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BITES AND STINGS

Severity of Irukandji syndrome and nematocyst identification from skin scrapings

Truc T Huynh, Jamie Seymour, Peter Pereira, Richard Mulcahy, Paul Cullen, Teresa Carrette and Mark Little

JELLYFISH STINGS in northern Aus- ABSTRACT tralia cause significant morbidity and mortality.The Medical Since Journal early ofdescriptions Australia ISSN: of Objectives: (1) To identify the causative jellyfish species by examining skin scrapings Irukandji0025-729X syndrome, 6 January1,2 2003relatively 178 1 38-41little in patients presenting to Cairns Base Hospital with marine stings, and (2) to describe further©The knowledge Medical Journal has of beenAustralia gained 2002 clinical outcomes of those with Irukandji syndrome and those in whom nematocysts www.mja.com.au about it. Although Carukia barnesi has were identified from skin scrapings. Bites and Stings 3 been shown to cause the syndrome, Design and setting: (1) A retrospective case series of 128 patients, identified from other species of jellyfish are also sus- 3-7 Cairns Base Hospital emergency department records with discharge diagnoses of pected to be responsible. marine stings between 1 July 2001 and 30 June 2002. (2) A prospective study of skin We hypothesise, firstly, that many dif- scrapings from 50 patients presenting with marine stings from the same period. ferent cubozoans may produce Iru- kandji syndrome in Cairns, and Main outcome measures: Number of patients with Irukandji syndrome, their opioid secondly, that these different species of requirements and cardiac findings (where available); identification of causative species jellyfish may be responsible for different from nematocysts isolated from skin scrapings. severities of this syndrome. Results: 116 patients retrospectively identified with marine stings had Irukandji syndrome. Of 50 patients who had skin scrapings, 39 had nematocysts consistent with Carukia barnesi. Symptoms experienced ranged from local pain alone to severe Irukandji syndrome with elevated troponin I levels, changes on electrocardiogram, METHODS cardiac dysfunction on echocardiography, and high opioid dose requirements. One Retrospective case series patient had an unidentified cnidome on his skin scraping. He developed severe Irukandji syndrome and subsequently died from its complications. All patients with a discharge diagnosis Conclusion: This is the first published report of Carukia barnesi being successfully of “marine stings” (ICD-10 code identified from skin scrapings. Most patients with identifiable cnidomes experiencing T63.6)8 after presenting to Cairns Base Hospital, Queensland, between 1 July Irukandji syndrome were stung by Carukia barnesi, which we show causes a wide 2001 and 30 June 2002 were retrospec- range of illness, including cardiac dysfunction. Our finding of a cnidome not consistent tively identified from the emergency with Carukia barnesi in the setting of Irukandji syndrome makes it possible that other department computer database, and species of jellyfish may also cause this syndrome. epidemiological and clinical data were MJA 2003; 178: 38–41 extracted and entered on a standardised form. Details collected included geo- fentanyl according to clinician prefer- ing to emergency department protocols, graphic location of sting, physiological ence, we arbitrarily converted their opi- and additionally had skin scrapings of parameters, analgesia required, bio- oid dose to “morphine equivalents” their sting site performed. Exceptions chemical abnormalities, electrocardio- (where 1 mg morphine = 10 mg were distressed children, patients with graphic and echocardiographic findings. pethidine = 10 ␮g fentanyl) to give a stings to the face, women with stings to We assessed the clinical severity of rough comparison of analgesic require- the breast region, and patients in whom each patient’s condition at presentation ments between patients. an obvious sting site could not be iden- according to peak systolic blood pres- tified; these patients did not have skin sure, total opioid dose administered, scrapings performed. Prospective case series peak troponin I level, and length of The sampling procedure was hospital stay. As individual patients Patients presenting with marine stings explained to patients and verbal consent received either morphine, pethidine or during this period were treated accord- was obtained. The sting site was scraped firmly with a sterile scalpel Emergency Department, Cairns Base Hospital, Cairns, QLD. blade, which was then placed in a sterile Truc T Huynh, MB BS, Emergency Registrar; Peter Pereira, FACEM, Director of Emergency; specimen container containing 10% Richard Mulcahy, FACEM, Emergency Consultant; Paul Cullen, FACEM, Emergency Consultant. buffered formalin. The scalpel was School of Tropical Biology, James Cook University, Smithfield, QLD. shaken vigorously in the specimen con- Jamie Seymour, PhD, Senior Lecturer; Teresa Carrette, BSc, Marine scientist. Emergency Department, Sir Charles Gairdner Hospital, Perth, WA. tainer to cause adherent scrapings to fall Mark Little, FACEM, Emergency Consultant. off. The specimen was then centrifuged Reprints will not be available from the authors. Correspondence: Dr Peter Pereira, Emergency at 5000 revolutions per minute for 10 Department, Cairns Base Hospital, PO Box 902, Cairns, QLD 4870. [email protected] minutes, stained with eosin and distrib-

