For Our EMS Providers

Virginia   Snakes –

A Little “Bite” of What You Need to Know This Summer

By Jill Eckenberger, MD

This is a topic we could spend a great deal of time discussing, but here are a few of the important points.   Despite their widespread “bad guy” reputation, snakes generally do not pose a threat to humans and actually play a very important role in our ecosystem.  There are 30 species of snakes living in Virginia, only three of which are venomous.  They are members of the subfamily Crotalidae (pit vipers): the Northern Copperhead found in wooded areas statewide, the Timber Rattlesnake found in the western mountain range and southeast wetlands(where it is also known as the Canebrake), and the Eastern Cottonmouth found only in the southeastern plain. 

Of the nearly 8000 people bitten by venomous snakes every year in the US, only 5 to 10 die.  By far the most common cause of bites is a result of an attempt to handle the snakes.  Alcohol, not surprisingly is also a common denominator.  Pit viper venom is made up of nearly 50 identified components.  These can be divided into 4 major categories: Proteolytic enzymes (destroy tissue), Inflammatory mediators (pain, swelling, erythema, and potentially distributive shock), Fibrinolytic enzymes (coagulopathies), Antiplatelet factors (causing thrombocytopenia).  Of note, bites from the Copperheads and Cottonmouth are generally less serious envenomations than what we see in rattlesnakes.  Clinically significant systemic bleeding occurs in less than 5% of copperhead envenomations.  Treatment is based on the severity of the envenomation.  “Dry bites” are bites without envenomation and occur frequently (25% of pit viper bites and 50% of coral snake bites).

When you have a patient that has been bitten:

·          Per ACLS, support the airway, breathing, and circulation with O2, monitors, large bore IVs, and fluids. 

·          Minimize activity and remove any tight fitting clothes or jewelry.

·          Note the time elapsed since the bite.

·          Obtain a description of the snake (did it have a rattle, etc.).  Consider photographing the snake from a safe distance if possible but do not  attempt to capture it. 

·          Note history of prior exposure to snakebites or antivenin.

·          Note any symptoms of local swelling, pain, or paresthesias; nausea, vomiting, diarrhea, syncope, difficulty swallowing or breathing.

·          Note history of comorbid conditions or medications (anticoagulants, etc.)

·          Use a pen to mark and time the border of advancing edema or tenderness.  This should be done every 15 minutes. 

·          Maintain the limb in a position below heart level to reduce the spread of venom.

·          Lymphatic constriction bands may inhibit the spread of venom but it is still not clear that they improve outcome.  If this is done, apply a bandage 2-4 inches above the bite.  This should be loose enough to allow a finger to slip underneath.  Tourniquets are not recommended. 

·          No benefithas been demonstrated with negative pressure devices (like the Sawyer Extractor) and can in fact cause additional injury.  Other interventions potentially more harmful than the snakebite include electric shock, alcohol, stimulants, aspirin, application of ice, and herbal medications.

·          DO NOTmake an incision across the fang marks.  Do not attempt to suction venom by mouth. 

·          Immediately transfer to definitive care. 

Please refer to the Virginia Herpetological Society’s website for more information and some great photos of these animals.  http://www.virginiaherpetologicalsociety.com/reptiles/snakes/snakes_of_virginia.htm