Wilderness and Environmental Medicine, 4,291-296 (1996) ORIGINAL ARTICLE Lionfish envenomations in an urban wilderness BRIAN ALDREDI, TIMOTHY ERICKSONl,2*, and JACK LIPSCOMB2 IDepartment ofemergency Medicine, University ofillinois, Chicago, JL, USA 2Toxikon Consortium: University ofillinois, Cook County Hospital, Rush-Presbyterian St, Luke:' Medical Center and Poison Control Center, Chicago, JL, USA Marine envenomations are commonly encountered along coastal regions of the United States, Although less frequent, marine bites and stings do occur in landlocked locales, such as the Midwest, because of an increased interest in keeping these exotic creatures as pets. We report 33 cases ofenvenomations by captive lionfish (Pterois volitans) called to a regional Chicago poison control center over a 2-year period. All stings were accidental, and 10 (30%) were treated in an emergency department. The wounds were uniformly on the hand, and all presented with local, intense pain. The majority of envenomations were responsive to prompt immersion in nonscalding water within 90 min, and all were advised on tetanus prophylaxis and local wound care. Two patients (6%) required hospitalization. In all cases, those patients envenomated recovered without permanent sequelae. As a result ofincreasing encounters with lionfish as pets, health care providers, regardless of their locale, should be familiar with the current treatment recommendations. Key words: envenomations, immersion, lionfish, tetanus prophylaxis Introduction The scorpion fish family (Scorpaenidae) contains several hundred species of marine fish. Inhabiting a wide range oftemperate and tropical ocean waters, these exotic creatures are revered for their intrigue, danger, and undaunting beauty. Scorpaenidae is further divided into three genera: Pterois, which includes the lionfish; Scorpaena; and Synanceja (represented by its most infamous member, the deadly stonefish), The genera are classified by variations of their venom apparatus and are listed in increasing potency of venom. The lionfish is characterized by long, thin spines with small venom glands and thus delivers a less potent sting (see Figure 1), In contrast, the stonefish is well known for its potentially fatal venom extruded through short, broad spines from highly developed venom glands [1,2]. This venom has been likened in potency to the cobra snake [3], Common to the family are 12-13 dorsal, two pelvic, and three anal spines each with paired venom glands, Venom travels from the glands at the base of the spines through anterolateral depressions. An integumentary sheath covers each spine comprising the venom apparatus. The similar plumelike pectoral spines are innocuous [4]. The venom toxicity is due to high molecular weight proteins with antigenic properties. Treatment is based on the proposed heat labile characteristics of these proteins. Normally docile creatures, Scorpaenidae inflict most injuries to careless fishermen or divers and occasionally to the foot ofa swimmer because oftheir bottom-dwelling tendencies. More recently, pet owners have become more prevalent victims with the increasing number of marine aquarists [5, 6]. Many of these stings occur in landlocked *Address for correspondence: Department of Emergency Medicine, University of Illinois, CMW Room 618 (M/C 724), 1819 Polk Street, Chicago, 1L 60612, USA. 1080-6032 1996 Chapman & Hall
292 B Aldred, T Erickson and J Lipscomb Fig. 1. Lionfish (Pterois volitans) in captivity. Photo courtesy of John G. Shedd Aquarium, Chicago, IL. locales of the country. We report 33 cases of lionfish envenomations reported to a regional poison control center in Chicago, Illinois. Methods A retrospective case review of alliionfish envenomations referred to the regional poison control center in Chicago, Illinois, over a 2-year period (1993-1994) included incidence, clinical presentation, anatomic location of sting(s), severity of injury and symptoms, treatments rendered, location of treatment, premorbid medical conditions, and interval follow-up to determine sequelae. Results Thirty-three consecutive documented cases of lionfish stings were reported to the poison control center during January 1993 to December 1994. This comprised one or two cases per month of approximately 4000 total monthly poison referrals. Males outnumbered females nearly 3: 1 with ages ranging from 13 to 49 years (mean age = 30 years). Ten of the 33 subjects (30%) were evaluated in local emergency departments (ED). The remaining patients had only minor local reactions consisting of pain, redness, and swelling and were treated at home with hot water soaks, oral analgesics, and, occasionally, topical antibiotics. Our data were inconclusive on how many patients actually received antibiotics and which agents were prescribed. Eleven patients (33%) had complete resolution of symptoms within 2 hours following continuous nonscalding water soaks for 60-90 min. In the remainder, 94% had pain resolution within 24 hours, and most had
