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Abstract
Critters and creatures can strike fear into anyone who thinks about dangerous animals. This article focuses on the management of the most common North American scorpion, arachnid, hymenoptera, and snake envenomations that cause clinically significant problems. Water creatures and less common animal envenomations are not covered in this article. Critical care management of envenomed patients can be challenging for unfamiliar clinicians. Although the animals are located in specific geographic areas, patients envenomed on passenger airliners and those who travel to endemic areas may present to health care facilities distant from the exposure.
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Bush SP, Seifert SA, Oakes J, Smith SD, Phan TH, Pearl SR, Reibling ET. Continuous IV Crotalidae Polyvalent Immune Fab (Ovine) (FabAV) for selected North American rattlesnake bite patients. Toxicon 2013; 69:29-37. [PMID: 23474267 DOI: 10.1016/j.toxicon.2013.02.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 01/10/2013] [Accepted: 02/05/2013] [Indexed: 11/25/2022]
Abstract
BACKGROUND In patients bitten by North American rattlesnakes and treated with Crotalidae Polyvalent Immune Fab (Ovine) (FabAV), late hematologic abnormalities-persistent, recurrent, or late, new onset of hypofibrinogenemia, prolonged PT/INR, prolonged PTT, and/or thrombocytopenia beyond 48 h post-envenomation-are common, difficult to manage, and may result in morbidity and mortality are common, difficult to manage, and may result in morbidity and mortality. The optimal management of late hematologic abnormalities, particularly the use of further treatment with antivenom, has not been well defined. The current FabAV treatment regimen is to give antivenom as a bolus dose over a one-hour period. We describe our experience using a continuous intravenous infusion of FabAV for late hematologic effects and/or associated bleeding complications in rattlesnake envenomation. METHODS This is a retrospective, observational case series of patients envenomated by North American rattlesnakes at three medical centers managed with a continuous intravenous infusion of FabAV for late hematologic abnormalities and/or associated bleeding complications. Indications, dilution and infusion protocols, and duration of therapy were individualized. RESULTS Five cases were identified between July 2010 and September 2011. All patients had profound late hematologic abnormalities and/or were associated with bleeding complications. Several patients had received repeat bolus infusions of FabAV, with or without human blood products, with either inadequate or only transient beneficial response. All patients were then managed with a continuous intravenous infusion of FabAV and all appeared to respond to the continuous intravenous infusion of FabAV, titrated to effect, with cessation of progression and, in most cases, improvement in hematologic abnormalities. Rates of infusion varied from 2 to 4 vials per 24 h (mean = 3.1 ± 0.4 vials/day). The termination of FabAV infusion was between day 6 and day 14 from the time of envenomation (mean = 10 ± 3 days), after which hematologic values were normalized or were normalizing in all patients and continued to do so. DISCUSSION The use of FabAV as a continuous intravenous infusion, particularly after the acute phase of envenomation has passed, provides a continuous source of circulating antibodies to neutralize venom components reaching circulation from tissue stores and allows natural replenishment of hematologic factors such as platelets and/or fibrinogen. This method is an efficient use of FabAV, avoiding the wasteful excess of a bolus dose, may be more effective, eliminating the potential for destruction of hematologic factors when protective antivenom levels are lost between bolus FabAV doses, and appears to be safe. Further assessments of the stability and sterility of the product during infusion are needed. The need to continue hospitalization is the major drawback, but continued observation and inpatient care may be needed for other indications (e.g. bleeding) in this subset of patients. CONCLUSIONS A continuous intravenous infusion of FabAV between 2 and 4 vials per day, titrated to effect, and continued for 6-14 days post-envenomation appeared to be associated with reversal of late hematologic effects of rattlesnake envenomation and, when combined with indicated human blood products, control of significant bleeding. Continuous intravenous infusion of FabAV may be safer, more efficacious, and more cost-effective than observation without FabAV treatment or as-needed bolus dosing in selected patients with late hematologic abnormalities.
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Affiliation(s)
- Sean P Bush
- Department of Emergency Medicine, Loma Linda University, School of Medicine, Loma Linda, CA, USA.
