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Jeanphilippe Chippaux - One of the best experts on this subject based on the ideXlab platform.
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contribution of ultrasonography to the diagnosis of internal bleeding in snakebite Envenomation
Journal of Venomous Animals and Toxins Including Tropical Diseases, 2016Co-Authors: Blaise Adelin Tchaou, Jeanphilippe Chippaux, Kofimensa Savi De Tove, Yolande Sissinto Savi De Tove, Aurelien Tchemaha C Djomga, Abdourahman Aguemon, Achille MassougbodjiAbstract:Background In Africa, snakebite Envenomations are frequently complicated by life-threatening hemorrhagic syndromes. The authors of the present study conducted a prospective analysis at the University Hospital of Parakou (north of Benin) for seven months (January 1 to July 31, 2014) to assess the contribution of ultrasonography to the diagnosis of internal bleedings and management of Envenomation.
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Contribution of ultrasonography to the diagnosis of internal bleeding in snakebite Envenomation
Journal of Venomous Animals and Toxins including Tropical Diseases, 2016Co-Authors: Blaise Adelin Tchaou, Aurelien Tchemaha C Djomga, Abdourahman Aguemon, Achille Massougbodji, Kofi-mensa Savi De Tové, Yolande Sissinto-savi De Tové, Jeanphilippe ChippauxAbstract:Background In Africa, snakebite Envenomations are frequently complicated by life-threatening hemorrhagic syndromes. The authors of the present study conducted a prospective analysis at the University Hospital of Parakou (north of Benin) for seven months (January 1 to July 31, 2014) to assess the contribution of ultrasonography to the diagnosis of internal bleedings and management of Envenomation. Methods An ultrasound examination was performed in all patients with clinical Envenomation regardless of its severity. The study involved 32 patients admitted to the ICU of the University Hospital of Parakou. Results The average age was 27 ± 13.9 years. The main signs of severity were: prolongation of clotting time (88 %), severe anemia (41 %), clinical hemorrhage (47 %), and shock (19 %). The ultrasound imaging showed internal hemorrhage in 18 patients (56 %). There were hematomas (22 %), hemoperitoneum (13 %) or a combination of both (22 %). The occurrence of internal bleeding and hemoperitoneum were mainly related to the delay of hospital presentation ( p = 0.007) and the existence of external bleeding ( p = 0.04). Thirty patients (94 %) received antivenom. Case fatality rate was 3.1 %. Conclusion Ultrasonography may help in diagnosing internal bleeding, even in patients that did not show external hemorrhages, and evaluating its importance. As a consequence, the management of snakebite victims may be significantly improved.
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Use of antivenoms for the treatment of Envenomation by Elapidae snakes in Guinea, Sub-Saharan Africa
Journal of Venomous Animals and Toxins including Tropical Diseases, 2013Co-Authors: Mamadou C Baldé, Jeanphilippe Chippaux, Roberto P. Stock, Mamadou Y Boiro, Achille MassougbodjiAbstract:Background In Guinea Elapids are responsible for 20% of Envenomations. The associated case fatality rate (CFR) ranged 15-27%, irrespective of treatment. Results We studied 77 neurotoxic Envenomations divided in 3 groups: a set of patients that received only traditional or symptomatic treatments, and two other groups that received either 2 or 4 initial vials of Antivipmyn® Africa renewed as necessary. CFR was 27.3%, 15.4% and 17.6%, respectively. Although antivenom treatment was likely to reduce CFR, it didn’t seem to have an obvious clinical benefit for the patients, suggesting a low treatment efficacy. Mean delay to treatment or clinical stages were not significantly different between the patients who recovered and the patients who died, or between groups. Interpretation of these results is complicated by the lack of systematic studies under comparable conditions. Of particular importance is the absence of assisted ventilation, available to patients in all the other clinical studies of neurotoxic Envenomation. Conclusion The apparent lack of clinical benefit may have several causes. The hypothesis of a limited therapeutic window, i.e. an insufficient formation of antigen-antibody complexes once toxins are bound to their targets and/or distributed beyond the reach of antivenom, should be explored.
