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Snake Envenomation, Rattle

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
Contributor Information and Disclosures

Updated: Jul 24, 2008

Introduction

Background

Rattlesnakes are pit vipers and include the genera Crotalus and Sistrurus. Pit vipers may be identified by a heat-sensing pit anteroinferior to the eye. Rattlesnakes may be identified in all but one species by a rattle at the tip of the tail. Rattlesnakes are indigenous from North America to South America.

Juvenile southern Pacific rattlesnake (<EM>Crotal...

Juvenile southern Pacific rattlesnake (Crotalus oreganus helleri). Photo by Sean Bush, MD.

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Juvenile southern Pacific rattlesnake (<EM>Crotal...

Juvenile southern Pacific rattlesnake (Crotalus oreganus helleri). Photo by Sean Bush, MD.


Pathophysiology

Venom is usually injected into subcutaneous tissue via hollow movable fangs located in the anterior mouth. Occasionally, intramuscular or (probably rarely) intravenous injection occurs. Rattlesnake venom is generally composed of several digestive enzymes and spreading factors, which result in local and systemic injury.

Clinically, local effects most commonly predominate, progressing from pain and edema to ecchymosis and bullae. Hematologic abnormalities, including defibrination with or without thrombocytopenia, may result, but serious bleeding is uncommon. Local or diffuse myotoxicity may result in complications such as compartment syndrome or rhabdomyolysis. Other general effects include shock, myokymia/fasciculations, taste changes, and vomiting. Rarely, direct cardiotoxicity or allergy to venom may occur. Some rattlesnakes may exhibit neurotoxicity with minimal local tissue effects (see Snake Envenomations, Mohave Rattle).

Frequency

United States

Approximately 7,000-8,000 reptile bites are reported to the American Association of Poison Control Centers (AAPCC) each year. However, this figure is probably conservative because of underreporting. Rattlesnakes cause the majority of all bites by identified venomous snakes in the United States. Dry bite (ie, no clinical evidence of envenomation) occurs in between 10 and 50% of strikes.

International

An estimated 300,000-400,000 venomous snakebites occur per year. Although rattlesnakes are not found naturally outside of North America, Central America, and South America, they are imported into zoos, museums, and private collections in other regions of the world.

Mortality/Morbidity

Fewer than half a dozen deaths occur per year as a result of snakebite in the United States; most are caused by rattlesnake bites. Estimates of deaths each year from snakebite range from 30,000-110,000 worldwide. Up to 5 times as many individuals experience permanent morbidity.

US mortality with administration of antivenin is approximately 0.28%. Without antivenin being administered, mortality is approximately 2.6%.

Sex

Males are bitten more commonly than females.

Age

Young adults are bitten most commonly.

Clinical

History

All or none of the following may be present. Note that symptoms are subject to change, and this change can be very rapid or very insidious. In addition, severity is generally guided by the most severely affected parameter.

  • Pain around the bite site
  • Swelling
  • Taste changes (eg, a metallic taste)
  • Difficulty breathing
  • Chest pain
  • Nausea, vomiting, or diarrhea
  • Hematemesis, hematochezia
  • Neurologic symptoms
    • Weakness
    • Paresthesias
  • Syncope, near syncope

Physical

  • Fang marks - May be 1, 2, or more, or may be unable to discern
Moderate rattlesnake envenomation in a toddler af...

Moderate rattlesnake envenomation in a toddler after treatment with antivenom. Photo by Sean Bush, MD.

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Moderate rattlesnake envenomation in a toddler af...

Moderate rattlesnake envenomation in a toddler after treatment with antivenom. Photo by Sean Bush, MD.

  • Tenderness surrounding the bite site
  • Local edema
    • Use a pen to mark and time the border of advancing edema every 15-20 minutes initially. Once stabilization with antivenom has occurred, repeat measurements every 1-2 hours.
    • Rapidly progressive swelling is usually indicative of a severe envenomation.
  • Erythema
  • Ecchymosis
  • Bullae
  • Bleeding
  • Hypotension/hypertension
  • Tachycardia
  • Myokymia (muscle fasciculations)
  • Neurologic effects
  • Lethargy

Causes

A large percentage of bites occur when a snake is handled, kept as a pet, or abused. These are considered intentionally interactive bites. Many bites are associated with ethanol use.

