eMedicine Specialties > Emergency Medicine > Environmental

Snake Envenomation, Mohave Rattle: Differential Diagnoses & Workup

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

Differential Diagnoses

Bee and Hymenoptera Stings
Scorpion Envenomations
Bites, Animal
Snake Envenomations, Coral
Bites, Insects
Snake Envenomations, Rattle
Cellulitis
Spider Envenomations, Brown Recluse
Centipede Envenomations
Spider Envenomations, Tarantula
Lizard Envenomations
Spider Envenomations, Widow
Millipede Envenomations
Necrotizing Fasciitis

Workup

Laboratory Studies

  • Rhabdomyolysis may occur from severe snake envenomations but is best described after canebrake (Crotalus horridus atricaudatus) and Mohave (C scutulatus) rattlesnake envenomations. Rhabdomyolysis may lead to myoglobinuric renal failure and subsequent electrolyte abnormalities, such as hyper- or hypokalemia or hypocalcemia.
    • Creatine kinase (CK)
    • Electrolytes
    • Blood urea nitrogen (BUN) and creatinine
    • Calcium
    • Phosphorus
    • Urinalysis
  • Mohave toxin has less effect on coagulation than other rattlesnake venoms. However, coagulopathies may occur. (See Snake Envenomations, Rattle for suggested laboratory tests.)
  • For respiratory difficulty, consider arterial blood gas (ABG) measurements.
  • Obtain laboratory and other diagnostic data on a case-by-case basis. Factors to consider may include severity of envenomation, physician preference, and cost.

Imaging Studies

  • Radiographic findings may reveal teeth or fangs retained in the wound.

Other Tests

  • Obtain an electrocardiogram (ECG), if indicated. Although cardiac enzymes may rise with severe rhabdomyolysis, current literature suggests that this does not reflect cardiac injury.
  • Skin testing
    • Skin testing is not necessary before administering Crotaline Fab antivenom (CroFab) therapy.
    • Intracutaneous injection of 0.02-0.03 mL of a 1:10 dilution of horse serum or antivenom is recommended in the Antivenin Crotalidae Polyvalent package insert.
      • A positive test result is manifested by the development of a wheal within 5-30 minutes. However, skin testing is unreliable. False-positive and false-negative results may occur.
      • Using antivenom (further diluted to 1:100) rather than the horse serum control that is supplied may increase the sensitivity and specificity of the test.
      • Skin testing may be considered variably useful in predicting immediate hypersensitivity in cases of moderate envenomation when it is uncertain if the need for antivenom outweighs the risk of anaphylaxis.
      • Skin testing may sensitize individuals at risk for future exposures to antivenom, or it may precipitate anaphylaxis.
      • If antivenom is clearly indicated, begin administration as described below, without waiting to perform a skin test.

Procedures

  • Central venous or interosseous access may need to be obtained. However, avoid placing a central line in a noncompressible site (eg, subclavian) because of the risk of bleeding from venom-induced coagulopathy.
  • Fasciotomy probably is not indicated in Mohave (venom A) envenomation. If severe swelling is noted, suspect envenomation by a snake other than a venom A Mohave rattlesnake and treat accordingly (see Snake Envenomations, Rattle).

More on Snake Envenomation, Mohave Rattle

Overview: Snake Envenomation, Mohave Rattle
Differential Diagnoses & Workup: Snake Envenomation, Mohave Rattle
Treatment & Medication: Snake Envenomation, Mohave Rattle
Follow-up: Snake Envenomation, Mohave Rattle
Multimedia: Snake Envenomation, Mohave Rattle
References
[ CLOSE WINDOW ]

References

  1. 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].

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

  3. Bush SP, Cardwell MD. Mojave rattlesnake (Crotalus scutulatus scutulatus) identification. Wilderness Environ Med. Spring 1999;10(1):6-9. [Medline].

  4. 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].

  5. 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].

  6. 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].

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

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

  9. Carroll RR, Hall EL, Kitchens CS. Canebrake rattlesnake envenomation. Ann Emerg Med. Jul 1997;30(1):45-8. [Medline].

  10. Clark RF, Williams SR, Nordt SP, Boyer-Hassen LV. Successful treatment of crotalid-induced neurotoxicity with a new polyspecific crotalid Fab antivenom. Ann Emerg Med. Jul 1997;30(1):54-7. [Medline].

  11. Farstad D, Thomas T, Chow T, Bush S, Stiegler P. Mojave rattlesnake envenomation in southern California: a review of suspected cases. Wilderness Environ Med. May 1997;8(2):89-93. [Medline].

  12. 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].

  13. Glenn JL, Straight RC. Intergradation of two different venom populations of the Mojave rattlesnake (Crotalus scutulatus scutulatus) in Arizona. Toxicon. 1989;27(4):411-8. [Medline].

  14. Hardy DL. Envenomation by the Mojave rattlesnake (Crotalus scutulatus scutulatus) in southern Arizona, U.S.A. Toxicon. 1983;21(1):111-8. [Medline].

  15. Hardy DL. Fatal rattlesnake envenomation in Arizona: 1969-1984. J Toxicol Clin Toxicol. 1986;24(1):1-10. [Medline].

  16. Jansen PW, Perkin RM, Van Stralen D. Mojave rattlesnake envenomation: prolonged neurotoxicity and rhabdomyolysis. Ann Emerg Med. Mar 1992;21(3):322-5. [Medline].

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

[ CLOSE WINDOW ]

Further Reading

[ CLOSE WINDOW ]

Keywords

Mohave rattlesnake, Mojave rattlesnake bite, rattle snake envenomation, rattlesnake bite, Crotalus scutulatus, Mojave rattlesnake, snake envenomation, venom A, venom B, lethal venom, antivenom

[ CLOSE WINDOW ]

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

RELATED MEDSCAPE ARTICLES
Articles
 
 
HONcode

We subscribe to the
HONcode principles of the
Health On the Net Foundation

All material on this website is protected by copyright, Copyright© 1994- by Medscape.
This website also contains material copyrighted by 3rd parties.

DISCLAIMER: The content of this Website is not influenced by sponsors. The site is designed primarily for use by qualified physicians and other medical professionals. The information contained herein should NOT be used as a substitute for the advice of an appropriately qualified and licensed physician or other health care provider. The information provided here is for educational and informational purposes only. In no way should it be considered as offering medical advice. Please check with a physician if you suspect you are ill.