Part 1 of 2. Read part 2 here.

Surf and turf, anyone?

And when I say “surf,” I am, of course, referring to our ocean-dwelling friends who “turf” water sport enthusiasts to the emergency department with their various bites and stings.

Before we “dive” (last nautical pun—we promise) into part one of our two-part series on marine envenomations, let’s review some general information and definitions.

General Management for All Marine Injuries

Yes, the vast majority of marine envenomations are completely benign in terms of long-term morbidity and mortality. Our goals in assessing these patients should be:

1. To evaluate and monitor for potential life threats
2. To decrease risk for future infection
3. To reassure.

Pain is a big factor with marine envenomations. Surprisingly, some attempts to manage symptoms in benign cases may potentially worsen the envenomation or lead to unnecessary prescribing of strong pain medications. Reassurance that this is a self-limiting event and that there is no evidence of a life-threatening condition is of utmost importance.

Initial approach: All wounds should be irrigated (seawater or saline for saltwater species; freshwater for freshwater species) and explored for retained foreign bodies. Nematocysts, barbs, spines, and other foreign bodies can be removed manually (with gloves!) using forceps, adhesive tape, rubber cement, or facial peels. If the injury is deep or extensive or there is concern for a foreign body, obtain X-ray imaging. If X-rays are negative or if there is concern for radiolucent material, use ultrasound.

Treatment and management: For deep wounds, especially those involving joints or body cavities, early surgical consultation may be necessary. Infections from marine-associated injuries tend to be polymicrobial. Wounds should be swabbed (special media or cultures may be needed), and all patients should have tetanus vaccination updated. Be aware of the potential for necrotizing fasciitis (sometimes caused by Vibrio species), which is associated with serious saltwater injuries, especially in patients with pre-existing liver disease. Avoid suturing deep puncture wounds due to the high risk of infection. Pain should be managed with nonsteroidal anti-inflammatory drugs, acetaminophen, opioids, and/or topical analgesics (eg, lidocaine).

The following species-dependent topical measures may also be implemented:

• Hot water immersion (HWI): The injured area should be immersed in water that is 43-45°C (111–114°F) for 10–30 minutes (or until pain is controlled)
• Vinegar: 4–5 percent acetic acid solution should be applied to the injured area for at least 30 seconds. This treatment really only has evidence of benefit with the Australian box jellyfish. Studies with other species have actually shown it to encourage further nematocyte discharge.
• Stingose: A topical solution composed of 20 percent aluminum sulfate and 1.1 percent surfactant, Stingose is used for pain control, venom removal via osmosis, and venom neutralization via denaturation of proteins and polysaccharides through interactions with the aluminum ion.¹

Note: There is very little danger in using fresh water, however, this may increase the patient’s pain due to increased nematocyst firing in certain species. It is always reasonable to attempt a small amount of vinegar initially and assess its effect.¹ 

Antibiotic Treatment Recommendations²

No antibiotics are indicated if:

• Healthy patient
• Prompt wound care
• Wound is small or superficial and does not have associated foreign bod orbone or joint involvement

Prophylactic outpatient (oral) antibiotics if:

• Late wound care
• Large laceration or injuries
• Early or local inflammation

Hospital admission (IV antibiotics) if:

• Signs of systemic illness
• Deep wounds or significant trauma
• Retained foreign bodies
• Progressive inflammatory changes
• Penetration of bone, joint space, or body cavity
• Comorbid medical conditions

First generation cephalosporin or methicillin-resistant Staphylococcus aureus coverage (if concern) are appropriate for all patients requiring antibiotics and

• For seawater associated injuries (Vibrio coverage): fluoroquinolone or third generation cephalosporin

OR

• For freshwater associated injuries (Aeromonas coverage): fluoroquinolone or trimethoprim-sulfamethoxazole or carbapenem

Antivenom

Although the literature discusses antivenom indications and dosing, the availability of such agents can be an issue. For example, the only location that has readily available marine antivenom is Australia (specifically, antivenom for stonefish and box jellyfish made by the Commonwealth Serum Laboratories).

