Tetrodotoxin Toxicity Clinical Presentation

Updated: Aug 09, 2021
  • Author: Theodore I Benzer, MD, PhD; Chief Editor: Asim Tarabar, MD  more...
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The first symptoms occur 15 minutes to several hours postingestion of tetrodotoxin-containing food; however, initial symptoms have been reported to occur up to 20 hours after ingestion. Initial symptoms include lip and tongue paresthesias, followed by facial and extremity paresthesias and numbness. Salivation, nausea, vomiting, and diarrhea with abdominal pain develop early.

Motor dysfunction with weakness, hypoventilation (may be from dysfunction of central and peripheral nervous systems), and speech difficulties then develop. A rapid ascending paralysis occurs over 4-24 hours. Extremity paralysis precedes bulbar paralysis, which is followed by respiratory muscle paralysis. Deep tendon reflexes are preserved early in the course of paralysis.

Finally, cardiac dysfunction with hypotension and dysrhythmias (bradycardia), central nervous system (CNS) dysfunction (eg, coma), and seizures develop. Patients with severe toxicity may have deep coma, fixed nonreactive pupils, apnea, and loss of all brain stem reflexes.  Death can occur within 4-6 hours. Typically, death occurs from respiratory muscle paralysis and respiratory failure.



Physical Examination

Loss of sensory and motor neuron function and ascending paralysis with respiratory depression are prominent findings. Cyanosis occurs with respiratory failure. Hypotension can occur with myocardial dysfunction. Cardiac rhythm disturbances, especially bradycardia, at ntricular (AV)–nodal block, and bundle-branch block, can be life threatening. GI effects are not prominent, but vomiting, diarrhea and abdominal tenderness can occur.