First aid for irukandji stings consists of analgesia and reassurance.
A number of related jellyfish can cause Irukandji syndrome. Carukia barnesi, however, is the jellyfish conclusively known to do so. Irukandji is a small (~2 cm diameter bell) jellyfish responsible for an unusual and dramatic syndrome observed most commonly in North Queensland, and stings have been recorded from Bundaberg in Queensland to Broome in Western Australia.
Signs and Symptoms
The sting itself is only moderately painful, with little associated tissue damage, but approximately 30 minutes later, the patient develops a complex of systemic symptoms including severe back and abdominal pain, limb or joint pain, nausea and vomiting, profuse sweating and agitation. They may also experience numbness or paraesthesia. Hypertension and tachycardia are frequently seen, and are thought to be related to catecholamine release. Victims frequently require hospitalisation for analgesia and sometimes intravenous antihypertensive therapy; alpha-blocking agents such as phentolamine have been used for this purpose. Supraventricular tachycardia and transient dilated cardiomyopathy have been reported following irukandji stings, and it has been suggested that serial echocardiography be performed to monitor the progress of severely affected patients.
Treatment
Analgesia is usually required, and may need to be given intravenously when pain is severe. The role of vinegar to inactivate undischarged nematocysts remains uncertain, with initial work proving inconclusive. Antihypertensives, such as phentolamine and glyceral trinitrate may be used, however, caution should be taken in patients with proven cardiac dysfunction. Acute pulmonary oedema should be treated in the usual manner with supplemental oxygen, inotropic support and positive pressure ventilation. Cardiac dysfunction is normally transient and generally returns to normal within 3–4 days. Magnesium has been shown to be of advantage with a loading dose of 10mmoL followed by an infusion of 5mmol per hour.Box jellyfish antivenom does not appear to be useful for this syndrome.
Last updated: July 2005