An envenomation or antivenom administration can cause anaphylaxis, and this may initially be difficult to distinguish clinically. Signs include hypotension, bronchospasm, facial and airway swelling, pruritus, urticaria, nausea, vomiting, and diarrhea. Most reactions occur within 15–30 minutes and nearly all occur within six hours. A recipient of antivenom should be pretreated with 50–100 mg of IV diphenhydramine (1 mg/kg in children). The initial dose of antivenom should be administered no faster than one vial over five minutes. If antivenom is necessary and anaphylaxis develops, administer 0.1–0.2-mL aliquots of antivenom alternated with 0.03–0.1-mg IV doses of epinephrine. Alternatively, an epinephrine drip may be started and titrated to maintain a heart rate less than 150 beats/min.

Phylum: Cnidaria

Class: Cubozoa (Cubozoa species produce the highest morbidity and mortality of all Cnidaria.¹)

Sea Wasp or Marine Stinger (Chironex fleckeri)

Location: Indo-Pacific Ocean, southeast United States (rare)

Epidemiology: Ninety-two percent of stings occur during “stinger season” (Australian summer, Oct. 1–June 1) between 3 and 6 p.m., with 83 percent occurring in <1 m of water.³

Appearance: The sea wasp has a large bell (body) measuring an average of 25 to 30 cm in diameter. Each of its four corners contains about 15 tentacles that contain millions of “stinging cells” called nematocysts (ie, cnidocytes) and can measure up to 3 m in length.¹

Pathophysiology and Symptoms: Contact with the tentacles causes rapid development of a pruritic/burning, erythematous maculopapular rash with a characteristic “ladder-rung” pattern. Severe pain is the most common complaint and can last for several hours due to sustained muscle contractions caused by myotoxins within the venom.⁴ This can result in rhabdomyolysis, depending on the duration and intensity of the contractions. Although uncommon, cardiovascular collapse can occur due to a combination of dysrhythmias (due to hyperkalemia) and osmotic dysregulation of endothelial and cardiac tissues from pore-forming toxins within the venom.⁵ This ultimately leads to cardiogenic pulmonary edema, severe hypotension, and death in as few as 30 seconds.⁶ Additional complications include altered mentation, dizziness, ataxia, and hemolysis.

Management: Pain should be managed with vinegar, HWI, local lidocaine (infiltration or topical), and/or Stingose solution (pain relief has been shown within five seconds of application).⁷ Compressive dressings are controversial and have recently been recommended against in the management of all Cnidaria envenomations due to demonstrated increase in venom release from nematocysts.^1,8,9 Obtain an ECG, serial cardiac biomarkers, and chemistry panel to assess for electrolyte abnormalities. Box jellyfish antivenom is available and has been shown to prevent all toxicity in animal studies when administered prophylactically.¹⁰ However, current beachside (ie, Surf Life Saving Australia’s beach lifeguard group) dosing recommendations of three vials intramuscularly at three separate sites may be too small a dose and too slow a route. Early IV administration of antivenom in large doses—initial treatment of one to three vials diluted 1:10 with saline, along with IV magnesium sulfate (0.2 mmol/kg, max 10 mmol in adults) bolused over 5–15 mins—is recommended if there are any signs of severe toxicity, intractable pain, or cardiac arrest. But even this may be too small a dose, and further research is needed.^11,12 The current maximum dose of antivenom is six vials undiluted and should be given via rapid IV push if the patient is in cardiac arrest.¹¹

Caveats: Contrary to previous studies in mice, verapamil has been shown to be ineffective and possibly detrimental; it exacerbated cardiovascular symptoms and increased mortality in pigs.^9,10,13–16 Additionally, felodipine and magnesium sulfate may actually worsen the effects of the venom, but further research is needed. C. fleckeri stings can be deadly, however, recent data suggest the fatality rate is actually much lower than the roughly 20 percent that was previously reported.^6,13,17 Morbidity and mortality are dose- and time-dependent, which explains why the majority of deaths have been in children.^12,18 Avoid treating with fresh water, alcohol, methylated spirits, and urine, as these have also been shown to increase nematocyst firing.¹⁹

Irukandji jellyfish (Carukia barnesi)

Location: Northern and western Australia; cases of Irukandji-like syndrome have been reported in the southeast United States and Hawaii^20,21

Appearance: Small bell that measures less than 2–3 cm in diameter with four tentacles measuring up to 1 m in length.