Lionfish envenomations in an urban wilderness 293 moderate relief within 6 hours with immersion therapy only. Twenty-five of 33 (76%) of the victims experienced edema at the site with occasional proximal extension. All patients were advised on tetanus prophylaxis and observation for systemic symptoms. One patient had preexisting hypertension, and one patient was intoxicated with alcohol. The location of the stings was uniformly on the hand with all exposures from a lionfish inhabiting an aquarium. All envenomations except one occurred in the home. Of the 10 victims evaluated in the ED, four had multiple stings with three having complications: one admitted with progressive hand and wrist swelling, one admitted with dysarthria, and one with signs of cellulitus who refused admission. Nine (27%) had symptom duration longer than 24 hours. Many had rendered treatment prior to contacting the poison control center. One had immersed his hand in "ice water," and another who received a sting at a pet store had placed an ice pack on the wound per the store owner's request. In addition, one patient cut his fingers open with a razor blade to "bleed out the poison." Symptoms had resolved in most patients within 72 hours. With the use of the grading system noted in the literature from erythema (Grade I) to vesicle formation (II) to tissue necrosis (III), our results showed 94% (31 of 33) Grade I lesions, two patients suffering Grade II wounds, and no Grade III envenomations [5]. No stonefish stings were observed in our study. Of the 33 cases, two required more aggressive therapy. One patient, a 40-year-old man with no significant medical problems was stung in the finger from an aquarium lionfish. He complained of mild local pain and "tingling" and had tried to "squeeze blood out" of the wound. After 30 min of home immersion therapy, he received intravenous fluids and tetanus toxoid at a local ED. On follow-up the next day, he complained of continued local pain, with increased swelling and redness and was recommended to return to the ED where the physician reported signs of local infection with the diagnosis of cellulitus. Hospital admission for receipt of intravenous antibiotics was advised. No foreign body was noted on exploration and radiograph. The patient refused admission and was treated with ciprofloxacin 500 mg bid on reevaluation with his private physician in 12-24 hours. Forty-eight hours postexposure, the swelling and pain were resolving and at 3 days they were minimal according to the subject. He never was reevaluated by his private physician. A 25-year-old man without pertinent medical history was seen in a hospital ED with multiple lionfish stings to his right hand 30 min prior to arrival. His complaints were local pain and decreased mobility of his digits. Of concern was his complaint of jaw tightness and observation by the medical personnel of a noticeable speech impairment. His vital signs were normal. A local skin reaction was noted with "red streaking" proximally up the affected extremity. There were three to four puncture wounds noted on the third and fourth digits. He received hot water soaks for 90 min, tetanus toxoid, and was admitted overnight for observation and supportive care. No antibiotics were administered. Epsom salt soaks were given as well as intravenous fluids and analgesics with resolution of jaw sensation and dysarthria within 12 hours. Local pain, edema, and erythema were mostly resolved within 48 hours, and the patient was discharged on hospital day 3. Discussion Lionfish and other members of the family Scorpaenidae are intriguing marine creatures that are becoming popular marine aquarists' pets. Commonly encountered in the Indo-Pacific region, they are respected by fishermen, divers, and water enthusiasts for their beauty and danger. Known by more regional names as the "nohu" and the "warty ghoul," entrepreneurs have discovered their marketing abilities, and many of the fish are being illegally imported to be sold
294 B Aldred, T Erickson and J Lipscomb as pets [1, 5]. Lacking in this transmission is the education and respect for these potentially dangerous animals. Upon envenomation, a multitude of local reactions may occur, the most prominent of which is immediate excruciating pain lasting minutes to days. Local injury has been characterized by three grades: erythema, vesicle formation, and local tissue necrosis. The severity is dependent on the number of stings, species, as well as the confounding medical illnesses of the victim [5, 7, 8]. As the heat labile toxins enter the tissue, local erythema, calor, and edema develop secondary to the activation of the inflammatory cascade. The mediators responsible for the tissue destruction recovered from analysis of vesicle fluid are prostaglandins and thromboxane [9]. The wound can appear ischemic and echymotic with rapid progression of tissue loss, especially without prompt and adequate treatment. Bleeding, cellulitus, and hypesthesias may complicate the wound. Systemically, the reactions may be more variable. Reported symptoms range from headache and nausea to arthralgias, arrhythmias, and shock [3-5]. Treatment begins with prompt immersion in nonscalding hot water (45 C) to inactivate the proposed heat labile proteins and thus blunt the inflammatory response and possible systemic sequelae [9, 10]. The affected area should be soaked in water as hot as can be tolerated for at least 30 min but preferably 60-90 min and repeated as pain persists. Appropriate