Irukandji syndrome

Every summer in northern Australia, more than 60 people are hospitalised with Irukandji syndrome. This syndrome is the result of a sting from the Irukandji (Carukia barnesi) jellyfish. Irukandji is a small cubozoan (or box) jellyfish found in the northern waters of Australia.The sting itself is only moderately painful, with limited local effects. However, approximately 30 minutes later some patients may develop a complex of systemic symptoms including severe abdominal pain, back, limb or joint pain, nausea and vomiting, profuse sweating and agitation. They may also experience numbness or paraesthesia (prickling, itching).

More severe reactions to irukandji stings can include hypertension and tachycardia (rapid heart beat). These responses are thought to be related to catecholamine release and should be treated with intravenous antihypertensive therapy with α-blocking agents such as phentolamine. There have been occasional reports of supraventricular tachycardia and of transient dilated cardiomyopathy following Irukandji stings. Analgesia is usually required, and given intravenously when pain is severe.

It is thought that irukandji live mostly in the deep waters of the reefs, although it may be swept onshore by prevailing currents. Stings have been recorded from Childers, Queensland to Broome, Western Australia. It has been suggested that other jellyfish, such as the jimble (Carybdea rastoni) may sometimes cause a milder version of irukandjii syndrome. These cases have also been described throughout the Pacific from Hawaii to China.