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methodology of clinical studies dealing with the treatment of Envenomation
Toxicon, 2010Co-Authors: Jeanphilippe Chippaux, Roberto P. Stock, Achille MassougbodjiAbstract:A total of 142 clinical studies have been devoted to the treatment of Envenomations, of which 115 address snake bites, 20 scorpion stings, and 8 other animals (one addresses both snake and spider Envenomation). Antivenom use was studied in 118, of which 82 addressed efficacy, 43 evaluated safety, 23 studied dosage and 8 explored other issues. Besides anecdotal clinical reports, three classes of clinical studies are distinguished: (a) observational clinical studies (55 of the total) which analyze series of cases, (b) comparative clinical studies (36) which compare therapeutic products or treatment regimens without a gold standard for comparison and (c) randomized clinical trials (RCT, 51). The goals, methods and constraints of design of RCT are determined by whether explanatory (analytical) or pragmatic considerations are prioritized. Explanation-oriented RCT rely on strict group comparability before and during treatment, in order to ensure the internal validity of the study. The pragmatically-oriented RCT aims at establishing the superiority of a treatment over another, the goal being to maximize the external validity of the trial (that is, its application in current practice). We found that all clinical studies of treatment of Envenomation lean markedly toward the explanatory end and suggest that, given some particularities of Envenomation as a medical condition, a more pragmatic approach may be of value, particularly under the conditions prevalent for clinical studies in developing nations.
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clinical trial of an f ab 2 polyvalent equine antivenom for african snake bites in benin
American Journal of Tropical Medicine and Hygiene, 2007Co-Authors: Jeanphilippe Chippaux, Roberto P. Stock, A. Massougbodji, Alejandro AlagonAbstract:We report the results of a trial designed to measure the safety and efficacy of African Antivipmyn, a new freeze-dried polyvalent equine F(ab')2-based antivenom. We tested 289 Envenomations. After treatment, 19% of treated patients had undesirable events, all benign. A possible adverse effect was attributed to this antivenom in 11% of the patients. Bleeding was observed in 48% of the patients; it stopped within 2 hours after treatment with antivenom in 60% of the patients. Blood incoagulability was observed in 80% of the patients. Restoration of coagulation was attained within 4 hours in 60% of the patients. Nine patients died; 6 arrived at the hospital in the final stage of complications and 5 arrived at the hospital more than 60 hours after the bite. The value of blood coagulation tests in diagnosis of Envenomation and bleeding as an indicator of renewal of treatment are emphasized. Secondary objectives were to evaluate the efficacy this an- tivenom by comparing the incidence of the deaths with pub- lished data for the same zone (10-12.3%, which was rounded to 10%) and the incidence of patients cured without sequelae; identify symptoms facilitating the surveillance and the choice of dosage; and propose an algorithm for management of snake bites (signs of Envenomation, doses, indicators of sur- veillance and criteria of cure).
Anne-michelle Ruha - One of the best experts on this subject based on the ideXlab platform.
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Epidemiology, Clinical Features, and Management of Texas Coral Snake (Micrurus tener) Envenomations Reported to the North American Snakebite Registry
Journal of Medical Toxicology, 2020Co-Authors: Spencer Greene, Anne-michelle Ruha, Sharan L. Campleman, Jeffrey BrentAbstract:Introduction Few of the 5000–8000 snakebites reported to poison control centers annually in the USA are attributed to coral snakes. This study describes Texas coral snake Envenomations reported to the North American Snakebite Registry. Methods All Texas coral snake Envenomation cases reported to the registry were identified for the period from January 1, 2015, through December 31, 2019. Data reviewed for this study included details regarding the snake encounter, patient demographics, signs and symptoms, treatment, and outcomes. Descriptive statistics were used to report results. Results Ten men and four nonpregnant women reported coral snake bites. The median patient age was 15.5 (range 5–72 years). There were 12 upper extremity bites and two bites to the lower extremity. The most common symptoms reported were paresthesias and pain. All subjects had paresthesias, often described as an “electric” sensation. Seven patients described them as painful. The most common clinical findings were erythema and swelling. No patient developed tissue damage, hematotoxicity, rhabdomyolysis, hypotension, weakness, or respiratory symptoms. Thirteen subjects were treated with opioids. Six patients were treated with antiemetics: three prophylactically and two for opioid-induced nausea. One patient developed nausea and non-bloody, nonbilious emesis within 1 hour of the bite, prior to receiving opioids. No patients were treated with antivenom. Antibiotics were not administered to any patient, and no infections were reported. Conclusions Envenomations from M. tener in Southeast Texas are characterized by painful paresthesias. Mild swelling and erythema are common. Neurotoxicity necessitating antivenom or mechanical ventilation did not occur.