More on Snake Envenomation, Rattle

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Treatment & Medication: Snake Envenomation, Rattle
Follow-up: Snake Envenomation, Rattle
Multimedia: Snake Envenomation, Rattle
References
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References

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  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].

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

  8. Bush SP, Green SM, Laack TA, Hayes WK, Cardwell MD, Tanen DA. Pressure immobilization delays mortality and increases intracompartmental pressure after artificial intramuscular rattlesnake envenomation in a porcine model. Ann Emerg Med. Dec 2004;44(6):599-604. [Medline].

  9. Bush SP, Green SM, Moynihan JA, Hayes WK, Cardwell MD. Crotalidae polyvalent immune Fab (ovine) antivenom is efficacious for envenomations by Southern Pacific rattlesnakes (Crotalus helleri). Ann Emerg Med. Dec 2002;40(6):619-24. [Medline].

  10. 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].

  11. Bush SP, Jansen PW. Severe rattlesnake envenomation with anaphylaxis and rhabdomyolysis. Ann Emerg Med. Jun 1995;25(6):845-8. [Medline].

  12. Bush SP, Wu VH, Corbett SW. Rattlesnake venom-induced thrombocytopenia response to Antivenin (Crotalidae) Polyvalent: a case series. Acad Emerg Med. Feb 2000;7(2):181-5. [Medline].

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  17. French WJ, Hayes WK, Bush SP, Cardwell MD, Bader JO, Rael ED. Mojave toxin in venom of Crotalus helleri (Southern Pacific Rattlesnake): molecular and geographic characterization. Toxicon. Dec 1 2004;44(7):781-91. [Medline].

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  22. Langley RL, Morrow WE. Deaths resulting from animal attacks in the United States. Wilderness Environ Med. 1997;8:8-16.

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  25. Offerman SR, Bush SP, Moynihan JA, Clark RF. Crotaline Fab antivenom for the treatment of children with rattlesnake envenomation. Pediatrics. Nov 2002;110(5):968-71. [Medline].

  26. Premawardhena AP, de Silva CE, Fonseka MM, Gunatilake SB, de Silva HJ. Low dose subcutaneous adrenaline to prevent acute adverse reactions to antivenom serum in people bitten by snakes: randomised, placebo controlled trial. BMJ. Apr 17 1999;318(7190):1041-3. [Medline].

  27. Riffer E, Curry SC, Gerkin R. Successful treatment with antivenin of marked thrombocytopenia without significant coagulopathy following rattlesnake bite. Ann Emerg Med. Nov 1987;16(11):1297-9. [Medline].

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  29. Watson WA, Litovitz TL, Klein-Schwartz W, Rodgers GC Jr, Youniss J, Reid N, et al. 2003 annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System. Am J Emerg Med. Sep 2004;22(5):335-404. [Medline].

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  31. Wingert WA, Chan L. Rattlesnake bites in southern California and rationale for recommended treatment. West J Med. Jan 1988;148(1):37-44. [Medline].

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Further Reading

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Keywords

rattlesnake, rattlesnake bite, rattlesnake venom, rattlesnake envenomation, Crotalus species, Sistrurus species, rattle snake envenomation, pit vipers

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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

Medical Editor

Robert L Norris, MD, Associate 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.

Pharmacy Editor

John T VanDeVoort, PharmD, Regional Director of Pharmacy, Sacred Heart & 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.

Managing Editor

James Steven Walker, DO, MS, Clinical Professor of Surgery, Department of Surgery, University of Oklahoma Health Sciences Center
James Steven Walker, DO, MS is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American College of Osteopathic Emergency Physicians, and American Osteopathic Association
Disclosure: Nothing to disclose.

CME Editor

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

Jonathan Adler, MD, Attending Physician, Department of Emergency Medicine, Massachusetts General Hospital; Division of Emergency Medicine, Harvard Medical School
Jonathan Adler, MD is a member of the following medical societies: American Academy of Emergency Medicine and Society for Academic Emergency Medicine
Disclosure: eMedicine.com, Inc. Consulting fee Consulting

 
 
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