Ciguatera

Background

• Foodborne illness caused by eating reef fish that have concentrated ciguatoxin
• Barracuda and moray eel are classic, but also amberjack, grouper, snapper, and parrotfish, and, rarely, farm-raised salmon

Pathophysiology

• Gambierdiscus dinoflagellates that live on or around coral make ciguatera toxin, which concentrates in the fish
• Toxin is heat-stable, acid-stable, and lipid-soluble

Clinical Manifestations

• Incubation period of 3 to 6 hours (range up to 30 hours)
• Can present with a variety of symptoms, including gastrointestinal, neurologic, and cardiovascular
• GI symptoms develop within 3 to 6 hours, and include nausea, vomiting, diarrhea, and abdominal pain
  • Can take up to 4 days to resolve
• Cardiovascular symptoms develop within a few hours, and include bradycardia, heart block, and hypotension
  • Can take up to 4 days to resolve
• Neurological symptoms develop within 3 to 72 hours of ingestion, and include hot-cold reversal, cold allodynia, and paresthesias
  • Can last for weeks to months in a minority of cases
• Concomitant alcohol consumption portends a higher risk of developing bradycardia, hypotension, and altered sensation

Investigations

• Mouse bioassay is the gold standard but not often done

Management

• Management is supportive
• Mannitol, gabapentin, amitriptyline, and pregabalin are sometimes used for the neurological symptoms