Marine envenomations can cause a diverse array of clinical syndromes. Systemic and life-threatening reactions, as well as delayed presentations, can occur. The pediatric population is at higher risk for serious reactions to envenomations because their greater body surface area and smaller body mass can lead to a higher relative venom load. Although the majority of the literature on marine envenomations is of low quality, the available literature does suggest that management varies depending on the geographic location. This issue reviews both common and life-threatening presentations of marine envenomations, highlights key aspects of the history and physical examination that will help narrow the differential, and offers recommendations for management based on the envenomating creature and geographic location.
A 4-year-old girl with the chief complaint of rash is brought to the ED. Her family is on a beach vacation to the Florida coast for the summer. After exiting the ocean today, she complained of a “stinging” feeling on her chest and abdomen. Later in the afternoon, while changing her clothes, her father noticed a rash and brought her to the ED. The girl complains that the rash is “very itchy.” On examination, you note an erythematous papular rash on her abdomen, chest, and buttocks, sparing the extremities, upper back, and face. Her vital signs are all within normal range, and she is well appearing, scratching occasionally at her rash. What is the best way to work up this patient? What treatment is needed? What is the expected clinical course of this condition?
An 11-year-old boy is brought into the ED by EMS. He is in severe pain after encountering a large, floating jellyfish while swimming off the Atlantic coast of the United States. The boy experienced immediate pain after contact, and EMS personnel say he became confused en route to the hospital. The boy's physical examination reveals linear, whip-like erythematous lesions on his neck and left upper extremity. Spasm and fasciculations of the bilateral upper extremities are observed. What type of jellyfish could cause these signs? What critical actions should be performed to manage this patient?
A 7-year-old girl presents to a Southern California ED by EMS. She is complaining of severe pain to her right foot that began after she jumped off her surfboard into waist-high water. On examination, a small puncture wound is noted on the plantar surface of her right midfoot, and edema is noted from the foot to the ankle. No foreign body is appreciated. EMS personnel administered intravenous opioids en route to the ED, but the patient is still in severe pain. What type of marine envenomation could cause this patient's pain? What laboratory or imaging studies—if any—should be ordered? What additional actions can be taken for pain control? Is the patient at risk for developing delayed sequelae?
A marine envenomation occurs when a venom is delivered to a person by a marine creature. Marine creatures have developed complex venoms with mechanisms of delivery that include bites and stings. Although these strategies are a means of defense or for capturing prey, inadvertent human contact and resultant envenomation can lead to serious morbidity and mortality.
Although most envenomations are mild, some can be life-threatening. Populations at greater risk for serious envenomation syndromes include the pediatric population, often due to larger relative venom dose; the elderly are also at greater risk, due to comorbidities. Most serious and life-threatening marine envenomations occur in the temperate or tropical Indo-Pacific region; in particular, the waters off the coast of Australia. North American waters, however, also support a wide range of dangerous venomous creatures. This, combined with increased international travel and exotic home aquariums, should keep marine envenomations on the mind of all emergency clinicians.
In the United States, the emergency department (ED) is the most likely place of initial presentation for patients with a life-threatening marine envenomation. Emergency clinicians should be familiar with cardinal presentations of serious envenomation. Life-threatening marine envenomations require stabilization and expert consultation in the ED, as severe envenomations can cause significant morbidity and mortality if prompt initial stabilization efforts are unsuccessful. Access to medical toxicologists, either as in-house consultants or through local Poison Control services (in the United States, 1-800-222-1222), should be available and sought out in all cases of severe envenomation.
Delayed sequelae of envenomations may also present to the ED. Less severe presentations may still develop significant delayed sequelae (eg, infection from retained spines and wounds). Proper risk stratification and evaluation is a critical component of the emergency evaluation.
This issue of Pediatric Emergency Medicine Practice reviews some of the most common venomous marine creatures and describes the typical clinical presenting features associated with their envenomation. It also provides recommendations for management of marine envenomations based on the envenomating creature and the geographic location.
