Marine Envenomations

[Section Outline]

Much of the management of envenomation by marine creatures is supportive in nature. Specific marine antivenom can be used when appropriate.

Invertebrates

Etiology: Injuries from cnidocysts (stinging cells) of hydroids, fire coral, jellyfish, Portuguese man-of-wars, and sea anemones cause similar clinical symptoms that differ in severity. Other invertebrates (e.g., sea sponges, annelid worms, sea urchins) have spines that can inflict painful stings.
Clinical features: Pain (prickling, burning, and throbbing), pruritus, and paresthesia develop immediately at the site of the bite. Neurologic, GI, renal, cardiovascular, respiratory, rheumatologic, and ocular symptoms have been described.

TREATMENT
Marine Invertebrate Envenomations Decontaminate the skin immediately with saline. Vinegar (5% acetic acid) is an all-purpose agent useful for pain caused by a number of different species. Rubbing alcohol (40-70% isopropanol) can be used as a substitute, although it may exacerbate nematocyst discharge in some species. After decontamination, topical anesthetics, antihistamines, or steroid lotions may be helpful. Narcotics may be necessary for persistent pain. Muscle spasms may respond to diazepam (2-5 mg titrated upward as needed) or IV 10% calcium gluconate (5-10 mL).

Vertebrates

Etiology: Many marine vertebrates including stingrays, scorpionfish (e.g., lionfish and stonefish), marine catfish, and horned venomous sharks are capable of envenomating humans.
Clinical features: Depend on the offending fish
- Stingrays: Inflict both an envenomation and a traumatic wound. The venom causes immediate, intense pain that peaks at 30-60 min and may last up to 48 h. The wound often becomes ischemic and heals poorly. Systemic effects can include weakness, dysrhythmias, hypotension, paralysis, and rare deaths.
- Stonefish: Because of the neuromuscular toxicity of the venom, stings may be life-threatening, and death may occur within 6-8 h. Local pain is immediate and intense and may last for days. Systemic effects are similar to those of stingray envenomations.

TREATMENT
Marine Vertebrate Envenomations Immerse the affected part immediately in nonscalding hot water (113°F/45°C) for 30-90 min or until there is significant pain relief. Repeated hot-water therapy may help with recurrent pain. Explore, debride, and vigorously irrigate the wound after local/regional anesthetics are given. Antivenom is available for stonefish and serious scorpionfish envenomations. In the United States, contact the nearest regional poison control center for assistance. Leave wounds to heal by secondary intention or to be treated by delayed primary closure. Update tetanus immunization. Consider empirical antibiotics to cover Staphylococcus and Streptococcus species for serious wounds or envenomations in immunocompromised hosts. Coverage should be broadened to include Vibrio species if the wound is primarily closed.