A 41-year-old woman arrived in a Hawaii emergency department with her husband early in the morning. The nursing triage note indicated vomiting with dizziness and tingling in her hands.

History revealed the patient and four family members had eaten fish for dinner, an 18-inch grouper. Her husband reported she had had similar symptoms about five years prior to this situation, also after eating fish. The patient was the only family member to eat the head of the fish. The island of Oahu had experienced extremely heavy rainstorms the week prior.

Initial vital signs were: temperature of 36.8 degrees Celsius (98.2 degrees Fahrenheit), pulse of 57, respiratory rate of 18, blood pressure of 106 over 57. Physical examination was remarkable for a tired and uncomfortable appearing woman. Sensation in the hands was intact, with no discernible abnormalities related to touching a cold surface. An EKG was performed on arrival, showing no abnormalities. The patient was treated with droperidol for nausea, which cured the vomiting. One hour later, heart rate decreased to 42 and the blood pressure dropped to 80 over 45. One liter of saline was given. Labs were unremarkable. Blood pressure improved with the saline bolus. The patient felt better and was discharged at 7:30 a.m. with instructions related to avoiding future exposure.

Ciguatera fish poisoning, a foodborne illness caused by consuming reef fish contaminated with ciguatoxins, is characterized by a combination of gastrointestinal, neurological, and cardiovascular symptoms. It is more common in tropical areas. The World Health Organization estimates that between 50,000 and 500,000 people are affected by ciguatoxin yearly, indicating that reporting is limited.¹ Ciguatoxins are difficult to detect and quantify: They are odorless, tasteless, heat stable, and present at very low levels in contaminated seafood.¹ Friedman and colleagues indicate regional levels of risk.³ If water temperatures continue to rise, the distribution of ciguatera poisoning may change.

The triage note for this patient offered a clue to the cause of the vomiting: altered sensation in the hands. Cold allodynia—the sensation that cold things feel hot to the touch is nearly pathognomonic for ciguatera poisoning.¹ The patient indicated that washing her hands in cold water felt strange.

Grouper are among the species of fish commonly associated with ciguatera. The local marine ecosystem, especially after heavy rains, can foster the growth of the microalgae that produce ciguatoxins. These toxins are then bioaccumulated up the food chain, from smaller fish to larger predatory reef fish like groupers. The most common species implicated in ciguatera poisoning include barracuda, grouper, snapper, wrasse, moray eel, and parrotfish.² The toxicity of fish can be dependent on the species, size, seasonal variations, water temperature, and location.