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When It Comes to Snakebites, Kids Are Little Adults: a Comparison of Adults and Children with Rattlesnake Bites
Journal of Medical Toxicology, 2020Co-Authors: Michael Levine, Anne-michelle Ruha, Jeffrey Brent, Brian Wolk, Martin Caravati, Sharan L. CamplemanAbstract:Background Rattlesnake Envenomations are a significant cause of morbidity in the USA. While pediatric rattlesnake Envenomations are relatively common, data comparing adult and pediatric patients with rattlesnake Envenomations remain limited. Methods This multi-center retrospective study used the North American Snakebite Registry (NASBR), a sub-registry of the Toxicology Investigator’s Consortium (ToxIC). All cases of rattlesnake Envenomations between January 1, 2013, and December 31, 2017, which were entered into the NASBR, were reviewed. Clinical and laboratory parameters, as well as treatment and outcome measurements, were compared between adult and pediatric patients. Results A total of 420 unique cases were identified, including 94 pediatric patients. Adult patients were more likely to be male (76% vs. 62%; OR 1.98) and sustain upper extremity Envenomations (57% vs. 25%; OR 4.4). After adjusting for bite location, adults were more likely to exhibit edema compared with pediatric patients. After controlling for Envenomation location, there was no difference in rates of necrosis between adult and pediatric patients. Adults exhibited early hematologic toxicity less frequently than pediatric patients, but there was no difference in the rates of late hematologic toxicity. There were no differences in the rates of hypotension or intubation. Conclusion While adult and pediatric patients have some differences in Envenomation characteristics and laboratory parameters, adults and pediatric patients had similar rates of systemic toxicity, severity, length of stay, and late hematologic toxicity.
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the epidemiology clinical course and management of snakebites in the north american snakebite registry
Journal of Medical Toxicology, 2017Co-Authors: Anne-michelle Ruha, Angela Padillajones, Spencer Greene, Meghan B. Spyres, Kurt C. Kleinschmidt, Jeffrey Brent, Sharan L. CamplemanAbstract:The American College of Medical Toxicology established the North American Snakebite Registry (NASBR), a national database of detailed, prospectively collected information regarding snake Envenomation in the United States, in 2013. This report describes the epidemiology, clinical course, and management of snakebites in the NASBR. All cases entered into the NASBR between January 1, 2013 and December 31, 2015 were identified. Descriptive statistics are used to report results. Fourteen sites in 10 states entered 450 snakebites. Native species comprised 99% of cases, almost all of which were pit viper bites. 56.3% were identified as rattlesnakes and 29.4% as copperheads. 69.3% were male and 28.2% were children age 12 and under. Fifty-four percent of bites were on the lower extremity. Twenty-seven percent of patients with lower extremity bites were not wearing shoes. Common tissue findings associated with Envenomation were swelling, ecchymosis, and erythema. Systemic effects and hematologic toxicity were more common in rattlesnake than copperhead or cottonmouth Envenomations. Crotalidae Polyvalent Immune Fab antivenom was given to 84% of patients. Twelve patients (4.3%) were re-admitted to the hospital after completion of treatment. Eight were re-treated with antivenom. The NASBR gathers detailed data on venomous snakebites across the US. In its initial years, useful information has already been gained. Data regarding footwear will inform public health interventions and education, and information regarding the clinical presentation may help physicians better anticipate effects and manage snakebite. As the number of cases in the NASBR grows, associations between patient-related factors and outcomes may be studied.
