Case Based for July

While bringing in toys from outside, an eight-year-old male was bitten by a juvenile Western Rattlesnake. He noticed immediate pain in his right third digit. EMS was activated and transported the patient 45 minutes to our facility in 45 minutes. EMS noted normal vital signs and discoloration to the digit. They also noted redness to the arm which was attributed to the blood pressure cuff.

The patient was immediately evaluated, and an envenomation was diagnosed. He was immediately given the four units of crotalid antivenom in the pharmacy. The areas of redness were noted to ascend to the right axilla. The outer limits were marked and timed. Labs to included CBC, CMP, PT/INR, and PTT were sent and normal. The patient’s arm was elevated with pillows.

The transfer process was initiated; however, the regional quaternary children’s hospital did not have antivenom in its formulary. Thus, a smaller hospital with pediatric capabilities was chosen. Air transport was unavailable due to significant thunderstorms in the area, and ground transport was also delayed. In the interim, the patient’s arm pain worsened, as did the erythema of the arm. Two additional doses of antivenom were acquired from a neighboring hospital and transported to our facility by EMS. Approximately five hours after arrival, the patient was transported to the receiving facility with the aircrew providing patient care and infusing the additional two vials of antivenom.

The patient was admitted to the ICU, received six additional vials of antivenom, and recovered well. He was discharged home four days later with instructions for daily wound care.

Each year, approximately 8,000 people are bitten by snakes in the United States. The overwhelming majority of these are from the crotalid family, which includes rattlesnakes, cottonmouths, and other pit vipers. Crotalid venom degrades structural proteins (like collagen and fibrin), which compromises capillary walls and causes rapid swelling, ecchymosis, and local necrosis. The venom directly attacks the victim’s clotting cascade. It contains procoagulant enzymes that consume fibrinogen—leading to paradoxical clotting and then depletion, leading to DIC. Other peptides prevent platelet aggregation, further inhibiting the formation of stable clots.

The breakdown of blood vessels causes intravascular fluid “third-spacing” into the surrounding tissue, which results in hypovolemia. Some venom peptides can also have direct cardiotoxic effects, leading to profound hypotension. While rare in most North American crotalids, specific species (e.g., the Mojave rattlesnake) carry a potent presynaptic neurotoxin that binds to nerve terminals and blocks neurotransmitter release, resulting in flaccid paralysis.

Treatment has evolved over the past decades, and tourniquets, vacuum devices, fasciotomies, and other interventions are no longer recommended. Initial treatment should include mild elevation of the extremity, IV access, and pain control. Four to six vials of crotalid antivenom (Anavip, Crofab) should be infused, depending on severity. Dosing is based on the severity of the bite, not the size of the patient. Labs should be drawn and include coagulation studies. Repeat dosing of antivenom is two doses every six hours until symptoms abate.

Recent research has demonstrated that compartment syndrome is rare, and prophylactic fasciotomies are not recommended. Evaluation of distal circulation and local wound care of the blistered digit is usually sufficient.

The National Snakebite Support organization provides real-time guidance on envenomation treatment. Long onto https://www.nationalsnakebitesupport.org/active-snakebite to connect with snakebite experts. Similarly, the Wilderness Medicine Society updated their clinical practice guidline. It may be found at https://journals.sagepub.com/doi/full/10.1177/10806032261451823.

Written by Joshua Corsa, MD

ERx Clinical Partners Medical Director

This is for informational purposes only. For medical advice or diagnosis, consult a physician