Snake bite

Mechanism: envenomnation!
  • Snakebites do not necessarily result in envenomation
  • Even if the snake is poisonous (up to 30% of bitten patients are not envenomated).
  • Charactistics of a venomous snake
    • Elliptical eyes
    • Pits behind the nostrils
    • Big fangs
    • Rattlers in the tail
      • notion image
 
Clinical presentation
  • Envenomation signs:
    • Severe local pain, swelling, and discoloration developing within 30 minutes of the bite.
 
Abordagem
  • Snake bite → is snake venomous? → was venom injected?
  • If suspect invenomnation present, draw blood for typing and crossmatch (they cannot be done later if needed), coagulation studies, and liver and renal function.
 
Treatment
  • Antivenin.
    • The currently preferred agent for crotalids is CROFAB, of which several vials are usually needed.
    • Antivenin dosage relates to the size of the envenomation, not the size of the patient (children get the same dosages as adults).
    • Surgical excision of the bite site or fasciotomy is very rarely needed.
    • The only valid first aid is to splint the extremity during transportation.
      • Do not make cruciate cuts, suck out venom, wrap with ice, or apply a tourniquet.