Irukandji syndrome

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Irukandji syndrome
A specimen of Malo kingi, a species of Irukandji jellyfish, in a clear plastic vial
SpecialtyMedical toxicology Edit this on Wikidata
Symptomsheadache, backache, chest and abdominal pain, nausea, vomiting, pathological sweating, severe and sudden onset anxiety, tachycardia[1][2][3]
Complicationshypertension, enlarged heart, pulmonary edema, cardiac arrest, possible heart failure[1][2][3]
Usual onset30 minutes after exposure
Duration4 to 30 hours, sometimes up to 2 weeks
CausesIrukandji jellyfish sting

Irukandji syndrome is a condition that results from envenomation by certain box jellyfish.[4] In rare instances the sting may result in cardiac arrest and death.[5] The most common jellyfish involved is the Carukia barnesi, a species of Irukandji jellyfish.[4] Those stung may experience severe or even excruciating pain.

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.[6]

Signs and symptoms[edit]

Most stings occur during the summer wet season in October–May in North Queensland, with different seasonal patterns elsewhere.[3] Because the jellyfish are very small, the venom is only injected through the tips of the nematocysts (the cnidocysts) rather than the entire lengths; as a result 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 subsequent 5 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.[2][3][7][8] Symptoms generally improve in four to 30 hours, but may take up to two weeks to resolve completely.[9]


When properly treated, a single sting is almost never fatal; however, two people in Australia are believed to have died from Irukandji stings,[10] 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.[10]


The exact mechanism of action of the venom is unknown, but catecholamine excess may be an underlying mechanism in severe cases.[11] Animal studies appear to confirm a relationship between envenoming and an increase in circulating noradrenaline and adrenaline.[12]


Similar to other box jellyfish stings, first aid consists of flushing the area with vinegar to neutralize the tentacle stinging apparatus.[13][14] As no antivenom is available, treatment is largely supportive, with analgesia being the mainstay of management. Nitroglycerin, a common drug used for cardiac conditions, is utilised by medical personnel to minimise the risk of pulmonary edema and to reduce hypertension.[15] Antihistamines may be of benefit for pain relief,[16] but most cases require intravenous opioid analgesia. Fentanyl or morphine are usually chosen. Pethidine (meperidine, brand name Demerol in the US) should be avoided, as large doses are often required for pain relief and in this situation significant adverse effects from the pethidine metabolite norpethidine may occur.[17]

Magnesium sulfate (Epsom Salts) has been proposed as a treatment for Irukandji syndrome after being apparently successfully used in one case.[18] Early evidence suggested a benefit;[19] however, according to a later report, a series of three patients failed to show any improvement with magnesium; the author emphasized the experimental status of this treatment.[20] Some preliminary laboratory experiments using the venom extracted from Malo maxima (the 'Broome Irukandji') on rat cardiovascular tissue in vitro has suggested that magnesium does in fact block many of the actions of this venom.[21]


Reports of Irukandji syndrome have come from Australia, the United States (Hawaii and Florida), the French Antilles, Bonaire, the Caribbean, Timor Leste and Papua New Guinea.[2][3] Cubozoan species other than Carukia barnesi are presumed to be responsible for envenomations outside Australia.[4]


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 9-year-old son and a local lifeguard, then observed the resulting symptoms.[2][22][23] Other cubozoans possibly can cause Irukandji syndrome;[9] those positively identified include Carukia barnesi, Alatina mordens, Alatina alata, Malo maxima, Malo kingi, Carybdea xaymacana, Keesingia gigas, an as-yet unnamed "fire jelly", and another unnamed species.[4][24][25]

Culture and society[edit]

A 2005 Discovery Channel program, Killer Jellyfish, portrayed the severity of the pain from an Irukandji jellyfish sting when two Australian researchers (Jamie Seymour and Teresa Carrette) were stung.[26] Another program aired on the Discovery Channel, Stings, Fangs and Spines, featured a 20-minute spot on Irukandji syndrome. In the segment, a young Australian woman was stung and developed a severe case.[citation needed]

A 2007 fictional Sea Patrol episode (S1, E4) involves two crew members of HMAS Hammersley being stung by an Irukandji jellyfish.[27]

On the television program Super Animal, a woman compared her experience with Irukandji syndrome to the pain of childbirth.[citation needed]

Steve Backshall reports with accounts from victims of Irukandji stings on his ITV wildlife series Fierce in 2016.[citation needed]


