Approach

Initial management of cases of marine toxin exposure requires clinical recognition, frequent re-assessment, and supportive management. Confirmation can be made through the identification of toxin in the flesh of shellfish or fish, or in the blood or urine of people exposed to marine toxins.[29] Marine toxin exposure carries a significant risk of public health impact. Most governmental agencies require reporting of suspicious cases to the appropriate public health authorities for investigation and control of further exposure.[28][32][33] 

Observation and supportive care

In general, the acute intoxication period occurs within the first 24 to 48 hours. It is during this time that the risk for acute decompensation and respiratory failure seems to be at its highest. In all patients, management requires close observation for several hours, and evaluation and monitoring of weakness, paralysis, and adequacy of ventilation. If no symptoms develop within 6 hours of exposure, expert opinion suggests that patients can be discharged with strict return precautions.[34] If a patient develops any symptoms, they should return to hospital quickly and they should be monitored for at least 24 hours.

Supportive care is the mainstay of management of marine toxin exposure. Several marine toxins have been shown to block voltage-gated sodium channels and to produce rapidly progressive neurological deterioration, paralysis, loss of airway control, and loss of ventilation. Predictors of the severity of neurological toxicity have not been identified.

Suspected or confirmed cases of marine toxin poisoning should be assessed and monitored for adequacy of airway-protective reflexes (gag and cough), control of oropharyngeal secretions, adequacy of oxygenation, and adequacy of ventilation.[14]

Airway control and mechanical ventilation should be considered for any patient with upper airway compromise (from pharyngeal muscle paralysis), progressive paralysis, or a decline in ventilation. Gastrointestinal decontamination with activated charcoal may reduce the absorption of toxins and could reduce the severity of poisoning if used soon after ingestion.[35] Gastric lavage is rarely done in clinical practice for marine toxin poisoning, and there is a lack of evidence to support its use in this situation. One case report of a uraemic patient with tetrodotoxin poisoning who improved following haemodialysis may indicate the potential benefit of dialysis for patients with renal failure or severe prolonged toxicity.[36] 

There are currently no available effective antidotes for these marine neurotoxins. Some case reports of tetrodotoxin poisoning describe a potential positive effect of anticholinesterase drugs in reversing neuromuscular paralysis, but a more recent review found no clear evidence of benefit.[37] 

Pressure and immobilisation of limb (blue-ring octopus bite/cone snail sting)

In cases of blue-ring octopus (tetrodotoxin) bite or cone snail (conotoxin) sting, treatment should include first aid with pressure and immobilisation of the affected limb.[38][39] 

Adults and children who have not received a tetanus booster within the past 5 years should receive tetanus prophylaxis for all marine toxin envenomation wounds.[40]

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