Something in the Water…: Board Review for Marine Animal Poisoning

In-training exam time is coming up fast, do you know your marine animal tox questions? This a great board review article written by our own Jennifer Luk, we’ll underline the pearls (not intended) and she even put in a helpful table for you to keep everything organized. Onward and downward…

Stingrays

• Location: Found in shallow coastal waters, particularly in sandy or muddy bottoms in tropical and subtropical regions.
• Injury Mechanism: Venomous tail barbs that can cause lacerations and envenomation.
• Clinical Presentation: Severe pain, bleeding, puncture wounds, and potential systemic effects of peripheral vasodilation including commonly syncope, weakness, nausea, and anxiety.
• Treatment:
  • Hot Water Immersion: Submerge the affected area in hot water (43-45°C) to denature the venom and alleviate pain.
  • Wound Irrigation and Debridement
  • Tetanus Prophylaxis and Antibiotics: Administer for open wounds to prevent Vibrio infections.
  • Radiographs: Use to detect any retained foreign bodies, such as barb fragments.¹

Bony Fish (e.g., Catfish, Scorpionfish, Lionfish)

• Location: Common in warm coastal waters and coral reefs; found in both shallow and deep waters.
• Injury Mechanism: Spines can inject venom or create puncture wounds.
• Clinical Presentation: Local pain, redness, and edema; systemic symptoms like weakness or hypotension may occur in severe cases.
• Treatment:
  • Hot Water Immersion: Similar to stingray injuries to inactivate venom.
  • Wound Care: Clean, irrigate, and debride the wound.
  • Antibiotics: Consider for secondary infection prevention.
  • Tetanus Prophylaxis: Administer as needed.

Sea Urchins

• Location: Found in shallow coastal waters, particularly in coral reefs and rocky areas.
• Injury Mechanism: Sharp spines or venomous appendages can cause puncture wounds or envenomation.
• Clinical Presentation: Pain, swelling, and potential for embedded spines; severe cases may lead to systemic symptoms, including paralysis from certain tropical species.
• Treatment:
  • Hot Water Immersion: Relieves pain and inactivates venom.
  • Spine Removal: Manually extract superficial spines; deeper or joint-embedded spines may require surgical intervention.
  • Tetanus Prophylaxis and Antibiotics: administer if needed

Cone Snails

• Location: Found in warm, shallow waters in tropical and subtropical regions, often on sandy bottoms or among coral reefs.
• Injury Mechanism: The cone snail’s venomous harpoon delivers neurotoxic venom.
• Clinical Presentation: Intense pain, swelling, paralysis, and in severe cases, respiratory failure.
• Treatment:
  • Wound Care: Clean and manage the puncture wound.
  • Neuromuscular Support: Monitor for paralysis and provide respiratory support if necessary.
  • No Specific Antivenom: Treatment is primarily supportive.

Jellyfish (including Portuguese Man O’War)

• Location: Found in both warm and temperate waters; often near beaches and in open ocean.
• Injury Mechanism: Nematocysts (stinging cells) release venom on contact.
• Clinical Presentation: Local pain, erythema, and urticaria; severe cases may result in respiratory distress or cardiovascular collapse.
• Treatment:
  • Hot or Sea Water Immersion: Provides pain relief and deactivates venom for many species. Do not use freshwater as it may activate undischarged nematocysts
  • Vinegar Rinse: Neutralizes venom in tropical species and box jellyfish stings. NOT FOR PORTUGUESE MAN O’WAR
  • The Portuguese Man O’War (pictured below)
    • Tentacle Removal: Use double gloved hands or forceps; avoid rubbing the area.
    • Antihistamines and NSAIDs: For pain and allergic reactions.
    • Systemic Treatment: Monitor for anaphylaxis or cardiovascular collapse in severe cases.

Coral

• Location: Found in tropical and subtropical oceans, often forming reefs in shallow waters.
• Injury Mechanism: Abrasions introducing toxins and causing infection.
• Clinical Presentation: Pain, swelling, and redness; risk of infection.
• Treatment:
  • Wound Irrigation and Debridement: Prevent infection from marine bacteria.
  • Tetanus Prophylaxis and Antibiotics: administer if needed, but especially for Vibrio coverage

Octopuses? Octopi? Octopodes?

eg Blue-Ringed Octopus

• Location: Found in tide pools and coral reefs in the Indo-Pacific region, particularly in shallow waters.
• Injury Mechanism: Neurotoxic venom, tetrodotoxin, is delivered via a bite.
• Clinical Presentation: Painless bite followed by paralysis, respiratory distress, and possible death.
• Treatment:
  • Supportive Care: No antivenom; focus on respiratory support (intubation if needed) and monitoring.
  • Wound Care: Clean and manage the bite site.

Summary

Most of these marine animal injuries are treated with supportive care, local wound care, and a tetanus vaccine as needed. Hot water immersion is the answer on boards with the exception of cone snails/octopi (neuromuscular support given the neurotoxin) and jellyfish (acetic acid/vinegar EXCEPT the Portuguese Man O’War which is tentacle removal and antihistamines).

Marine Animal	Location	Injury Mechanism	Clinical Presentation	Treatment
All	Ocean/Warm Coastal Areas	Venomous pokey bits	Severe pain, lacerations, punctures	Hot water immersion, remove foreign bodies, Tdap, Abx for open wounds
Stingray	Shallow coastal waters in tropical regions	Venomous tail barbs causing lacerations	Severe pain, bleeding, syncope, nausea	Hot water immersion, wound care, Tdap, Abx, radiographs
Bony Fish	Warm coastal waters and coral reefs	Venomous spines or puncture wounds	Local pain, redness, edema	Hot water immersion, wound care, Tdap, Abx
Sea Urchin	Shallow coastal waters, coral reefs	Sharp spines causing puncture wounds	Pain, swelling, possible paralysis	Hot water immersion, spine removal, Tdap, Abx
Cone Snail	Warm, shallow tropical waters	Venomous harpoon delivering neurotoxic venom	Intense pain, paralysis, respiratory failure	Wound care, neuromuscular support
Jellyfish	Warm and temperate waters, near beaches	Nematocysts releasing venom	Local pain, erythema, possible respiratory distress	Hot water immersion, vinegar (not for Portuguese Man O’ War), tentacle removal, antihistamines
Coral	Tropical and subtropical oceans	Abrasions introducing toxins	Pain, swelling, risk of infection	Wound irrigation, Tdap, Abx
Octopus (Blue-Ringed)	Tide pools and coral reefs in Indo-Pacific	Neurotoxic venom via bite	Painless bite, paralysis, respiratory distress	Supportive care, wound care

Cite this post: Jennifer Luk, MD. “Something in the Water…: Board Review for Marine Animal Poisoning”. GW EM Blog. 1/29/2025. Available at: https://gwemblog.com/marine-tox-review/

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References

1. Stingray Stings – Injuries; Poisoning. MSD Manual Professional Edition. https://www.msdmanuals.com/professional/injuries-poisoning/bites-and-stings/stingray-stings ↩︎