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.

Background: This study aims to verify whether the blood flow velocity and the diameter size, measured through intra-carotid artery Doppler measurements performed on sepsis patients visiting the emergency department, are useful as tools for predicting the risk of early death. Methods: As a prospective study, this research was performed on sepsis patients who visited a local emergency medical center from August 2021 to February 2023. The sepsis patients’ carotid artery was measured using Doppler imaging, and they were divided into patients measured for the size of systolic and diastolic mean blood flow velocity and diameter size: those measured for their qSOFA (quick sequential organ failure assessment) score and those measured using the SIRS (systemic inflammatory response syndrome) criteria. By measuring and comparing their mortality prediction accuracies, this study sought to verify the usefulness of blood flow velocity and the diameter size of the intra-carotid artery as tools to predict early death. Results: This study was conducted on 1026 patients, excluding 45 patients out of the total of 1071 patients. All sepsis patients were measured using systolic and diastolic blood flow velocity and diameter by Doppler imaging of the intra-carotid artery, assessed using qSOFA and evaluated using SIRS criteria. The results of the analysis performed to compare the mortality prediction accuracy were as follows. First, the hazard ratio (95% CI) of the intra-carotid artery was significant (p < 0.05), at 1.020 (1.004–1.036); the hazard ratio (95% CI) of qSOFA was significant (p < 0.05), at 3.871 (2.526–5.931); and the hazard ratio (95% CI) of SIRS showed no significant difference, at 1.002 (0.995–1.009). After 2 h of infusion treatment, the diameter size was 4.72 ± 1.23, showing a significant difference (p < 0.05). After 2 h of fluid treatment, the blood flow velocity was 101 m/s ± 21.12, which showed a significant difference (p < 0.05). Conclusions: Measuring the mean blood flow velocity in the intra-carotid arteries of sepsis patients who visit the emergency department is useful for predicting the risk of death at an early stage. And this study showed that Doppler measurement of the diameter size of the carotid artery significantly increased after performing fluid treatment after early recognition.