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Charlton NP, Morse PS, Borek HA, Lawrence DT, Brady WJ. The toxicology literature of 2011: issues impacting the emergency physician. Am J Emerg Med 2013; 31:597-601. [DOI: 10.1016/j.ajem.2012.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 10/24/2012] [Accepted: 10/24/2012] [Indexed: 11/17/2022] Open
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Moriarity RS, Dryer S, Replogle W, Summers RL. The role for coagulation markers in mild snakebite envenomations. West J Emerg Med 2012; 13:68-74. [PMID: 22461925 PMCID: PMC3298204 DOI: 10.5811/westjem.2011.6.6729] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 05/25/2011] [Accepted: 06/13/2011] [Indexed: 12/02/2022] Open
Abstract
Introduction The majority of patients seeking medical treatment for snakebites do not suffer from severe envenomation. However, no guidelines exist for ordering coagulation markers in patients with minimal or moderate envenomation, nor in those who do not receive antivenom. In this study, we sought to determine whether it was possible to limit the practice of ordering coagulation studies to those patients suffering severe envenomation, rattlesnake envenomation, or both. Methods A retrospective chart review was performed on all cases of crotalid snakebite presenting to an adult emergency department (ED) from April 1998 to June 2006. Each chart was abstracted for patient's age, gender, type of snake (if known), severity of envenomation at initial presentation, coagulation test results, whether antivenom was administered, and whether the patient was admitted. Results Over an approximately 8-year period, 131 snakebite cases presented that met the inclusion criteria, of which 35 (26.7%) had some type of coagulation marker abnormality. Limiting coagulation testing to patients suffering severe envenomation or rattlesnake envenomation would have resulted in failure to identify 89% or 77%, respectively, of the 35 patients who were found to have at least 1 abnormal coagulation marker. Conclusion Our study failed to identify a subset of patients that could be defined as low risk or for whom coagulation marker testing could be foregone. This study suggests that coagulation tests should be routinely performed on all patients presenting to the ED with complaints of envenomation by copperheads, moccasins, or rattlesnakes. Further clarification of when coagulation markers are indicated may require a prospective study that standardizes snake identification and the timing of coagulation marker testing.
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Affiliation(s)
- Risa S Moriarity
- University of Mississippi Medical Center, Department of Emergency Medicine, Jackson, Mississippi
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Lavonas EJ. Coagulopathy: the most important thing we still don't know about snakebite. West J Emerg Med 2012; 13:75-6. [PMID: 22461926 PMCID: PMC3298215 DOI: 10.5811/westjem.2011.8.6884] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 08/31/2011] [Indexed: 11/11/2022] Open
Affiliation(s)
- Eric J Lavonas
- Rocky Mountain Poison and Drug Center-Denver Health, Denver, Colorado
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Lefkowitz RY, Taylor J, Balfe D. Reality bites: a case of severe rattlesnake envenomation. J Intensive Care Med 2012; 28:314-9. [PMID: 22588374 DOI: 10.1177/0885066612446415] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rattlesnake venoms can cause a wide range of adverse human health effects. However, with the availability of modern antivenin, toxicity can generally be minimized and controlled. We present a rare case of rattlesnake envenomation resulting in severe systemic effects and syndrome relapse. Management considerations and patient course are described in the context of the current literature.
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Affiliation(s)
- Rafael Y Lefkowitz
- Department Fellow of Internal Medicine, Cedars Sinai Medical Center, Los Angeles, CA, USA
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Schaeffer TH, Khatri V, Reifler LM, Lavonas EJ. Incidence of immediate hypersensitivity reaction and serum sickness following administration of Crotalidae polyvalent immune Fab antivenom: a meta-analysis. Acad Emerg Med 2012; 19:121-31. [PMID: 22320362 DOI: 10.1111/j.1553-2712.2011.01276.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Crotalidae polyvalent immune Fab (ovine) (FabAV) is commonly used in the treatment of symptomatic North American crotaline snake envenomation. When approved by the U.S. Food and Drug Administration in 2000, the incidences of immediate hypersensitivity reactions and serum sickness were reported as 0.14 and 0.18, respectively. The objective of this meta-analysis was to evaluate the incidence of immediate hypersensitivity reactions and serum sickness reported in studies of patients treated with FabAV therapy after North American crotaline envenomation. METHODS The authors searched PubMed, Ovid MEDLINE, and EMBASE from January 1, 1997, to September 20, 2010, for English-language medical literature and cross-referenced bibliographies of reviewed articles. The published abstracts of the major toxicology conferences were also searched. All prospective and retrospective cohort studies with patients receiving FabAV therapy for North American crotaline envenomations were eligible for data abstraction. Two content experts reviewed full-text articles and extracted relevant study design and outcome data. Proportions of immediate hypersensitivity and serum sickness for each study were analyzed in a random-effects model to produce an overall estimate of immediate hypersensitivity and serum sickness incidence associated with FabAV administration. RESULTS The literature search revealed 11 unique studies of patients who received FabAV that contained information on immediate hypersensitivity reactions and serum sickness. The meta-analysis produced a combined estimate of the incidence of immediate hypersensitivity of 0.08 (95% confidence interval [CI] = 0.05 to 0.11) and a combined estimate of the incidence of serum sickness of 0.13 (95% CI = 0.07 to 0.21). CONCLUSIONS In this systematic literature review and meta-analysis, the combined estimates of the incidence of immediate hypersensitivity reactions and serum sickness from FabAV in the treatment of symptomatic North American crotaline envenomations appear to be lower than previously reported, at 0.08 and 0.13, respectively.
