Sea snakes are members of the elapid family of snakes that have evolved to survive in a variety of ocean habitats. There are over 70 species of sea snakes with the majority found in the tropical portions of the Indian and Pacific Oceans. Sea snakes are not found in the Atlantic Ocean or the Caribbean Sea. Most species of sea snakes live close to the coast, although there is a pelagic species, Pelamis platurus, that is found across a large swath of the Pacific Ocean. Reports vary regarding the docile nature of sea snakes. Some species have a much higher propensity to bite than others. Bites occur when the animal is disturbed or handled. There are many reports of bites occurring as fishermen are removing snakes from their nets. Because of the small size of the organism’s fangs, bites may be inconspicuous and are often painless. The majority of bites do not result in envenomation.
Sea Snake. The sea krait, seen here swimming free in the ocean, is very docile and rarely bites humans unless provoked. (Photo contributor: Ian D. Jones, MD.)
Sea Snake. A close-up view of a sea snake found feeding on a reef. (Photo contributor: Kevin J. Knoop, MD, MS.)
The most potent toxin in sea snake venoms, similar to other elapids, is a neurotoxin that competes for acetylcholine at the neuromuscular junction. Severe envenomations may ultimately lead to paralysis and respiratory failure. Additional components of the venom are myotoxic and may result in rhabdomyolysis and renal failure.
The symptoms of sea snake envenomation generally occur within 30 minutes of envenomation and may be quite variable. Common symptoms include confusion, headache, myalgias, and weakness of the facial muscles, followed by an ascending flaccid paralysis and, ultimately, respiratory arrest.
Management and Disposition
Treatment for a sea snake bite includes a combination of supportive care and the immediate administration of polyvalent sea snake antivenom. Supportive care should include intubation if indicated. The patient should also be carefully observed for signs of rhabdomyolysis and hyperkalemia. The patient should be aggressively hydrated to avoid further complications such as renal failure. A toxicologist or individual experienced in managing sea snake envenomations should be consulted.
An effective polyvalent antivenom exists and is effective against envenomation from all species of sea snakes.
In addition to respiratory support, victims of sea snake envenomation should be observed for the development of rhabdomyolysis and hyperkalemia.