Emergency Doc: Mr. Simpson, if in fact you've consumed the venom of the blowfish, and from what the chef has told me, it's quite probable, you have 24 hours to live.
Homer Simpson: 24 hours!
Emergency Doc: Well, 22. I'm sorry I kept you waiting so long. - The Simpsons
When a local Chicago sushi restaurant started serving fugu (blowfish) this winter, our toxicology group of course scheduled a gala dinner to enjoy a very close encounter with this much-discussed but rarely tasted delicacy.
Some in our group initially were reluctant to sample the dish, pointing out that blowfish poison — tetrodotoxin (TTX) — was the most potent nonprotein toxin in nature, hundreds of times more deadly than an equivalent weight of cyanide. An average-sized blowfish has, in fact, enough TTX to kill 30 adults.) Because TTX is heat-stable, they feared that even if we avoided the traditional raw sashimi preparation (fugu-sashi) we wouldn't stand a chance.
And because they knew that TTX blocks voltage-gated sodium channels (especially at the nodes of Ranvier), impairing saltatory conduction in the sensory and motor myelinated nerves, they could vividly picture the possible clinical aftereffects of our dinner: numbness and tingling around the mouth and tongue followed by more general paresthesias, lower extremity weakness progressing to an ascending paralysis that would quickly involve muscles of respiration, and finally respiratory arrest and death.
We wouldn't, they pointed out, even have the 24 hours promised to Homer Simpson. Typically the initial symptoms begin within 15 to 30 minutes of ingestion, and move predictably and rapidly through the classic four stages of TTX poisoning. (See table.) Without treatment, respiratory paralysis usually occurs within four to six hours.
I countered with the inspiring words of Kitaoji Rosanjin (1883–1959), the great Japanese ceramist and chef: “The taste of fugu is incomparable. If you eat it three or four times, you are enslaved. … Anyone who declines it for fear of death is really a pathetic individual.”
I went on to outline how restrictions imposed by the Food and Drug Administration governing the importation of fugu are probably even more stringent than immigration rules enforced by the Department of Homeland Security. All the fish have to come from a single market in the city of Shimonoseki, Japan, where it is prepared and approved by licensed sushi chefs who have survived a two- to three-year training program in all things fugu. Because each chef prepares and eats the dishes for his final examination, the grading system really is pass/fail.
Removing the Poison
The chefs in Shimonoseki carefully remove the poisonous organs of the fish — gonads, liver, intestine, skin — then freeze and ship the remaining tasty parts to the U.S. All fugu imported into this country has to be inspected and approved by experts at JFK Airport in New York. And as a last layer of protection, two of the sushi chefs at the restaurant where we'd be dining were board-certified in fugu, having completed the same rigorous training program as the chefs in Japan. Clearly, the regulation of the preparation and distribution of fugu is remarkably effective. Although a number of people die each year in Japan and other parts of Southeast Asia from TTX poisoning, most if not all of these cases involve untrained individuals who catch and prepare the blowfish themselves without really knowing what they're doing.
I also argued that fugu poisoning is not the absolute death sentence many believe it to be. In fact, it's usually quite treatable. While at this point there's no specific antidote — although interesting data from animal models suggest that monoclonal antibodies may be beneficial — general toxicological supportive care is usually life-saving. Early gastric lavage and activated charcoal, if indicated, may decrease systemic absorption of TTX. Some authors suggest lavage with 2% sodium bicarbonate because TTX becomes less stable in an alkaline medium. There is, however, no clinical evidence indicating that this would give added benefit to lavage with normal saline.
Even if respiratory failure ensues, most patients recover completely after two or three days on artificial ventilation. Fortunately for us, one of our toxicology colleagues was on duty in a nearby emergency department on the evening of our dinner, and knew full well that victims of severe TTX toxicity can present with fixed and dilated pupils, have no corneal and other brainstem reflexes, and yet be perfectly well 72 hours later. He promised not to declare us brain-dead prematurely.
Finally, the appointed night arrived, and our group entered the restaurant and was greeted by the sushi chef. We immediately ordered a round of Fugu Hire-zake, blowfish fins fried and served in hot sake. It was delicious. The lingering smokiness of the fried fin contrasted nicely with the sweet flowery warmth of the sake. The next variation, Fugu-nabe (fugu hot pot), was even better. Raw fugu on the bone was simmered in a mild broth with lotus root, enoki, shiitake and shimeji mushrooms, tofu, green onion, turnip, and fish cake, then dipped in a mixture of ponzu sauce, chives, and minced daikon radish. The dish had an earthy, complex flavor probably more due to the vegetables than to the fish. After all the solids had been consumed, the chef took the remaining liquid and mixed it with rice and an egg; the resulting porridge was a perfect finale to the dinner.
By the end of the meal, I was an avid fugu fan. I developed no symptoms at all, except for some mild tingling on the tongue while sipping the Fugu Hire-zake. I decided this was an effect of the sake, not TTX. And I could agree with the words of the ancient Japanese verse: “Those who eat fugu soup are stupid, but those who don't eat fugu soup are also stupid.”
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