom.  Nothing you can do without full blown medical care.

Bottom Line:  Without antivenom, you are really just hoping the person can handle the venom load without dying.

The good news is that the majority of people in the U.S. who do not get antivenom survive venomous snake bites (we don't know the number of people who get envenomated and get NO medical care though).  This is because our snakes are not as deadly as those in Australia for example.

Hope this helps,
Doc K

Offline DeltaEchoVictor

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Re: "Doc K's Snakebite Facts & First Aid"
« Reply #7 on: June 08, 2010, 01:41:52 AM »
Sooo... the "cut and suck" method is worthless?

Even if you use a sterile blade, and a tool to suck the venom? Then properly bandage the wound?

It really has nothing to do with technique.  The method itself just doesn't work.  Some researchers did a study where they injected radio-labeled "mock venom" into a person.  They waited one minute then used a venom extractor (I believe it was the Sawyer Extractor) to attempt to suck out the "venom".  They got almost nothing out.  Almost all the radio-labeled tracer stayed in the person's limb.  This was repeated multiple times with the same results.

They think that the venom disperses too quickly and mixes with normal body fluid to be "extracted" effectively. 

Bottom line:  Extractors do not help.  Then, on top of an envenomation, you get a hickey at best (at worst, there have been some cases of local necrosis from creating a vacuum on the skin using the venom extractors).  I will not use it.  I recommend people avoid them.

Doc K.

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Re: "Doc K's Snakebite Facts & First Aid"
« Reply #8 on: September 18, 2012, 06:07:08 AM »
Poke