Re: First Aid question - snakebite
Amick Robert (amick@SPOT.COLORADO.EDU)
Fri, 13 Dec 1996 14:11:05 -0700
I would agree with my esteemed colleague, Monty on his posts re:
snakebite; there is also some
additional information that may be of interest.
1. There are fewer than 15 deaths per year in the U.S. attributable to
the bite of the common pit viper family (rattlesnake, copperhead,
cottonmouth). There are far more deaths caused by bee/wasp stings
resulting in anaphylaxsis (last I heard, over 600 per year). The most
common fatalities tend to be those who are bitten by large diamondback
rattlers indigenous to Florida, Texas, Louisiana and other southern
states. Typically the fatalities have resulted when treatment has not been
administered or delayed significantly; Additionally, the victims
typically are those who are elderly,
small children or infants, and/or medically compromised from diseases such
as diabetes.
2. The venom of the pit viper is hemotoxic (i.e., it has components which
are designed to disable it's prey and then to "pre-digest" the tissues by
breaking down the cell structures through enzymatic action) For this
reason, when a person is bitten and if treatment in the form of antivenin
is delayed or witheld, the tissues affected by the venom tend to
become necrotic and form blisters, open ulcers, and slough away. Major
resconstructive surgery may be necessary and in some cases amputations of
fingers and other extremities have occurred due to tissue necrosis.
3. Pit vipers can selectively inject or withold venom when biting prey or
an "attacker." If a snake has just bitten something, it may also have
exhausted it's venom and be unable to inject much additional venom, so not
all bites are envenomated. Envenomation becomes evident with swelling,
burning sensation, blistering or in the rare cases noted above, falling
blood pressure and anaphylaxsis.
4. The most successful treatment for snakebite of course is injection of
antivenin, which is derived from horse serum. This normally works quite
well to neutralize the venom, however it is also capable of causing an
anaphylactic reaction in those sensitive to horse serum. Therefore a test
must be conducted before antivenin treatment commences to determine
sensitivity.
5. There are certain pit vipers such as the mojave rattler or sidewinder
that have a venom component which causes the blood pressure to fall to
dangerously low levels, and can therefore be life threatening. This was
recently pointed out by a noted herpetologist here at the University of
Colorado. If this occurs, advanced life support may be urgently
necessary, but such incidents are quite rare.
6. The only other venomous snake indigenous to the U.S. is the coral snake
which is a relative of the elapid or cobra family. The coral snake is not
typically agressive nor does it have frontal fangs, so the likelihood of a
bite is minimal unless it is being handled. It must grip it's prey and
then chew to inject venom from fangs located near the rear of it's mouth.
The venom, however is neurotoxic which causes neurological symptoms of
paralysis, palsy, drooping eyelids, double vision, cramping and loss of
muscle control and can affect breathing and other vital signs.
Identification or a coral snake with the mnemonic of "red and
yellow kill a fellow, red and black, venom lack" is not always accurate
due to genetic anomalies which
reverse the combinations on some specimens and result in confusion with
it's non-toxic relatives. Coral snakes are found more commonly in the
southern states. It's more fierce relatives in Australia, such as
the Taipan and Tiger snake, or the Cobra in Asia result in a higher
incidence of deaths due to extreme neurotoxicity of venom. In India,
about 4000 deaths per year are attributed to the bite of the cobra.
6. The black widow spider venom is also neurotoxic and is eight times
more toxic than cobra
venom but the quantities injected are so minute that the bite is rarely
fatal. However, it often results in hospitalization with the same
symptomology noted above. There is also an antivenin for black widow
spider venom but it also can cause anaphylaxsis and is sometimes witheld
in favor of other therapies for that reason.
7. As far as therapy/first aid measures noted in previous posts,
there is some controversy over whether the application of the higher
pressure suction units within 20 minutes of the bite may have some
benefit, however, because of diffusion in the tissues, the probability of
it being of any significant benefit is probably minimal. As noted,
cutting is totally inappropriate. Sucking venom by mouth is unlikely to
be of any benefit, and would be more likely to be a source of infection
for the wound (the only more highly bacterially contaminated mouth than a
human is a camel, but I digress..) but if for any reason any venom were
swallowed it would not likely be harmful since it would be decomposed by
stomach acid.
8. Bee/wasp stings can be successfuly treated by application of a paste
of Adolphs meat tenderizer (unseasoned). The papinase enzyme in the
tenderizer can chemically neutralize the bee venom. Mix a small amount of
water with the tenderizer and apply liberally over the bite. Then place a
moist gauze dressing over the paste, and tape in place. Allow to stand
for about 45 minutes, then remove. Usually, the patient will be free of
symptoms. Benadryl antihistamine capsules can also help minimize any
reaction to bee stings if given promptly after the bite.
Application of ice to the sting site is helpful in lessening pain and
swelling, but be sure to place a cloth in between the ice bag and the
tissues to avoid excessive cooling of the skin.
Be alert for any
signs of anaphylaxis resulting from the sting, such as itching, hives (red
and white blotches near the sting site, spreading away), shortness of
breath or difficulty breathing, paleness, dizziness, falling blood
pressure. This is a *red flag* emergency and requires paramedic
intervention immediately. Epinehprine (adrenalin) injections are used to
restore the blood pressure and control the reaction. Often those who are
known to be allergic will carry epi-pens which automatically inject a
pre-measured dose of epinephrine into the
thigh muscle and can be used even by minimally trained persons. Newer
medical treatment protocols are permitting emt's and first responders to
assist with this therapy in emergent situations.
It would be appreciated if anyone else with experience, expertise or views
on these topics would also contribute.
Bob Amick, EMT-B, Explorer Advisor, High Adventure Explorer Post 72
Boulder, CO
Terry Howerton Sakima Group, Inc. SCOUTER Magazine Kansas City |
