About 400 out of 3,000 species of snakes worldwide are poisonous. Only about 25 species of these poisonous snakes are found in North America.
Snakes are cold blooded and are unable to increase their body temperature and stay active when it is cold outside. This is why most snake bites occur in the summer. Poisonous snakes inject venom into their prey using their salivary glands. Venom passes from the salivary glands through ducts into the snake’s fangs. Snakes can regulate whether or not to release venom. About 25 percent to -50 percent of snake bites are dry bites where no venom is injected. However, the victim of the bite has no way of knowing whether the bite is dry or venomous.
Snake venom is composed of cytotoxins, hemotoxins, neurotoxins and cardiotoxins. Cytotoxins cause local tissue damage. Hemotoxins cause internal bleeding. Neurotoxins affect the nervous system. Cardiotoxins act directly on the heart.
There are between 1.2 and 5 million snake bites a year worldwide. Of these, about 7,000 bites are in the United States. Worldwide these bites account for between 20,000 and 125,000 deaths. But only five to 10 of these deaths occur in the United States per year.
There are two main families of snakes that are venomous. The elapid and the viper family. The elapid family includes snakes usually found in Asia and Africa. The viper family includes rattlesnakes, cottonmouth and copperhead snakes found in our area.
There are many signs and symptoms of snakebites. Bites can be painful and tender and can swell and bleed or blister. Bleeding can be local or diffuse. Internal organs can be involved. Bleeding may occur from the site or spontaneously from the mouth or old wounds. Bites can cause vision problems, speaking and breathing troubles and numbness close to or distant to the bite site. Muscle death can be local or diffuse and can cause rhabdomyloysis (break down of distant muscle), which if left untreated can clog kidneys and lead to kidney failure.
Any snakebite victim should go to the hospital or emergency room. Even bites by nonvenomous snakes require proper wound care. Victims should receive a tetanus booster if they have not had one within the last five years. If a venomous snakes is thought to be the culprit, then antivenin may be used.
When you arrive at the hospital an inspection and cleaning of the bite site will be performed. Blood work will usually be done to determine how well your clotting factors and kidney functions are doing. A number of old first aid techniques are inaccurate. Do not cut or suck the bite. Do not use ice. Do not use electric shock. Do not use alcohol. Do not use tourniquets or constriction bands.
Antivenin may be used if significant symptoms are present in the victim. Giving antivenin can be a difficult decision due to its significant side effects. These include allergic reaction or anaphylactic shock. Antivenin can also cause serum sickness which can affect the patient within five to 10 days after therapy. Serum sickness causes fever, joint aches, itching and fatigue. Even victims without significant symptoms should be monitored for several hours and even hospitalized at times. A snakebite victim who has been released from the hospital should return to the ER if he or she experiences difficulty breathing, confusion, bleeding, worsening pain or swelling. If antivenin was used and serum sickness develops, the victim should return to the ER.
Any snakebite victim should follow up with his or her doctor to make sure the site hasn’t gotten infected and to check the victims clotting factors. Follow up lab tests may be needed.