Upper Extremity Crotalid Envenomation: A Review of Incidence and Recent Trends in Management of Snakebites.

PURPOSE: The goal of this study was to evaluate the recent trends in the management of upper extremity Crotalid envenomation in the state of Georgia, United States. METHODS: A retrospective review of the Georgia Poison Center database looking at the reported snakebites to the upper extremity between 2015 and 2020 was performed. Patient demographics, timing and location of injury, severity of envenomation, treatment, including use of antivenin and surgical intervention, and reported complications related to the use of antivenin was extracted. RESULTS: A retrospective review of snakebites between 2015 and 2020 showed 2408 snakebite cases with a mean patient age of 37.4 years. Males incurred 62.8% of all bites. The highest incidence was in summer 52.5%, and between the hours of 5 PM to midnight 57.2%. Overall, 1010 (41.9%) of all bites were categorized as venomous snakebites (55.6% copperhead, 20% rattlesnake, 2.4% cottonmouth, and 22% miscellaneous [including 3 Elapid envenomations] or unidentified. The total number of venomous bites to the upper extremity was 575 (56.9%) and 567 patients received antivenin. Envenomation severity was mild in 29%, moderate in 45%, severe in 10%, and undetermined in 16% of cases. Crotalidae polyvalent immune Fab (Ovine) was the main antivenin used, with overall mean initial therapy dose of 6.2 vials and 59% of patients receiving maintenance therapy. Three patients (0.5%) had a severe anaphylactic reaction to antivenin requiring cessation of therapy. Seven patients had acute compartment syndrome of the upper extremity requiring fasciotomy (3 copperhead, 2 rattlesnake, and 2 unidentified). There was no reported mortality during this period. CONCLUSIONS: Hand surgeons should be familiar with the management of upper extremity Crotalid envenomation. Antivenin remains the main treatment for symptomatic patients. Crotalid snakebites rarely require operative intervention. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Crotalidae Polyvalent Immune Fab and Cost-Effective Management of Hospital Admissions for Snakebites.

BACKGROUND: Venomous snakebites are a common clinical scenario in the Southeastern United States. CroFab® (Crotalidae Polyvalent Immune Fab (Ovine), BTG, Wales, UK) antivenom is indicated in cases involving pit vipers and is known to be expensive. The treatment protocol for snakebites is based on clinically subjective measures triggering the application, or escalation of, antivenom administration. The purpose of this study is to characterize the use of CroFab at our institution and to evaluate the impact of its use regarding cost and overall outcomes. We suspect that it is often used but potentially less often needed. We hypothesized that CroFab use was associated with increased length of stay (LOS) without an observed difference in patient outcomes. MATERIALS AND METHODS: A retrospective chart review of snakebite patients at our level-1 trauma center from 2000 to 2016 was performed. Snakebite location, snake species, number of vials of CroFab administered, hospital LOS, intensive care unit (ICU) LOS, and complications were identified for each patient. Patients were divided into CroFab (C) and no CroFab (NC) groups. RESULTS: One hundred ninety patients with venomous snakebites were included. 53.7% of patients received CroFab. There was no difference in the complication rate of C versus NC groups, (P = .1118). CroFab use was associated with longer hospital LOS (P < .0001) and ICU LOS (P < .0001). DISCUSSION: CroFab use was associated with increased LOS in our patient population. There was no difference in observed outcomes between the C and NC groups. These findings imply that CroFab is potentially over-used in our patient population.

Initial experience with Crotalidae polyvalent immune Fab (ovine) antivenom in the treatment of copperhead snakebite.

STUDY OBJECTIVE: Crotalidae polyvalent immune Fab (ovine) (CroFab; FabAV) effectively treats patients bitten by rattlesnakes. The copperhead snake (Agkistrodon contortrix) caused 37% of venomous snakebites reported to US poison centers in 2001 and is the major envenomating reptile in the southeastern United States. FabAV has not been tested in human beings envenomated by copperhead snakes. METHODS: In this preliminary study, we performed a retrospective chart review of all copperhead snake envenomations reported to the Carolinas Poison Center that were treated with FabAV. Progression of limb swelling, coagulopathy, and hemodynamic status before and after FabAV administration, adverse effects of FabAV therapy, and recurrence phenomena were recorded. RESULTS: Of approximately 400 copperhead envenomation cases reported to the poison center during the study period, 32 received FabAV and were included. Most patients had moderate envenomation. The median time to FabAV administration was 4.0 hours. The median time to achieve initial control was 1.0 hour, with a median dose of 4 vials of FabAV. A rapid initial response, defined as cessation of the progression of local tissue injury within 4 hours of FabAV administration, occurred in 28 cases (88%; 95% confidence interval [CI] 76% to 99%). Four cases (13%; 95% CI 1% to 24%) were considered treatment failures. Recurrent swelling occurred in 6 cases (19%; 95% CI 5% to 32%). The incidence of recurrent swelling was not reduced by administration of repeated doses of antivenom on a planned schedule. One patient developed late-onset coagulopathy. One minor allergic reaction was observed. CONCLUSION: In this select group of patients bitten by copperhead snakes, local tissue effects of envenomation halted promptly after FabAV treatment in most cases. Treatment failures occurred, and recurrence of swelling and defibrination syndrome was sometimes problematic. Time to return to work and long-term limb function were not assessed. A controlled trial with long-term follow-up is needed to define the role of FabAV treatment for copperhead envenomation.