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late hematologic toxicity following treatment of rattlesnake Envenomation with crotalidae polyvalent immune fab antivenom
Toxicon, 2011Co-Authors: Anne-michelle Ruha, Steven C. Curry, Clay Albrecht, Barth Riley, Anthony F PizonAbstract:Abstract Background North American rattlesnake Envenomations commonly produce defibrination, coagulopathy and/or thrombocytopenia, which may be reversed following treatment with Crotalidae Polyvalent Immune Fab Ovine (FabAV). Despite initial resolution with FabAV, late onset or recurrence of venom-induced hematologic effects may occur. Time at which onset of late hematotoxicity may first be detected is unknown. The purpose of this study was to identify the incidence and time of onset of recurrent or new late hypofibrinogenemia, coagulopathy, or thrombocytopenia in a cohort of rattlesnake Envenomation patients seen in outpatient follow-up after treatment with FabAV, and to report hematologic outcomes in these patients. Methods Review of 66 charts of patients with rattlesnake Envenomation who were treated with FabAV, and subsequently had outpatient follow-up evaluation at least 48 h after last FabAV, was performed. Demographic information, rattlesnake and bite characteristics, dose and timing of antivenom administration, adverse events, in-patient laboratory values, length of hospital stay, and follow-up laboratory values were collected. The primary outcome parameters were recurrent or delayed onset coagulopathy, hypofibrinogenemia, or thrombocytopenia identified no sooner than 48 h after last dose of FabAV. Results Prior to control of the Envenomation with FabAV, 42 patients (63.6%) experienced hematologic toxicity. At follow-up, 21 patients (32%) were found to have late coagulopathy, hypofibrinogenemia, or thrombocytopenia. Of twenty-three patients (35%) with more than one follow-up visit, fifteen had normal laboratory findings at the first follow-up visit. Five of these 15 patients (8% of total study group; 33% of this subgroup) with normal hematologic studies at first follow-up exhibited late hematologic toxicity at second follow-up. Severe late hematologic toxicity developed in five of 66 (8%) patients. One patient was retreated with FabAV for late severe thrombocytopenia. Conclusion Recurrent and delayed onset of hematologic toxicity in rattlesnake Envenomation victims treated with FabAV is common. Follow-up more than three days after treatment is necessary to detect all cases of late hematologic toxicity.
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Cardiomyopathy following latrodectus Envenomation.
The western journal of emergency medicine, 2010Co-Authors: Michael Levine, Joshua Canning, Robyn Chase, Anne-michelle RuhaAbstract:Latrodectus Envenomations are common throughout the United States and the world. While many Envenomations can result in catecholamine release with resultant hypertension and tachycardia, myocarditis is very rare. We describe a case of a 22-year-old male who sustained a Latrodectus Envenomation complicated by cardiomyopathy.
Shin Yee Fung - One of the best experts on this subject based on the ideXlab platform.
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pharmacokinetics of the sri lankan hump nosed pit viper hypnale hypnale venom following intravenous and intramuscular injections of the venom into rabbits
Toxicon, 2014Co-Authors: Christeine Ariaranee Gnanathasan, Shin Yee FungAbstract:The knowledge of venom pharmacokinetics is essential to improve the understanding of Envenomation pathophysiology. Using a double-sandwich ELISA, this study investigated the pharmacokinetics of the venom of hump-nosed pit viper (Hypnale hypnale) following intravenous and intramuscular injections into rabbits. The pharmacokinetics of the venom injected intravenously fitted a three-compartment model. There is a rapid (t1/2π = 0.4 h) and a slow (t1/2α = 0.8 h) distribution phase, followed by a long elimination phase (t1/2β = 19.3 h) with a systemic clearance of 6.8 mL∙h(-1)∙kg(-1), consistent with the prolonged abnormal hemostasis reported in H. hypnale Envenomation. On intramuscular route, multiple peak concentrations observed in the beginning implied a more complex venom absorption and/or distribution pattern. The terminal half-life, volume of distribution by area and systemic clearance of the venom injected intramuscularly were nevertheless not significantly different (p > 0.05) from that of the venom injected intravenously. The intramuscular bioavailability was exceptionally low (Fi.m. = 4%), accountable for the highly varied median lethal doses between intravenous and intramuscular Envenomations in animals. The findings indicate that the intramuscular route of administration does not significantly alter the pharmacokinetics of H. hypnale venom although it significantly reduces the systemic bioavailability of the venom. Language: en
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pharmacokinetics of the sri lankan hump nosed pit viper hypnale hypnale venom following intravenous and intramuscular injections of the venom into rabbits
