AUTHOR'S NOTE: SNAKEBITE SHOULD BE TREATED BY TRAINED MEDICAL AUTHORITIES AND SHOULD NOT BE UNDERTAKEN BY AMATEURS REGARDLESS OF HOW WELL INTENTIONED THEY MIGHT BE. THE VICTIM SHOULD BE TRANSPORTED TO A HOSPITAL AS QUICKLY AS POSSIBLE. THE PUBLISHERS, AUTHORS, OR DISSEMINATORS OF THIS ARTICLE DO NOT BEAR ANY RESPONSIBILITY FOR INJURIES INCURRED DUE TO THE ACTIONS OF PERSONS WHO DO NOT HEED THIS WARNING OR WHO ACT RECKLESSLY OR IRRESPONSIBLY!

SNAKE BITE AND ITS TREATMENT

TYPES OF SNAKES AND THEIR VENOMS

Let's suppose that you're hiking through the woods and you step over a log. Suddenly you experience a tremendous pain in your leg and a feeling of intense heat. Then you see a rattlesnake crawling away out from under the log you just stepped over. This happens a lot and a simple look over the log before you stepped over it would have prevented the whole incident. But, now it's too late for that.

In this country there are two types of venomous snakes. The more common are the pit vipers which include rattlesnakes, copperheads, and the very aggressive water moccasin. The other type is the coral snake which is related to cobras, but fortunately very docile. The pit vipers characteristics include vertical pupils, a triangular-shaped head that's wider than the neck, on the head is a pit (which is a sensory organ) on either side of the between the eye and nose. Pit vipers inject venom through long fangs which grow one behind the other. Therefore, a strike may leave one, two, or even three puncture wounds in the skin. Nonpoisonous snakes can also bite, but the distinct puncture wounds of the fangs are absent.

If there is any doubt about which kind of snake has bitten you, in the interests of safety and health you must assume that it was poisonous. Exact identification of the viper isn't necessary as all North American pit vipers have similar venoms all of which can be treated with the same antivenin. The antivenin is administered along with antibiotics and careful observation in the hospital. This is the only effective way of treating a poisonous snakebite. Aside from the obvious effects of the toxin, doctors must also observe for the potentially lethal allergic reaction to the antivenin. So, this must be done by trained medical professionals under hospital surroundings.

Tourniquets, constriction bands, and ice packs are long time folk treatments that can cut off circulation and cause more harm than the poison itself. Cut-and-suck snakebite kits can also be dangerous. An inexperienced but well-intentioned rescuer using this method can accidentally cut tendons, nerves, and blood vessels. Trying to suck out the venom with your mouth drastically increases the risk of infection as the human mouth harbors many dangerous bacteria. Also, if the rescuer has a canker or burn in his mouth, or if he has a bad tooth or a loose filling, he can end up poisoning himself.

In order for suction to do any good at all, it needs to start within a couple of minutes of the bite. Since 40% of poisonous snakes bite without injecting any venom (this is called non-envenomated bites), there's a good chance that you'd be wasting valuable time better spent on evacuating the victim. Furthermore, suction should only be considered an absolutely last resort only if the victim is far from civilization. If you are within a few hours of medical attention then you should be investing your time and efforts in keeping the victim calm (excitement speeds up the pulse and the spread of the venom) and getting the patient evacuated.

A few years ago there was some interest in electric shock treatment for snakebite. Since some venoms have been inactivated by heat or electricity in the laboratory, it was theorized that if something resembling a cattle prod could zap the bite area, this might do some good. This hypothesis has not as of yet been proven out by subsequent medical studies.

If you are involved with a snake bite the first thing you should do is clean and bandage the wound and splint the affected area, if it's a foot or hand, to immobilize it. The fingers or toes should be exposed so circulation can be monitored. Then, the patient should be made comfortable and put in a position where they can exert as little energy as possible.

Pit viper venom is primarily hemotoxic, which means that it attacks body and blood cells. It begins to cause pain and swelling at the affected site within an hour. Knowing how rapidly symptoms progress helps the medical authorities decide it antivenin is necessary and in what dosage.

