Elapidae (Coral Snakes): Difference between revisions

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==Background==
==Background==
#All coral snakes are brightly colored with black, red, and yellow rings
*Coral snakes are the only ''Elapidae'' family members found in the United States
##Red and yellow rings touch in coral snakes, but are separated in nonpoisonous mimics
**Internationally, species include sea snakes, cobras, mambas, and kraits
###"Red touch yellow, kills a fellow; red touch black, venom lack"
*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'''
[[File:Coral 009.jpg|thumb|Coral snake.]]
*Venom: mainly neurotoxic (irreversibly binds to acetylcholine receptors)
**Does ''not'' cause significant local tissue injury unlike [[Crotaline (Pit Vipers)]] venom.


==Clinical Features==
==Clinical Features==
#Local injury is often minimal
*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
*Venom effects may develop hours after a bite


==Treatment==
===Serious complications===
#Antivenom
*Systemic signs may be delayed up to 13h after bite<ref>http://www.emdocs.net/management-of-venomous-snake-bites-in-north-america/</ref>
##Give 3-5 vials of Antivenin to ALL pts who have definitely been bitten
*Neurotoxicities in particular for coral snakes
###It may not be possible to prevent further effects or reverse effects once they develop
**Local [[numbness]] rather than pain/swelling
###Additional doses of antivenom are reserved for cases in which symptoms/signs appear
**[[Cranial nerve palsies]]
#Monitor for respiratory respiratory failure
**[[Altered mental status]]
**[[Weakness]]
**[[Respiratory failure]] due to paralysis
*Hypovolemic [[shock]]
*Venom-induced consumption coagulopathy ([[DIC]]-like syndrome)<ref>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.</ref> (uncommon, but reported<ref>https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/elapidae</ref>)
 
==Differential Diagnosis==
{{Bites and stings DDX}}
 
==Evaluation==
*CBC with diff
*[[DIC]] labs: PT/PTT/INR, fibrinogen, fibrin degradation products, [[d-dimer]]
*BMP
*[[LFTs]]
*CK
 
==Management==
{{Snake bite local treatment}}
*[[Pressure Immobilization Dressing]]<ref>Robert L. Norris, Sean P. Bush, Michael D. Cardwell. Bites by Venomous Reptiles in the United States, Canada, and Mexico. Paul S. Auerbach. In: Auerbach’s Wilderness Medicine. 7th Ed. 2017: 742.</ref>
**Wrap the length of the bitten extremity with an elastic bandage
**Splint the extremity in neutral position to immobilize
**Immobilize victim and transport to medical care
**''If a patient presents with a tourniquet or pressure immobilization dressing, obtain IV access for potential resuscitation before removing.''
 
===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]]===
*Respiratory failure results from neurotoxicity rather than edema as in crotalids
*Frequently reevaluate respiratory function and ability to handle secretions
**Consider bedside spirometry testing
*Aggressive airway management with any sign of respiratory decline including mechanical ventillation as needed


==Disposition==
==Disposition==
#Admit all pts (even if initially symptom free)
*Admit all patients (even if initially symptom free)
 
==Source==
Tintinalli


==See Also==
==See Also==
*[[Snake bites]]
*[[Snake bites]]


[[Category:Environ]]
==References==
[[Category:Tox]]
<references/>
*Medscape. Antivenin, Eastern & Texas Coral Snakes (Rx) - Antivenin (Micrurus fulvius). http://reference.medscape.com/drug/micrurus-fulvius-antivenin-eastern-texas-coral-snakes-343718.
*Juckett G and Hancox JG. Venomous Snakebites in the United States: Management Review and Update. Am Fam Physician. 2002 Apr 1;65(7):1367-1375.
 
[[Category:Environmental]]
[[Category:Toxicology]]

Latest revision as of 01:19, 2 August 2021

Background

  • Coral snakes are the only Elapidae family members found in the United States
    • Internationally, species include sea snakes, cobras, mambas, and kraits
  • 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: mainly neurotoxic (irreversibly binds to acetylcholine receptors)

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

Differential Diagnosis

Envenomations, bites and stings

Evaluation

  • CBC with diff
  • DIC labs: PT/PTT/INR, fibrinogen, fibrin degradation products, d-dimer
  • BMP
  • LFTs
  • CK

Management

Local Care

  • Do:
    • Remove all jewelry
    • Mark the leading edge of erythema/edema
  • 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.
  • Pressure Immobilization Dressing[4]
    • Wrap the length of the bitten extremity with an elastic bandage
    • Splint the extremity in neutral position to immobilize
    • Immobilize victim and transport to medical care
    • If a patient presents with a tourniquet or pressure immobilization dressing, obtain IV access for potential resuscitation before removing.

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

  • Respiratory failure results from neurotoxicity rather than edema as in crotalids
  • Frequently reevaluate respiratory function and ability to handle secretions
    • Consider bedside spirometry testing
  • Aggressive airway management with any sign of respiratory decline including mechanical ventillation as needed

Disposition

  • Admit all patients (even if initially symptom free)

See Also

References

  1. ↑ http://www.emdocs.net/management-of-venomous-snake-bites-in-north-america/
  2. ↑ 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.
  3. ↑ https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/elapidae
  4. ↑ Robert L. Norris, Sean P. Bush, Michael D. Cardwell. Bites by Venomous Reptiles in the United States, Canada, and Mexico. Paul S. Auerbach. In: Auerbach’s Wilderness Medicine. 7th Ed. 2017: 742.
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