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Treating Stingray Envenomation And Injury In The Lower Extremity
Stingrays are cartilaginous fish related to sharks. They have a flat body structure with a tail containing one or more barbed spines. The spines are covered with a thin integumentary layer that concentrates venom secreted by glands on their inferior surface.1 Stingrays are not aggressive toward humans. They only use their spines as a self-defense mechanism.
However, injuries from stingrays are relatively common in temperate coastal areas. Stingrays live on the sandy ocean bottom and injury occurs when a person steps on the fish causing a defensive strike to the foot, ankle or lower leg. Stingray strikes can result in several injuries including envenomation, laceration from the spine, retained spine fragments and secondary bacterial infection.1
A stingray's tails contain one or more barbed spines. The spines have serrated edges and strikes often result in a deep, jagged laceration. The majority of stings occur on the lower extremity secondary to stepping on the fish. While rare, the spines may potentially injure neurovascular structures. Fatal stings are rare but have been reported.2 In 2006, Steve Irwin, an Australian wildlife expert and television personality, was killed by a stingray strike when the stinger penetrated his thoracic wall, causing massive trauma.3
Stingray spines are covered in an integumentary sheath that contains their protein-based venom. Stingray venom causes both local and systemic effects. Local effects of stingray venom include: severe pain, edema, cyanosis, erythema, petechiae, local necrosis, ulceration and delayed wound healing.4 Systemic effects of stingray venom include: syncope, nausea, vomiting, diarrhea, diaphoresis, muscle cramps, fasciculations, abdominal pain, seizures and hypotension.5
Stingray venom is a very heat sensitive protein. The recommended initial treatment is immersion in hot water that patients maintain at a temperature of 110º to 115º (if tolerable) for 30 to 90 minutes. Heat in theory rapidly denatures the venom protein, providing significant and rapid pain relief.5-7 Local anesthetic also theoretically counteracts stingray venom and physicians have used it to provide pain relief in the management of acute stingray injuries.8
Stingray venom can cause significant tissue necrosis, which can lead to delayed wound healing.9 Additionally, the venom causes local vasoconstriction and ischemia, which can contribute to delayed wound healing as well.10 There have been reports of chronic wounds secondary to stingray injuries.11-13 Numerous treatment modalities exist for these chronic wounds and they include debridement, hyperbaric oxygen and collagenase.11-13
Pieces of the stingray spine can break off in the deeper soft tissues, causing prolonged release of venom and foreign body reaction, and contributing to secondary bacterial infections.1 Stingray spines are typically radiopaque and visible on plain film radiographs, but may have radiolucent cartilaginous parts requiring ultrasound evaluation.14 Plain film radiographs are recommended to evaluate stingray wounds for any retained spines or foreign material. Ultrasound is also recommended for evaluation if radiographs are negative and one can ultrasound to aid foreign body removal as well.8
Following radiographic/ultrasound evaluation, one should explore the wounds, remove all foreign material and debride necrotic tissue.1,15 Clinicians should thoroughly irrigate the wound and allow it to heal via secondary intention if the wound is small or with loose primary closure if it is very large.1,15 Determine the patient’s tetanus immunization status and administer a booster if needed.15
There is a high potential for bacterial contamination in stingray puncture wounds and these injuries can be complicated by secondary bacterial infections including cellulitis, osteomyelitis, necrotizing fasciitis and septicemia.16 Staphylococci and Streptococci are the most common bacteria causing infection secondary to stingray injury but bacteria specific to water environments, namely Vibrio species in saltwater and Aeromonas in freshwater, are also pathogens of concern. A study by Clark and colleagues showed a very high number of infections in stingray wounds in patients who did not receive prophylactic antibiotics upon the initial presentation.5 Prophylactic antibiotic selection should cover Staphylococci, Streptococci and pathogens expected in the involved water.
In Summary
Stingray injuries most commonly occur on the lower extremity and can be complicated by soft tissue necrosis, delayed wound healing, retained spines and secondary bacterial infection. Radiography and ultrasound imaging, wound care including exploration, debridement and irrigation, and prophylactic antibiotics are the mainstays of management of these injuries.
References
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2. Slaughter RJ, Beasley DM, Lambie BS, Schep LJ. New Zealand's venomous creatures. N Zealand Med J. 2009;122(1290):83-97.
3. Callinan R. Death of a Crocodile Hunter. Time. 2006. https://content.time.com/time/world/article/0,8599,1531446,00.html . Accessed April 4, 2015.
4. Germain M, Smith KJ, Skelton H. The cutaneous cellular infiltrate to stingray envenomization contains increased TIA+ cells. Br J Dermatol. 2000;143(5):1074-1077.
5. Clark RF, Girard RH, Rao D, Ly BT, Davis DP. Stingray envenomation: a retrospective review of clinical presentation and treatment in 119 cases. J Emer Med. 2007;33(1):33-37.
6. Guenin DG. Trauma and envenomations from marine fauna. In Tintinalli JE SS, Cline DM (ed.): Emergency Medicine: A Comprehensive Study Guide. McGraw-Hill, New York, 1996.
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8. Fenner PJ, Williamson JA, Skinner RA. Fatal and non-fatal stingray envenomation. Med J Austral. 1989;151(11-12):621-625.
9. Barss P. Wound necrosis caused by the venom of stingrays. Pathological findings and surgical management. Med J Austral. 1984;141(12-13):854-855.
10. Auerbach PS. Marine envenomations. N Engl J Med. 1991;325(7):486-493.
11. Flint DJ, Sugrue WJ. Stingray injuries: a lesson in debridement. N Zealand Med J. 1999;112(1086):137-138.
12. Rocca AF, Moran EA, Lippert FG, 3rd. Hyperbaric oxygen therapy in the treatment of soft tissue necrosis resulting from a stingray puncture. Foot Ankle Int. 2001;22(4):318-323.
13. Fino P, Onesti MG, Felli A, Scuderi N. Clinical Examination and Treatment of a Leg Ulcer Caused by a Stingray Puncture. Int J Lower Extrem Wounds. 2014.
14. Srinivasan S, Bosco JI, Lohan R. Marine stingray injuries to the extremities: Series of three cases with emphasis on imaging. J Postgrad Med. 2013;59(4):309-311.
15. Perkins RA, Morgan SS. Poisoning, envenomation, and trauma from marine creatures. Am Fam Phys. 2004;69(4):885-890.
16. Barber GR, Swygert JS. Necrotizing fasciitis due to Photobacterium damsela in a man lashed by a stingray. N Engl J Med. 2000;342(11):824.
