Rattlesnake Bites

Here in New Mexico we have many rattlesnakes slithering around. Have you ever encountered one of these in your path? I once cared for a patient who had a rattlesnake on her front lawn and she tried to shoo it away. Obviously this didn't go well because she became my patient later that night! What do you do if someone has been bit by a rattlesnake?

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Symptoms of a Rattlesnake Bite

Rattlesnakes do not usually attack humans unless they feel threatened or surprised.  There are about 30 species of rattlesnakes in the world. Because of a continuing reflex, they can still bite hours after death.  About 7,000 to 8,000 people will get bit by rattlesnakes each year, and only about 5 of these people will die.  If a bite occurs, the area will immediately swell up and change color.

Symptoms can include the following:

  • Bleeding
  • Difficulty breathing
  • Blurred vision
  • Numbness in face and limbs
  • Sweating
  • Salivating
  • Low blood pressure
  • Nausea and vomiting
  • Rapid pulse
  • Tissue damage

Rattlesnake venom has hemotoxic properties which damages internal tissues, destroys blood cells, and causes internal bleeding.  It can also have neurotoxic properties which causes nervous system issues including making the person stop breathing. Usually rattlesnake venom has more hemotoxic effects than neurotoxic effects.

Treatment for Rattlesnake Bite

It is a medical emergency if someone has been bit by a rattlesnake.  If left untreated, rattlesnake bites can be fatal.  If you are there when a person receives the bite, wash the affected area with soap and water and cover it with a bandage. Try and keep the affected area below the level of the heart.  Do not try to suck out the venom. Get the person to the hospital as soon as possible.

The main course of treatment is the rattlesnake antivenom, also known as antivenin (crotalidae) polyvalent or Crofab, given in the hospital setting. This is created from the blood of a horse or sheep injected with rattlesnake venom. Dosing is as follows:

The following initial doses are recommended: no envenomation–none. minimal envenomation–20-40 mL (contents of 2 to 4 vials). moderate envenomation–50-90 mL (contents of 5 to 9 vials). severe envenomation–100-150 mL or more (contents of 10 to 15 or more vials). These recommended initial-dosage volumes are in general accord with those of others.

The need for additional Antivenin must be based on the clinical response to the initial dose and continuing assessment of the severity of poisoning. If swelling continues to progress or if systemic symptoms or signs of envenomation increase in severity or if new manifestations appear, for example, fall in hematocrit or hypotension, administer an additional 10 to 50 mL (contents of 1 to 5 vials) or more intravenously. For severe envenomation, a total of 200 to 400 mL (contents of 20 to 40 vials) may be necessary. There is not a recommended maximum dose. The total required dose is the amount needed to neutralize the venom as determined by clinical response.
— Rx List

Side Note: Each vial of antivenin costs approximately $2,500! Say someone requires 40 vials of antivenin, that is $100,000 in just pharmacy bills.  Wow.

The antivenin is most effective when given within four hours of the bite.  Give the first portion of the antivenin slowly and watch the patients for signs of anaphylaxis.  This can happen as a reaction to the serum, so be prepared in case their airway swelling.

In addition to giving the antivenin, the other main issue that we were focused on with the patient I previously spoke of was compartment syndrome.  She had been bit on her hand and had a large amount of swelling in her hand and forearm.  We had an orthopedic surgeon come by to evaluate and make sure that she didn't need a fasciotomy to be performed. Her arm looked like there was no way that it could get anymore swollen.  Luckily, she did not need to have a fasciotomy performed and the swelling eventually subsided.

Other relevant articles include:

References

Medical News Today

Healthline

Rx List

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