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General clinical findings Forty-two patients (36%) were dis- 1: Map showing the coastline, charged home directly from the emer- islands and reef where patients Peak systolic blood pressure in the 94 were stung gency department within eight hours of adults with Irukandji syndrome ranged presentation. Fifty-four patients (47%) from 100 mmHg to 230 mmHg, with a 16 N were discharged from the emergency Cape Tribulation 147 mean of 145 mmHg. Nineteen of the 22 department observation ward the next Opal Reef G children had their blood pressures day, eight were transferred to the coro- r e recorded. Seven had a systolic blood a nary care unit (CCU), and 11 were t pressure 140 mmHg or above; the high- transferred to the general medical or est of these was 165/95 mmHg in a 12- paediatric ward for ongoing analgesia. year-old child. B Additionally, one patient was trans- a Port Douglas r Total analgesic requirements for r ferred to the intensive care unit in ie adults during their hospital stay ranged r Townsville General Hospital for neuro- from 0 to 255 mg of morphine equiva- surgical care for an intracerebral haem- lents (mean, 31 mg). Of the 10 children orrhage. Palm Cove who had their weight recorded, analge- Green island R sic dose ranged from 0 to 1.4 mg per kg e Skin scrapings e morphine equivalents (mean, 0.29 mg f Cairns per kg). Skin scrapings were taken from 50 Fitzroy Island patients. Of these, four patients had

