by Paul Auerbach

There are two excellent photographs of a rattlesnake bite victim that appear in the June 10, 2010 issue of the New England Journal of Medicine (362;23:2212). Entitled “Rattlesnake Envenomation” in the IMAGES IN CLINICAL MEDICINE feature, they show the bitten finger and the effects on the torso of a man who presented for medical care within a half hour of having been bitten by a rattlesnake. He was treated with antivenom prior to being admitted to the hospital.

The finger image shows the local effect of the venom in this victim, which could have caused tissue destruction (but did not, which is most likely attributable to the timely administration of a sufficient amount of antivenom). The torso image shows the extensive bruising associated with the blood clotting disorder that developed because of the systemic effects of the venom, which combined to prolong bleeding time in this victim. Despite the initial administration of antivenom, the victim continued to develop his bleeding problem, so was administered additional antivenom, which is needed to counteract the venom effects. The patient had a full recovery, which is a credit both to the victim (for promptly seeking medical care) and to the treating physicians, who knew how to properly treat a venomous rattlesnake bite with antivenom.

For the benefit of anyone who might suffer a rattlesnake bite, here are instructions about what to do in the field:

  • If a person is bitten by a snake that could be poisonous, act swiftly. The definitive treatment for serious snake venom poisoning is the administration of antivenom. The most important aspect of therapy is to get the victim to an appropriate medical facility as quickly as possible.
  • Don’t panic. Most bites, even by venomous snakes, do not result in medically significant envenomations. Reassure the victim and keep him from acting in an energy-consuming, purposeless fashion.
  • Retreat out of the striking range of the snake, which for safety’s sake should be considered to be the snake’s body length (for pit vipers, it is actually approximately half the body length). A rattlesnake can strike at a speed of 8 ft (2.4 m) per second.
  • Locate the snake. If possible, identify the species. If you cannot do this with confidence (which is really only important for the Mojave rattlesnake and coral snake), you might be able photograph the snake using a digital camera, but be careful. Do not attempt to capture or kill the snake, for fear of wasting time and perhaps provoking another bite. Never delay transport of the victim to capture a snake. If the snake is dead, take care to handle it with a very long stick or shovel, and to carry the dead animal in a container that will not allow the head of the snake to bite another victim (the jaws can bite in a reflex action for up to 90 minutes after death). If you are not sure how to collect the snake, it is best just to get away from it.
  • Splint the bitten body part to avoid unnecessary motion. Allow room for swelling within the splint. Maintain the bitten arm or leg in a position of comfort. Remove any jewelry that could become an inadvertent tourniquet.
  • Transport the victim to the nearest hospital.
  • Do not apply ice directly to the wound or immerse the part in ice water. An ice pack placed over the wound (as one would do for a sprain) is of no proven value to retard absorption of venom, but may be useful for pain control. Application of extreme cold can cause an injury similar to frostbite, and possibly lead to enough tissue loss to require amputation.
  • Application of the Extractor Pump is at best controversial, and is no longer recommended by snakebite experts. The manufacturer claims that if the device is applied according to the instructions provided, it can remove venom without the need for a skin incision. Animal research appears to refute this notion, and even to suggest that by using the device for a rattlesnake bite, it might cause concentration of tissue-toxic venom under the suction cup, leading to a more severe reaction.
  • If the victim is more than 2 hours from medical attention, and the bite is on an arm or leg, one may use the pressure immobilization technique: place a 2 in by 2 in (5 cm by 5 cm) cloth pad over the bite and apply an elastic wrap firmly around the involved limb directly over the padded bite site with a margin of at least 4 to 6 in (10 to 15 cm) on either side of the wound, taking care to check for adequate circulation in the fingers and toes (normal pulses, feeling, and color). An alternative method is to simply wrap the entire limb at the described tightness with an elastic bandage. The wrap is meant to impede absorption of venom into the general circulation by containing it within the compressed tissue and microscopic blood and lymphatic vessels near the limb surface. You should then splint the limb to prevent motion. If the bite is on a hand or arm, also apply a sling. It should be noted that this recommendation is controversial, in that some experts believe that localizing venom in a single area might lead to an increased chance for tissue damage.
  • An alternative to the pressure immobilization technique is a constriction band (not a tourniquet) wrapped a few inches closer to the heart than the bite marks on the bitten limb. This should be applied tightly enough to only occlude the superficial veins and lymph passages. To gauge tightness, the rescuer should be able to slip one or two fingers under the band, and normal pulses should be present. The band may be advanced periodically to stay ahead of the swelling. It is of questionable usefulness if 30 minutes have intervened between the time of the bite and the application of the constriction band (or pressure immobilization technique). Again, this recommendation is controversial, for the reasons mentioned in the previous paragraph.
  • The impression of most snakebite experts is that incision and suction are of little value and probably should be abandoned. It appears that little venom can actually be removed from the bite site. Furthermore, the incision may set the stage for inoculation of bacteria, infection, and a poorly healing wound. Mouth contact with the incision may cause a nasty infection that leaves a noticeable scar; there is also the risk of transmission of blood-borne disease to the rescuer.
  • “Snakebite medicine” (whiskey) is of no value and may actually be harmful if it increases circulation to the skin.
  • There is no scientific evidence that electrical shocks applied to snakebites are of any value. On the contrary, there are experiments that refute this concept.
  • The bite wound should be washed vigorously with soap and water, and the victim treated with dicloxacillin, erythromycin, or cephalexin.
  • If the victim is many hours or days from a hospital, assist him to walk out or arrange for a litter rescue, allowing frequent rest periods and adequate oral hydration. Splinting and positioning (e.g., elevating or lowering) the bitten part are secondary to any effort to reach a facility where antivenom can be administered.
  • Watch for an allergic reaction caused by the snakebite. This might cause the victim to be short of breath with or without an airway obstruction from swelling of the mouth, tongue, and throat. Once the victim is in the hospital, the severity of envenomation will be ascertained, and the victim treated with antivenom if necessary. Such therapy must be carried out under the supervision of a physician, because serious allergic reactions to antivenom are possible.

 

Reprinted with permission from Healthline.com