Introduction
Background
Octopuses, which are organisms of the class Cephalopoda in the phylum Mollusca, are generally harmless and unlikely to be aggressive unless provoked.
Their bites are rarely life threatening, except for the bite of the greater blue-ringed octopus, Hapalochlaena lunulata and the southern blue-ringed octopus (also known as the Australian spotted octopus) Hapalochlaena maculosa, which are found in coastal waters and tide pools around Australia. A third species, the blue-lined octopus Hapalochlaena fasciata, has also been described. These octopuses grow up to 20 cm in length with tentacles extended. They are normally light-colored with dark brown bands and blue rings or patches. When disturbed, their bodies darken, and the blue circles turn iridescent blue. Their venom can be released into the water to paralyze their prey, but its effects on humans primarily occur by injection of the venom upon biting.
Pathophysiology
There are many fractions in the venom secreted from the salivary glands of the blue-ringed octopus, one of which is identical to tetrodotoxin. This substance blocks voltage-gated fast sodium channel conduction, blocking peripheral nerve conduction, which can lead to paralysis and death from respiratory failure. Nerve conduction studies in tetrodotoxin-poisoned (puffer fish) persons have demonstrated reduced motor and sensory conduction velocities consistent with inhibition of sodium currents at the node of Ranvier. Reported central nervous system effects of tetrodotoxin in humans have included nausea and emesis, miosis, diabetes insipidus, and depressed cortical activity.
Other fractions of the venom include 5-hydroxytryptamine, hyaluronidase, tyramine, histamine, tryptamine, octopamine, taurine, acetylcholine, and dopamine.
Frequency
United States
The blue-ringed octopus does not naturally dwell in the coastal waters of the US.
International
Rare cases of octopus envenomation occur in the Indo-Pacific region.
Mortality/Morbidity
Mortality is rare. Full recovery is expected when appropriate measures are undertaken.
Age
Individuals bitten by a blue-ringed octopus would have to be old enough and mobile enough to be able to walk or swim in the tide pools and coastal waters of Australia.
Clinical
History
Any octopus can bite with its parrot-like chitinous beak.
- The bite of the blue-ringed octopus is usually painless; however, the individual may experience a reaction similar to a bee sting.
- If envenomation has occurred, symptoms are likely to start within 10 minutes of being bitten.
- If a significant envenomation has occurred, the individual will rapidly progress from perioral and peripheral paresthesias through the following signs and symptoms.
- Nausea and vomiting
- Blurred vision
- Ataxia
- Muscle paralysis
- Respiratory failure, which may lead to cardiac arrest and death
- Anaphylactoid or anaphylactic reactions have rarely been reported.
Physical
- The individual is usually bitten on an extremity and sustains 1-2 small puncture wounds.
- Local reaction may be minimal, but it can progress to include pain, edema, and erythema of the entire extremity.
- The patient becomes flaccid once paralyzed.
Causes
Envenomations usually occur when an individual picks up a blue-ringed octopus or accidentally steps on one.
More on Octopus Envenomation |
 Overview: Octopus Envenomation |
| Differential Diagnoses & Workup: Octopus Envenomation |
| Treatment & Medication: Octopus Envenomation |
| Follow-up: Octopus Envenomation |
| Multimedia: Octopus Envenomation |
| References |
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References
Auerbach PS. Marine envenomations. N Engl J Med. Aug 15 1991;325(7):486-93. [Medline].
Chang FCT, Spriggs DL, Benton BJ, et al. 4-Aminopyridine reverses saxitoxin (STX)- and tetrodotoxin (TTX)- induced cardiorespiratory depression in chronically instrumented guinea pigs. Fundam Appl Toxicol. Jul 1997;38(1):75-88. [Medline].
Flachsenberger WA. Respiratory failure and lethal hypotension due to blue-ringed octopus and tetrodotoxin envenomation observed and counteracted in animal models. J Toxicol Clin Toxicol. 1986-87;24(6):485-502. [Medline].
Kizer KW. Marine envenomations. J Toxicol Clin Toxicol. 1983-84;21(4-5):527-55. [Medline].
McGoldrick J, Marx JA. Marine envenomations. Part 2: Invertebrates. J Emerg Med. Jan-Feb 1992;10(1):71-7. [Medline].
Nimorakiotakis B, Winkel KD. Marine envenomations. Part 2--Other marine envenomations. Aust Fam Physician. Dec 2003;32(12):975-9. [Medline].
Oda K, Araki K, Totoki T, et al. Nerve conduction study of human tetrodotoxication. Neurology. May 1989;39(5):743-5. [Medline].
Walker DG. Survival after severe envenomation by the blue-ringed octopus (Hapalochlaena maculosa). Med J Aust. Dec 10-24 1983;2(12):663-5. [Medline].
Watters MR, Stommel EW. Marine Neurotoxins: Envenomations and Contact Toxins. Curr Treat Options Neurol. Mar 2004;6(2):115-123. [Medline].
Further Reading
Keywords
octopus envenomation, octopus poisoning, octopus bite, blue-ringed octopus envenomation, Hapalochlaena lunulata envenomation, Hapalochlaena maculosa envenomation, Cephalopoda, Mollusca
