Tetrodotoxin Toxicity Workup

Updated: Aug 09, 2021
  • Author: Theodore I Benzer, MD, PhD; Chief Editor: Asim Tarabar, MD  more...
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Workup

Laboratory Studies

No specific laboratory test that confirms tetrodotoxin ingestion exists; thus, dietary history is key for diagnosis.

Mouse bioassays for paralytic shellfish toxin (ie, saxitoxin) exist that are positive with tetrodotoxin. There are research chromatography techniques for tetrodotoxin as well; liquid chromatography–mass spectrometry (LC–MS) and liquid chromatography–tandem mass spectrometry (LC–MS/MS) are the most simple, powerful, and sensitive methods for qualitative and quantitative determination of TTX from human urine, blood, or other fluids. [13]  However, neither is available in the acute clinical situation. [14]

Measure routine serum electrolytes, calcium, magnesium, and ABGs to rule out metabolic causes of diffuse sensory and motor neuron dysfunction.

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Imaging Studies

Patients with evidence of cyanosis or respiratory insufficiency should have a chest x-ray to exclude local lung pathology (eg, aspiration pneumonia). Obtain a plain film and upright x-ray of the abdomen in patients with persistent vomiting or severe abdominal pain to exclude obstruction or hollow viscus perforation.

Perform a CT scan of the brain if the patient exhibits any focal neurologic dysfunction or seizures.

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Staging

The following is the classic grading system for tetrodotoxin poisoning based on symptoms and signs [8] :

  • Grade 1 - Perioral numbness and paraesthesia, with or without GI symptoms (mainly nausea)

  • Grade 2 - Numbness of tongue, face, and other areas (distal); early motor paralysis and incoordination; slurred speech; normal reflexes

  • Grade 3 - Generalized flaccid paralysis, respiratory failure (dyspnea), aphonia, and fixed/dilated pupils; patient still conscious

  • Grade 4 - Severe respiratory failure and hypoxia; hypotension, bradycardia, and cardiac dysrhythmias; unconsciousness may occur

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