Bored Review and Something's Fishy

I have some great news. You’ve been working your little booty off all year, and it’s finally time for your much-needed vacation. This year you’re doing it right with a getaway to the far reaches of Caribbean where you will soak up sun, mai-tais, and delicious fresh food.

Finding Nemo Poster

On your second day, a few hours after eating an unbelievable meal cooked beach-side in a tiki-truck, you are preparing for a scuba dive to Hilmas Hooker when you suddenly start to feel nauseous with vomiting and crampy abdominal pain. You “Code Brown” your wet suit. You return to the hotel defeated and try to take a hot shower but it feels freezing cold, and you then develop painful paresthesias in your hands and painful gums…. What a vacation, eh?!

What gruesome affliction is currently ruining your one week of reprise from the insanity of residency: yersinia infection, scromboid poisoning, ciguatera poisoning, tetrodotoxin poisoning, or vibrio vulnificus infection? What fish is at fault here?

The answer is: CIGUATERA POISONING!

Caused by a reef toxin on algae-> that is eaten by little fish -> who are then eaten by big fish-> who are then eaten by you. These big fish are grouper, barracuda, snapper, king mackerel, sea bass, sturgeon, and some others. The toxin accumulates in the fish’s body without affecting them. It is HEAT STABLE so had nothing to do with how well you fry that fish.
Toxin affects sodium channels, classically causing first GI symptoms and then neurologic problems like temperature distortion (cold things feel painful and thus are sensed as hot), painful paresthesias and neuropathy, ataxia, vertigo, and in severe cases, altered mental status and coma.

What cardiac problem can result from this poisoning?

Bradycardia- In severe cases, treat with atropine.

What is the treatment?

Supportive care. Historically mannitol was used for severe neurologic deficits based on one old study, but a more recent and robust study shows no benefit and is not recommended.

You're back from your anticlimactic vacation and decide to have one last fishy feast before your shift tomorrow. You order swordfish and tuna tartar. What is the most common fish poisoning in the US that you have just ingested with this meal? What are the symptoms and treatment? What if you had just ordered your tuna tartar well-done?

Scromboid poisoning. Found also in bigger, dark-meat fish like tuna, mackerel, bonito, swordfish, mahi-mahi.
Toxin originates from normal bacteria on the fish producing histamine-like substances that trigger histamine-like reactions in us. Although the toxin is also HEAT STABLE (so enjoy your tartar), it’s formation is the result of improper refrigeration/ preservation of the fish that allows surface bacteria to continue producing histamine.
Symptoms are typical of a histamine reaction: redness/flushing, diarrhea, abdominal cramping, pruritus or urticaria, and throbbing headache.
Treat with anti-histamines– IV or IM diphenhydramine should do the trick.

References

Rosen’s Emergency Medicine, 8th ed. Craig SA. Chapter 92, Gastroenteritis.

Shout out to the educational inspiration of Schandra Singh who ate a bad barracuda recently and had her vacation ruined as above. Sorry dude.

And special thanks to Jimmy “King Mackerel” Willis for always schooling us fishes.