February 7th, 2013

Ciguatera Is Hot (But It Could Be Cold)

The news about the cases of ciguatera fish poisoning in New York (NY Times here, MMWR here) reminded me of several unusual things about this form of “harmful algal bloom,” as it is so artfully called by the experts.

Specifically, here are six:

  1. Symptoms are bizarre.  It starts out like a standard case of gastroenteritis — nausea and vomiting — but since ciguatera is a neurotoxin, here’s some of the weird stuff that follows: tingling, numbness, bradycardia, hypotension, muscle cramps, tooth pain, and most famously, “paradoxical dysesthesias”, where cold feels hot and hot feels cold. You ask 100 ID doctors about that last symptom, and 99 will shout, CIGUATERA! Just don’t do it in a crowded room.
  2. We can’t detect it. Vegetarian fish ingest the ciguatera toxin by eating algae off of seaweed and coral reefs; it’s then further concentrated inside larger fish (barracuda, grouper, snapper, amberjack, and surgeonfish) when these little fishies are eaten. (Don’t blame the big fish — this is what fish do — see image.) The problem is that the neurotoxin is odorless and colorless; fish with ciguatera toxin look and smell totally fine. Various folk remedies in Australia and the Caribbean (where ciguatera is common) have been proposed, including allowing cats to be our taste testers:  if a cat eats some of the fish and is fine afterwards, then we will be too.  Of course, this means adding a significant amount of time to your meal preparation — bad for work nights — and what if you don’t have a cat? Still, it sure beats the other method, which involves putting the fish in an ant pile, and seeing whether the ants avoid the fish — they apparently can tell. But would you want to eat the fish after it’s been in an ant pile? If you’re really worried, better get one of these gizmos, a Cigua-Check.
  3. We can’t prevent it.  The toxin is heat- and cold-stable; our stomach acidity doesn’t touch it either. This means that fish that are perfectly handled, look and smell fresh, and are then cooked appropriately still can have high levels of ciguatera toxin. Freezing, pickling, and marinating also do nothing. What other kind of food poisoning is so occult and so impervious to best practices? Scary!
  4. Treatment is “supportive.”  Beware any condition for which treatment is “supportive.” What this really means is that modern medicine is a lot like what it was several decades (OK, centuries) ago. We “support” the patient while he/she has nausea, vomiting, tingling, numbness, bradycardia, hypotension, muscle cramps, and tooth pain — and thinks that cold things are hot and hot things cold. No anti-toxin, no antibiotic, sorry. After a certain amount of time with this “support”, the patient slowly gets better, and we can take credit for it.
  5. The words are unfamiliar. We deal with bugs that have complicated names all the time, so barely bat an eye at Acinetobacter calcoaceticusbaumannii or parvovirus B19 or Diphyllobothrium latum. But the ciguatera toxin arises from marine dinoflagellates of the genus Gambierdiscus, specifically Gambierdiscus toxicus. What the heck is that?
  6. The ID boards are obsessed with marine toxins. Based on the number of practice board questions that deal with ciguatera, scombroid, and paralytic shellfish poisoning, you’d think that these conditions occur almost as frequently as the common cold. One way you can tell someone who is preparing for their ID boards is that they are suddenly experts on these weird diseases, casually mentioning scombroid as the possible cause of any sort of flushing, or red tide as the cause of diarrhea. Fortunately, this sort of diagnostic bias fades very quickly after taking the exam.

If the above six items are not enough, here’s a fun fact:  Nobel Prize-winning novelist Saul Bellow had a severe case of ciguatera poisoning, using it as a key plot line in his final novel Ravelstein. One critic actually credited the ciguatera illness as making Ravelstein his favorite Bellow novel and concluded by making a bold proposal:

It certainly seems to me that a number of American novelists could benefit from a cruise to the Western Caribbean of the sort Bellow took, and as many sumptuous seafood meals (red snapper and barracuda especially recommended) as necessary to raise the level of their art through a slightly less-than-lethal dose of cigua.

I suggest that they bring their cats.

24 Responses to “Ciguatera Is Hot (But It Could Be Cold)”

  1. Sarah Albee says:

    Great post. I love the “supportive” treatment protocol. But as your colleagues of centuries past “supported” their patients with bleeding, cupping, and blister poultices, we’re probably a bit better off today.
    What is paralytic shellfish poisoning????!!!!
    Off to boil up some lentils…

  2. Paul Sax says:

    Hi Sarah,

    1) Yes good point, “supportive” has improved.
    2) I am particularly fond of paralytic shellfish poisoning because the toxin is called “Saxitoxin.” More than you want to know in this paper.


