Cigua Toxin Poisoning
Epidemiology
- Incidence: most common foodborne illness related to consumption of fish in US and worldwide
- Endemic Areas: Caribbean/Indo-Pacific areas (worldwide belt from 35 degrees north to 35 degrees south latitude)
- 90% of outbreaks are in Hawaii and Florida
- Incidence in Caribbean: 500-600 cases per 10,000 people
- Sporadic Outbreaks: have occurred in California/North Carolina/Vermont
Physiology
- Ingestion of Cigua Toxins in Contaminated Ciguatera Fish: toxin is produced by the Dinoflagellate plankton Gambierdiscus Toxicus
Most Common Associated Fish Species in US
- General Comments: >400 fish species have been implicated
- Most Cases Result from Consumption of Large Predatory Fish: these species concentrate the toxin in their organs/flesh, but are not affected by it
- Amberjack
- Barracuda
- Grouper
- Moray Eel
- Snapper
Fish Inspection and Toxin Stability
- Inspected Fish Cannot Be Identified by Screening: fish tastes, smells, and appears normal
- Toxins are Stable and are Not Destroyed by Cooking, Marinating, Freezing, or Stewing
Toxins
Ciguatoxin-1
- Heat-Stable: stable after freezing, salting, drying, smoking, and exposure to gastric acid
- Lipid-Soluble
- Mechanism: directly stimulates intestinal secretion (by opening voltage-dependent sodium channels in nerves and muscles) without mucosal damage
- May Cause Long-Term Disruption of Cerebral Function in Animal Models Via Upregulation of Sodium Channels Expression in Astrocytes
Maitotoxin
- Water-Soluble
- Mechanism: opens calcium channels
- Toxins can cross the placenta (although not believed to be teratogenic, can affect fetus)
Scaritoxin
- Mechanism: increases permeability of sodium channels, resulting in norepinephrine and acetlycholine release
Diagnosis
Clinical Manifestations
General Comments
- Severity of illness is related to repeated exposures to toxin
Cardiovascular Manifestations
- Hypotension (see Hypotension, [[Hypotension]]): systolic BP <80 occurs in only 2% of cases
- Sinus Bradycardia (see Sinus Bradycardia, [[Sinus Bradycardia]]): HR <60 occurs in only 14% of cases
Gastroenterologic Manifestations (78% of cases)
- General Comments
- Onset: gastrointestinal symptoms begin min-24 hrs after ingestion
- Duration: gastrointestinal symptoms last for 1-2 days
- Hypersalivation (see Hypersalivation, [[Hypersalivation]])
- Nausea/Vomiting (see Nausea and Vomiting, [[Nausea and Vomiting]]): 35-38% of cases
- Abdominal Cramps (see Abdominal Pain, [[Abdominal Pain]]): 47-52% of cases
- Watery Diarrhea (see Diarrhea, [[Diarrhea]]): 64-70% of cases
Neurologic Manifestations
- Cranial Nerve Dysfunction
- Reversal of Sensation of Hot and Cold (76-88%)
- Parasthesias, Dysesthesias of Circumoral Region and Extremities: 66-89% of cases and 71-89% of cases, respectively
- Exacerbated by ethanol consumption
- Generalized/Localized Pruritus: 45-76% of cases
- Exacerbated by ethanol consumption
- Headache
- Weakness
- Dizziness
- Looseness or pain in teeth: 25-37% of cases
- Ataxia: 38-54% of cases
- Vertigo: 42-45% of cases
Other Manifestations
- Xerostomia
- Myalgias/Arthralgias
- Chills
- Flushing: although fever is unusual
- Dysuria (see Dysuria, [[Dysuria]]): 20% of cases
- Exacerbated by sexual intercourse
- Diaphoresis
Treatment
- Supportive: most cases are self-limited
- Atropine: may be required for bradycardia
- Mannitol infusion (1 g/kg IV over 30-45 min.): unclear mechanism of action, but best benefit is seen in first 24 hours after onset of symptoms
- Amitriptyline (25 mg BID): use-ful for long-term symptoms
- May modulate sodium channels
- Other: tocainide/ mexilitene/ nifedipine have been used with variable success
- Prevention: avoid ingestion of fish from areas with “red tide” of plankton
Prognosis
- Prognosis: case-fatality rate is 0.1%
- Median duration of illness is 2-3 weeks (may last months-years)
- Chronicity is predicted by more severe symptoms, long latency period, and longer duration of peak symptoms
References