Mojave Rattlesnake Envenomation Workup

Updated: Apr 09, 2021
  • Author: Sean P Bush, MD, FACEP; Chief Editor: Joe Alcock, MD, MS  more...
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Laboratory Studies

Rhabdomyolysis may occur from severe snake envenomations but is best described after canebrake (Crotalus horridus atricaudatus) and Mojave (C scutulatus) rattlesnake envenomations. [7, 8, 13] 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

Mojave toxin has less effect on coagulation than other rattlesnake venoms. However, coagulopathies may occur. (See Rattlesnake Envenomation 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 either the Crotalidae immune Fab ovine (CroFab) or equine (Anavip) antivenins. Sensitivity testing was previously required for the older polyvalent equine derived antivenin that is no longer on the U.S. market.



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 Mojave (venom A) envenomation. If severe swelling is noted, suspect envenomation by a snake other than a venom A Mojave rattlesnake and treat accordingly (see Rattlesnake Envenomation).