Epidemiology

Geography (Clin Infect Dis, 2005) [MEDLINE] and (Epidemiol Infect, 2010) [MEDLINE]

• Southeastern Coast of the US
• Gulf of Mexico
• Caribbean
• New Zealand

Outbreaks

• Two Outbreaks were Reported to the CDC In the US Between 1998-2002 (Clin Infect Dis, 2005) [MEDLINE]
  • No Fatalities were Reported

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Etiology

• Ingestion of Brevetoxin-Contaminated Bivalve Shellfish
  • Cases are Associated with Occurrence of “Red Tides”
• Inhalation of Sea Spray/Aerosols
  • Cases are Associated with Occurrence of “Red Tides”

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Physiology

• Brevetoxins
  • Brevetoxins are Synthesized by Dinoflagellate, Karenia Brevis (Formerly Gymnodidium Breve and Ptychodiscus Brevis): these dinoflagellates synthesize both hemolytic toxins and neurotoxins (Epidemiol Infect, 2010) [MEDLINE]
  • Brevetoxins are Taken Up by Bivalve Shellfish and are Aerosolized During Algal Blooms
  • Brevetoxins Act to Impair Sodium Channel Function and Inhibit Cathepsins (Which are Lysosomal Proteinases Found in Macrophages and Other Phagocytes)

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Diagnosis

• Detection of Brevetoxins in Suspected Contaminated Shellfish

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Clinical Manifestations

Ingestion Syndrome

General Comments

• Onset: onset within 30 min-3 hrs after ingestion

Gastrointestinal Manifestations

• Abdominal Pain (see Abdominal Pain, Abdominal Pain)
• Diarrhea (see Diarrhea, Diarrhea)
• Nausea/Vomiting (see Nausea and Vomiting, Nausea and Vomiting)

Neurologic Manifestations

• Ataxia (see Ataxia, Ataxia)
• Dizziness (see Dizziness, Dizziness)
• Facial/Oral/Extremity Parasthesias (see Parasthesias, Parasthesias)
• Obtundation/Coma (see Obtundation-Coma, Obtundation-Coma)
  • Clinical: coma has been reported in severe cases (Toxicon, 2000) [MEDLINE]
• Seizures (see Seizures, Seizures)
  • Clinical: seizures have been reported in severe cases (Toxicon, 2000) [MEDLINE]
• Temperature-Related Dysesthesia (see Dysesthesias, Dysesthesias)
  • Clinical: hot-cold temperature reversal (Am J Public Health, 1991) [MEDLINE]
• Weakness (see Weakness, Weakness)
  • Clinical: paralysis has been reported in severe cases (Toxicon, 2000) [MEDLINE]

Rheumatologic Manifestations

• Muscle Cramps (see Muscle Cramps, Muscle Cramps)

Inhalation Syndrome (Aerosolized Red Tide Respiratory Irritation, ARTRI)

Otolaryngologic Manifestations

• Nasal Irritation
• Rhinorrhea (see Rhinorrhea, Rhinorrhea)

Pulmonary Manifestations

• Bronchospasm (see Obstructive Lung Disease, Obstructive Lung Disease)
  • Epidemiology
    • Highest Risk in Patients with Asthma and Chronic Lung Disease
  • Clinical
    • Wheezing (see Wheezing, Wheezing)

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Treatment

Ingestion Syndrome

General Comments

• Clinical Manifestations Usually Resolve within a 72 hrs

Supportive Care

• Antiemetics
  • Ondansetron (Zofran) (see Ondansetron, Ondansetron)
• Intravenous Fluids

Activated Charcoal (see Activated Charcoal, Activated Charcoal)

• Recommended to Bind Toxin in Unabsorbed Food (Although Evidence is Lacking)

Inhalation Syndrome

• Bronchodilators
  • Albuterol (see Albuterol, Albuterol)

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Prognosis

• Not Usually Fatal in Humans
  • However, Fatalities are Common in Birds, Fish, and Manatees

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References

• Clinical and epidemiological features of neurotoxic shellfish poisoning in North Carolina. Am J Public Health. 1991 Apr;81(4):471-4 [MEDLINE]
• Shellfish poisonings. Shoreland’s Travel Medicine Monthly. 1999;3:1 [MEDLINE]
• Pfiesteria, “the cell from hell,” and other toxic algal nightmares. Clin Infect Dis. 1999;28(6):1191 [MEDLINE]
• Neurotoxic shellfish poisoning and brevetoxin metabolites: a case study from Florida. Toxicon. 2000;38(7):981 [MEDLINE]
• Illnesses caused by marine toxins. Clin Infect Dis. 2005;41(9):1290 [MEDLINE]
• Aerosolized red-tide toxins (brevetoxins) and asthma. Chest. 2007;131(1):187 [MEDLINE]
• Reported respiratory symptom intensity in asthmatics during exposure to aerosolized Florida red tide toxins. J Asthma. 2007;44(7):583 [MEDLINE]
• Neurotoxins from marine dinoflagellates: a brief review. Mar Drugs. 2008 Jun 11;6(2):349-71. doi: 10.3390/md20080016 [MEDLINE]
• Shellfish toxicity: human health implications of marine algal toxins. Epidemiol Infect. 2010 Jul;138(7):927-40 [MEDLINE]