Cone Snail Envenomation

Aka: Cone Snail Envenomation, Cone Snail, Conus Geographus, Conus Textile, Conus Marmoreus, Conotoxin

advertisement

II. Pathophysiology

  1. Cone Snails (genus Conus, Family Conidae) are venomous, nocturnal, fish-hunting mollusks
    1. Of the 800 Cone Snail species, 34 cause significant Envenomations in humans
    2. Three Cone Snail species are associated with fatal Envenomations
      1. Conus Geographus (most toxic)
      2. Conus Textile
      3. Conus Marmoreus
    3. Distribution
      1. Most concentrated in tropical ocean (esp. Western Indo-Pacific)
      2. Australia
      3. New Guinea
      4. California
    4. Exposures
      1. Shallow water, under rocks, in sand, or around reefs
    5. Envenomation
      1. Radicular tooth is propelled from the Cone Snail proboscis
        1. Able to embed in skin through clothing
      2. Venom contains multiple components
        1. Conotoxins (omega, alpha, mu)
        2. Lipases
        3. Proteases
        4. Hyaluronidases
  2. Conotoxin
    1. Conotoxins are peptide Neurotoxins containing 13 to 29 Amino Acids (1-4 kDa)
      1. Strongly basic
      2. Highly cross-linked by disulfide bonds
    2. Conotoxin Types
      1. Omega
        1. Inhibits voltage-activated Calcium entry at the presynaptic membrane
        2. Inhibits release of Acetylcholine
      2. Alpha
        1. Inhibits postsynaptic Acetylcholine receptor
      3. Mu
        1. Inhibits the generation of muscle Action Potentials

III. Risk Factors: Severe or fatal Envenomation

  1. Envenomation by Conus Geographus (or to lesser extent by C. textile or C. maroreus)
  2. Large Cone Snail shell size
  3. Age <15 years

IV. Toxicology

  1. Conotoxin is rapidly cleared within minutes to hours
    1. Human proteases (tissue, blood)
    2. Renal elimination

V. Findings

  1. Rapid onset of cardiovascular and neuromuscular symptoms after Envenomation
  2. Flaccid Paralysis with Respiratory Failure in lethal Envenomations
    1. Onset ranges 0.2 to 10 hours after Envenomation (average 2.4 hours)
  3. Local effects
    1. Mild to severe pain, numbness and Paresthesias at sting site
    2. Local tissue ischemia
  4. Cardiovascular effects
    1. Hypotension or cardiovascular collapse
    2. Chest Pain
  5. Neurologic effects
    1. Bulbar symptoms (Diplopia, Dysphagia, Dysarthria)
    2. Flaccid Paralysis
    3. Coma

VI. Labs

  1. See Acute Poisoning
  2. Fingerstick Glucose
  3. Pregnancy Test

VII. Diagnostics

  1. Pulmonary Function Assessment of Respiratory Muscle Strength (e.g. Negative Inspiratory Flow)
  2. Electrocardiogram

VIII. Management

  1. See Marine Envenomation
  2. ABC Management
    1. Endotracheal Intubation may be needed (e.g. Flaccid Paralysis, Respiratory Failure)
  3. Cardiovascular collapse with Hypotension
    1. Intravenous crystalloid
    2. Norepinephrine
  4. Wound care
    1. Consider hot water immersion (113 F, 45 C)
  5. Other measures
    1. Tetanus Prophylaxis
    2. No specific antivenom is available for Cone Snail Envenomation
  6. Disposition
    1. Hospital observation of at least 6 hours
    2. Admit patients wih Abnormal Vital Signs, neurologic symptoms, cardiovascular findings

IX. Resources

  1. Kapil (2023) Cone Snail Toxicity, StatPearls
    1. https://www.ncbi.nlm.nih.gov/books/NBK470586/

X. References

  1. Carroll and Yakey (2025) Crit Dec Emerg Med 39(12): 40

Images: Related links to external sites (from Bing)

These images are a random sampling from a Bing search on the term "Cone Snail Envenomation." Click on the image (or right click) to open the source website in a new browser window. Search Bing for all related images

Related Topics in Dermatology

advertisement