  3. Loretta S says:

    Your posts make me wish I worked in ID. 🙂

  4. Wow! I’ve subscribed to Journal Watch for years, and this is absolutely the most entertaining post I’ve ever read there. You should go on the Colbert show, Paul! Thanks for brightening my day. Actually, you have also given me new purpose. I pwn horses – and thus a hay barn, and I’m having terrible problems with a stray male cat defiling the hay. With new hope, I am now on a mission to find some ciguatera. That cat has caused me way too much anguish. It’s pay back time!

  5. Paola says:

    Best entry ever in Journal Watch! Reading you was fun, informative and very memorable (with so many facts in medicine that we have to remember, that is a big compliment)
    Looking foward to reading more articles from you!

  6. Pat Pryor says:

    I would have be the one out of 100 that answered the question on paradoxical dysesthesias with “duh?”

  7. Mark Voysey says:

    Dear Barbara- are you American? Every animal that bothers you is not entitled to be the object of your homicidal rage. Use a few minutes of your obviously superior animal friendly brain time to find a less lethal, permanent cat deterent solution – adoption out, smell deterents, trap and release or taking the cat into your house (paradoxically!). This enriches the planet – not degenerates it – that’s what medicine is all about right?

  8. Rob Molyneaux says:

    @ Sarah: One correction for the first post: we still “bleed” patients. It’s just been relabeled as “labs.” 😉 Granted it’s supposed to be diagnostic, not as treatment. But the anemia is the same…..
    @ Barbara J.: Try tossing citrus peels around the hay. Cats hate the smell. I doubt the horses would care about “orange zest” in their hay.. Oranges are easier to find than ciguatera contaminated fish….

  9. Mark Drapkin says:

    You have outdone yourself, Paul. I’ll be on the lookout for folks staggering out of seafood restaurants and commenting on how hot they feel as blizzard Nemo hits Boston later today. Having been involved with composing ID recert board questions, I may be able to offer some insight as to why odd diseases are over-represented on the boards. Committee members who are super-experts in a field nix most questions in that field, since they are aware of weird exceptions to every rule. Since none of the members knows a thing about odd illnesses — just hit the textbooks, compose a question, and no one will argue. Paul, you are the best. Keep it up! Mark

  10. MD says:

    Just wanted to let you know again how much I appreciate the humor in your Journal Watch postings! The latest one is a hoot! I have always thought the toxin in the fish was in a specific section and not throughout, is that correct? Grouper is delicious. Have I deluded myself into thinking the chef knows what portion to remove from the fish with the toxin?

    Hope Snowmaggedon doesn’t produce any infectious diseases!

    • Paul Sax says:

      I don’t think chefs have those powers, unfortunately. But I do agree grouper is delicious. Seems that barracuda around tropical reefs are among the highest risk fish — that makes sense, given their place in the food chain!

  11. Robert Barker says:

    Since the symptoms are somewhat non specific, I would suspect that it occurs much more often than it is diagnosed. Are there any serologic studies available that would enable researchers to estimate the number of persons who have had exposure to ciguatera, but who may not have been I’ll or diagnosed?

  12. Susanna says:

    What an interesting post! I am not a doctor but my dad is a nurse practitioner and passed the link on to me.

    I live in the Virgin Islands and had a brush with ciguatera a few years ago. Most folks who live here have their own ‘fish poisoning’ story. I remember going to the local clinic where the doctor gave me a steroid injection (I think) that helped a great deal with my red, swollen and itchy face but I do agree that the ‘paradoxical dysesthesias’ was one of the oddest sensations I have ever experienced. My case was mild but I have known people to be hospitalised for 2 weeks with severe cases. I was home sick for about a week.

    Around here people who have had fish poisoning are advised not to eat any kind of seafood for 6 months or more after they get over the initial illness since apparently even non-infected fish can trigger a relapse if your body is not totally free of the toxins. Or at least that is what they say. It is also a common belief that ‘poison’ fish tastes unusually ‘sweet’, ie – good, which my experience bears out.

    There is a lot of folk wisdom around here about which fish poison and which don’t, and fishing areas which should be avoided because fish in those areas tend to poison. But I think that global warming will make it a bigger problem.

  13. Cathie Currie, Ph.D. says:

    Islanders try to tell scuba divers and sailors to not fish or kill barracuda, but many visitors ignore their ‘folk’ wisdom. The islanders say the predator has ‘bad flesh’ and that they are a diver’s friend.

    I had an approaching shark stop, then turned away from me, whilst I hyperventilated half my tank. At which point I became aware of a 5-foot+ barracuda swimming next to me, gnashing its vicious-looking teeth. Though fearsome, barracuda attacks on humans are generally targeted on bright shiny objects: rings, watches, diving belt buckles. Wise divers remove or scour/tape anything bright. Other divers have reported similar protections. Leave them be.

    Grouper and red snapper are so delicious . . .