Pathophysiology and Symptoms: Most commonly causes local inflammation and erythema. Symptoms can progress to a sympathomimetic toxidrome-like presentation called Irukandji syndrome, which usually develops within two hours of envenomation and can last up to two days.^1,22 This rare but serious complication manifests in diverse ways (eg, chest, abdominal, and back pain, myalgias/severe muscle spasm, headache, vomiting, and diaphoresis). In severe toxicity, exposure can lead to hypertensive crisis with nonspecific ECG abnormalities, elevated cardiac biomarkers, cardiogenic pulmonary edema, intracranial hemorrhage, and death.

Management: Manage pain with vinegar and HWI. IV magnesium sulfate (0.2 mmol/kg, max 10 mmol in adults) bolused over 5–15 mins can be used for pain refractory to opioids (and it also theoretically will help with hypertension), however, data are limited and efficacy has not been established. If there is concern for Irukandji syndrome: stat ECG, serial cardiac biomarkers, echocardiography, chemistry panel, and/or CT of the head without contrast. Hypertension should be treated with short-acting, titratable medications (eg, phentolamine, esmolol, nitroprusside, nicardipine) due to potential for hypotension in the later stages of toxicity.¹

Class: Hydrozoa

Portuguese Man-of-War (Physalia physalis and Physalia utriculus)

Location: Atlantic, Indian, and Pacific Oceans

Epidemiology: Approximately 10,000 stings from Physalia spp. are recorded each year in Australia.²³

Appearance: Physalia species are considered siphonophores, meaning they are composed of multiple smaller organisms acting together as a single colony. P. physalis has a sail-shaped, bluish-purple pneumatophore (the origin of their alternative name “Bluebottle”) that floats on the surface and can be inflated and deflated for flotation and submersion purposes. The pneumatophore ranges from a few inches to one foot in diameter and houses up to 40 tentacles that can reach a length of greater than 30 m.¹ P. utriculus has a similar appearance but has only one tentacle that measures about 15 m in length.¹

Pathophysiology and Symptoms: Contact with the tentacles causes local, sharp pain and an erythematous, maculopapular rash in a linear distribution that resolves after 24–72 hours. More significant toxicity can result in Irukandji syndrome (see above), cardiovascular collapse/dysrhythmia, and hemolysis.

Management: A small randomized controlled trial found Stingose to be superior to salt water irrigation in decreasing pain after Physalia envenomation.²⁴ HWI may also be used. Irukandji syndrome should be managed the same way it is for C. barnesi envenomation.

Caveats: Avoid vinegar and methylated spirits because they increase firing of nematocysts. No antivenom is available.

