Poisonous Lizard Bite

Epidemiology

  • Only 2 of the almost 3000 lizard species in the world are venomous
    • Gila Monster (Heloderma suspectum): present in southwestern US and Mexico
    • Mexican Beaded Lizard (Heloderma horridum): present in Mexico
  • These lizards are not aggressive and most bites are related to human-initiated interaction with the lizard

Etiology

  • Gila Monster (Heloderma suspectum)
  • Mexican Beaded Lizard (Heloderma horridum)


Physiology

  • Mechanism of Envenomation
    • Venom is elaborated from 8 glands in the floor of the lizard’s mouth and bathes the oral cavity
    • Teeth are grooved posteriorly
    • Lizard bites tenaciously and is often difficult to dislodge: may require removal of head, submersion in water, application of fire to dislodge
  • Venom Components
    • VIP-Like Biopeptides
    • Kallikrein-like substances
    • Neurotoxin: causes neuropathy

Clinical Manifestations

  • Local Wound
    • Excruciating pain with massive tissue edema, and erythrema
      • Intense hyperesthesia of the wound may persist for weeks
  • Systemic Symptoms

Treatment

  • Removal of Lizard: may require removal of head, submersion in water, application of fire to dislodge lizard
  • No Antivenin Available
  • Constriction Band
  • Cooling of the Wound Area
  • Antibiotics
    • Including coverage for Tetanus (Tetanus Toxoid or Immune Globulin)
  • Analgesia: necessary
    • Local
    • Parenteral

References

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