Morning Report: 3/8/2013 - The Original Kings of County

Here’s Dr. Basile with today’s Morning Report!

Ciguatera Poisoning

– One of the most common reported forms of vertebrate fishborne poisonings in the United States (more than half of the reported cases)

– Endemic to warm-water, bottom-dwelling shore reef fish living between 35 degrees south and north latitude (Indian Ocean, South Pacific, Caribbean, etc.)

– 90% of all cases in the US are reported in Hawaii and Florida (May through August)

– Most common fish are barracuda, sea bass, parrot fish, red snapper, grouper, amber jack, kingfish, and sturgeon (large size)

– 50,000 cases are reported worldwide annually

– 5-70 cases per 10,000 in the US in ciguatera-endemic areas

– It is believed to be underreported (only 2-10% of cases reported)

Ciguatoxin:

– Found in blue-green algae, protozoa, and free algae dinoflagellates

– These are nutritional source for smaller herbivorous fish which are then the food source for the larger carnivorous fish–> increases the ciguatoxin concentrations

– Heat stable, lipid soluble, acid stable, odorless, and tasteless

Humans:

– Binds to voltage-sensitive sodium channels

– Causes a shift in the voltage dependence of channel activation, which opens the sodium channel leading to depolarization and action potentials (alters the voltage necessary for depolarization)

– One of the most potent natural substances known –> risk at low concentrations (0.08-0.1 ug/kg)

– Can be afflicted after eating fresh or frozen fish that was prepared by boiling, baking, frying, stewing, or broiling

– Appearance, taste, and smell unremarkable

Symptoms:

– Majority of symptomatic episodes begin 2-6 hours after ingestion, 75% within 12 hours and 96% within 24 hours

– Cardiovascular and Neurologic symptoms can last for several days to weeks

– No documented deaths in the US, but deaths have been reported internationally due to respiratory paralysis and seizures (Severe dehydration or cardiovascular collapse also possible)

– Eating fish organs or viscera is associated with more severe toxicity (higher concentration)

GI:

– Abdominal pain with cramps, nausea, vomiting, profuse watery diarrhea

– Develop within 6-24 hours and usually resolve spontaneously within 1-4 days

Cardiovascular:

– Bradycardia and orthostatic hypotension

Neurologic and Neuropsychiatric:

– Most characteristically is reversal of temperature discrimination

– Peripheral dyesthesias and paresthesias predominating

– Sensation of loose or painful teeth, watery eyes, tingling, metallic taste

– Numbness of tongue, lips, throat, and perioral area

– Myalgias, arthralgias, ataxia, weakness, vertigo, seizures, and visual disturbances

– Anxiety, depression, subjective memory loss, hallucinations, giddiness

Treatment:

– Supportive care (IVF, electrolyte replacement, pressors, mechanical ventilation)

– Elimination of toxin is accelerated if vomiting and diarrhea have occurred

– Bradycardia with atropine and/or cardiac pacing

– Mannitol for neurologic and muscular symptoms (Controversial if it works and can cause hypotension)–> thought to work by osmotic reduction of neuronal edema, scavenger of free radicals produced by the toxin, and reduction in the action of the toxin at the channel

– Inconsistency in the literature about the effectiveness, but there does seem to be some benefit

– Mannitol only recommended if fish was consumed within 48-72 hours

– For chronic symptoms SSRIs may help

– Should avoid dehydration for 3-6 months until all symptoms have resolved as dehydration worsens symptoms

– Should avoid alcohol and particular foods (caffeine, nuts, chicken, pork) for 3-6 months if exposure worsens or causes recurrence symptoms (based on anecdotal information)

References:

Centers for Disease Control and Prevention Cluster of ciguatera fish poisoning in North Carolina, 2007. MMWR Morb Mortal Wkly Rep. 2009;58:283–285.

Friedman MA, Fleming LE, Fernandez M, Bienfang P, Schrank K, Dickey R, et al. 2008. Ciguatera fish poisoning: treatment, prevention and management. Mar Drugs 6:456–479.

Tunik MG. Chapter 45. Food Poisoning. In: Hoffman RS, Nelson LS, Goldfrank LR, Howland MA, Lewin NA, Flomenbaum NE, eds. Goldfrank’s Toxicologic Emergencies. 9th ed. New York: McGraw-Hill; 2011. http://www.accessemergencymedicine.com/content.aspx?aID=6513232. Accessed December 19, 2012.

The views expressed on this blog are the author's own and do not reflect the views of their employer. Please read our full disclaimer here. Any references to clinical cases refer to patients treated at a virtual hospital, Janus General Hospital.

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Jay Khadpe MD

Editor in Chief of "The Original Kings of County" Assistant Professor of Emergency Medicine Assistant Residency Director SUNY Downstate / Kings County Hospital