Copperhead bites – do they need antivenom?
June 8, 2012, 7:20 pm
Current Management of Copperhead Snakebite. Walker JP et al. J Am Coll Surg 2011 Apr;212:470-4.
Of all the major crotalids, copperhead snakes most often produce bites that are clinically mild, requiring only supportive care and observation. The authors of this paper state that death is rare; the chapter on snakebite in Goldfrank’s Toxicologic Emergencies (9th edition, 2011) say that “[a]lthough serious copperhead bites occasionally occur, no reports of death can be found in the medical literature”.
The authors did a retrospective study of all snakebites that presented to their level III trauma center (East Texas MEdical Center, Crockett, TX) with snakebites from 1995 to 2010. The identified 88 patients bitten by the Southern copperhead (Agkistrodon contortrix). Unfortunately, they give no information on how the snakes were identified. The most common symptoms were pain and swelling; 85% of these patients had mild, grade I envenomations, with no systemic manifestations. Ten patients had an elevated PT, but there were no instances of clinical bleeding. No patient received antivenom or required fasciotomy, and there were no deaths.
The authors conclude:
. . . a bite from a snake that is positivelyidentified as a copperhead (A. contortrix) can almost always be managed by observation, will only rarely require antivenom, and even less often will required surgical intervention.
As was pointed out in the discussion that followed presentation of this paper at the Southern Surgical Association in 2010, the authors’ results and conclusions should be taken with some caution. It is not clear that the overwhelmingly mild cases of envenomation they saw was not a local phenomenon, and would apply to bites from the same snakes in different regions of the county. In addition, the authors did not report what proportion of their patients were young children, who would be more susceptible to develop more severe manifestations.
The paper includes an interesting survey of treatments for snakebite through the ages. My favorite was from a paper by Allen FM, Mechanical treatment of venomous bites and wounds. (Southern Med J 1938 Dec:1248-1253):
For gaining time (a tourniquet can be placed) preliminary to amputation. If a bite is believed to be of a fatal character, and if there is nobody qualified to amputate, a tight tourniquet can by applied by any companion or by the victim himself and it can be expected to prevent all symptoms for a least several hours, until surgical aid is obtained or, if necessary, until the numbed limb can be hacked off by anybody”.
[Photograph of copperhead snake from wikipedia.org]