Wilderness and Rescue Medicine 7th Edition Jeffrey Isaac, PA-C and David E. Johnson, MD

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Section V: Environmental Medicine

Most types of spiny toxins are inactivated by heat. Immerse the affected part in water as hot as the patient can tolerate until pain is relieved. Often this will be within a few minutes, but treat- ment may need to be continued for an hour or more.

well understood. Ice applications may help relieve persistent pain later. The use of alcohol, meat ten- derizer, urine, or other chemicals to flush the skin is not helpful, and possibly harmful.

Spiny Injury

General Principles

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Treatment: • Immerse extremity in hot water up to 90 minutes • High-risk wound care, anticipate infection • BLS/ALS and immediate evacuation for progressive neurologic symptoms (lionfish, stonefish, cone shell) • Pain control Typically tissue toxin, sometimes combined with neurotoxin

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The long tentacles on jellyfish carry the potential for large surface area stings. Persistent skin inflammation can be treated for several days with twice daily applications of a steroid cream or ointment (e.g., hydrocorti- sone). Antihistamines may also help because a local allergic reaction may be part of the patient’s discomfort. As with any open wound, infection is an anticipated problem.

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Nematocyst Sting Nematocysts are structures in the stinging parts of jellyfish, corals, and anemones, that fire some- thing resembling a microscopic harpoon when touched. These harpoons then inject a potent neu- rotoxin into the skin. Individually, the amount of toxin is miniscule, but the toxin load can be considerable when the patient has contact with thousands of nematocysts at once. Of particular concern are stings from the Indo-Pacific box jel- lyfish (Chironex fleckeri), due to the high potency of the venom, and the Portuguese man-of-war (Physalia physalis), due to the potential for large surface area exposure. The field treatment for stinging jellyfish includes removing tentacles by flushing with seawater and picking off any remaining tentacles with forceps or gloved fingers. Seawater is considered by some authorities to be preferable to fresh water because the osmotic difference of fresh water may stimulate more nematocysts to fire. Flushing and soaking the skin with vinegar will inactivate the nematocysts of some species and is specifically recommended for box jellyfish, fire worm, and sponge stings. There is also evidence that hot water soaks, as with spiny envenomation, or even a hot shower may reduce the pain immediately after the sting, although the mechanism is not

Nematocyst Injury

General Principles

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Treatment: • Rinse with salt water, remove tentacles • Hot water soaks • General wound care, topical corticosteroids and topical anesthetics • BLS/ALS and immediate evacuation for progressive neurologic symptoms (box jelly, man-of-war) • Pain control

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Systemic effects from large or potent exposure to nematocyst-borne neurotoxins include pain, spasm, and cramping. An exposure occupying more than 50% of a limb should be considered potentially serious with anticipated systemic neurotoxic effects. Truly life-threatening symp- toms are generally limited to Portuguese man- of-war and the Indo-Pacific box jellyfish. Medical