17 Cardiac findings local symptoms only, and the remainder had symptoms consistent with Irukandji Queensland Normanby Troponin levels (cTnI) were measured syndrome. Forty patients (80%) had Island in 103 patients whose pain did not settle positive scrapings, while, in the remain- with a single dose of parenteral opioid der, either no nematocysts were found uted onto a Kova slide for microscopic analgesia. Twenty five (22%) had ele- or the nematocysts were too damaged to examination. vated cTnI levels, ranging from 1.0 to be confidently identified (positive pre- Specimens were prepared and exam- 34.0 ␮g/L (reference range, < 0.7 ␮g/ dictive value of 80%). Thirty-nine ined by one of the authors (J S), who L). None of these patients had clinical patients had a nematocyst cnidome was blinded to the source. Identification or chest x-ray findings of pulmonary identifiable as Carukia barnesi; two of of jellyfish species was based on a cnid- oedema. Eleven patients had non-spe- these experienced only a mild sting at ome database (a cnidome is a collection cific electrocardiogram (ECG) abnor- the site, and 37 had Irukandji syn- of nematocysts used to distinguish malities, most involving T-wave drome. Of these 39 patients, 13 had a between species of jellyfish) being for- inversion and ST-segment depression. raised cTnI level; five of these had mulated by the examiner and due for Echocardiograms were performed in 18 abnormal echocardiograms and seven publication in 2003. of the 25 patients with elevated cTnI had abnormal ECGs. Thirty-one The results of the species identifica- levels, and abnormalities were found in patients with Carukia barnesi identified tion was then matched to the clinical six. Echocardiographic abnormalities on skin scrapings (79%) were stung at data. ranged from mild impairment of systolic local mainland beaches. The rest were function to moderate dysfunction with stung at Fitzroy Island (4), Green Island segmental hypokinesis. One patient had (1), and Normanby Island (1) (see Box global myocardial dysfunction. Two 1). RESULTS patients had serial echocardiographic The patient with the most severe studies showing normalisation of their symptoms who had Carukia barnesi From 1 July 2001 to 30 June 2002, 128 systolic function over time (one within identified from skin scrapings was a 44- patients at the Cairns Base Hospital three months and the other over six year-old man with a peak blood pres- emergency department had a discharge months). sure of 160/100 mmHg and peak cTnI diagnosis of marine stings. Of these, Among the 91 remaining patients level of 30.8 ␮g/L, who required a total 116 had symptoms consistent with Iru- only one had an abnormal ECG. He morphine equivalent dose of 255 mg kandji syndrome. Sixty-seven of the 116 was a previously well 33-year-old man over five days. He had widespread T- patients (58%) were male and their who developed paroxysmal atrial fibril- wave inversion and ST-segment depres- average age was 26.5 years (range, 3–63 lation (which resolved spontaneously sion on his ECG. His echocardiogram years). over several hours); his echocardiogram showed severe left ventricular dysfunc- Of the 116 patients with Irukandji was normal. tion and anteroseptal hypokinesis, with syndrome, 89 (7%) were stung along an ejection fraction of 30%–35%. Six the shore, 26 (22%) were stung offshore Hospital admissions months later his echocardiogram was (Great Barrier Reef and islands; see Box completely normal. 1), and one patient did not have the Average length of admission was 1.6 One 44-year-old man had an uniden- location recorded. days and the longest was five days. tified cnidome on skin scraping, which

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While acknowledging some limitations, 2: Nematocysts from Carukia barnesi compared with unidentified nematocysts from a fatal envenomation it is reasonable in this setting to equate the species identified through cnidome assessment with causation. Therefore, we can, with reasonable confidence, assert that Carukia barnesi was causative in 39 patients. We can also deduce that envenomation by this species produces a wide range in severity of illness, and that it was the only identifiable causative cuboidal jellyfish in patients stung on the Cairns beaches. We can less confi- dently claim that a single victim may have been stung by an unknown species A: Discharged nematocyst from the tentacle B: Discharged nematocyst from the bell of box jellyfish, ultimately leading to his of Carukia barnesi. of Carukia barnesi. death. The cnidome in this case was similar to, but with distinct differences from that of, Carukia barnesi (Box 2). We acknowledge that Carukia barnesi may have been causative in this instance, as the mastigophore isolated from this patient may have been an incidental finding. A further possibility is that the Carukia barnesi cnidome may change to include mastigophores as the animal ages or grows (as is seen with Chironex fleckeri). We are ignorant of the C: Discharged nematocyst from D: Cigar-shaped nematocyst from unidentified species of jellyfish (similar unidentified species of jellyfish. life cycle of Carukia barnesi, and there- morphology to [A]). fore can only speculate. There are obvious serious implica- tions if the cnidome is that of an uni- is of concern, as he was one of two associated with cardiac failure and pul- dentified cuboidal jellyfish. It has long patients reported to have died from monary oedema. However, it has been been suspected that jellyfish species Irukandji syndrome (the other having observed that most stings in the Cairns other than Carukia barnesi can cause occurred in the Whitsundays).9 region are, in fact, mild, without serious Irukandji syndrome.3-7 Case reports Although some of the nematocysts iden- complications, and do not require include a patient with severe Irukandji tified were similar to those from Carukia admission to hospital.4 Our study con- syndrome in whom a 2 mm length of barnesi, a morphologically different firms this, as most patients were dis- tentacle not from Carukia barnesi was additional nematocyst was also present charged within 24 hours of presentation. found in a skin scraping of the sting (Box 2). It is possible that this nemato- Surprisingly, myocardial damage, as site,6 and where tentacles isolated cyst was a “rogue” mastigmophore, and measured by an elevated cTnI level, was resembled, but were distinctly different hence may be an incidental finding from seen in 25 patients (22%) experiencing from, those of Carukia barnesi.7 Our another source. Alternatively, the cnid- Irukandji syndrome. Six of these results provide further supportive evi- ome may represent an unidentified jelly- patients had echocardiographic evi- dence that species other than Carukia fish. The patient was stung at Opal Reef dence of myocardial dysfunction. It is barnesi may be linked to Irukandji syn- (see Box 1), had a peak blood pressure evident that those with continuing pain drome. of 230/90 mmHg, peak cTnI level of and analgesic requirements are at risk of Interestingly, two patients with cnid- 34 ␮g/L, and required 30mg of mor- cardiac complications. Clinicians omes consistent with Carukia barnesi phine equivalents before being intu- should therefore consider closely moni- did not develop Irukandji syndrome. bated for a depressed level of con- toring these patients with serial cTnI These patients had mild local symptoms sciousness from an intracerebral haem- level measurements, and, if these are only. Thus, a sting by Carukia barnesi orrhage. abnormal, consider echocardiographic does not necessarily result in Irukandji evaluation. syndrome. Factors affecting venom Skin-scraping methods have been load, such as thickness of the kera- DISCUSSION described for a number of jellyfish spe- tinised skin, presence of hair, length of cies,14-17 but, to date, there are no pub- tentacle involved, duration and pressure In recent years a number of serious lished data on successful identification of the contact between tentacle and skin envenomations causing Irukandji syn- of Carukia barnesi nematocysts in have been proposed by other drome have been described,6,10-13 all patients with Irukandji syndrome. authors.3,17

