Tetrodotoxin-induced involuntary movements: a case report

Background: Tetrodotoxin (TTX) is a potent neurotoxin found in pufferfish that blocks voltage-gated sodium channels and leads to flaccid paralysis. Although its effects are typically limited to the peripheral nervous system, rare central neurological manifestations may be under-recognized. Case: A 70-year-old male presented to the emergency department approximately 10 h after consuming pufferfish stew. The initial symptoms included slurred speech, facial weakness, and general fatigue without respiratory compromise. Vital signs and laboratory evaluations, including cardiac enzyme levels, blood gas analysis, and toxicology screening, were within normal limits. Brain computed tomography and electrocardiogramrevealed no acute abnormalities. Shortly after arrival, the patient developed progressive involuntary side-to-side head movements and repetitive swaying of the upper body. Comprehensive toxicological screening revealed negative results for other neurotoxins. Supportive care was administered and no antidotes were available. Over the course of 12 to 24 h, the involuntary movements gradually subsided and fully resolved by 48 h post-ingestion, with complete neurological recovery. Conclusion: This case report describes a rare presentation of tetrodotoxin poisoning involving involuntary motor activity, suggesting potential central nervous system involvement. This challenges the conventional understanding that tetrodotoxin toxicity is confined to the peripheral nervous system. Clinicians should be aware of such atypical features to ensure a timely diagnosis and appropriate supportive care.