Snake Bites. What you need to know.
As a family, we spend much of our free time outdoors trying to teach our kids basic skills such as hiking, fishing and staying safe. On a recent camping trip in Western North Carolina my five year old found an adult copperhead behind our tent.
Fortunately, we have had many snake encounters and he was able to recognize the snake and let us know. This encounter got me thinking, what if one of us got bit? What would we do? We were a good one hour hike to the trail head where our car was parked. Do we know where the nearest hospital is? And most importantly, do they have antivenom if needed?
Many of us spend time outdoors doing various activities including but not limited to mountain biking, hiking, camping, fishing, trail running etc. The more time we spend outside, the more we are exposed to all the elements of nature.
Broadly speaking, there are four types of venomous snakes in the United States. These include the Rattlesnake, Copperhead, Water Moccasin and Coral snake. Bites from venomous snakes can pose significant threat to your health.
For the most part they can be treated successfully and the chances of actually dying from a snake bite in the United States, although not zero, is pretty low.
The treatment requires prompt medical evaluation, and if deemed necessary, the timely administration of antivenom.
Here we will discuss snakes commonly found in the United states, their venom, initial field management and definitive treatment.
The most common venomous snakes in the United States include snakes that fall under the category of pit vipers. Coral snakes are elapids and will not be covered here.
What are venomous snakes?
These snakes have fangs, special teeth that are capable of producing and injecting venom into tissues. This is used to hunt and kill their prey. In contrast non venomous snakes lack the venom but make up for it with sheer strength and squeeze their food to death.
Rattlesnakes, water moccasins (commonly referred to as cottonmouths), and copperheads are members of the pit viper family. They are called pit vipers because of the heat sensing pit located behind the nostrils.
The pit vipers have hemo-toxin. This venom destroys cells and tissues which can cause tissue damage and destruction. For the snake, this aids in digestion once they start to eat the animal they have killed. Bites from these snakes can leave disfiguring scars.
Rattlesnakes, water moccasins and copperheads are the most numerous and cause the most snake bites in the United States.
Approximately 5000 snake bites are reported to the American Association of Poison Control Centers annually.
Most of these occur in adults. As expected, bites in children are more serious and morbidity and potential mortality is higher as well. Hospitalization occurs in about half of all envenomation victims.
Most snake bites occur in the summer months. This is when snakes are most active. Southern and Western states with warmer climates report the greatest number of venomous snake bites. These states include Texas, Florida, California, Arizona, Louisiana, Georgia, and North Carolina.
Where are pit vipers found?
Rattlesnakes, water moccasins, and copperheads are widely distributed throughout the United States.
Rattlesnakes live throughout the continental United States. The only place you won’t find this snake is Alaska, Hawaii, and Maine.
Water moccasin are found in the Southeast and South, from Virginia to Texas.
Copperheads are commonly found in the Eastern-half of the continental United States, from Massachusetts to Texas.
What to do if you see a venomous snake?
LEAVE IT ALONE! This is not the time to try to be Steve Irwin. Stay back, observe this beautiful animal, but do it at a safe distance.
Unfortunately, most snake bites occur when you don’t see the snake and accidentally step on the snake or startle the snake by stepping close to it.
What if you are bitten?
If you don’t know what bit you, play it safe and assume it may have been a venomous snake and seek medical attention.
There are two types of snake bites by venomous snakes.
One is when the snake injects its venom into the tissue it has bitten.
The other type of venomous snake bite is when a snake bites but there are no signs or symptoms of envenomation.
A good percentage of venomous snake bites in humans do occur without venom injection. This phenomenon is termed as "dry" bite.
Management of snake bites
We have found the following measures to be helpful:
Remove the snake bite victim from where the bite occurred.
Stay calm! Keep the person calm!
Immobilize the injured body part at the level of the heart. Placing the extremity below the level of the heart may lead to increased tissue damage.
Remove any rings, watches, or constrictive clothing from the affected extremity.
DO NOT apply pressure dressing, tourniquets, or constrictive dressings.
Cleanse the wound.
Get to the nearest medical facility as quickly as possible.
While it is helpful to identify the snake, DO NOT put yourself in danger and do not delay transport to a medical facility. If you have your smart-phone on you, try to snap a picture at a safe distance.
Is the snake venomous?
If you are not familiar with snakes in your area, it may be difficult to determine whether a snake is venomous or not.
Typically, pit vipers have a triangular shaped head, elliptical pupils, and hollow, retractable fangs. In contrast, nonvenomous snakes have a rounded head, round pupils, and lack fangs.
Things that you should NOT do:
Historically several methods to treat snake bites in the field have been proposed and for the most part ALL have been proven unhelpful and potentially harmful.
Tourniquets, cutting and sucking on the wound, suction devices are not recommended.
Tourniquets can damage nerves, tendons, and blood vessels, and oral suction...well, I’m not going to elaborate too much about all the reasons not to do it, just know it is NOT effective!
Pressure immobilization is application of an elastic bandage to the affected limb with a goal of achieving a tight dressing.
The theory is that this may delay systemic absorption of snake venom by preventing lymphatic spread in the affected limb.
Although pressure immobilization is mentioned as a potential first aid therapy for snake bites in the United States by the American Heart Association, there are NO studies that have shown any benefit in humans envenomated by pit vipers.
Many snake bite experts do not support pressure immobilization for pit viper bites because pit viper venom causes local tissue damage and sequestering the venom in the affected limb may increase local tissue damage.
This is a treatment that is not without potential complication and requires consultation with a medical toxicologist unless the physician you are seeing has experience with snake bite treatment.
Phone consultation with a medical toxicologist is available through a United States regional poison control center by calling 1-800-222-1222.
Antivenom therapy is most effective when given within six hours of envenomation.
Long term recovery after a bite
Almost everyone bitten by a venomous snake in the United States recovers. Morbidity is uncommon and associated with bites to the face or upper extremity.
Loss of range of motion in the bitten extremity is the most common long term complication. Other chronic problems may include weakness, pain, abnormal sensation or skin discoloration.
Tissue necrosis can occur with pit viper bites and if it does, it may require surgical debridement. This is a rare complication.
Death following snake bites in the United States is highly unusual. In fact it occurs in less than 1 percent of all bites.
Risk of death due to snake bites is highest with rattlesnake bites, location of the bite (eg, face, neck, trunk), no antivenom therapy available, or inadequate resuscitation of those in shock due to systemic venom toxicity.
The phone number for the National Poison Information hotline, administered by the American Association of Poison Control Centers is 1-800-222-1222.
Take away points
●Most bites in the United States are caused by rattlesnakes, water moccasins (or cottonmouths), and copperheads (pit viper family).
●Symptomatic (rattlesnake, water moccasin, or copperhead) envenomation typically causes local tissue damage.
●First aid consists of removal from the vicinity of the snake, keeping the patient calm and at rest, immobilizing the affected extremity above the level of the heart, and rapid transport to definitive care.
●Do not use pressure dressings for pit viper bites.
●A medical toxicologist or a physician with experience in managing snake bites should be consulted prior to antivenom administration.
Please remember that medical information provided by us must be considered an educational service only. This blog should not be relied upon as medical judgement and does not replace your physician’s independent judgement. This is NOT medical advice. Please seek the advice of your physician.