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

  • Stool culture: negative

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
    • no controlled trials
  • 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

  • xxx