Toxicon, 2014Co-Authors: Choo Hock Tan, Christeine Ariaranee Gnanathasan, Shin Yee Fung, Si Mui Sim, Nget Hong TanAbstract:The knowledge of venom pharmacokinetics is essential to improve the understanding of Envenomation pathophysiology. Using a double-sandwich ELISA, this study investigated the pharmacokinetics of the venom of hump-nosed pit viper (Hypnale hypnale) following intravenous and intramuscular injections into rabbits. The pharmacokinetics of the venom injected intravenously fitted a three-compartment model. There is a rapid (t1/2π = 0.4 h) and a slow (t1/2α = 0.8 h) distribution phase, followed by a long elimination phase (t1/2β = 19.3 h) with a systemic clearance of 6.8 mL∙h(-1)∙kg(-1), consistent with the prolonged abnormal hemostasis reported in H. hypnale Envenomation. On intramuscular route, multiple peak concentrations observed in the beginning implied a more complex venom absorption and/or distribution pattern. The terminal half-life, volume of distribution by area and systemic clearance of the venom injected intramuscularly were nevertheless not significantly different (p > 0.05) from that of the venom injected intravenously. The intramuscular bioavailability was exceptionally low (Fi.m. = 4%), accountable for the highly varied median lethal doses between intravenous and intramuscular Envenomations in animals. The findings indicate that the intramuscular route of administration does not significantly alter the pharmacokinetics of H. hypnale venom although it significantly reduces the systemic bioavailability of the venom. Language: en
Christeine Ariaranee Gnanathasan - One of the best experts on this subject based on the ideXlab platform.
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pharmacokinetics of the sri lankan hump nosed pit viper hypnale hypnale venom following intravenous and intramuscular injections of the venom into rabbits
Toxicon, 2014Co-Authors: Christeine Ariaranee Gnanathasan, Shin Yee FungAbstract:The knowledge of venom pharmacokinetics is essential to improve the understanding of Envenomation pathophysiology. Using a double-sandwich ELISA, this study investigated the pharmacokinetics of the venom of hump-nosed pit viper (Hypnale hypnale) following intravenous and intramuscular injections into rabbits. The pharmacokinetics of the venom injected intravenously fitted a three-compartment model. There is a rapid (t1/2π = 0.4 h) and a slow (t1/2α = 0.8 h) distribution phase, followed by a long elimination phase (t1/2β = 19.3 h) with a systemic clearance of 6.8 mL∙h(-1)∙kg(-1), consistent with the prolonged abnormal hemostasis reported in H. hypnale Envenomation. On intramuscular route, multiple peak concentrations observed in the beginning implied a more complex venom absorption and/or distribution pattern. The terminal half-life, volume of distribution by area and systemic clearance of the venom injected intramuscularly were nevertheless not significantly different (p > 0.05) from that of the venom injected intravenously. The intramuscular bioavailability was exceptionally low (Fi.m. = 4%), accountable for the highly varied median lethal doses between intravenous and intramuscular Envenomations in animals. The findings indicate that the intramuscular route of administration does not significantly alter the pharmacokinetics of H. hypnale venom although it significantly reduces the systemic bioavailability of the venom. Language: en
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pharmacokinetics of the sri lankan hump nosed pit viper hypnale hypnale venom following intravenous and intramuscular injections of the venom into rabbits
Toxicon, 2014Co-Authors: Choo Hock Tan, Christeine Ariaranee Gnanathasan, Shin Yee Fung, Si Mui Sim, Nget Hong TanAbstract:The knowledge of venom pharmacokinetics is essential to improve the understanding of Envenomation pathophysiology. Using a double-sandwich ELISA, this study investigated the pharmacokinetics of the venom of hump-nosed pit viper (Hypnale hypnale) following intravenous and intramuscular injections into rabbits. The pharmacokinetics of the venom injected intravenously fitted a three-compartment model. There is a rapid (t1/2π = 0.4 h) and a slow (t1/2α = 0.8 h) distribution phase, followed by a long elimination phase (t1/2β = 19.3 h) with a systemic clearance of 6.8 mL∙h(-1)∙kg(-1), consistent with the prolonged abnormal hemostasis reported in H. hypnale Envenomation. On intramuscular route, multiple peak concentrations observed in the beginning implied a more complex venom absorption and/or distribution pattern. The terminal half-life, volume of distribution by area and systemic clearance of the venom injected intramuscularly were nevertheless not significantly different (p > 0.05) from that of the venom injected intravenously. The intramuscular bioavailability was exceptionally low (Fi.m. = 4%), accountable for the highly varied median lethal doses between intravenous and intramuscular Envenomations in animals. The findings indicate that the intramuscular route of administration does not significantly alter the pharmacokinetics of H. hypnale venom although it significantly reduces the systemic bioavailability of the venom. Language: en
Sean P. Bush - One of the best experts on this subject based on the ideXlab platform.
