Stingray sting stings!

Abstract

Introduction

Stingrays are a group of sea rays, a type of cartilaginous fish closely related to sharks. There are more than 150 species of stingray worldwide, habituating both salt and freshwater. Stingrays had always been considered a speciality delicacy within South East Asia. Despite this, stingray-related injuries in Malaysia are relatively uncommon.

Case report

A 25 years old stingray enthusiast visited the emergency department for alleged stung on the right hand by his pet stingray while attempting to shave its barb. He complains of severe throbbing pain over the right hand, radiating up to his right arm with a pain score of 8/10. Local examination shows a tiny puncture wound over the right dorsum, with diffuse right hand swelling up to the wrist level. The stingray was identified as the Xingu River ray (Potamotrygon leopoldi sp). Immediate local wound care and anti-tetanus toxoid were given. Xray of the right hand shows no fracture or foreign bodies. Despite multiple repeated doses of diclofenac, tramadol, fentanyl, and morphine, it was a futile attempt to relieve the patient. We proceed with a trial of hot water immersion of his right hand, which diminish his pain after thirty minutes. He was discharged well later on the same day.

Discussion

There are two mechanisms of stingray stings – Mechanical and venomous injury. The barb pierces through the skin, causing a puncture and jagged laceration. Venoms are then released from the serrated spine, causing tremendous pain to the victim, which is the commonest venomous effect. The first-line treatment for stingray injuries is hot water immersion, as stingray venom is heat-labile and can be inactivated by heat. A water temperature of 40-45 degrees or the highest water temperature tolerated by the patient on the non-affected limb can be used. In a retrospective series of 97 patients with stingray envenomation, 67 percent had complete analgesia with hot water immersion alone. Opioids or nonsteroidal anti-inflammatory drugs (NSAIDs) can be added if pain persists. Local wound care, such as meticulous cleaning of the wound, identifying and removing foreign bodies, and accompanying tetanus prophylaxis, are required. Antibiotics are not required in superficial wounds.