Poison Center, MacKay Memorial Hospital: Ciguatoxins Poisoning

2026年7月13日星期一

Ciguatoxins Poisoning

Substance Ciguatoxins (CTXs)

雪卡毒素，又名雪卡魚毒素或西加魚毒素。

Common names

Ciguatera toxins in 熱帶與亞熱帶的珊瑚礁魚類

Ciguatera fish toxins: resistant to cooking, freezing, drying, and gastric acid.

Ciguatoxins are potent marine neurotoxins produced by benthic dinoflagellates of the genera Gambierdiscus and Fukuyoa, which inhabit coral reef ecosystems in tropical and subtropical oceans. [1, 2]

Herbivorous reef fish ingest these microalgae, allowing the toxins to bioaccumulate and become progressively concentrated through the marine food chain. [1] Consequently, large predatory reef fish contain the highest toxin concentrations and are responsible for most cases of human poisoning.

Geographic Distribution

Ciguatera fish poisoning (CFP) is endemic in tropical and subtropical coral reef regions between approximately 35°N and 35°S, particularly in the Pacific Ocean, Caribbean Sea, and Indian Ocean. Increasing sea surface temperatures and coral reef disturbances associated with climate change have expanded the distribution of toxin-producing dinoflagellates, leading to a gradual increase in CFP cases in previously unaffected regions.

Common Toxic Fish

Frequently implicated species include:

Barracuda (Sphyraena spp.)梭魚 [3].

Grouper (Epinephelus spp.)石斑魚 [4].

Coral trout (Plectropomus spp.)豹紋鰓棘鱸/珊瑚鱒 [5].

Snapper (Lutjanus spp.)笛鯛 [3].

Amberjack (Seriola spp.)琥珀魚/鰤魚 [6].

Moray eel (Gymnothorax spp.)裸胸鱔/海鰻 [7].

The liver, roe, intestines, and head generally contain higher toxin concentrations than skeletal muscle.

Involving System

Toxicity and mechanism

Ciguatoxins are lipid-soluble, heat-stable polyether compounds that activate voltage-gated sodium channels, causing persistent membrane depolarization and neuronal hyperexcitability. [8]

Several congeners have been identified, including Pacific (P-CTX), Caribbean (C-CTX), and Indian Ocean (I-CTX) ciguatoxins, with Pacific ciguatoxins (太平洋雪卡毒素) generally exhibiting the greatest potency. [9].

Gastrointestinal: Nausea; Vomiting, Abdominal cramps, Diarrhea [3, 10].

Neurological: Circumoral and distal paresthesia, Temperature sensation reversal (cold allodynia or cold–hot reversal), [10]

Presentation

Clinical Manifestations, Onset

Symptoms usually develop within 1–24 hours after ingestion of contaminated fish.

Musculoskeletal: Pruritus, Myalgia, Arthralgia, Weakness [10].

Dizziness, ataxia [10].

Neurological symptoms may persist for weeks to months and occasionally for years. [11].

Cold temperature reversal is a characteristic clinical feature.

Cardiovascular: Bradycardia, hypotension, cardiac conduction abnormalities (occasionally) [12].

Severe poisoning may require intensive supportive care.

Diagnosis is primarily clinical and relies on:

Recent consumption of tropical or subtropical reef fish [1]

Characteristic neurological findings, particularly cold temperature reversal

Compatible gastrointestinal and cardiovascular manifestations

Routine laboratory investigations are generally nonspecific. Specialized toxin detection using liquid chromatography–mass spectrometry (LC–MS/MS) is available only in selected reference laboratories. [13].

Antidote and Treatment

There is no specific antidote. Treatment is primarily supportive, with no established antidote.

Management consists of:

Airway, breathing, and circulation stabilization

Intravenous fluid replacement

Antiemetics and analgesics

Atropine for symptomatic bradycardia, [14].

Vasopressors for refractory hypotension

Intravenous mannitol has been reported to improve neurological symptoms when administered within 24–48 hours after exposure; however, clinical evidence remains inconsistent, and its routine use is controversial. Persistent neuropathic symptoms may be managed with gabapentin, pregabalin, or amitriptyline on an individual basis.

Disposition

Avoid consuming large predatory coral reef fish from endemic regions.

Do not consume fish liver, roe, intestines, or head.

Travelers to endemic tropical regions should be informed of the potential risk of ciguatera fish poisoning.

Ciguatoxins are heat-stable, lipid-soluble marine neurotoxins.

Poisoning results from eating contaminated coral reef fish rather than shellfish. [1]

Prevention through avoidance of high-risk reef fish remains the most effective strategy.

References

[1]. https://pubmed.ncbi.nlm.nih.gov/42301912/

[2]. https://pubmed.ncbi.nlm.nih.gov/40628156/

[3]. https://pubmed.ncbi.nlm.nih.gov/39997191/

[4]. https://pubmed.ncbi.nlm.nih.gov/41591150/