Moccasin Envenomation Workup

  • Author: Sean P Bush, MD, FACEP; Chief Editor: Rick Kulkarni, MD   more...
 
Updated: May 3, 2011
 

Laboratory Studies

Coagulopathy and thrombocytopenia may occur with pit viper envenomation. However, these problems are much less common after moccasin envenomations than after rattlesnake envenomations. Numeric coagulopathy and/or thrombocytopenia occur in approximately 10% of copperhead envenomations; clinically significant bleeding occurs in less than 5%. For a more detailed discussion of coagulopathy induced by pit viper venom, see Snake Envenomations, Rattle.

  • CBC including platelet count
  • PT/INR
  • Activated partial thromboplastin time (aPTT)
  • Fibrinogen
  • Type and screen, only if severe coagulopathy/thrombocytopenia are present or clinical bleeding is suspected.

Additional laboratory and other diagnostic data should be obtained on a case-by-case basis. Factors to consider may include severity of envenomation, physician preference, and cost.

  • Bacterial cultures are rarely helpful. The incidence of infection in these envenomations is approximately 2%.
  • Patients who develop shock, respiratory failure, or signs suggesting rhabdomyolysis may benefit from measurements of electrolytes, BUN, creatinine, creatine phosphokinase (CPK), and arterial blood gases, on a case-by-case basis.
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Imaging Studies

Plain radiographs may depict teeth or fangs retained in wound. However, this finding is uncommon; routine radiography is not recommended.

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Other Tests

Skin testing for allergy to antivenom: Skin testing is not necessary prior to administration of ovine Fab antivenom (CroFab).

Because moccasin venom is not cardiotoxic, routine examination with electrocardiography is not required. An ECG may be useful in cases of shock.

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Procedures

Fasciotomy is rarely indicated in cases of moccasin envenomation.

Because envenomation produces limb swelling, severe pain, and pain with passive stretch, it is common for envenomated limbs to appear similar to limbs with compartment syndrome. However, true compartment syndrome is present in less than 2% of moccasin envenomations.

Compartment pressure monitoring is indicated in cases of suspected compartment syndrome.

The preferred therapy for compartment syndrome due to moccasin envenomation is administration of antivenom. Crotaline Fab antivenom has been shown to improve perfusion pressures in an animal model and in human case reports.

Fasciotomy should be reserved for cases in which compartment pressures remain elevated despite administration of adequate doses of antivenom, or in cases of compartment syndrome when antivenom cannot be obtained.

Because tissue pressures in the fingers and toes cannot be measured accurately, the diagnosis of suspected compartment syndrome in the digits is difficult. If capillary refill is poor, administer antivenom to reduce swelling and attempt to restore perfusion. If capillary refill remains poor after administration of adequate doses of antivenom, digit dermotomy may be indicated.

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Contributor Information and Disclosures
Author

Sean P Bush, MD, FACEP  Professor of Emergency Medicine, Loma Linda University School of Medicine; Consulting Staff, Envenomation Specialist, Department of Emergency Medicine, Loma Linda University Medical Center

Sean P Bush, MD, FACEP is a member of the following medical societies: American College of Emergency Physicians, International Society on Toxicology, Society for Academic Emergency Medicine, and Wilderness Medical Society

Disclosure: Protherics Consulting fee Consulting; Nycomed (formerly Fougera) Grant/research funds Speaking and teaching; Rare Disease Therapeutics Grant/research funds Research; Bioclon Grant/research funds Research

Coauthor(s)

Eric J Lavonas, MD, FACEP  Associate Director, Rocky Mountain Poison and Drug Center; Assistant Professor, University of Colorado School of Medicine

Eric J Lavonas, MD, FACEP is a member of the following medical societies: Alpha Omega Alpha, American Academy of Clinical Toxicology, American College of Emergency Physicians, American College of Medical Toxicology, Colorado Medical Society, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

Robert L Norris, MD  Professor, Department of Surgery, Chief, Division of Emergency Medicine, Stanford University Medical Center

Robert L Norris, MD is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, California Medical Association, International Society of Toxinology, Society for Academic Emergency Medicine, and Wilderness Medical Society

Disclosure: Nothing to disclose.

John T VanDeVoort, PharmD  Regional Director of Pharmacy, Sacred Heart and St Joseph's Hospitals

John T VanDeVoort, PharmD is a member of the following medical societies: American Society of Health-System Pharmacists

Disclosure: Nothing to disclose.

David Eitel, MD, MBA  Associate Professor, Department of Emergency Medicine, York Hospital; Physician Advisor for Case Management, Wellspan Health System, York

David Eitel, MD, MBA is a member of the following medical societies: American College of Emergency Physicians, American Society of Pediatric Nephrology, Society for Academic Emergency Medicine, and Society of Critical Care Medicine

Disclosure: Nothing to disclose.

