tetrodoxina

Tetrodoxina, also known as tetrodotoxin (TTX), is a highly potent neurotoxin produced by certain marine bacteria and accumulated in a range of animals, most famously pufferfish. It is a small, heat-stable compound that can remain toxic even after cooking. The toxin occurs in various tissues, especially in the liver, ovaries, and skin of some species, and can be present in other marine organisms that accumulate it through the food chain.

Natural sources and distribution include pufferfish (fugu) and their organs, blue-ringed octopuses, and certain amphibians such as newts and some salamanders. The toxin is produced by symbiotic bacteria and concentrates within the tissues of these animals, enabling exposure through consumption or, less commonly, handling.

Mechanism of action: tetrodoxina binds selectively to voltage-gated sodium channels (Nav) on nerve and muscle membranes, inhibiting sodium influx and action potential propagation. This blocks neural signaling and muscle contraction, leading to numbness, weakness, autonomic changes, and potentially paralysis of the respiratory muscles.

Clinical features and course: symptoms typically begin within minutes to hours after ingestion and start with perioral numbness and paresthesias, followed by weakness, dizziness, and nausea. As the toxin progresses, dysarthria, diplopia, ataxia, and respiratory failure can occur. There is no fever or inflammatory response; the severity depends on the dose and the amount ingested.

Diagnosis and treatment: there is no antidote. Diagnosis relies on exposure history and clinical presentation, with laboratory confirmation possible in specialized settings. Management is supportive: protect the airway, provide oxygen or mechanical ventilation as needed, and monitor cardiovascular function. Activated charcoal may be considered if ingestion was recent.

Prevention and public health: risk is associated with traditional preparations of pufferfish in some countries. In many regions, pufferfish handling and preparation are restricted to licensed specialists to reduce the risk of poisoning.