Box jellyfish envenomation

Background

Box jellyfish

Nematocyst stages of discharge

• Cnidarian invertebrates distinguished by their cube-shaped medusae
• Chironex fleckeri or sea wasp is cause of most deaths
• Largely restricted to the Indo-Pacific Ocean/Australian waters but various species can be found widely
• 83% occur in < 1m of water.
• Most stings are benign (requiring local treatment only), recent data suggests fatality rate is much lower than the 20% previously reported.
  • Morbidity and Mortality are dose- and time-dependent, which explains why majority of deaths have been children.

Mechanism

• Has about 15 tentacles (measure up to 3m in length) that contain millions of "stinging cells" called nematocysts.
• Contact with the tentacles cause rapid onset of pruritic/burning
• Thought to affect sodium/potassium/calcium channels
• Rhabodmyolysis can occur from sustained muscle contractions caused by myotoxins in venom.
• Cardiovascular collapse can occur d/t dysrhythmia (from hyperkalemia) and osmotic dysregulation of endothelial and cardiac tissues from pore-forming toxins within the venom.
• Chironex fleckeri venom causes cell membranes to become porous allowing K+ influx/hyperkalemia

Clinical Features

Patient stung by multiple box jellyfish tentacles.

Patient stung by multiple box jellyfish tentacles.

Box jellyfish sting.

Pediatric box jellyfish sting.

• Stings associated with immediate pain, lasting up to 8 hours, and linear welts in a cross-hatched "ladder-rung" pattern
  • Erythematous maculopapular rash
  • May progress to blisters/necrosis
• 25-30% may still have tentacles attached
• Systemic envenomation (usually >10% BSA) can manifest as cardiac arrhythmias, respiratory dysfunction, death
  • Usually manifests within 5 minutes of sting
• Delayed hypersensitivity reactions occur in >50%
  • Itching, redness at sting sites 7-14d after initial incidence

Differential Diagnosis

Marine toxins, envenomations, and bites

• Toxins
  • Ciguatera
  • Scombroid
  • Tetrodotoxin (e.g. pufferfish)
  • Shellfish poisoning
    • Amnesic shellfish poisoning
    • Diarrheal shellfish poisoning
    • Neurotoxic shellfish poisoning
    • Paralytic shellfish poisoning
• Stingers
  • Stingray injury
• Venomous fish
  • Cone shell
  • Lionfish
  • Sea urchins
  • Crown-of-Thorns Starfish
  • Stonefish
  • Other: Catfish, zebrafish, scorpion fish
• Nematocysts
  • Coral reef
  • Fire coral
  • Jellyfish (Cnidaria)
    • Box jellyfish
      • Irukandji syndrome
    • Sea wasp
  • Portuguese man-of-war
  • Sea anemones
  • Seabather's eruption
• Phylum porifera (sponges)
• Bites
  • Alligator and crocodile attacks
  • Octopus bite
  • Shark bite
• Infections
  • Vibrio species in saltwater
  • Aeromonas species in freshwater

Evaluation

• Generally a clinical diagnosis

Management

• First remove any tentacles
  • tentacles separated from medusae can still emit venom
• 4-5% acetic acid/vinegar solution should be applied to the injured area for at least 30 seconds.
• Pain control
• Supportive measures for minor envenomations
  • Ice recommended but heat may actually work better
• Antihistamines and steroids for hypersensitivity reaction
• Do NOT pressure bandage
• Antivenom for life-threatening envenomations
  • Bovine IgG Fab with 20,000 units/ampule
• Avoid treating with fresh water, alcohol, methylated spirits, or urine as these have shown to increase nematocyst firing.

Antivenom Indications^

• Cardiac arrest
  • undiluted antivenom administered as an IV Push: up to 6 vials
  • if no response then give magnesium IV (0.2mmol/kg, max 10mmol in adults)
• Hypotension, tachycardia, shock, arrhythmia
  • dilute 3 amps antivenom in 100mL NS and run over 20 minutes
  • can repeat for a total of 6 vials
• Intractable pain
  • give 1 amp diluted in 100mL NS run over 20 minutes

Anti-venom can cause serum sickness 4-14 days after administration

See Also

• Marine toxins and envenomations
• Sea wasp sting

References

1. Bastian Bentlage, Paulyn Cartwright, Angel A. Yanagihara, Cheryl Lewis, Gemma S. Richards and Allen G. Collins.Evolution of box jellyfishes (Cnidaria: Cubozoa), a group of highly toxic invertebrates. Proceedings of the Royal Society, November 18, 2009 DOI:10.1098/rspb.2009.1707
2. Currie BJ, Jacups SP. Prospective study of Chironex fleckeri and other box jellyfish stings in the “Top End” of Australia’s Northern Territory. Med J Aust 2005; 183: 631-636
3. Hughes RJ, Angus JA, Winkel KD, Wright CE. A pharmacological investigation of the venom extract of the Australian box jellyfish, Chironex fleckeri, in cardiac and vascular tissues. Toxicol Lett. 2012 Feb 25;209(1):11-20. Epub 2011 Dec 2.
4. http://www.toxinology.com/generic_static_files/cslavh_antivenom_boxjelly.html