Irukandji syndrome

Background

• Caused by certain jellyfish from the Cubozoa class (box jellyfish) species
• Usually develops within 2 hours of envenomation & can last up to 2 days
• The sympathomimetic-like manifestations are due to the venom, which is proteinaceous and contains a neural sodium channel activator. **Acts on the same sodium channels that are sensitive to tetrodotoxin, causing the release of catecholamines, particularly norepinephrine and epinephrine, and also direct vasoconstrictor effects.

Clinical Features

• Rare but potentially fatal complications can manifest in diverse ways:
  • Myalgias
  • Back pain
  • Chest pain
  • Abdominal pain
  • Nausea and vomiting
  • Diaphoresis
  • Hypertensive crisis
  • Cardiogenic pulmonary edema
  • Intracranial hemorrhage
  • Death

Differential Diagnosis

• Marine toxins and envenomations
  • Toxins (ciguatera, neurotoxic shellfish poisoning, paralytic shellfish poisoning, scombroid, tetrodotoxin
  • Stingers (stingray injury)
  • Venomous fish (catfish, zebrafish, scorpion fish, stonefish, cone shells, lionfish, sea urchins)
  • Nematocysts (coral reef, fire coral, box jellyfish, sea wasp, portuguese man-of-war, sea anemones)
  • Phylum porifera (sponges)
  • Bites (alligator/crocodile, octopus, shark)

Evaluation

• EKG
• Troponin & ProBNP
• CBC
• CMP
• Lipase
• Chest X-ray
• CT imaging of the brain in cases of headache or acute encephalopathy

Management

• Manage pain with 4-5% acetic acid (household vinegar) & Hot water immersion (111-114F)
• IV magnesium sulfate (0.2mmol/kg, max 10mmol in adults) given as a bolus over 5-15 minutes for pain refractory to opioids
• Hypertension should be treated with short-acting titratable medications (eg., phentolamine, esmolol, nicardipine, nitroprusside) d/t potential for hypotension in the later stages of toxicity