    Do the cat-screeners recover?

  14. Rebeca Plank says:

    Cats, usually the suspects in any “unknown” ID case, could turn out to be the heroes of a Ciguatera caper!

  15. Timothy Lane,MD says:

    The Xenodiagnostic Cat:A fisherman presented with occular nerve palsies but oriented. The differential diagnosis was initally long and frightening until his wife offered that the family cat was found dead in the yard hours after eating the remainder of the husband’s bad tasting formerly fronzedn fish that he didn’t finish. Both needed only molecular doses of botulinum toxin to become ill. The cat gave his owner’s physicians a diagnostic shortcut. I have admired cats ever since and especially those that are willing to make the ultimate sacrifice.

  16. Michele H says:

    I am continuing to enjoy your blog, including this one! How about having the cat try a sample of the fish instead of the whole fish?

    And you know, I find that supportive care is not bogus, it actually saves people without complicated drugs, by preventing deadly cascades of organ damage.It’s amazing how much better people feel after a liter of iv saline when they are dehydrated…

  17. Marvin Rabinowitz says:

    My cat cannot tell me she confuses hot and cold.

  18. Carolyn says:

    Wish I could have found the blog amusing. I got the poisoning back in the 90’s from eating grouper at a restaurant in Blowing Rock, NC. There was an outbreak over the state because the smaller grouper off the coast of NC had been depleted by fishermen and distributers were supplying restaurants with large grouper from the warm coral reef waters further south. It is endemic among poor islanders and they know that it doesn’t always “go away with time”. The islanders know that a long lasting symptom (forever in some, me included) can be an extremely bothersome itching deep inside the toes, feet — triggered from then on by some amino acid in protein. I have to avoid fish, beans, nuts, etc. It can also be triggered by heat to the feet. When I lived in Fla. a friend almost died from eating some large Sea Bass in the islands. Many people in Fla. avoid eating grouper unless they know the fish is a small one.

  19. DP says:

    I LOVED your blog on ciguatera. Here is a funny discussion, which I found while trying to locate a place to purchase the kit: http://www.hawaiiskindiver.com/community/viewtopic.php?f=3&t=13050
    The comment reproduced below is found about 40% of the way up from the bottom of the page. Thought you might like to know.
    I was especially interested because I am a sometimes spearfisherman… (:o
    “Also, even if those “Ciguacheck” tests are beginning to restock, they are still a waste of money in my opinion. I talked to the guys running the Ciguatera Research Progam here at UH Manoa and they said that they tested those kits themselves and found them to be extremely inaccurate and told me that I would get better results flipping a coin to “test” whether or not a fish has cig than to use on of those tests. The Ciguacheck ones are only about 30% accurate that’s why as compared to a coin that is 50%. You do the math.”

  20. Paul Sax says:

    Carolyn, thanks for the helpful reminder that cigauatera can be a VERY serious condition — in fact, Saul Bellow nearly died from it! Hope our discussion here will alert people to avoid consuming risky fish.


  21. Amanda says:

    Hi everyone
    I have add ciguatera poisoning for two years. In and out of hospital still. Still can’t eat much or drink very little fluids. One cuppa tea a day, water is toxic foreign object to me! Got PEG-J feeding tube going straight into my small intestine so supportive tube feeding I need everyday by-passes my stomach . Pain and hot cold reversals is excruciating and wake up most days unable to walk. this is such an awful lonely disease. Wouldn’t wish it upon anyone or anything including stray cats. Been in the news abit to try and get the word out there about the dangers of eatting sub tropical and tropical fish. Doctors here in NZ know nothing about ciguatera so I have been a big learning curve for them. Hopefully someone else will benefit from what they have learned from my case. Look forward to anyone wanting to chat about this nasty toxin!
    Cheers Amanda

  22. Tracy says:

    I am so happy to have this blog site and to understand and know more about this horrible illness. 3 weeks ago while in Atlantis, Bahamas I ate a fillet Grouper and got ciguatera poisoning. I have never been so sick, numbness of the tongue, burning hands and of course all the sickness that goes with it!!. I am alarmed that this happens to people and I am still having reoccurring symptoms especially with the food that I eat.
    Has anyone any more suggestions about the foods to avoid and does anyone know a good doctor here in Houston that can help?

  23. Frank says:

    In the 1980’s I had a discussion with a bloke who worked for Queensland Health, about ciguatera poisoning. He told me that if you totally remove all bone from the fillets ( usually Spanish mackerel Don’t cut into steaks) before cooking you won’t have a problem, as the poison is specific to the fishes bones. Has this thinking been disproven or have I just been lucky.

HIV Information: Author Paul Sax, M.D.

Paul E. Sax, MD

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NEJM Journal Watch
Infectious Diseases

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