Cone Snail

 First aid for cone snail sting is pressure-immobilisation.

The venom apparatus of a cone snail consists of a muscular venom bulb which forces venom down a long duct towards the radula sac, which contains up to 20 developing radula teeth. The chitinous tooth, which is shaped and barbed like a harpoon, is soaked in venom and held by the tip of the proboscis, which drives it into the prey. Venom is pushed along the hollow tooth to emerge at the tip. The venom consists of numerous small (12-30 amino acid), neurotoxic peptides, called conotoxins, as well as other toxins. The action of the toxins is shown in the table.

Signs and Symptoms

A sharp pain is felt initially, and the stung area may become swollen and pale or cyanotic. Numbness may follow the initial pain. Symptoms and signs of neurologic impairment including weakness, lack of co-ordination and disturbance of vision, speech and hearing may progress rapidly. Less common systemic symptoms include nausea and generalised pruritus. Severe envenomation may result in death secondary to respiratory paralysis within hours. Victims may experience weakness and numbness for several days to weeks afterward .

Treatment

In the event of a cone snail sting, pressure immobilisation first aid should be applied and left in place until resuscitation facilities are available, as assisted ventilation may be required. Several patients have recovered after a period of mechanical ventilation. There is no antivenom or other specific treatment for cone snail stings. The wound should be regarded as potentially contaminated, and tetanus prophylaxis should be updated if required. Infection may occur, and foreign bodies and marine micro-organisms should be considered. There is no antivenom available.