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ACMT Toxicology Visual Pearls: Exotic Viper Envenomation

Posted by Bryan Judge, MD, FACMT on

A man was bitten twice on the dorsal radial aspect of his right hand while feeding his pet West African Bush Viper. The patient immediately tied multiple tourniquets around his right arm before presenting to the emergency department. During examination he is complaining of swelling and severe pain in his right upper extremity, but has no other complaints. What are the appropriate next steps in managing this patient?

  1. Apply ice to the bites
  2. Measure compartment pressures in the right arm and forearm
  3. Perform a fasciotomy
  4. Remove the tourniquets and order hematologic studies
  5. Use a venom extractor to reduce venom burden


Reveal the Answer

Answer: 4 – Remove the tourniquets and order hematologic studies

The West African Bush Viper (Atheris chlorechis) is an arboreal species of bush viper endemic to portions of West Africa. In the United States this viper can be easily purchased through the internet by snake enthusiasts. Envenomation can result in significant soft-tissue injury and severe coagulopathy.1,2 The appropriate next steps in this situation include removing the tourniquet(s) that the patient applied, providing adequate analgesia, and obtaining hematologic studies (CBC, PT/PTT, fibrinogen concentration, and fibrinogen degradation products).

Bedside Pearls for Exotic Viper Envenomation

Avoiding Patient Harm

  • Ice should not be applied to the bitten area since this treatment is not effective in neutralizing venom, and can worsen the initial injury.3
  • Although envenomation may mimic compartment syndrome, the use of fasciotomy is not recommended since much of the edema produced after envenomation does not occur in compartmentalized areas.4,5
  • Venom extractors are unproven therapy and are not recommended.6

Monitoring

  • Because findings of coagulopathy and systemic envenomation can be delayed for several hours after a snakebite, all patients who report a history of snakebite from an exotic viper should be observed for 8-12 hours after the bite, if the skin is broken and the suspect snake cannot be positively identified as nonvenomous.
  • Monitoring trends in the coagulation profile can assist in assessing the gravity of envenomation and the response to treatment with antivenom.

Medical Toxicology Consultation

  • A medical toxicologist should be consulted to help manage any snakebite from an exotic viper.
  • If antivenom for an exotic viper bite is necessary, the Antivenom Index can be used with the assistance of a Poison Center (1-800-222-1222) to help determine the appropriate antivenom and its location, which may be your local zoo!

The American College of Medical Toxicology (ACMT) hosts this Toxicology Visual Pearls series.

References

1.
Top L, Tulleken J, Ligtenberg J, Meertens J, van der, Zijlstra J. Serious envenomation after a snakebite by a Western bush viper (Atheris chlorechis) in the Netherlands: a case report. Neth J Med. 2006;64(5):153-156. [PubMed]
2.
American C. Abstracts from the 2017 American College of Medical Toxicology (ACMT) Annual Scientific Meeting. J Med Toxicol. 2017;13(1):3-46. [PubMed]
3.
Gold B, Dart R, Barish R. Bites of venomous snakes. N Engl J Med. 2002;347(5):347-356. [PubMed]
4.
Hall E. Role of surgical intervention in the management of crotaline snake envenomation. Ann Emerg Med. 2001;37(2):175-180. [PubMed]
5.
Tanen D, Danish D, Grice G, Riffenburgh R, Clark R. Fasciotomy worsens the amount of myonecrosis in a porcine model of crotaline envenomation. Ann Emerg Med. 2004;44(2):99-104. [PubMed]
6.
Alberts M, Shalit M, LoGalbo F. Suction for venomous snakebite: a study of “mock venom” extraction in a human model. Ann Emerg Med. 2004;43(2):181-186. [PubMed]

Author information

Bryan Judge, MD, FACMT

Professor of Emergency Medicine
Michigan State University College of Human Medicine

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