The PubMed database was searched using the following terms: marine envenomations, pediatric marine envenomations, jellyfish envenomation/sting, sea snake envenomation, cone snail envenomation/sting, stonefish envenomation/sting, scorpionfish envenomation/sting, lionfish envenomation/sting, stingray envenomation/sting, octopus envenomation, sea urchin envenomation/sting, crown-of-thorns envenomation/sting, box jellyfish envenomation/sting, Irukandji envenomation/sting, Portuguese man-of-war envenomation/sting, and Physalia envenomation/sting. No restrictions were placed on the publication date; article publication dates ranged from 1957 to 2018. Of the 255 articles selected as clinically relevant, 141 were included. The majority of the literature on marine envenomation is of low quality, primarily consisting of case reports, review articles, and uncontrolled studies.
The cnidocyte is a specialized cell unique to the phylum Cnidaria. These cells contain nematocysts (cnidocysts) that function as the mechanism for venom delivery. Each cnidarian tentacle contains thousands of cnidocytes. In response to osmotic pressure or chemical changes, the nematocyst will trigger and release a coiled harpoon bathed in venom. The harpoon penetrates into the epidermis, dermis, or occasionally the capillaries of its target, resulting in an envenomation.1,2
Many species of invertebrates and vertebrates employ spines as deterrent and direct defense mechanisms and as a means to deploy venom to potential predators and prey.
Several members of the phylum Echinodermata (sea urchins and sea stars) possess a venom apparatus connected to a spine that can deliver venom to an unsuspecting diver’s hand or a shore wader’s foot. These thin spines are generally comprised of calcium carbonate and lack a barb. In addition to facilitating venom delivery to tissues, the spines often break off and pose a danger as retained foreign bodies.
Predatory cone snails of the genus Conus use a modified dental structure (radula) that sits within a flexible feeding tube known as a proboscis. The proboscis is extended as a self-defense mechanism and to search for prey. Once deployed, the barbed, harpoon-like radula penetrates the tissue and delivers a potent neurotoxin.
Members of the Chondrichthyes class (stingrays) possess a modified spine that is located on the distal end of a whip-like tail. The barbed spine generally detaches and embeds into the victim, and venom is delivered through grooves in the internal structure of the spine, resulting in local direct tissue destruction and envenomation.
Members of the Scorpaenidae family (stonefish) have venom glands in dorsal spines that are used as a mechanism for venom delivery. In the case of the stonefish, pressure-sensitive nerves trigger venom injection through the wound created by the spine.
Both invertebrates and vertebrates may employ biting mechanisms in order to transfer venom to potential predators and prey. The most notable invertebrate example is cephalopods belonging to the genus Hapalochlaena. Blue-ringed octopods bite using a powerful, bony beak, and deliver potent neurotoxins into the tissues of a victim. Sea snakes are venomous elapids that also bite, delivering venom from glands in their skull through grooves in small, fixed front fangs that are similar to terrestrial cobras, kraits, and mambas.
3. “It doesn’t really matter where you are, treatment of these stings is always the same.”
Treatment recommendations may vary between geographic regions, mirroring the biodiversity of the animals involved. Acetic acid is commonly recommended for jellyfish envenomation in Australia and the South Pacific, but is generally not recommended for Portuguese man-of-war envenomations, due to concern for increased nematocyte firing. Hot water is recommended for pain control after North American jellyfish envenomations.
6. “I didn’t palpate a retained foreign body, and the plain film x-ray was negative, so I discharged the patient home.”
Missing a retained foreign body in the setting of a marine envenomation can have serious consequences. Advanced imaging (computed tomography/magnetic resonance imaging) may be indicated, depending on clinical presentation and pretest probability. Specialist consultation should be sought for the removal of foreign bodies if they are not removable in the ED.
8. “I’ve seen this envenomation in an adult, and he was fine. I didn’t know kids could have a different reaction.”
Likely due to their increased surface area compared to mass, longer times in the water, and lack of awareness of their surroundings, children are at higher risk for more serious envenomation syndromes.
Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.
To help the reader judge the strength of each reference, pertinent information about the study is included in bold type following the reference, where available. In addition, the most informative references cited in this paper, as determined by the author, are highlighted.
Meghan B. Spyres, MD; Jeff Lapoint, DO
Chris Pitotti, MD, FACEP; Mark Waltzman, MD
April 2, 2020
May 2, 2023
4 AMA PRA Category 1 Credits™, 4 ACEP Category I Credits, 4 AAP Prescribed Credits, 4 AOA Category 2-A or 2-B Credits.
Date of Original Release: April 1, 2020. Date of most recent review: March 15, 2020. Termination date: April 1, 2023.
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