Southern Stingrays
Introduction
Stingrays primarily inhabit shallow tropical to semi-tropical waters with sandy bottoms, so it is no surprise that we surfers often cross paths with these evil-looking bottom feeders. Indeed certain locales, such as Nosara, Costa Rica, Southern California, and New Zealand’s North Island are infamous for their large populations of rays. Though, closely related to sharks they share none of the dentition or aggressive behavior of their oft-feared cousins. In fact, stingrays are timid, docile creatures that feed primarily on snails, worms and crustaceans residing on the sea floor. However, as their name implies, stingrays are capable of inflicting extremely painful and occasionally dangerous stings when accidentally stepped on by unsuspecting surfers. This brief review will discuss prevention, treatment, and complications of stingray injuries and envenomation.
Because they are well camouflaged, and often lay on the bottom partially buried in sand, stingrays are notoriously difficult to see. When stepped upon, they reflexively whip their muscular tails up and back, often striking the victim in the foot or lower leg with a sharp, serrated, bony barb located on the dorsal aspect of the tail. Depending on the species, the tail may be armed with one to four barbs, which can vary in length between less than 1 cm to as long as 30 cm, and tend to create jagged puncture wounds in their victims. 
Adding insult to injury, two ventral grooves in the spine are filled with venom-producing tissue that injects venom into the wound at time of impact.
Sting Ray Injuries
Though the wounds created by a stingray injury are usually no more than 1 cm across they may be deep, and occasionally contain retained fragments of spine, or bits of the cartilaginous sheath surrounding the spine. The wound may be dusky in appearance, swollen, and may bleed more than anticipated as a result of anticoagulants in the venom. On rare occasions, as was the case with “Crocodile Hunter” Steve Irwin, the spine may penetrate the chest, abdomen, or an artery with potential for life-threatening consequences. (1)
The envenomation results in instantaneous burning or “electrical” pain, peaking in intensity in 30 to 60 minutes, which may radiate up the extremity. Venoms have been incompletely characterized and vary considerably between species, but are known to contain neurotoxic and cardiotoxic molecules and proteins, including serotonin, 5’-nucleotidase, and phosphodiesterase, as well as vasoconstrictive and anticoagulant elements. Systemic symptoms are rare, but may include nausea, vomiting, diarrhea, muscle cramps, muscle fasciculation, seizures and syncope. (2) Deaths have been reported but appear to be from traumatic injury rather than from envenomation.
Wound healing is often slow, and may be complicated by infection, necrosis or ulcer formation. In a retrospective review of 120 stingray envenomations, the rate of infection was approximately 16% in patients who did not receive antibiotics, and 3% in patients who received prophylactic antibiotics. (3) In our experience, rates of infection are considerably lower. Osteomyelitis, fasciitis, and compartment syndrome are other uncommon complications. (4)
Treatment
Initial management of a stingray injury involves wound irrigation, control of hemorrhage, and pain management.
A sink or shower, is an excellent means of would irrigation, preferably using hot water. If running water is not available, field irrigation is best accomplished by boring a small hole in the top of a plastic bottle of drinking water and squeezing the bottle to create a forceful stream. Because salt water contains many microorganisms it should not be used for irrigation, however potable water is an excellent irrigating solution. Alcohol, betadine, hydrogen peroxide, and that old surfer’s standby, urine, should be avoided because they are cytotoxic and delay the healing process.
Like many other marine venoms (e.g. Stonefish, Weever Fish, Hawaiian Box jellyfish), the protein-based stingray venom is heat-labile, and can easily be denatured. As a result, hot water immersion (1150 F/450 C) of the affected is an extremely effective and rapid method of analgesia. Clark and Girard found that in 90% of cases hot water immersion alone provided satisfactory pain relief and obviated the need for oral or parenteral analgesics. The limb should be placed in tub of water as hot as can be tolerated for 20 – 30 minutes, being careful not to cause a thermal burn. Water in the tub or bucket may need to be replenished if it cools and the process may need to be repeated if the pain returns after the first hot-water soak.
After the wound has been soaked and irrigated it should be explored for retained foreign bodies such as spine fragments, or sand. Though Clark and Girard reported foreign material in only 1% of their San Diego series (3), there are numerous reports in the literature of embedded foreign spines, often leading to complications such as infection, delayed wound healing, and even TIA. (5) Hook-like serrations of the spine often interdigitate with surrounding tissue causing further local damage on removal. (1) X-rays or ultrasound are excellent at detecting spine fragments but remnants of the cartilaginous sheath surrounding the stinger are difficult to detect with either modality. Due to risk of infection wounds should be left open and allowed to heal by secondary intention and not be sutured. A topical antibiotic such as Bacitracin can be applied to the wound, which should then be covered by a loose dry dressing.
Consideration should be given to prophylactic oral antibiotics, particularly to deep puncture wounds of the hands or feet. Most authorities suggest using antibiotics such as Ciproflaxacin or Doxycyline, which cover Vibrio species as well as other marine organisms.(3) Severe infections may require hospital admission for parenteral antibiotics, wound exploration and debridement. A tetanus booster should be given as indicated.
Stingray barbs that have penetrated the chest and abdomen, and those that are in the proximity of major arteries should be left in place until the patient can be transferred to a medical facility staffed with the appropriate surgical staff. (1)
Prevention
When surfing in waters known to be populated with stingrays it is best to paddle ones board, or swim whenever possible, avoiding the temptation to stand up in shallow water. In areas too shallow to paddle, surfers can avoid getting stung by shuffling their feet through the sand, creating vibrations that will scare the skittish animals away, a maneuver known as the “stingray shuffle”. Traveling surfers visiting a new break for the first time are well advised to talk to local surfers regarding any hazards in the lineup, stingrays included.
References
- Jhamb S1, Corsetti RL. Management of penetrating thoracoabdominal stingray trauma. Am Surg. 2013 Feb;79(2):E54-5
- Diaz JH. The evaluation, management, and prevention of stingray injuries in travelers. J Travel Med 2008;15:102–9.
- Clark RF, Girard RH, Rao D, et al. Stingray envenomation: a retrospective review of clinical presentation and treatment in 119 cases. J Emerg Med 2007;33:33–7.
- Jarvis HC1, Matheny LM, Clanton TO. Stingray injury to the webspace of the foot Orthopedics 2012 May;35(5):e762-5
- Gan DC, Huilgol RL, Westcott MJ. Transient ischaemic attack caused by an ingested stingray barb. Med J Aust. 2008 Dec 1-15;189(11-12):668-9