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As only a single cnidome suggestive of cause illness ranging from local symp- 7. Taylor D, Pereira P, Seymour J, Winkel K. A sting from an unknown jellyfish species associated with a different jellyfish species was found, toms to severe Irukandji syndrome with persistent symptoms and raised troponin I levels. we can make no statistical inferences cardiac dysfunction. Our finding of a Emerg. Med 2002; 14: 175-180. about the severity of Irukandji syn- cnidome that was not that of Carukia 8. National Centre for Classification in Health – ICD-10 drome and the jellyfish species identi- –Australian Modification. Sydney, NCCH Publishers, barnesi suggests that other species of Shannon Books, 2002. fied from skin scrapings. Additionally, jellyfish may cause Irukandji syndrome. 9. Fenner PJ, Hadok JC. Fatal envenomation by jelly- patients were not randomly selected in fish causing Irukandji syndrome. Med J Aust 2002; terms of whether or not they would have 177: 362-363. skin scrapings performed. Thus, it is 10. Fenner PJ, Burnett JW, Colquhoun DM, et al. The COMPETING INTERESTS “Irukandji Syndrome” and acute pulmonary oedema. possible that more seriously affected Med J Aust 1988; 149: 150-156. patients would have attracted more 11. Herceg I. Pulmonary oedema following an Irukandji None identified interest and were more likely to have sting. SPUMS J (South Pacific Underwater Medicine skin scrapings performed. Society Journal) 1987; 17: 95-97. 12. Martin JC, Audley I. Cardiac failure following Iru- Our interpretation of these findings is kandji envenomation. Med J Aust 1990; 153: 164- based on a number of assumptions. Our REFERENCES 166. conversion of “equivalent doses” of nar- 13. Fenner PJ, Williamson J, Callanan VI, Audley I. cotics has not taken into account the 1. Southcott RV. Fatal stings in North Queensland Further understandings of and a new treatment for bathers. Med J Aust 1952; 1: 272-273. “Irukandji” (Carukia barnesi) stings. Med J Aust differences in their duration of action. 2. Flecker H. Irukandji sting to North Queensland bath- 1986; 145: 569-574. Finally, we have assumed that jellyfish ers without production of wheals but severe general 14. Barnes JH. Observations on jellyfish stingings in (indicated by their cnidome) caused the symptoms. Med J Aust 1952; 2: 89-91. North Queensland. Med J Aust 1960; 2: 993-999. patients’ symptoms. 3. Barnes JH. Cause and effect in Irukandji stingings. 15. Currie BJ, Wood YK. Identification of Chironex fleck- Med J Aust 1964; 1: 897-904. eri envenomation by nematocyst recovery from skin. In conclusion, we can infer that, in 4. Little M, Mulcahy RF. A year's experience of Irukandji Med J Aust 1995; 162: 478-480. patients with Irukandji syndrome, the envenomation in far north Queensland. Med J Aust 16. Fenner PJ, Fitzpatrick PF, Hartwick RJ, Skinner R. causative jellyfish can usually be suc- 1998; 169: 638-641. “Morbakka”, another cubomedusan. Med J Aust 1985; 143: 550-555. cessfully identified from skin scrapings 5. Fenner P, Carney I. The Irukandji syndrome. A devastating syndrome caused by a north Australian 17. Lumley J, Williamson A, Fenner PJ, et al. Fatal on the basis of known cnidomes. Most jellyfish. Aust Fam Physician 1999; 28: 1131-1137. envenomation by Chironex fleckeri, the north Aus- patients with Irukandji syndrome in the 6. Little M, Mulcahy RF, Wenck DJ. Life-threatening tralian jellyfish: the continuing search for lethal Cairns region were stung by Carukia cardiac failure in a healthy young female with Iru- mechanisms. Med J Aust 1988; 148: 527-534. kandji syndrome. Anaesth Intensive Care 2001; 29: barnesi, which has now been shown to 178-180. (Received 23 Sep 2002, accepted 1 Nov 2002) ❏