  1. ^ a b Fenner Peter J., Hadok John C. (2002). "Fatal envenomation by jellyfish causing Irukandji syndrome". The Medical Journal of Australia. 177 (7): 362–63. doi:10.5694/j.1326-5377.2002.tb04838.x. PMID 12358578. S2CID 2157752.
  2. ^ a b c d e Barnes J (1964). "Cause and effect in Irukandji stingings". Med J Aust. 1 (24): 897–904. doi:10.5694/j.1326-5377.1964.tb114424.x. PMID 14172390.
  3. ^ a b c d e Nickson CP, Waugh EB, Jacups S, Currie B (2009). "Irukandji syndrome case series from Australia's tropical Northern Territory". Ann Emerg Med. 54 (3): 395–403. doi:10.1016/j.annemergmed.2009.03.022. PMID 19409658.
  4. ^ a b c d Little M; P. Pereira; T. Carrette; J. Seymour (2006). "Jellyfish Responsible for Irukandji Syndrome". Q J Med. 99 (6): 425–27. doi:10.1093/qjmed/hcl057. PMID 16687419.
  5. ^ "Irukandji syndrome". 18 December 2008. Archived from the original on 18 August 2013. Retrieved 20 April 2018.
  6. ^ Flecker H (1952). "Irukandji sting to North Queensland bathers without production of weals but with severe general symptoms". Med J Aust. 2 (3): 89–91. doi:10.5694/j.1326-5377.1952.tb100081.x. PMID 14956317. S2CID 29684377.
  7. ^ Little M; Pereira P.; Mulcahy R.; Cullen P.; Carrette T.; Seymour J. (2003). "Severe cardiac failure associated with presumed jellyfish sting. Irukandji syndrome?". Anaesth Intensive Care. 31 (6): 642–47. doi:10.1177/0310057x0303100605. PMID 14719425.
  8. ^ "Irukandji Jellyfish". Australian Broadcasting Corporation. 23 June 2006. Archived from the original on 26 January 2009. Retrieved 2 January 2009.
  9. ^ a b Grady J, Burnett J (2003). "Irukandji-like syndrome in South Florida divers". Ann Emerg Med. 42 (6): 763–66. doi:10.1016/S0196-0644(03)00513-4. PMID 14634600.
  10. ^ a b P. Fenner; J. Hadok (2002). "Fatal envenomation by jellyfish causing Irukandji syndrome". Med J Aust. 177 (7): 362–63. doi:10.5694/j.1326-5377.2002.tb04838.x. PMID 12358578. S2CID 2157752.
  11. ^ J. Burnett; D. Weinrich; J. Williamson; P. Fenner; L. Lutz; D. Bloom (1998). "Autonomic neurotoxicity of jellyfish and marine animal venoms". Clin Auton Res. 8 (2): 125–30. doi:10.1007/BF02267823. PMID 9613803. S2CID 31187771.
  12. ^ J. Tibballs; G. Hawdon; K. Winkel (2001). "Mechanism of cardiac failure in Irukandji syndrome and first aid treatment for stings". Anaesth Intensive Care. 29 (5): 552. PMID 11669442.
  13. ^ "Jellyfish Sting Treatment". WebMD. 2013. Archived from the original on 18 May 2015. Retrieved 10 May 2015.
  14. ^ Wilcox, Christie (9 April 2014). "Should we stop using vinegar to treat box jelly stings? Not yet—Venom experts weigh in on recent study". Science Sushi. Discover Magazine Blogs. Archived from the original on 6 June 2017. Retrieved 26 April 2015.
  15. ^ "Sublingual glyceryl trinitrate as prehospital treatment for hypertension in Irukandji syndrome" (PDF). 15 December 2003. Archived (PDF) from the original on 11 February 2017. Retrieved 11 February 2017.
  16. ^ Little M, Mulcahy R (1998). "A year's experience of Irukandji envenomation in far north Queensland". Med J Aust. 169 (11–12): 638–41. doi:10.5694/j.1326-5377.1998.tb123443.x. PMID 9887916. S2CID 37058912.
  17. ^ Bailey P, Little M, Jelinek G, Wilce J (2003). "Jellyfish envenoming syndromes: unknown toxic mechanisms and unproven therapies". Med J Aust. 178 (1): 34–37. doi:10.5694/j.1326-5377.2003.tb05040.x. PMID 12492389. S2CID 1196885.
  18. ^ Corkeron M (2003). "Magnesium infusion to treat Irukandji syndrome". Med J Aust. 178 (8): 411. doi:10.5694/j.1326-5377.2003.tb05263.x. PMID 12697017. S2CID 28335891.
  19. ^ Corkeron M, Pereira P, Makrocanis C (2004). "Early experience with magnesium administration in Irukandji syndrome". Anaesth Intensive Care. 32 (5): 666–69. doi:10.1177/0310057x0403200510. PMID 15535491.
  20. ^ Little M (2005). "Failure of magnesium in treatment of Irukandji syndrome". Anaesth Intensive Care. 33 (4): 541–2. PMID 16119507.
  21. ^ Li, R. (2011). "The pharmacology of Malo maxima jellyfish venom extract in isolated cardiovascular tissues: A probable cause of the Irukandji syndrome in Western Australia". Toxicology Letters. 201 (3): 221–29. doi:10.1016/j.toxlet.2011.01.003. PMID 21237252.
  22. ^ "Stingy Scientist". Archived from the original on 5 February 2012. Retrieved 16 February 2012.
  23. ^ Baker, Joe. "Barnes, John Handyside (Jack) (1922–1985)". Australian Dictionary of Biography. National Centre of Biography, Australian National University. ISSN 1833-7538. Archived from the original on 21 March 2017. Retrieved 20 March 2017.
  24. ^ Little M, J. Seymour (2003). "Another cause of "Irukandji stingings"". Med J Aust. 179 (11–12): 654. doi:10.5694/j.1326-5377.2003.tb05738.x. PMID 14636148. S2CID 27049446.
  25. ^ "New jellyfish discovered: giant venomous species found off Australia". The Guardian. Australian Associated Press. 8 August 2014. Archived from the original on 12 August 2018. Retrieved 27 May 2018.
  26. ^ "Killer Jellyfish". Killer Jellyfish. 2005. Discovery Channel. Archived from the original on 29 April 2011.
  27. ^ "Sea Patrol S1 E4". 9Now. Retrieved 21 June 2021.