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Rattlesnake buzz is not a sound that most forget

There is little question that rattlesnakes exist in the vicinity of Durango. According to our local Parks and Wildlife, a rattlesnake sighting at the dog park occurred 10 days before this column.

Sightings are sporadic, and bites are rare. Paul Gibson, Mercy Regional Medical Center’s emergency room director, recalls only two bites in his 27 emergency room years. Nationally, the Poison Center reports, it is estimated that 6,000 to 8,000 people experience venomous bites annually. That includes all species: diamondbacks, copperheads, water moccasins, coral snakes and exotics.

Yet, very few people die – about a dozen annually, one-tenth of bee-sting fatalities.

However, exposure to snakes (and bites) is much less frequent than bee stings. There’s no common denominator – the apples versus oranges thing all over again.

In the Four Corners, most bites (and poison-delivering bites) are from diamondback rattlesnakes. The Western variety, Crotalus atrox and the southeastern cousin, Crotalus adamanteus, are the “largest and most dangerous snakes in this country.” Research has also demonstrated that the larger the snake, the more venom injected. Denim clothing “has proved effective at reducing venom injection.” Mountain biking in denim?

Bites are far worse for children; a 40-pound child gets five times the dose of a 200-pound adult. Kids don’t do well.

Having treated two people bitten by rattlers, I’m no expert, but I am impressed. In New Mexico, a woman in a city park reached behind a rock, failing to see a snake lurking there. She was bitten on the hand – upper and lower extremities are the commonest bite sites. If pain and swelling occur sooner than 20 or 30 minutes, the snake has done his work. Black and blue discoloration and blistering follow with worse to come: nausea, vomiting, dropping blood pressure, disappearing platelets and blood-clotting factors. Bleeding from all body orifices, delirium, seizures, coma and death may result in hours. It’s general quarters in the ER.

The silver bullet is antivenom (or antivenin), formerly Antivenin (Crotalidae) Polyvalent (ACP), extracted from horse serum. A newer product CroFab is produced from sheep and probably results in fewer allergic reactions. Both are powders, in vials, and mixed to a liquid for intravenous use.

There is no science in dosing; it’s black magic, a bit like licking a finger to guess wind direction. Milder symptoms get five to 10 vials; moderate, 15 to 20; severe and rapidly developing symptoms, more – even dozens. However, hospitals usually stock only a few vials; antivenom is hugely expensive and may outdate before need to use it arises. A posse of law enforcement is usually sent to “nearby” hospitals to round up vials.

The woman mentioned was treated in the ER, spent three days on morphine in the hospital, and survived.

A second person, crawling under a mobile home, heard the rattle (or buzz), but persisted. The snake struck, but the person came in a day later, left arm purple and swollen stiff to the shoulder. The patient professed “no ride,” an explanation so lame that no further questions ensued. A poisoned brain may have preceded the poisoned limb.

www.alanfraserhouston.com. Dr. Fraser Houston is a retired emergency room physician who worked at area hospitals after moving to Southwest Colorado from New Hampshire in 1990.