Elapidae (Coral Snakes)

Background

  • All coral snakes are brightly colored with black, red, and yellow rings
  • Red and yellow rings touch in coral snakes, but are separated in nonpoisonous mimics
    • "Red touch yellow, kills a fellow; red touch black, venom lack"
    • This tool for identifying coral snakes does not apply to Mexican species
Coral snake.

Venom

Coral snake venom is mainly neurotoxic (irreversibly binds to acetylcholine receptors) and does not cause significant local tissue injury unlike Crotaline (Pit Vipers) venom.

Clinical Features

  • Local injury is often minimal and easy to miss as venom is delivered via chewing rather than injection
  • Venom effects may develop hours after a bite

Serious complications

  • Venom-induced consumption coagulopathy (DIC-like syndrome)[1]
  • Renal failure
  • Hypovolemic shock
  • Neurotoxicities in particular for coral snaktes
    • Local numbness rather than pain/swelling
    • CN palsies
    • Respiratory paralysis

Differential Diagnosis

Envenomations, bites and stings

Evaluation

  • CBC with diff
  • PT/PTT/INR
  • Fibrinogen
  • Fibrin degradation products
  • BMP
  • LFT
  • CK
  • ABG if respiratory compromise

Management

Local Care

  • Do:
    • Immobilize limb in a neutral position
    • Remove all jewelry
  • Do not:
    • Attempt to suck out the venom
    • Place the affected part in cold water
    • Use a tourniquet or wrap
    • Antivenom is first line treatment for compartment syndrome; fasciotomy is last resort if elevated pressures persist.

Antivenom

  • Give 3-5 vials of Antivenin (Micrurus fulvius) to ALL patients who have definitely been bitten
    • It may not be possible to prevent further effects or reverse effects once they develop
    • Additional doses of antivenom are reserved for cases in which symptoms/signs appear
  • Prepare for allergic reaction from equine produced Antivenin (may dilute solution, or administer with epinephrine/benadryl)

Monitor for respiratory failure

Disposition

  • Admit all patients (even if initially symptom free)

See Also

References

  1. Isbister GK. Snakebite does not cause disseminated intravascular coagulation: coagulopathy and thrombotic microangiopathy in snake envenoming. Semin Thromb Hemost. 2010 Jun;36(4):444-51.