Class: Asteroidea

Crown-of-Thorns Starfish (Acanthaster planci)

Location: Indo-Pacific Ocean, Red Sea, east coast of Africa, and west coast of Central America

Appearance: A central disk with radiating arms (usually more than 15–20 arms), densely covered with spines. Adults are often dull brown to green colored (although some have bright colors to warn predators) and normally range from 9–14 inches in diameter.

Pathophysiology and Symptoms: Spines pierce the skin and cause severe pain (usually lasting ≤3 hours) with local inflammation. The spines are coated with a slime that is extremely toxic and, in severe cases, can cause paralysis, hemolysis, and hepatotoxicity. Additional symptoms include paresthesias, nausea, vomiting, and secondary infection.

Management: Same as Echinoidea/sea urchins (see above).

Phylum: Porifera

Class: Demospongiae

Fire Sponge (Tedania ignis), Poison-Bun Sponge or Touch-Me-Not Sponge (Neofibularia nolitangere), Red Moss or Red Beard Sponge (Clathria prolifera), and Australian Stinging Sponge (Neofibularia mordens)

Location: Worldwide

Pathophysiology and Symptoms: These sponges produce crinotoxins (dermal irritants) that cause a maculopapular rash with local edema, bullae formation, paresthesias, and possible joint swelling that resolves spontaneously in approximately seven days. More severe reactions may cause fevers, chills, fatigue, nausea, and myalgias with delayed immunologic responses that manifest as erythema multiforme or dyshidrotic eczema. Additionally, sponges may also be colonized with Cnidaria species and cause a necrotic skin reaction (ie, sponge divers’ disease).² Note: Rewetting a dried sponge can cause it to regain its toxicity, even after several years.

Management: Control pain with vinegar. Topical steroids and oral anthistamines are used for mild symptoms, and oral steroids for erythema multiforme or dyshidrotic eczema.^2–4

Phylum: Chordata

Subphylum: Vertebrata

Family: Elapidae

Subfamilies: Hydrophiinae and Laticaudinae

Stokes’ Sea Snake (Astoria stokesii), Beaked Sea Snake (Enhydrina schistose), and Yellow-Bellied Sea Snake (Pelamis platurus)

Location: Indo-Pacific Ocean (as far north as San Diego, Calif.), Central and South America

Appearance: Variable appearance. All species are venomous and deliver their venom via a set of small front fangs.

Pathophysiology and Symptoms: Initially, symptoms include a painless or mildly painful bite with local inflammation. However, this can rapidly progress to rhabdomyolysis, hemolysis, cardiac dysrhythmias, renal failure, hepatic failure, seizures, and ascending paralysis with subsequent respiratory failure within minutes to hours. Additional symptoms include cranial nerve abnormalities (eg, dysphasia, dysphagia, ptosis), nausea, and vomiting.

Management: A broad laboratory workup with serial measurements should be undertaken, including complete blood count, chemistry panel, creatine phosphokinase, liver function tests (transaminitis is seen in severe toxicity), and urinalysis. Pressure immobilization (not tourniquets) of an affected extremity should be performed. Supportive care, including IV fluids, and observation for at least eight hours is indicated.⁵ Multiple antivenoms are available though no evidence suggests any one preferred agent—if you have antivenom, give it. Antivenoms include:

1. CSL sea snake antivenom: Administer one to three vials (1,000 units per vial) for any evidence of envenomation (with a 1:10 dilution (1:5 for small children) with 0.9% sodium chloride given via IV over 30 minutes). It is reported that up to seven vials have been safely administered.⁶
2. Terrestrial tiger snake antivenom: Effective for all sea snakes. Administer one vial (3,000 units).
3. Thai neuro polyvalent antivenom (NPAV): Effective for beaked sea snake or spine-bellied sea snake.