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coagulation parameters in copperhead compared to other crotalinae Envenomation secondary analysis of the f ab 2 versus fab antivenom trial
Clinical Toxicology, 2017Co-Authors: Charles J Gerardo, Joao Ricardo Nickenig Vissoci, Michael W J Brown, Sean P. BushAbstract:AbstractContext: Coagulation derangements in copperhead Envenomation are considered less severe than other crotaline Envenomations, resulting in recommendations to limit both coagulation testing and antivenom treatment. A prospective, blinded, multicenter, randomized clinical trial comparing the effectiveness of F(ab’)2 versus Fab antivenom in crotaline Envenomation patients was completed in 2011. We determined the difference between coagulation parameters in copperhead compared to other crotaline Envenomations.Methods: We performed a post hoc analysis comparing the coagulation parameters (platelets and fibrinogen) prospectively obtained in the aforementioned trial. All the patients received antivenom in one of three treatment arms [F(ab’)2 with maintenance, F(ab’)2 with placebo maintenance, or Fab with maintenance]. Coagulation parameters were measured at pretreatment baseline, during acute hospitalization, day 5, day 8, and day 15 post-Envenomation. Mean platelet count and fibrinogen levels for the copp...
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initial experience with crotalidae polyvalent immune fab ovine antivenom in the treatment of copperhead snakebite
Annals of Emergency Medicine, 2004Co-Authors: Eric J Lavonas, Charles J Gerardo, Sean P. Bush, William Banner, Gerald F Omalley, Thomas C Arnold, Mark Steffens, William KernsAbstract:Abstract 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.
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crotalidae polyvalent immune fab ovine antivenom is efficacious for Envenomations by southern pacific rattlesnakes crotalus helleri
Annals of Emergency Medicine, 2002Co-Authors: Sean P. Bush, Steven M Green, James A Moynihan, William K Hayes, Michael D CardwellAbstract:Methods: We conducted a prospective observational study of 23 consecutive rattlesnake Envenomations that were treated with FabAV at our center. Patients were excluded if the species of snake could not be confirmed, if FabAV antivenom was not given, or if Antivenin (Crotalidae) polyvalent (equine) was given. We collected serial physical examination and laboratory data over a 24-hour period to serially evaluate the severity score and performed follow-up to evaluate delayed reactions. Results: There were 15 patients who received FabAV and had the species of rattlesnake confirmed (9 C helleri, 4 C scutulatus scutulatus, 1 C mitchellii pyrrhus, 1 C ruber ruber). C helleri Envenomations demonstrated similar improvement in serial snakebite severity scores to those of other species. Three patients treated with scheduled dosing had recurrence of progressive swelling (2 C helleri and 1 C mitchellii pyrrhus) during the 24-hour study period. Conclusion: We observed similar improvement in FabAV-treated patients with C helleri Envenomation compared with those of other species and conclude that this treatment in standard doses appears efficacious for bites by this species. Progressive swelling may recur despite scheduled dosing.