Case Definition: Tetrodotoxin

Clinical description

The consumption of toxic amounts of tetrodotoxin found in seafood such as puffer fish and blue ring octopus results primarily in neurologic and gastroentestinal signs and symptoms. In severe poisoning, dysrhythmias, hypotension, and even death may occur (1, 2). To meet the clinical description for tedrotoxin poisoning, rapid onset of the following signs and symptoms are needed: 1) oral paresthesias (may progress to include the arms and legs), 2) cranial nerve dysfunction, 3) weakness (may progress to paralysis), or 4) nausea or vomiting.

Laboratory criteria for diagnosis

• Biologic: No biologic marker for tetrodotoxin exposure is readily available.
• Environmental: A laboratory test exists for assessing tetrodotoxin levels in seafood, but its availability is limited.

Case classification

• Suspected: A case in which a potentially exposed person is being evaluated by healthcare workers or public health officials for poisoning by a particular chemical agent, but no specific credible threat exists.
• Probable: A clinically compatible case in which a high index of suspicion (credible threat or patient history regarding location and time) exists for tetrodotoxin exposure, or an epidemiologic link exists between this case and a laboratory-confirmed case.
• Confirmed: A clinically compatible case in which laboratory tests on environmental samples are confirmatory.

The case can be confirmed even if laboratory testing was not performed because either a predominant amount of clinical and nonspecific laboratory evidence of a particular chemical was present or the etiology of the agent is known with 100% certainty.

Additional resources

1. Sims JK, Ostman DC. Pufferfish poisoning: emergency diagnosis and management of mild human tetrodotoxication. Ann Emerg Med 1986;15:1094-8.
2. Torda TA, Sinclair E, Ulyatt DB. Puffer fish (tetrodotoxin) poisoning: clinical record and suggested management. Med J Aust 1973;1:599-602.
3. Cohen et. al. Public health response to puffer fish (Tedrotoxin) poisoning from mislabeled product. J Food Prot. 2009 Apr; 72(4):810-7.