book review

Stoking the fires of drug controversy

Modernising Australia’s drug policy. Alex D Wodak outcomes. Its assertions are not referenced, but the and Timothy Moore. Sydney: UNSW Press, 2002 authors speak from a position of authority after years of (103pp, $19.95). ISBN 0 86840 482 9. contributing to the debate. It is an easy read. THE DISCUSSION OF ILLICIT drugs policy The book urges the separation of cannabis markets from is littered with controversy, stoked by strong heroin and cocaine, but is critical of half-hearted decrimi- feelings on both sides and full of assertions nalisation when legalisation, with regulation, taxation and that fundamental morality is at stake. Those health advice about cannabis, would be far more appropri- who support prohibition and have a clear ate. The rationale is compelling. It argues clearly that the view of law enforcement as the answer need major problems for society from illicit drugs — crime, not read this book, as they will find little to relate to. corruption, disease and overdose deaths — are primarily The authors have a long record of challenging the the consequences of prohibition rather than the drugs. current international philosophy of prohibition, stemming Misleading advocacy and misuse of naltrexone are well as it does from the muscular nationalism of Teddy Roo- discussed. There is little coverage of cocaine and ampheta- sevelt, who convened the Shanghai Conference in 1909. mines. Although occasionally repetitive, it is worthwhile That policy has been honed and developed with US reading for all concerned citizens, including politicians, leadership in successive international treaties of 1912, medical practitioners and parents. It is good value as a 1926, 1961, 1971 and 1988. Richard Nixon’s invention of paperback entry to a difficult area of public policy. the politically potent “War on Drugs” in 1972 is given attention in its Australian incarnation “Tough on Drugs”. David G Penington Emeritus Professor, and Past Chairman The book is readable, rather than scholarly, and tells of the Victorian Premier's Drug Advisory Council folly of this ideological commitment in terms of failed Melbourne, VIC

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