thorough wound care is a mainstay of therapy and is of utmost importance. Copious irrigation and investigation for foreign bodies by inspection and possibly radiographs will ensure optimal healing. Tetanus prophylaxis is important, and booster immunization may be necessary. Because many of these envenomations occur as puncture wounds to the hands and feet, prophylactic antibiotics are frequently recommended. If infected, a foreign body, usually a fractured spine, must be suspected. The common inciting organisms are Staphylococcus, Streptococcus, and, occasionally, Vibrio species [1]. A logical first-line antibiotic would be trimethoprim-sulfamethoxazole. In addition to hot water soaks for pain control, local and systemic analgesics, including prostaglandin inhibitors (i.e., ibuprofen) and more likely narcotics, are often required. Various anecdotal treatments ranging from mineral spirits to mangrove sap have been reported, but none are well studied [1]. Although the lionfish sting rarely causes more than local reactions, stonefish envenomation has been dreaded for generations. An antivenom has been developed by an Australian firm, Commonwealth Serum Laboratories, which may be used for serious systemic symptoms secondary to any Scorpaenidae species, although the antivenom is not recommended for typical lionfish stings [11]. As with most injuries, prevention is the basis of all therapies. However, as more pet owners harbor lionfish in their aquariums, envenomations have become more frequent [5]. Education of all those encountering these beautiful and intriguing creatures will further diminish toxic exposures and their sequelae. Our results support the findings ofthe two prior large retrospective studies conducted by Kizer et al. of 51 cases in a coastal locale and Trestrail and AI-Mahasneh of 23 cases in a landlocked community (see Table 1 for summary of all three studies) [5, 6]. Patients typically present with severe, local pain that is promptly responsive to immersion therapy. Trestrail and AI-Mahasneh noted 8.7% (2 of 23) Grade II wounds and one complication (4.3%) of cellulitus, whereas Kizer et al. reported nearly all Grade I wounds with one exception, an indolent, necrotic ulcer (Grade III). Also, 13% of victims had variable systemic symptoms. One patient required intravenous antibiotics for cellulitus or tenosynovitis, and one hypotensive patient responded well to intravenous fluids. None of the 101 cases reported in these three studies required antivenom. The aforementioned cases illustrate the classic local reactions inherent to captive lionfish envenomations. These sequelae mayor may not be as benign in the natural environment (outside aquaria) because of the prevalence of marine microorganisms. Predictably, all cases were accidental
Lionfish envenomations in an urban wilderness 295 Table 1. Presentation of lionfish envenomations in 101 cases Local pain (%) Swelling (%) Systemic symptoms (%) Age (years) Male (%) Female (%) Grade (%) I II III Pain relief with immersion (%) Antivenom administration (%) 92 60 13 29.2 77 23 95 4 I 97 o Present study was combined with Refs. 5 and 6. stings to pet owners or potential owners. Non-scalding water submersion and proper wound care, including wound toilet and tetanus prophylaxis recommended by the poison control center, proved effective in most cases. In our study, multiple stings in two victims, noted by three or more puncture sites, led to more serious sequelae as previously reported in the literature [7]. Chicago has long been associated with skyscrapers, fresh lake water, and seemingly endless surrounding cornfields. Despite this landlocked urban locale, we have noticed an increasing number of marine envenomations, in particular lionfish (33 cases), reported to the local poison control center. It is clear from the now over 100 reported cases of lionfish envenomations in the medical literature that nearly all patients will have only a local response to a sting and rarely require systemic treatment including antibiotics, analgesics, and antivenom. Extrapolation of the benign nature of these stings to other Scorpaenidae members, including the stonefish, should be discouraged. Local hot water immersion therapy and rigorous wound care, including wound toilet, are the most effective treatment modalities for the vast majority of victims. As expected, the preponderance ofthe cases were minor in severity (Grade I), and all wounds were inflicted on the hands of unwary marine aquarists. Acknowledgments The authors thank Dr. Timothy Bajema, Diane Mekus, and Jeff Sanders for their dedicated contributions. References 1. Auerbach, P.S. Marine envenomation. In Auerbach, P.S., eds. Management of Wilderness and Environmental Emergencies, 3rd ed. Mosby, St. Louis, MO: 1995: 1359-1362. 2. Russell, F.E. Comparative pharmacology of some animal toxins. Fed Proc 1967; 26, 1206. 3. Fisher, A.A. Atlas ofaquatic Dermatology. Grune and Stratton, New York: 1978. 4. Halstead, B.W. Poisonous and Venomous Marine Animals ofthe World. Darwin Press, Princeton, NJ: 1978. 5. Kizer, K.W., McKinney, H.E., and Auerbach, P.S. Scorpaenidae envenomation: a five-year poison center experience. lama 1985; 253, 807.
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