Viper venom usually has little neurotoxic effect. Neurotoxins attack the nervous system and cause numbness, tingling, and breathing difficulties. Since neurotoxins are designed to immobilize the victim small prey quickly succumb to it. It is rarely lethal to healthy adults, but it can be deadly to small children or adults in poor health. Of the pit vipers, the Mojave rattler has the highest percentage of neurotoxins in its venom. Where this snake is common doctors watch for neurotoxic effects as well as for local pain and swelling.

The other type of poisonous snake in North America, the coral snake, is much more deadly. Its venom is primarily neurotoxic and symptoms can be delayed for hours after envenomation. The usual symptoms are nausea, tingling, numbness, and weakness, rather than the pain experienced in viper bites. Rare case result in respiratory paralysis and death.

Coral snakes are small, being less than three feet in length, and are easily identifiable with their red, yellow, and black bands. The head is small and round and no larger than the neck. Its color pattern is similar to the nonpoisonous kingsnake (which also eats poisonous snakes). The difference is the position of the color bands in their sequence. A mnemonic to use to distinguish these two snakes from each other is, "red on black, venom lack; red on yellow, kill a fellow".

Fortunately, coral snake bites are rare because the animals is quite docile. They have tiny fangs that must be chewed into the skin in order for venom to be injected. the usual victims are children who see the pretty snake and try and pick it up. The treatment for coral snake venom is to administer the specific antivenin. Evacuation must be rapid.

FIRST AID CHECKLIST

Is it a coral snake or a pit viper? Exact identification can be very helpful to attending physicians.

Clean: Irrigate the wound site with water and clean the skin with soap to reduce possibility of infection.

Splint: Remove rings, watches, or any other constricting jewelry. Immobilize the extremity, provided that it won't interfere with medical care.

Calm: Keep victim calm and ensure that they expend as little energy as possible.

Evacuate: Walk, paddle, or drive. Get the patient to medical help as quickly as possible.

Monitor: Observe and record the progression of symptoms while patient is being evacuated. Loosen splints and bandages if swelling begins so circulation won't be restricted (then gangrene can develop). Perform basic life support if needed.

A WORD OF ADVICE TO TRAVELERS

It is worth remembering that snakes in other parts of the world are far more deadly than ours in North America. If you travel over seas and visit wild and remote areas, check with the local medical or wildlife authorities on how to treat bites of native snakes before you head into a potentially dangerous situation.

NEW TREATMENTS BEING STUDIED

The most commonly used antivenin employed in this country is the Wyeth antivenin which is made by injecting horses with pit viper venom. After the horses develop antibodies, blood is drawn and made into serum. It is then partially purified, freeze-dried and made ready for medical usage. Unfortunately, horse serum is full of inactive proteins that can cause serious life threatening allergic reactions in humans. When injected with antivenin you must be carefully monitored in a hospital. Administering antivenin in the field is impractical and dangerous.

Doctors Wyath Decker and Richard Dart report that they are testing a very promising new serum they call Polyvalent Crotalidae Antivenin (from Crotalus which is the genus of the rattlesnake). It's made by injecting sheep rather than horses, and with cottonmouth water moccasins, eastern and western diamondback rattlesnakes, and Mojave rattlers. Testing on mice show this new antivenin to be 5.2 times more potent than the Wyeth and the first human trials show that the patients all benefited from the treatment without allergic reactions. Although not yet approved for general distribution, PVA is being tried in poison treatment centers around the country. If the early tests are successful, outdoorsmen might soon be seeing a new and improved antivenin which not only is more effective, but could also be used in field survival kits.

Recent studies in Australia (which has more venomous snakes than any other continent) are showing that applying a wide pressure bandage to any extremity bitten by a neurotoxic snake can slow down the absorption of the venom and the onset of symptoms. These studies may result in new field treatments for the coral snake and the Mojave rattlesnake, but these finding are very preliminary and should not be put into practice until further data is available.
Copyright © 1996 AJS