A 36‐year‐old man with no known medical history presented to a Georgia hospital after returning from a fishing trip to Florida complaining of severe watery diarrhea, perioral paresthesias, intense pruritis, dizziness, and chest pain. Symptoms were heralded by an episode of profuse vomiting that began hours after consuming wild‐caught barracuda. Three others with him consumed the same fish and experienced similar symptoms. Physical examination revealed marked orthostasis, an irregularly irregular pulse, diaphoresis, and diffuse abdominal tenderness. Laboratory studies were unremarkable. EKG revealed atrial fibrillation. While hospitalized, the patient remained orthostatic despite aggressive intravenous fluid resuscitation. He received loperamide and gabapentin for symptom management and underwent successful electrical cardioversion. By the fourth hospital day his diarrhea subsided and orthostatic hypotension improved. He was discharged home with intermittent pruritis and neuralgias. Florida health authorities performed liquid chromatography‐mass spectrometry analysis of the fish remains, which confirmed the presence of Caribbean ciguatera toxins 1 and 2.
Ciguatera toxin (CTX) poisoning is the most commonly reported marine toxin illness worldwide. CTX is a potent neurotoxin derived from bottom‐dwelling dinoflagellates of the genus Gambierdiscus. The toxin is found in high levels in certain reef‐dwelling carnivorous fish including barracuda, grouper, and red snapper and can cause gastrointestinal, neurological, and cardiovascular symptoms following ingestion. CTX binds to and activates voltage‐gated sodium channels, causing neural hyperexcitability. Acute gastroenteritis typically occurs within 12 hours of ingestion, followed by neurologic symptoms including paresthesias, pruritis, and reversal of hot/cold temperature sensation. Bradycardia is common, while hypotension occurs rarely but can be severe. Although atrioventricular block is commonly described, atrial fibrillation has not previously been reported. CTX exerts both cholinergic and adrenergic effects on the heart, and this patient's atrial fibrillation may be an example of the autonomic effects of the toxin.
Although ciguatera toxin poisoning is rarely seen in the United States outside of Hawaii and southern Florida, the increasing frequency of travel and wide distribution of fish products mandates that clinicians outside of endemic regions are able to identify the presenting symptoms of this condition. Clinicians should consider CTX poisoning in patients presenting with acute gastroenteritis following fish ingestion, especially in the presence of new‐onset neurologic abnormalities. Cardiovascular symptoms are less common but may include bradycardia, hypotension, heart block, and arrhythmias. Here we report the first documented case of CTX‐induced atrial fibrillation.
To cite this abstract:Cassidy L, Lofgren S, Thulasi P, Beer L, Dressler D. Something Fishy in Dixie. Abstract published at Hospital Medicine 2013, May 16-19, National Harbor, Md. Abstract 414. Journal of Hospital Medicine. 2013; 8 (suppl 2). https://www.shmabstracts.com/abstract/something-fishy-in-dixie/. Accessed March 28, 2020.