Snakebite

Overview

A snakebite is an injury caused by a bite from a snake, often resulting in puncture wounds inflicted by the animal's fangs and sometimes resulting in envenomation. Although the majority of snake species are non-venomous and typically kill their prey with constriction rather than venom, venomous snakes can be found on every continent except Antarctica. Snakes often bite their prey as a method of hunting, but also for defensive purposes against predators. Since the physical appearance of snakes may differ, there is often no practical way to identify a species and professional medical attention should be sought.

source: wikipedia

Symptoms

Symptoms depend on the type of snake, but may include:

  • Bleeding from wound
  • Blurred visionBlurred vision
  • Burning of the skin
  • ConvulsionsConvulsions
  • DiarrheaDiarrhea
  • DizzinessDizziness
  • Excessive sweatingExcessive sweating
  • FaintingFainting
  • Fang marks in the skin
  • FeverFever
  • Increased thirstIncreased thirst
  • Loss of muscle coordinationLoss of muscle coordination
  • Nausea and vomitingNausea and vomiting
  • Numbness and tinglingNumbness and tingling
  • Rapid pulseRapid pulse
  • Tissue death
  • Severe pain
  • Skin discoloration
  • SwellingSwelling at the site of the bite
  • WeaknessWeakness

Rattlesnake bites are painful when they occur. Symptoms usually begin right away and may include:

  • Bleeding
  • Breathing difficulty
  • Blurred visionBlurred vision
  • Eyelid droopingEyelid drooping
  • Low blood pressureLow blood pressure
  • Nausea and vomiting
  • NumbnessNumbness
  • Pain at site of bite
  • Paralysis
  • Rapid pulse
  • Skin color changesSkin color changes
  • Swelling
  • Tingling
  • Tissue damage
  • Thirst
  • Tiredness
  • Weakness
  • Weak pulse

Cottonmouth and copperhead bites are painful right when they occur. Symptoms, which usually begin right away, may include:

  • Bleeding
  • Breathing difficulty
  • Low blood pressure
  • Nausea and vomiting
  • Numbness and tingling
  • Pain at site of bite
  • Shock
  • Skin color changes
  • Swelling
  • Thirst
  • Tiredness
  • Tissue damage
  • Weakness
  • Weak pulse

Coral snake bites may be painless at first. Major symptoms may not develop for hours. Do NOT make the mistake of thinking you will be fine if the bite area looks good and you are not in a lot of pain. Untreated coral snake bites can be deadly. Symptoms may include:

  • Blurred vision
  • Breathing difficulty
  • ConvulsionsConvulsions
  • Drowsiness
  • Eyelid drooping
  • Headache
  • Low blood pressure
  • Mouth watering (excessive salivationexcessive salivation)
  • Nausea and vomiting
  • Numbness
  • Pain and swelling at site of bite
  • Paralysis
  • Shock
  • Slurred speech
  • Swallowing difficultySwallowing difficulty
  • Swelling of tongue and throat
  • Weakness
  • Skin color changes
  • Skin tissue damage
  • Stomach or abdominal pain
  • Weak pulse

source: MedLinePlus

Causes

Poisonous snake bites include bites by any of the following:

  • Cobra
  • Copperhead
  • Coral snake
  • Cottonmouth (water moccasin)
  • Rattlesnake
  • Various snakes found at zoos

All snakes will bite when threatened or surprised, but most will usually avoid people if possible and only bite as a last resort.

Snakes found in and near water are often mistaken as being poisonous. Most species of snake are harmless and many bites are not life-threatening, but unless you are absolutely sure that you know the species, treat it seriously.

source: MedLinePlus

Prevention

  • Avoid areas where snakes may be hiding, such as under rocks and logs.
  • Even though most snakes are not poisonous, avoid picking up or playing with any snake unless you have been properly trained.
  • If you hike often, consider buying a snake bite kit (available from hiking supply stores). Do not use older snake bite kits, such as those containing razor blades and suction bulbs.
  • Don't provoke a snake. That is when many serious snake bites occur.
  • Tap ahead of you with a walking stick before entering an area where you can't see your feet. Snakes will try to avoid you if given enough warning.
  • When hiking in an area known to have snakes, wear long pants and boots if possible.

source: MedLinePlus

Treatment

Reassurance and immobilization of the affected limb with prompt transfer to a medical facility are the cornerstones of the immediate care of snakebite. Pressure immobilization is used for some elapid species.

The mainstay of treatment of snakebite is the infusion of an appropriate antivenom. Snake venoms are diverse, and therefore the efficacy of antivenoms is geographically and biologically restricted, meaning that a large number of antivenoms have been developed for use in different settings.

Antivenoms are manufactured by immunizing horse or sheep with venom from a particular species and then processing the serum from the animal.

Both monospecific and polyspecific antivenoms are available; monospecific antivenoms are produced using the venom of a single species, whereas polyspecific antivenoms are produced against the venoms of several species that are prevalent in a geographic region.

In the rural tropics, victims are often bitten in an agricultural field or jungle, and in many instances the biting species is not identified. In such situations, treatment with polyspecific rather than monospecific antivenoms may be more appropriate.

The need for many different antivenoms means that production is not always economically viable and in some parts of the world, particularly Africa, there is a crisis regarding production, distribution and accessibility of antivenoms.

In addition, the need to restrict the cost of these products when manufactured on a small scale means that relatively limited processing leads to high adverse reaction rates with some products, including life threatening anaphylaxis.

Another problem is that currently available antivenoms are not effective against the local necrotic effects of snake venom which can lead to long-term disability and disfigurement.

In addition to antivenom therapy, management of snakebite also includes supportive therapy, such as ventilation for respiratory paralysis, which is often lifesaving for victims bitten by species which cause severe neurotoxicity.

source: WHO

Resources

First Aid

1. Keep the person calm, reassuring them that bites can be effectively treated in an emergency room. Restrict movement, and keep the affected area below heart level to reduce the flow of venom.

2. If you have a pump suction device (such as that made by Sawyer), follow the manufacturer's directions.

3. Remove any rings or constricting items because the affected area may swell. Create a loose splint to help restrict movement of the area.

4. If the area of the bite begins to swell and change color, the snake was probably poisonous.

5. Monitor the person's vital signsvital signs -- temperature, pulsepulse, rate of breathing, and blood pressureblood pressure -- if possible. If there are signs of shockshock (such as palenesspaleness), lay the person flat, raise the feet about a foot, and cover the person with a blanket.

6. Get medical help right away.

7. Bring in the dead snake only if this can be done safely. Do not waste time hunting for the snake, and do not risk another bite if it is not easy to kill the snake. Be careful of the head when transporting it -- a snake can actually bite for up to an hour after it's dead (from a reflex).

DO NOT

  • Do NOT allow the person to become over-exerted. If necessary, carry the person to safety.
  • Do NOT apply a tourniquet.
  • Do NOT apply cold compresses to a snake bite.
  • Do NOT cut into a snake bite with a knife or razor.
  • Do NOT try to suck out the venom by mouth.
  • Do NOT give the person stimulantsstimulants or pain medicationspain medications unless a doctor tells you to do so.
  • Do NOT give the person anything by mouth.
  • Do NOT raise the site of the bite above the level of the person's heart.

source: MedLinePlus