References

1. Nelson LS, Howland M, Lewin NA, et al. Goldfrank’s Toxicologic Emergencies, 11 ed. New York: McGraw-Hill, 2019.
2. Tintinalli JE, Ma O, Yealy DM, et al. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 9 ed. New York, NY: McGraw-Hill, 2020.
3. Currie BJ, Jacups SP. Prospective study of Chironex fleckeri and other box jellyfish stings in the “Top End” of Australia’s Northern Territory. Med J Aust. 2005;183(11-12):631-636.
4. Endean R. Separation of two myotoxins from nematocysts of the box jellyfish (Chironex fleckeri). Toxicon. 1987;25(5):483-492.
5. Saggiomo SLA, Seymour JE. Cardiotoxic effects of venom fractions from the Australian box jellyfish Chironex fleckeri on human myocardiocytes. Toxicon. 2012;60(3):391-395.
6. Rosson CL, Tolle SW. Management of marine stings and scrapes. West J Med. 1989;150(1):97-100.
7. Henderson D, Easton RG. Stingose. A new and effective treatment for bites and stings. Med J Aus. 1980;2(3):146-150.
8. Pereira PL, Carrette T, Cullen P, et al. Pressure immobilisation bandages in first-aid treatment of jellyfish envenomation: current recommendations reconsidered. Med J Aus. 2000;173(11-12):650-652.
9. Fenner PJ, Williamson JA, Blenkin JA. Successful use of Chironex antivenom by members of the Queensland Ambulance Transport Brigade. Med J Aus. 1989;151(11-12):708-710.
10. Tibballs J, Williams D, Sutherland SK. The effects of antivenom and verapamil on the haemodynamic actions of Chironex fleckeri (box jellyfish) venom. Anaesth Intensive Care. 1998;26(1):40-45.
11. White J. A clinician’s guide to Australian venomous bites and stings. Melbourne: CSL Ltd., 2013. 245-263.
12. Andreosso A, Smout MJ, Seymour JE. Dose and time dependence of box jellyfish antivenom. J Venom Anim Toxins Incl Trop Dis.2014;20:34.
13. Konstantakopoulos N, Isbister GK, Seymour JE, et al. A cell-based assay for screening of antidotes to, and antivenom against Chironex fleckeri (box jellyfish) venom. J Pharmacol Toxicol Methods. 2009;59(3):166-170.
14. Burnett JW, Calton GJ. Response of the box-jellyfish (Chironex fleckeri) cardiotoxin to intravenous administration of verapamil. Med J Aus. 1983;2(4):192-194.
15. Burnett JW, Othman IB, Endean R, et al. Verapamil potentiation of Chironex (box-jellyfish) antivenom. Toxicon. 1990;28(2):242-244.
16. Bloom DA, Burnett JW, Hebel JR, et al. Effects of verapamil and CSL antivenom on Chironex fleckeri (box-jellyfish) induced mortality. Toxicon. 1999; 37(11):1621-1626.
17. O’Reilly GM, et al. Prospective study of jellyfish stings from tropical Australia, including the major box jellyfish Chironex fleckeri. Med J Aus. 2001;175(11-12):652-655.
18. Currie BJ. Marine antivenoms. J Toxicol Clin Toxico 2003;41(3):301-308.
19. Hartwick R, Callanan V, Williamson J. Disarming the box-jellyfish: nematocyst inhibition in Chironex fleckeri. Med J Aus. 1980;1(1):15-20.
20. Grady JD, Burnett JW. Irukandji-like syndrome in South Florida divers. Ann Emerg Med. 2003;42(6):763-766.
21. Yoshimoto CM, Yanagihara AA. Cnidarian (coelenterate) envenomations in Hawai’i improve following heat application. Trans R Soc Trop Med Hyg. 2002;96(3):300-303.
22. Winkel KD, Tibballs J, Molenaar P, et al. Cardiovascular actions of the venom from the Irukandji (Carukia barnesi) jellyfish: effects in human, rat and guinea-pig tissues in vitro and in pigs in vitro. Clin Exp Pharmacol Physiol. 2005;32(9):777-788.
23. Fenner PJ, Williamson JA. Worldwide deaths and severe envenomation from jellyfish stings. Med J Aust. 1996;165(11-12):658-661.
24. Turner B, Sullivan P. Disarming the bluebottle: treatment of Physalia envenomation. Med J Aus. 1980;2(7):394-395.

Dr. Hauglid is an emergency medicine resident at the University at Buffalo.

Dr. Kiel is assistant professor of emergency medicine and sports medicine at the University of Florida College of Medicine-Jacksonville.

Dr Schmidt is assistant professor of emergency medicine at the University of Florida College of Medicine-Jacksonville.