Irukandji syndrome A specimen of Malo kingi, a species of Irukandji jellyfish, in a clear plastic vial Specialty Medical toxicology Symptoms headache, backache, chest and abdominal pain, nausea, vomiting, pathological sweating, severe and sudden onset anxiety, tachycardia[1][2][3] Complications hypertension, enlarged heart, pulmonary edema, cardiac arrest, possible heart failure[1][2][3] Usual onset 30 minutes after exposure Duration 4 to 30 hours, sometimes up to 2 weeks Causes Irukandji jellyfish sting