Emergency Department Management of North American Snake Envenomations - Trauma EXTRA Supplement (Trauma CME and Pharmacology CME)

Table of Contents

 

About This Issue

Venomous snake families native to North America include the pit vipers (copperheads, water moccasins/cottonmouths, and rattlesnakes) and coral snakes. Management strategies and antivenom options are different for each of these subfamilies, and there are conflicting recommendations, local practices, and “folklore” surrounding snakebites. In this issue, you will learn:

Whether ice, pressure immobilization, incision, or suction are still recommended in the management of snakebites.

How to tell whether (and how much) venom was injected.

Why it is important to mark and time edema and erythema from a snakebite.

The differences between FabAV and F(ab’)2AV, the crotalinae antivenoms approved for use in the United States.

The antivenom options available for coral snake bites, including during times of shortage.

The risks for anaphylaxis associated with the snake bite itself and with administration of antivenom.

1. About This Issue
2. Abstract
3. Case Presentations
4. Introduction
5. Crotalinae Family: The Pit Vipers
6. Elapidae Family: The Coral Snakes
7. Epidemiology and Pathophysiology
   1. Snakebite Severity
8. Differential Diagnosis
9. Prehospital Care
   1. Pressure Immobilization
10. Emergency Department Evaluation
    1. Initial Assessment and Stabilization
    2. History
    3. Physical Examination
       1. Cardiovascular Effects
       2. Respiratory Effects
       3. Neurologic Effects
    4. Hematologic Effects
       1. Dermal Effects
       2. Musculoskeletal Effects
       3. Rare Reported Effects
11. Diagnostic Studies
    1. General Recommendations
    2. Coagulation Studies
    3. Imaging
    4. Monitoring/Observation
12. Treatment
    1. Grading of Envenomation Severity to Guide Treatment With Antivenom
    2. Antivenom Treatment of Pit Viper Envenomation
       1. FabAV
       2. F(ab’)2AV
       3. Dosing of Antivenom
          1. Dosing of FabAV
          2. Dosing of F(ab’)2AV
       4. Contraindications for Antivenom
       5. Use of Antivenom for Copperhead Envenomation
       6. Use of Antivenom in Compartment Syndrome
       7. Use of Antivenom in Coagulopathy
    3. Antivenom Treatment of Coral Snake Envenomation
       1. Suspected Micrurus fulvius (Eastern Coral Snake) Envenomation
       2. Suspected Micrurus tener (Texas Coral Snake) Envenomation
       3. Dosage of North American Coral Snake Antivenin
       4. Experimental Coral Snake Antivenoms and Treatments
    4. Treatment of Non–Native Snake Envenomation
13. Special Populations
    1. Pregnant Patients
    2. Pediatric Patients
    3. Anticoagulated Patients
14. Controversies and Cutting Edge
    1. Controversies
    2. Cutting Edge
15. Disposition
    1. Observation
    2. Admission
    3. Follow-Up
16. Summary
17. Risk Management Pitfalls for Managing Patients with Snakebites in the Emergency Department
18. Time- and Cost-Effective Strategies
19. Case Conclusions
20. Clinical Pathways
    1. Clinical Pathway for Management of Patients With Suspected North American Pit Viper Bite
    2. Clinical Pathway for Management of Patients With Suspected North American Coral Snake Bite
21. Tables and Figures
22. References

Abstract

There are approximately 10,000 emergency department visits in the United States for snakebites every year, and one-third of those involve venomous species. Venomous North American indigenous snakes include species from the Crotalinae (pit vipers) and Elapidae (coral snakes) subfamilies. Treatment relies on supportive care, plus antivenom for select cases. While certain principles of management are widely accepted, controversies exist with regard to prehospital use of pressure immobilization, antivenom use, coagulation testing after copperhead envenomation, and fasciotomy. An evidence-based approach to management of North American venomous snakebites will be discussed, along with a review of the current controversies.

Case Presentations

A 4-year-old boy is brought to your ED by his distraught parents an hour after being bitten by a snake in his backyard…

• The mother states that it was a foot-long black, yellow, and red snake. She reports that she had to pull quite hard before it would release.
• The child has several small marks on the palm of his left hand. There is minimal redness, and no swelling is apparent.
• The father took a picture of the snake with his phone. You recognize it as a coral snake.
• The child is asymptomatic currently, but the nearest pediatric ICU is more than an hour away. You wonder: should you transfer this patient to the ICU, or can you observe him in the ED—and should you start antivenom?

A 26-year-old man arrives at the ED via private vehicle with his arm in a makeshift sling after being bitten by his pet rattlesnake…

• He reports that the snake bit him on his right index finger about 45 minutes ago.
• His hand and wrist are swollen.
• He reports no past medical history except his 3 previous visits for snakebites. He says he had a “reaction” to the snakebite antidote during his last visit.
• You wonder whether you should you give this patient antivenom again...

A 51-year-old man with a history of a rattlesnake bite approximately 4 days ago presents to your ED…

• He was directed to go to the ED by his primary care physician's office due to ”abnormal lab results.“
• He reports easy bruising and some bleeding when he brushes his teeth, but is otherwise asymptomatic.
• You wonder how you should manage this patient...

