Wednesday, May 10, 2006

Stingray injury (and how not to manage it!)

Dr. Bruce Miller, diving dermatologist, sent us this report about how not to treat a stingray injury. [Photo by Kris Judish]

"A good friend was in Mexico wading and stepped on a small stingray. It nailed him (large red dot). The 3 smaller ones are xylocaine injection sites. He's a big tough dude and said that it was by far the most excruciatingly painful thing he's ever experienced.

He was sent to the doc at the hotel who hooked him up to a monitor and started an IV. Told his assistant to pour hot water on the wound so this guy pours BOILING water on it. Stopped the venom pain but caused a 2nd degree burn with a large blister. I saw him 3 days later. The area was red and somewhat tender but no streaks. I put him on cipro just in case. Apparently the doc also explored the wound but no sheath remnants.

We hear about encounters such as this at all the dive med meetings but rarely do we see it.

More about stingray injuries

Phylum Chordata, Class Chondrichthyes. These possess a serrated bony spine at the base of the dorsal surface of the tail. An integumentary sheath discharges venom when ruptured.

Most injuries occur when the ray is stepped on, the tail is thrust upward and forward and fired into the foot or leg. The venom is thermolabile (deactivated with heat) and induces severe vasoconstriction.

Symptoms: Intense pain is felt at the site; there is local ischemia (loss of blood supply), and edema. Edges are jagged, may contain pieces of spine and secondary infection is common. Systemic effects include salivation, sweating, vomiting, diarrhea, cramps, hypotension (low blood pressure), and cardiovascular collapse.

Treatment: Irrigate and remove remaining spine. Immerse in hot (50 C) water until pain subsides. Give local or systemic pain relief. Cleanse, debride and suture the wound. Give tetanus protection, infection prophylaxis and monitor / support cardio-respiratory system as indicated.

Dr. Carl Edmonds sends us the following good information about the temperature of the water for relief:
"Notice in your 10 foot stop that you recommend 50 degrees C for stingray injury.

We did say, in the 70s that the temperature can go up to 50 degrees, but we were adding hot water to cold and doing it slowly. We later changed to 45 degrees because of 3 reasons

1. If you immediately immerse a limb into 50 degrees, many people find this exceptionally painful, and jump off the examination couch
2. There is a suggestion that this temperature may do tissue damage
3. It is not needed. 45 degrees works just fine."

If you don't have a way to measure the temperature - one would suppose that it can be tested on one's self on the back of the hand, as in testing an infants milk bottle. A rule of thumb would be "as hot as you can stand it on the back of the hand!"
Re water temp for spine injuries ( including stingray)- I advise my nurses to have the water as hot as can be tolerated by the unaffected limb ( ie put both feet in!!)- usually 40-45C
Dr Neil Banham
Emergency Physician

See also: