Urgent Message: Urgent care providers in coastal areas need to be prepared to treat stingray envenomation. Immersion in water heated to a precise temperature is the key to pain relief.

Authors: George Kamajian, DO, and Blake Singletary, OMS3
George Kamajian, DO, is a Medical Director at Largo Clinic and Adjunct Professor of Emergency Medicine at Lake Erie College of Osteopathic Medicine in Largo, FL. Blake Singletary, OMS4, is a 4th year medical student at Lake Erie College of Osteopathic Medicine in Bradenton, FL. He will be beginning residency training in Internal Medicine at Largo Medical Center this year.

Introduction

Stingray stings and envenomations, though not extremely common in clinical practice, can be both painful and distressing to patients. Literature suggests 1,500 to 2,000 incidents reported in the United States annually and many times that number go unreported.1,2 It is important for urgent care providers in coastal areas to be prepared to treat the associated pain of these stings and envenomations. Current care consists of applying heat to the area of injury to reduce or eliminate pain, although available case studies give little precise information regarding the precise temperature for treatment. We present an accumulation of 21 cases of stingray injuries with accurate temperature levels for optimum treatment of pain.

Mechanics of a Sting

Along with venom, stingrays common to the Florida coastline have serrated, barb-like “stingers” in the proximal one-third of their tails. When an unprotected person steps on a ray, this stinger can be thrust upward with great force through even bone, and most injuries involve the lower extremities. The venom of a stingray, consisting of serotonin and two enzymes (5-nucleotidase and phosphodiesterase), causes immense pain and distress to individuals who encounter a surprised ray.3,4

Treatment for Envenomation

Current medical care for stingray injuries involves control of bleeding, infection prophylaxis, and pain control. Wound exploration should be performed to rule out the presence of any residual foreign body (stingray barb).3,4 Radiologic review is extremely unlikely to be helpful in a clinical setting. Pain relief to this point has been achieved by applying anesthetics or “heat” to the injured area.1-3

Lessons Learned From Cases

Careful observation of our studies has yielded a specific temperature for injuries that occur specifically in the Gulf of Mexico near St. Petersburg, FL. Over the course of the last 2 years we have seen 21 separate incidents of stingray envenomations. These patients presented within 15 to 120 minutes of the injury, and were seen immediately upon arrival at our clinic. All wounds involved the feet only. Both plantar and dorsal aspects of the foot were affected. Patients uniformly rated the pain 10/10 on the patient pain scale upon arrival. Following assessment, therapy using heated water was initiated.

Treatment and observation consisted of the following. A patient’s injured foot was immersed in water that was being evenly heated at the onset of therapy. The temperature of the water was increased at 5-minute intervals until a patient reported a subjective decrease in pain: this was monitored and recorded at regular intervals using an Acu-Rite meat thermometer obtained from our local supermarket. Following a patient’s initial report of pain relief, temperature was increased until the patient reported no additional relief. Our endpoint was a subjective statement that the patient’s pain was reported as “minimum” or “resolved.”

Onset of pain relief was consistently found at 115°F. Optimum temperature was consistently 118°F. Further pain relief was not accomplished with continued escalation in temperature of the water bath but pain returned whenever the water temperature dropped below 115°F. This target temperature was held for 30 to 90 minutes based on return of pain once the foot was removed from hot water bath. After that, patients reported their pain to be 0-1/10 on the patient pain scale, and no patients needed additional management of pain on follow up.

Discussion

To draw novel conclusions on the treatment of stingray injuries from this data set is reasonable. Previous studies have shown the benefits of heat in relieving the pain associated with stingray injuries. No studies have, as of yet, given such an exact therapeutic window for temperature-driven relief of pain. Although this study was conducted on a relatively small patient population, the breadth of stingray injuries across the State of Florida and the southeast United States is vast, and a study such as this has the potential to provide great benefit to patients. Submerging an injured foot or leg in a water bath maintained at 118°F for 90 minutes provides maximal pain relief for individuals envenomated by a stingray, with no return of pain reported.

References

  1. Perkins AR, Morgan SS. Poisoning, envenomation and trauma from marine creatures. Am Fam Physician. 2004;69(4):885-890.
  2. Cline A. Stingray envenomation of the foot: a case report. The Foot & Ankle Journal. 2008;1(6):4.
  3. Ganard S. Stingray Injuries, Envenomation, and Medical Management. Accessed April 10, 2014. http://www.potamotrygon.de/fremdes/stingray%20article.htm
  4. Evans,RJ, Davies RS. Stingray injury. J Accid Emerg Med. 1996;13(3):224-225.
Case Series: Stingray Envenomation
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