How would you manage these patients? Subscribe for evidence-based best practices and to discover the outcomes.

Clinical Pathways

Subscribe to access the complete flowchart to guide your clinical decision making.

Tables and Figures

Subscribe for full access to all Tables and Figures.

Key References

Following are the most informative references cited in this paper, as determined by the authors.

6. * Wood A, Schauben J, Thundiyil J, et al. Review of Eastern coral snake (Micrurus fulvius fulvius) exposures managed by the Florida Poison Information Center Network: 1998-2010. Clin Toxicol (Phila). 2013;51(8):783-788. (Retrospective; 387 patients) DOI: 10.3109/15563650.2013.828841

31. * Lavonas EJ, Ruha AM, Banner W, et al. Unified treatment algorithm for the management of crotaline snakebite in the United States: results of an evidence-informed consensus workshop. BMC Emerg Med. 2011;11:2. (Consensus panel) DOI: 10.1186/1471-227X-11-2

32. * American College of Medical Toxicology, American Academy of Clinical Toxicology, American Association of Poison Control Centers, et al. Pressure immobilization after North American Crotalinae snake envenomation. Clin Toxicol (Phila). 2011;49(10):881-882. (Position statement) DOI: 10.3109/15563650.2011.610802

46. * Cumpston KL. Is there a role for fasciotomy in Crotalinae envenomations in North America? Clin Toxicol (Phila). 2011;49(5):351-365. (Review) DOI: 10.3109/15563650.2011.597032

72. * Bush SP, Ruha AM, Seifert SA, et al. Comparison of F(ab’)2 versus Fab antivenom for pit viper envenomation: a prospective, blinded, multicenter, randomized clinical trial. Clin Toxicol (Phila). 2015;53(1):37-45. (Randomized controlled trial; 121 patients) DOI: 10.3109/15563650.2014.974263

74. United States Food and Drug Administration. Highlights of prescribing information, ANAVIP. Updated April 2021. Accessed February 1, 2024. (FDA package insert)

80. * Mascarenas DN, Fullerton L, Smolinske SC, et al. Comparison of F(ab’)(2) and Fab antivenoms in rattlesnake envenomation: First year’s post-marketing experience with F(ab’)(2) in New Mexico. Toxicon. 2020;186:42-45. (Retrospective; 37 patients) DOI: 10.1016/j.toxicon.2020.08.002

81. * Gerardo CJ, Keyler DE, Rapp-Olson M, et al. Control of venom-induced tissue injury in copperhead snakebite patients: a post hoc sub-group analysis of a clinical trial comparing F(ab’)(2) to Fab antivenom. Clin Toxicol (Phila). 2022;60(4):521-523. (Post hoc analysis; 21 clinical trial patients) DOI: 10.1080/15563650.2021.1973489

82. * Walker JP, Morrison RL. Current management of copperhead snakebite. J Am Coll Surg. 2011;212(4):470-474. (Retrospective; 142 patients) DOI: 10.1016/j.jamcollsurg.2010.12.049

89. * Kitchens C, Eskin T. Fatality in a case of envenomation by Crotalus adamanteus initially successfully treated with polyvalent ovine antivenom followed by recurrence of defibrinogenation syndrome. J Med Toxicol. 2008;4(3):180-183. (Case report) DOI: 10.1007/BF03161198

98. United States Food and Drug Administration. Expiration date extension for North American coral snake antivenin (Micrurus fulvius) (Equine Origin) Lot L67530 through January 31, 2019. 2019. Accessed February 1, 2024. (FDA press release)

Seifert SA. Evaluation and management of coral snakebites. In: UpToDate, Danzl DF, Stolback A, eds. Updated May 4, 2022. Accessed February 1, 2024. (Online textbook chapter)

Sánchez EE, Lopez-Johnston JC, Rodríguez-Acosta A, et al. Neutralization of two North American coral snake venoms with United States and Mexican antivenoms. Toxicon. 2008;51(2):297-303. (Lab)

102. Emergency treatment of coral snake envenomation with antivenom. ClinicialTrials.gov. Updated May 26, 2023. Accessed February 1, 2024. (Clinical trial record)

110. Center for Biologics Evaluation and Research, United States Food and Drug Administration. Thimerosal and vaccines. 2022. Updated December 18, 2022. Accessed February 1, 2024.

117. Cribari C. Management of poisonous snakebites. American College of Surgeons Committee on Trauma; 2004. Accessed February 1, 2024. (Guidelines)

130. * Hwang CW, Flach FE. Recurrent coagulopathy after rattlesnake bite requiring continuous intravenous dosing of antivenom. Case Rep Emerg Med. 2015;2015:719302. (Case report) DOI: 10.1155/2015/719302

Subscribe to get the full list of 132 references and see how the authors distilled all of the evidence into a concise, clinically relevant, practical resource.

Keywords: snake, snake bite, envenomation, pit viper, copperhead, water moccasin, rattlesnake, cottonmouth, coral snake, venom, NACSA, FabAV, F(ab’)2AV, antivenom, coagulopathy