Medicine for the Outdoors
Medicine for the Outdoors

Dr. Paul Auerbach is the world's leading outdoor health expert. His blog offers tips on outdoor safety and advice on how to handle wilderness emergencies.

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Jellyfish and Such

This is the fourth post based upon my presentation given at the Wilderness Medical Society Annual Meeting held in Snowmass, Colorado from July 24-29, 2009. The presentation was entitled “Just When You Thought It Was Safe to Go Back in the Water.”” The topic was an overview of hazardous marine animals and it was delivered by me. In the previous posts, there was information about sharks, stingrays and scorpionfishes, and sea urchins. In this post, there is information about injuries from jellyfishes incurred in the marine environment.

Jellyfishes are stinging creatures with stinging “cells,” which are highly specialized and designed to inoculate prey with venom. There may be millions of these stinging cells on the tentacles or near the mouth of the animal. When the cells are stimulated, they shoot out a stinging thread that releases microscopic granules of venom into the victim.

The victim may suffer immediate burning pain, skin rash, blistering, allergic reaction, or a number of systemic symptoms, including neurological sydromes, low blood pressure, abnormal heart rhythms, difficulty breathing, abdominal pain, nausea and vomiting, diarrhea, muscle cramping, and many others.

Treatment should be swift in order to minimize the clinical syndrome.

  1. Rinse the wound with seawater or concentrated salt solution if possible. A gentle fresh water rinse may cause more stinging cells to discharge their venom. 
  2. There is growing support for hot water immersion therapy (113 degrees Fahrenheit or 45 degrees Centigrade), similar to that for a stingray or scorpionfish envenomation, for treatment of certain jellyfish stings. This recommendation emanates from experts in Australia. It is not known if this therapy is effective against North American, European, and non-Australian (Indo-Pacific) jellyfish species.
  3. Anticipate an allergic reaction and be prepared to treat with injectable epinephrine and/or oral antihistamines.
  4. Do not rub the wound.
  5. Wear protective gloves (double thickness of a surgical glove or a thick dishwashing glove preferred).
  6. If the sting is from the box jellyfish Chironex fleckeri, flood the area with topical acetic acid 5% (vinegar) immediately and with a continuous application for a minimum of 30 minutes.
  7. Remove large tentacle fragments with forceps.
  8. DO NOT apply the pressure immobilization technique.
  9. Other topical decontaminants that may work, depending on the jellyfish species, include isopropyl (rubbing) alcohol, dilute ammonium hydroxide (household ammonia), powdered bicarbonate (baking soda), unseasoned meat tenderizer (papain), papaya fruit or juice, or lime or lemon (citrus) juice.
  10. After decontamination, remove adherent nematocysts by applying shaving cream or a paste of baking soda and shaving with a sharp edge, such as a safety razor.
  11. For a mild skin reaction, apply a topical corticosteroid (“steroid”) cream, ointment or lotion.
  12. If the reaction is moderate to severe, a physician may prescribe a systemic steroid or administer a steroid injection.
  13. Anti-tetanus immunization is standard.
  14. Observe closely for development of a wound infection.
  15. If the sting is from the box jellyfish Chironex fleckeri, there is an antivenom available in certain locales. The true efficacy of this therapy is currently under scrutiny.
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Tags: Bites & Stings , In the Water

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About the Author

Dr. Paul S. Auerbach is the world’s leading authority on wilderness medicine.