John D Halamka, MD, MS  Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center

John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Chief Editor

Rick Kulkarni, MD  Attending Physician, Department of Emergency Medicine, Cambridge Health Alliance, Division of Emergency Medicine, Harvard Medical School

Rick Kulkarni, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: WebMD Salary Employment

References

  1. Wingert WA, Pattabhiraman TR, Cleland R, Meyer P, Pattabhiraman R, Russell FE. Distribution and pathology of copperhead (agkistrodon contortrix) venom. Toxicon. 1980;18(5-6):591-601. [Medline].

  2. Sullivan JB, Wingert WA, Norris RL Jr. North American venomous reptile bites. In: PS Auerbach, ed. Wilderness Medicine: Management of Wilderness and Environmental Emergencies. Vol 2. St. Louis: Mosby-Year Book; 1995:680-709.

  3. Thorson A, Lavonas EJ, Rouse AM, Kerns WP 2nd. Copperhead envenomations in the Carolinas. J Toxicol Clin Toxicol. 2003;41(1):29-35. [Medline].

  4. Bronstein AC, Spyker DA, Cantilena LR Jr, Green J, Rumack BH, Heard SE. 2006 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS). Clin Toxicol (Phila). Dec 2007;45(8):815-917. [Medline].

  5. Spiller HA, Bosse GM. Prospective study of morbidity associated with snakebite envenomation. J Toxicol Clin Toxicol. 2003;41(2):125-30. [Medline].

  6. Bush SP, Thomas TL, et al. Envenomations in children. Pediatr Emerg Med Rep. 1997;2:1-12.

  7. Scharman EJ, Noffsinger VD. Copperhead snakebites: clinical severity of local effects. Ann Emerg Med. Jul 2001;38(1):55-61. [Medline].

  8. Bush SP, Hegewald KG, Green SM, Cardwell MD, Hayes WK. Effects of a negative pressure venom extraction device (Extractor) on local tissue injury after artificial rattlesnake envenomation in a porcine model. Wilderness Environ Med. Fall 2000;11(3):180-8. [Medline].

  9. Bush SP. Snakebite suction devices don't remove venom: they just suck. Ann Emerg Med. Feb 2004;43(2):187-8. [Medline].

  10. Burch JM, Agarwal R, Mattox KL, Feliciano DV, Jordan GL Jr. The treatment of crotalid envenomation without antivenin. J Trauma. Jan 1988;28(1):35-43. [Medline].

  11. Whitley RE. Conservative treatment of copperhead snakebites without antivenin. J Trauma. Aug 1996;41(2):219-21. [Medline].

  12. Dart RC, McNally JT, Spaite DW, Gustafson R. The Sequelae of Pitviper Poisoning in the United States. In: Campbell JA, Brooks DE, editors. Biology of the Pitvipers: Tyler, TX: Selva; 2002:395-404.

  13. Gold BS, Wingert WA. Snake venom poisoning in the United States: a review of therapeutic practice. South Med J. Jun 1994;87(6):579-89. [Medline].

  14. Lavonas EJ, Ruha AM, Banner W, Bebarta V, Bernstein JN, Bush SP, 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. Feb 3 2011;11:2. [Medline]. [Full Text].

  15. Dart RC, Seifert SA, Carroll L, Clark RF, Hall E, Boyer-Hassen LV, et al. Affinity-purified, mixed monospecific crotalid antivenom ovine Fab for the treatment of crotalid venom poisoning. Ann Emerg Med. Jul 1997;30(1):33-9. [Medline].

  16. Lawrence WT, Giannopoulos A, Hansen A. Pit viper bites: rational management in locales in which copperheads and cottonmouths predominate. Ann Plast Surg. Mar 1996;36(3):276-85. [Medline].

  17. Ruha AM, Curry SC, Beuhler M, Katz K, Brooks DE, Graeme KA, et al. Initial postmarketing experience with crotalidae polyvalent immune Fab for treatment of rattlesnake envenomation. Ann Emerg Med. Jun 2002;39(6):609-15. [Medline].

  18. Dart RC, Seifert SA, Boyer LV, Clark RF, Hall E, McKinney P, et al. A randomized multicenter trial of crotalinae polyvalent immune Fab (ovine) antivenom for the treatment for crotaline snakebite in the United States. Arch Intern Med. Sep 10 2001;161(16):2030-6. [Medline].

  19. Jurkovich GJ, Luterman A, McCullar K, et al. Complications of Crotalidae Antivenin Therapy. Journal of Trauma. 1998;28:1032-1037.

  20. Lavonas EJ, Gerardo CJ, O'Malley G, Arnold TC, Bush SP, Banner W Jr, et al. Initial experience with Crotalidae polyvalent immune Fab (ovine) antivenom in the treatment of copperhead snakebite. Ann Emerg Med. Feb 2004;43(2):200-6. [Medline].

 
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Snake envenomations, moccasins. Copperhead (Agkistrodon contortrix). Photo courtesy of Sean Bush, MD.
Snake envenomations, moccasins. Cottonmouth or water moccasin (Agkistrodon piscivorus). Photo courtesy of Sean Bush, MD.
Snake envenomations, moccasins. Copperhead (Agkistrodon contortrix). Photo courtesy of George Bush.
Wound measurement in snakebites. Courtesy of Carolinas Poison Center.
Crotaline treatment algorithm.
 
 
 
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