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Irukandji syndrome

From Openwaterpedia

noun - Irukandji syndrome is a condition induced by venomization by the sting of C. barnesi, a species of Irukandji jellyfish, and certain other box jellyfish. The condition is rarely fatal, but if immediate medical action is not taken, within only 20 minutes, the victim could go into cardiac arrest and die. The syndrome was given its name in 1952 by Hugo Flecker, after the Aboriginal Irukandji people who live in Palm Cove, north of Cairns, Queensland, Australia, where stings are common.

In 1964, Jack Barnes confirmed the cause of the syndrome was a sting from a small box jellyfish: the Irukandji jellyfish, which can fire venom-filled stingers out of its body and into passing victims. To prove that the jellyfish was the cause of the syndrome, he captured one and deliberately stung himself. His son and a local lifeguard observed the resulting symptoms. Other cubozoans possibly can cause Irukandji syndrome, but only seven jellyfish are positively identified (C. barnesi, Alatina cf. mordens, Carybdea alata, Malo maximus, Malo kingi, Carybdea xaymacana, an as-yet unnamed "fire jelly", and another unnamed species).


When properly treated, a single sting is normally not fatal; however, two people in Australia are believed to have died from Irukandji stings, which has greatly increased public awareness of Irukandji syndrome. It is unknown how many other deaths from Irukandji syndrome have been wrongly attributed to other causes. The exact mechanism of action of the venom is unknown, but catecholamine excess may be an underlying mechanism in severe cases. Animal studies appear to confirm a relationship between envenoming and an increase in circulating noradrenaline and adrenaline.


Because the jellyfish is very small, and the venom is only injected through the tips of the nematocysts (the cnidocysts) rather than the entire lengths, the sting may barely be noticed at first. It has been described as feeling like little more than a mosquito bite. The symptoms, however, gradually become apparent and then more and more intense in the following five to 120 minutes (30 minutes on average). Irukandji syndrome includes an array of systemic symptoms, including severe headache, backache, muscle pains, chest and abdominal pain, nausea and vomiting, sweating, anxiety, hypertension, tachycardia and pulmonary edema. One unusual symptom associated with the syndrome is a feeling of "impending doom". Patients have been reported as being so certain they are going to die, they beg their doctors to kill them to get it over with. Symptoms generally abate in four to 30 hours, but may take up to two weeks to resolve completely.


As no antivenom is available, treatment is largely supportive, with analgesia being the mainstay of management. Flushing with vinegar, once believed to be useful at neutralizing the tentacle stinging apparatus of box jellyfish, has been shown to amplify rather than palliate the effects of a box jellyfish sting.

Geographic distribution[edit]

Reports of Irukandji syndrome have come from Australia, Hawaii, Florida, the French West Indies, Bonaire, the Caribbean, Timor Leste and Papua New Guinea. Cubozoan species other than C. barnesi are presumed to be responsible for envenomations outside Australia.

Description of Pain[edit]

On the television program Super Animal, a woman compared her pain from childbirth to her experience with Irukandji syndrome: "It's like when you're in labor, having a baby, and you've reached the peak of a contraction—that absolute peak—and you feel like you just can't do it anymore. That's the minimum that Irukandji pain is at, and it just builds from there."