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Tetrodotoxin is a neurotoxin that is found in pufferfish, like those served at fugu restaurants. Patients develop signs and symptoms within 30 minutes of ingestion, such as vomiting and diarrhea.

Tetrodotoxin exerts its neurologic effects by binding to and blocking fast voltage-gated sodium channels. These channels are needed for nerve impulses, and patients can develop paresthesias, paralysis, and decreased reflexes. Severe paralysis can cause respiratory arrest, which can be lethal.

Treatment is generally supportive, with intubation if respiratory function is impaired.

Find Tetrodotoxin and more Toxins among Pixorize's visual mnemonics for the USMLE Step 1 and NBME Shelf Exams.