Ciguatera poisoning: an unwelcome vacation experience.

married couple in their late 50s trav-eled to Costa Rica on vacation. They both dined frequently on local fish. While in the country , they developed nausea, vomiting, and diarrhea, with up to 10 bowel movements per day. These symptoms were followed by tingling of the extremities and a sensation of " pricking by pins and needles " that was exacerbated by the movement of air over the skin. In addition, they reported a peculiar feeling of migratory alternating hot and cold sensations of the limbs. Fatigue, photophobia, and the perception of flashing lights were also reported. The gastroin-testinal symptoms resolved after 1 week but other symptoms persisted for 3 months. After nonproductive visits to three different physicians, they sought additional consultation. Examinations were normal except for decreased vibratory and temperature sensation of the lower legs and hands. Their strength and reflexes were normal, as were results of a complete blood count, chemistry profile, sedimentation rate, urinalysis, and thyroid studies. Blood samples were sent to a research laboratory at the Wilmington. Microarray analysis for gene expression at both laboratories reported markers that were similar to samples from other patients with clinical diagnoses of ciguatera poisoning. Amitriptyline was prescribed, and symptoms progressively diminished over a 3-week period, more so for the female than for the male. Their symptoms were still present 3 months after the institution of treatment but were minimal. DISCUSSION Ciguatera fish poisoning is caused by Gambierdiscus toxicus, the most common marine toxin on our planet. It is frequently unrecognized and misdiagnosed. At least 50,000 people per year are estimated to develop the disease, and this number is thought to represent only a fraction of actual cases. The Centers for Disease Control and Prevention estimated that only 2% to 10% of ciguatera cases are reported. G. toxicus is found in association with algae that grow on coral reefs. Smaller herbivore fish acquire the toxin as they eat the algae. The toxin concentrates as it moves up the food chain when smaller affected fish are eaten by larger ones. Most cases in humans come from the consumption of large barracuda, grouper, amberjack, and marlin (Figure). Ingestion of barracuda fish is the most cited cause in the medical literature. None of the mentioned fish contain the toxin consistently. Contamination is dependent upon the presence of the toxin in the feeding waters, and this varies by location and also over time in …