History and exam

Key diagnostic factors

common

presence of risk factors

Risk factors include shellfish or xanthid crab ingestion (saxitoxin); seafood ingestion or handling of blue-ringed octopus (tetrodotoxin); handling of cone snail shells (conotoxin).

oral numbness

Presenting symptom in all case reports of marine toxin exposure.

dysphagia

Presenting symptom in all case reports of marine toxin exposure.

dysarthria (common)

Presenting symptom in all case reports of marine toxin exposure.

nausea (saxitoxin, tetrodotoxin)

Presenting symptom in most case reports of shellfish and puffer fish poisoning.

vomiting (saxitoxin, tetrodotoxin)

Presenting symptom in most case reports of shellfish and puffer fish poisoning.

diarrhoea (saxitoxin, tetrodotoxin)

Presenting symptom in most case reports of shellfish and puffer fish poisoning.

weakness

Presenting symptom in all case reports of marine toxin exposure.

ataxia/incoordination

May be presenting sign of marine toxin exposure.

hypertension (saxitoxin)

Presenting sign in many case reports of shellfish poisoning.

extreme pain (conotoxin)

As a result of cone snail envenomation.

uncommon

hypotension or cardiovascular instability

May be a presenting feature of marine toxin poisoning.

Can be seen in all marine toxin poisonings if severe.

Other diagnostic factors

common

light-headedness/dizziness

May be a symptom in marine toxin exposure.

postural near-syncope/syncope

May be a symptom in marine toxin exposure.

anxiety

May be a symptom in marine toxin exposure.

uncommon

loss of airway-protective reflexes

Evidence of disease progression and need for airway control in cases of severe marine toxin poisoning.

loss of adequate ventilation

Evidence of disease progression and need for ventilation in cases of severe marine toxin poisoning.

hypoxia

Evidence of disease progression and need for oxygenation in cases of severe marine toxin poisoning.

bradycardia

Evidence of disease progression and impending cardiovascular collapse in cases of severe marine toxin poisoning.

apnoea

Evidence of disease progression and need for oxygenation and ventilation in cases of severe marine toxin poisoning.

ventricular dysrhythmias

Evidence of disease progression and impending cardiovascular collapse in cases of severe marine toxin poisoning.

Risk factors

strong

warmer waters

Global warming is expanding the risk of marine toxin exposure to historically unaffected regions.[2] Toxic algae blooms and key marine organisms require warm waters. As the temperature of the sea rises, the risk of marine toxin exposure increases.[22] 

shellfish ingestion (saxitoxin)

Shellfish poisoning, including paralytic shellfish poisoning from saxitoxin, occurs after shellfish consumption from contaminated bays.

xanthid crab ingestion (saxitoxin)

Saxitoxin poisonings can occur after consumption of crab later identified as a xanthid crab with saxitoxin-contaminated flesh.

seafood ingestion (tetrodotoxin)

Tetrodotoxin poisonings occur most often after consumption of fish later identified as puffer fish (Tetraodontidae) with contaminated flesh.

handling of blue-ringed octopus (tetrodotoxin)

Tetrodotoxin poisonings can occur from handling blue-ringed octopus, Hapalochlaena.

handling of cone snail shells (conotoxin)

Conotoxin poisonings occur most often from handling shells of the cone snail, Conus geographus.

exposure to toxins in research/laboratory settings

People who work with marine toxins in a research or laboratory setting should take adequate precautions.[23]​​

weak

bioterrorism

Saxitoxin, tetrodotoxin, and conotoxin have been highlighted by the US authorities as having the potential to pose a severe threat to public health and safety as possible agents for bioterrorism.[24]

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