Dr. Spencer Greene explains why surgical intervention is very rarely appropriate following a snakebite.
Spencer Greene, MD, MS, FACEP, FACMT, FAACT, FAAEM 06 July 2021
Historically, the management of snake envenomations involved surgical intervention, including wound debridement, fasciotomy, and, occasionally, amputation. The authors of a 1976 article in JAMA claimed that “early surgical inspection of the snakebite wound is as essential as early appendectomy in appendicitis.” They further argued that disability from snake envenomation was due to insufficient surgical management and a reliance on non-invasive treatment.
Ironically, multiple studies have since demonstrated that surgical intervention is fraught with complications and leads to disability and disfigurement. Velmahos et al. cited a 31% complication rate following fasciotomy. Long-term sequelae such as dysesthesias, swelling, and tethered scars were observed in more than 75% of surgical patients in a different study. Animal studies prove that morbidity and mortality are increased following prophylactic fasciotomy when compared to antivenom.
There is no evidence that early surgical debridement of a snakebite improves outcomes. In fact, it exacerbates disability, and a working group of surgeons and medical toxicologists with expertise in snakebite management advised against it. They also specifically stated “prophylactic fasciotomy does not improve the outcomes and should not be performed for the treatment of snakebite.”
It is important to know that, even though it is frequently taught that compartment syndrome is a concern following crotalid envenomation, it is rarely seen in clinical practice. I have treated ~ 1000 snakebite victims in 20 years. Several hundred of these envenomations were from rattlesnakes, which, on average, cause more severe local and systemic toxicity than copperhead and cottonmouth bites. I have never had a patient with an actual compartment syndrome. And if/when I do encounter a patient with an objectively confirmed compartment syndrome, I am going to treat him or her with antivenom. You see, elevated compartment pressure is a sign of a severe envenomation, but it is not the cause of the morbidity.
An analogy I like to use is hyperkalemia in the setting of acute digoxin toxicity. A 1973 French study demonstrated that all patients with a potassium > 5.5 from digoxin toxicity died if the poisoning went untreated, even if the hyperkalemia itself was treated. But, if the patients received digoxin Fab fragments, they improved, and the potassium normalized. The hyperkalemia is a marker of badness, but not the cause of it. In snake envenomation, if we only treat the elevated compartment pressure by opening the fascial compartments, the pressure measurements will improve, but the muscle still dies. On the other hand, if we treat the underlying problem – the venom – the muscle is preserved and the pressures normalize. The expert working group arrived at a similar conclusion and stated that, even in the exceptionally rare case of confirmed compartment syndrome, the initial treatment should be additional doses of antivenom, not fasciotomy.
Is surgical intervention ever necessary following snakebite? Very rarely in the acute setting. Fasciotomy is theoretically warranted for an actual compartment syndrome that fails to respond to appropriately dosed antivenom. But that’s a once-in-several-lifetimes situation.
Surgical intervention following envenomation is indicated when there is full-thickness necrosis requiring amputation. But I need to emphasize the full-thickness part. Superficial necrosis may look scary but will recover well when managed conservatively. On rare occasion, skin grafting may be required. But this is a delayed intervention that would not be necessary during the initial hospitalization.
The bottom line is that North American crotalid envenomation (and coral snake envenomation, for that matter) is a medical emergency. The treatment is not surgery. It’s antivenom and supportive care.
Dr. Greene is a paid consultant for BTG International Inc.
Spencer Greene, MD, MS, FACEP, FACMT, FAACT, FAAEM is a board-certified medical toxicologist and emergency physician. He currently serves as the Director of Toxicology and an attending emergency physician at HCA Houston Healthcare-Kingwood. He is a Clinical Professor at the University of Houston College of Medicine. Dr. Greene is a recognized expert in the management of snake envenomation in the US. He has treated more than 1000 snakebites at the bedside and has authored more than 50 scholarly articles and book chapters. He has also served as the course director for the Houston Venom Conference since 2013.