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.

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 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).

Treatment & Management

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Farstad D, Thomas T, Chow T, Bush S, Stiegler P. Mojave rattlesnake envenomation in southern California: a review of suspected cases. Wilderness Environ Med. 1997 May. 8(2):89-93. [QxMD MEDLINE Link].
Hardy DL. Envenomation by the Mojave rattlesnake (Crotalus scutulatus scutulatus) in southern Arizona, U.S.A. Toxicon. 1983. 21(1):111-8. [QxMD MEDLINE Link].
Hardy DL. Fatal rattlesnake envenomation in Arizona: 1969-1984. J Toxicol Clin Toxicol. 1986. 24(1):1-10. [QxMD MEDLINE Link].
Wingert WA, Chan L. Rattlesnake bites in southern California and rationale for recommended treatment. West J Med. 1988 Jan. 148(1):37-44. [QxMD MEDLINE Link].
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Bush SP, Jansen PW. Severe rattlesnake envenomation with anaphylaxis and rhabdomyolysis. Ann Emerg Med. 1995 Jun. 25(6):845-8. [QxMD MEDLINE Link].
Bush SP, Jansen PW. Severe rattlesnake envenomation with anaphylaxis and rhabdomyolysis. Ann Emerg Med. 1995 Jun. 25(6):845-8. [QxMD MEDLINE Link].
Jansen PW, Perkin RM, Van Stralen D. Mojave rattlesnake envenomation: prolonged neurotoxicity and rhabdomyolysis. Ann Emerg Med. 1992 Mar. 21(3):322-5. [QxMD MEDLINE Link].
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). 2007 Dec. 45(8):815-917. [QxMD MEDLINE Link].
Gummin DD, Mowry JB, Spyker DA, Brooks DE, Fraser MO, Banner W. 2016 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS): 34th Annual Report. Clin Toxicol (Phila). 2017 Dec. 55 (10):1072-1252. [QxMD MEDLINE Link].
Massey DJ, Calvete JJ, Sánchez EE, Sanz L, Richards K, Curtis R, et al. Venom variability and envenoming severity outcomes of the Crotalus scutulatus scutulatus (Mojave rattlesnake) from Southern Arizona. J Proteomics. 2012 May 17. 75(9):2576-87. [QxMD MEDLINE Link].
Carroll RR, Hall EL, Kitchens CS. Canebrake rattlesnake envenomation. Ann Emerg Med. 1997 Jul. 30(1):45-8. [QxMD MEDLINE Link].
Bush SP. Snakebite suction devices don't remove venom: they just suck. Ann Emerg Med. 2004 Feb. 43(2):187-8. [QxMD MEDLINE Link].
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. 2000 Fall. 11(3):180-8. [QxMD MEDLINE Link].
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. 2004 Dec. 44(6):599-604. [QxMD MEDLINE Link].
Bush SP, Cardwell MD. Mojave rattlesnake (Crotalus scutulatus scutulatus) identification. Wilderness Environ Med. 1999 Spring. 10(1):6-9. [QxMD MEDLINE Link].
Gerardo CJ, Quackenbush E, Lewis B, Rose SR, Greene S, Toschlog EA, et al. The Efficacy of Crotalidae Polyvalent Immune Fab (Ovine) Antivenom Versus Placebo Plus Optional Rescue Therapy on Recovery From Copperhead Snake Envenomation: A Randomized, Double-Blind, Placebo-Controlled, Clinical Trial. Ann Emerg Med. 2017 Aug. 70 (2):233-244.e3. [QxMD MEDLINE Link].
Carstairs SD, Kreshak AA, Tanen DA. Crotaline Fab antivenom reverses platelet dysfunction induced by Crotalus scutulatus venom: an in vitro study. Acad Emerg Med. 2013 May. 20(5):522-5. [QxMD MEDLINE Link].
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Media Gallery

Mojave rattlesnake (Crotalus scutulatus). Note the diamond pattern fades into bands along the caudal third of the back and the white tail rings are wider than the black. Photo by Sean Bush, MD.
This is the typical appearance of a southern California Mojave rattlesnake bite site. Photo by Sean Bush, MD.
Mojave rattlesnake (Crotalus scutulatus). Photo by Sean Bush, MD.
A red diamond rattlesnake (Crotalus ruber). The postocular light stripe extends above the angle of the mouth in Mojave rattlesnakes. Photo by Sean Bush, MD.
This is a juvenile Mojave rattlesnake (postmortem). Note that the diamondback pattern fades into bands along the latter part of the snake's dorsum. Photo by Sean Bush, MD.
A western diamondback rattlesnake (Crotalus atrox). Photo by Sean Bush, MD.