By Buck Tilton
Reprinted from The Leader, Summer 2001, Vol. 16, No. 3
It slithers on scales controlled by abdominal muscles or scuttles on eight impossibly coordinated legs, and it gets your attention. You just can't turn your back. In fact, you're probably drawn irresistibly for a closer look. And you probably gather your students around, at a safe distance, of course, for a peek. It's always worth avoiding a painful and deeply personal encounter, but is it dangerous? Often no-sometimes yes. Read on.
All scorpions love the night and hide by day. They all sting with the tip of their "tail"-the last few segments of their abdomen. Their pincers are for holding and tearing apart their prey. Insects are their primary source of food. Most victims report no more pain than a vicious bee sting. An attack of the species Centruroides may be different. In North America only the Centruroides is a known killer of humans. They are usually straw-yellow or yellow with dark longitudinal stripes, and reach from 2 to 7.5 centimeters in length. Their pincers are long and slender as opposed to bulky and lobster-like. The sting is immediately very painful, with the pain increased by a light tap on the site. But resulting deaths have almost exclusively been in small children, the elderly, and the severely allergic. This scorpion is only found in Mexico and the extreme southwestern United States.
First aid for any scorpion attack should involve cooling the wound which allows the body to more easily break down the molecular structure of the venom. Cooling also reduces pain. Use ice or cool running water if available. On a warm night, a wet compress will help. And keep the victim calm and still. Panic and activity speed up the venom's spread. If the scorpion was Centruroides, post-sting manifestations may include heavy sweating, difficulty swallowing, blurred vision, loss of bowel control, jerky muscular reflexes, and respiratory distress. These serious signs are cause for quick evacuation to a medical facility. Antitoxins are available in many areas where dangerous scorpions live.
An estimated 200 species of snakes, worldwide, carry the potential for human death in their venom, and a best guess by experts places the number of deaths each year at more than 50,000. Few of these deaths occur in the United States: none in 1990, one in 1991, one in 1992. Ninety-nine out of every 100 poisonous bites by indigenous snakes in the U.S. are received from a pit viper: rattlesnakes, copperheads, and water moccasins. A pit viper's danger comes from two very special teeth, hinged to swing downward at a 90° angle from the upper jaw. The jaw opens very, very wide, allowing the venom to be ejected down canals within the fangs, and into a prey's tissue. The amount of venom and the toxicity of the venom determine the danger to the bitten. For instance, the poison of the Mojave rattlesnake is approximately 44 times more potent than the southern copperhead's. Arizona is the most likely place to die of a snakebite, with Florida, Georgia, Texas, and Alabama filling out the top five
Mild envenomations hurt, swell, turn black and blue, and sometimes form a blister at the site. Moderate envenomations add swelling that moves up the arm or leg toward the heart, numbness, and swollen lymph nodes. A severe envenomation might add big jumps in pulse rates and breathing rates, profound swelling, blurred vision, headache, lightheadedness, sweating, and chills. Death is possible.
How dangerous is snake venom to a human? Depends on the age, size, health, and emotional stability of the victims. Additionally, whether or not they're allergic to the venom, where they were bitten (near vital organs being the most dangerous), how deep the fangs go, how upset the snake is, the species and size of the snake, and the first aid provided.
Around the world, snake venom often varies greatly depending on the species, and specific treatment may vary. Most patients will benefit from these guidelines which have been developed especially for North American pit viper envenomation: Calm and reassure the patient. Keep the patient physically at rest with the bitten extremity immobilized and kept lower than the heart. Remove rings, watches, or anything else that might reduce the circulation if swelling occurs. Wash the wound. Measure the circumference of the extremity at the site of the bite and at a couple of sites between the bite and the heart, and monitor swelling. Evacuate the patient by carrying, or going for help to carry, or, if the patient is stable, by slow walking. Do NOT cut and suck. Mechanical suction (NOT oral suction) may be valuable if you get there in the first five minutes. Suction should be applied for 30 minutes via the Sawyer Extractor®. Do NOT give painkillers unless the patient is very stable, showing no signs of getting worse. Do NOT apply ice or immerse the wound in cold water. Do NOT apply a tourniquet. Do NOT give alcohol to drink. Do NOT electrically shock the patient.