Lionfish and Stonefish Envenomation Treatment & Management

Prehospital care should address recognition of the injury as a potential envenomation, gentle removal of visible spines, direct pressure to control bleeding, administration of analgesia, and transport for definitive medical evaluation.

Recognition of serious systemic symptoms and prompt institution of appropriate life-saving procedures, such as cardiopulmonary resuscitation (CPR) and treatment for anaphylaxis, should be paramount in the prehospital care setting.

Emergency department (ED) management of Scorpaenidae envenomations involves addressing the venom exposure as well as the accompanying inflicted trauma. General rules of therapy include prompt analgesia, wound management, antivenom administration, and supportive treatment for significant envenomations.

CPR and advanced cardiac life support (ACLS) procedures are rarely indicated but always take absolute precedence.

Wound debridement

Gentle manual removal of obviously protruding spines prevents further penetration or breakage.

With proper anesthesia, surgical removal of embedded spines is indicated when they are in proximity to joints, nerves, or vessels.

Weight-bearing surfaces may require removal of spines to prevent chronic pain.

Always irrigate copiously after adequate anesthesia.

Hot water immersion technique

Heat treatment is widely recommended as effective initial treatment for envenomations by Scorpaenidae, as well as echinoderms, stingrays, and other venomous spine injuries.

The affected limb should be immersed in water no warmer than 114ºF or 45ºC.

Be careful not to inflict thermal burns by placing an insensate limb (as a result of local anesthesia or decreased sensitivity as a result of pain) into scalding water.

Local or regional anesthesia, if available, is a suggested means of adjunctive analgesia.

Analgesia

Methods of recommended analgesia vary depending upon the reference cited and range from immersion techniques to local or regional anesthesia to parenteral analgesics.

Most references recommend that initial therapy consist of immersion in nonscalding hot water (upper limit of 114ºF or 45ºC) after removal of visible spines and sheath, in order to inactivate the thermolabile components of the venom that might otherwise cause a severe systemic reaction.

Adjunctive regional or local anesthesia offers several benefits that are not conferred by immersion techniques with analgesia. In addition to the absence of the risk of thermal injury, reliable, prompt, and prolonged analgesia allows for simultaneous debridement of the wound.

Parenteral analgesics and/or sedatives may be needed for patients who have wounds that are difficult to immerse or anesthetize, or for persons exhibiting significant anxiety reactions to the envenomation.

Wound management principles

Wound management principles include identification of foreign material, adequate debridement, tetanus prophylaxis, and appropriate referral for retained fragments that are not easily accessible in the ED.

Although the spines rarely break off into the skin, debridement of loose spines should be undertaken promptly, because retained spines continue to envenomate. Embedded structures should be pulled straight out with forceps to avoid breaking them.

Ultrasound and plain radiography may help locate retained fragments, many of which require referral for consideration of operative removal (eg, proximity to nerves, vessels, joints, weight-bearing surfaces). Retained fragments act as foreign bodies, causing inflammation and eventually becoming encapsulated into granulomata, which may lead to delayed healing and secondary infection.

Tetanus prophylaxis is indicated in all patients who have experienced traumatic marine injury and who have insufficient or uncertain immunization histories.

Severe to life-threatening systemic symptoms of envenomation most commonly result from envenomations by the Synanceia genus and only rarely result from envenomations by other genera of the Scorpaenidae family.

Stonefish antivenom

Stonefish antivenom from Australia's Commonwealth Serum Laboratories (CSL) is recommended only for predilution intramuscular usage. However, for serious envenomations, this route may not be ideal because of erratic absorption. Following dilution, a slow intravenous administration may be preferable: 1 ampule (2000 U) for every 1-2 punctures, up to 3 ampules for more than 4 punctures. It should be diluted in 50-100 mL of isotonic sodium chloride solution and run through at least 20 minutes.

As this is a hyperimmunized equine antisera, there are risks of allergic reaction and serum sickness in the recipient. Skin testing and/or pretreatment should precede administration. Rather than skin testing, Australian sources tend to recommend pretreatment with subcutaneous epinephrine and an intramuscular antihistamine, adding an intramuscular corticosteroid for known hypersensitivity.

Also see Medication.

Consultation with an appropriate surgical specialist is advised for all complicated puncture wounds, including those in proximity to articular and neurovascular structures.

Spine extraction is best performed acutely with an operating microscope in the surgical suite.

Plantar puncture wounds are a potentially complicated injury, and they may require consultation or referral for foreign material that is not easily extracted in the ED.

Consultation and admission to a general internist for supportive care may be warranted when symptoms of serious envenomation are present.

Protracted pain, nausea, muscular weakness, respiratory distress, and hypotension are a few systemic symptoms that indicate the need for admission.

Additionally, in the rare case of Vibrio or Aeromonas sepsis, a coordinated multispecialty effort is needed to address wound debridement, antibiosis, and critical care support.

Most injuries and envenomations caused by Scorpaenidae result from inadvertently stepping on, carelessly handling, or harassing them.

Most Scorpaena (eg, scorpionfish) and Synanceia (eg, stonefish) species are never seen until a sting occurs because of their excellent camouflage amongst rocks or along the sea bottom. Wading in bare feet, particularly at night, should be avoided. While shoes, diving booties, gloves, and wetsuits may provide some protection, they are easily penetrated by the stout, sharp spines of stonefish, and it is best to avoid touching the sea bottom or to use a shuffling gait while wading.

Pterois (eg, lionfish) species are frequently free-swimming or hovering in small caves or crevices for protection. Do not provoke or corner these fish, as they may dart forward, resulting in an envenomation. Marine aquarists, in particular, must be cautious when cleaning their tanks or attempting to transfer captive lionfish.