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Affiliation(s)
- Tammi H Schaeffer
- Rocky Mountain Poison & Drug Center, Denver Health and Hospital Authority, Denver, CO, USA.
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Seifert SA, I Kirschner R, Martin N. Recurrent, persistent, or late, new-onset hematologic abnormalities in Crotaline snakebite. Clin Toxicol (Phila) 2011; 49:324-9. [PMID: 21563909 DOI: 10.3109/15563650.2011.566883] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND. Hematologic effects from rattlesnake envenomation exhibit a phenomenon of recurrent, persistent or late, new onset (late) abnormalities in some Fab antivenom-treated patients 4 or more days post-envenomation. Indicators that reliably identify or exclude those patients at risk of late hematologic effects have not been developed. METHODS. This was a retrospective, observational case series of rattlesnake bite records at two US poison centers. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for D-dimer, fibrinogen, platelets, platelet count trend, INR and PTT associated with late hematologic abnormalities, were determined. RESULTS. Three hundred seventy six cases were reviewed. Sixty cases met inclusion criteria. Overall, 17 of 60 patients (28%) had a hematologic abnormality as a result of envenomation. Eleven of 60 patients (65% of those with a hematologic abnormality; 18% overall) developed late hematologic abnormalities 4 or more days post-envenomation. Four patients had late, new onset hypofibrinogenemia and/or thrombocytopenia. All were associated with early D-dimer elevation and/or platelet rise in response to FabAV treatment, respectively. Normal hematologic parameters in the first 48 h post-envenomation and the lack of a greater than 20% rise in platelets within 4 h post-antivenom administration had a 100% NPV for late hematologic effects. CONCLUSIONS. Patients with early onset hypofibrinogenemia, a positive D-dimer, thrombocytopenia, or a 20% increase in platelet count within 4 h post-treatment had a significant likelihood of late hematologic effects. Patients in whom fibrinogen, D-dimer, INR, PTT, and platelet counts remained normal throughout the first 48 h post-envenomation, and who did not exhibit a >20% increase in platelet count within 4 h post-antivenom administration, did not develop late hematologic effects.
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Affiliation(s)
- Steven A Seifert
- New Mexico Poison and Drug Information Center, Albuquerque, NM, USA.
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Peterson ME, Matz M, Seibold K, Plunkett S, Johnson S, Fitzgerald K. A randomized multicenter trial of Crotalidae polyvalent immune F(ab) antivenom for the treatment of rattlesnake envenomation in dogs. J Vet Emerg Crit Care (San Antonio) 2011; 21:335-45. [PMID: 21827591 DOI: 10.1111/j.1476-4431.2011.00643.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To determine clinical efficacy of the Crotalidae polyvalent immune F(ab) (ovine) antivenom (OPCA) against progressive crotalid envenomation in the dog as reflected in stabilization or improvement of snakebite severity scores (SSS). Additionally, due to the potential decreased half-life of the F(ab) antibodies in dogs we compared SSS between dogs receiving 2 different dosing regimes. DESIGN Prospective, clinical trial. SETTING Five veterinary emergency and critical care facilities. ANIMALS One hundred and fifteen client-owned Crotalid (rattlesnake) snake bitten dogs in whom worsening of the envenomation syndrome was observed before OPCA treatment. INTERVENTIONS In a multicenter randomized clinical trial a single dose (1 vial) of OPCA alone was compared with 2 doses (1/2 vial each) administered 6 hours apart. Standard supportive care was provided in all cases. MEASUREMENTS AND MAIN RESULTS Data were available for 115 patients, 9 of which were fatalities. All patients' clinical condition was documented with a standardized SSS system accounting for each major body system. Each fatality received maximum severity scores of 20. The mean severity score of the 115 patients decreased from 4.19 to 3.29 points and there was no difference between the 2 treatment groups. The mean severity score of the 107 patients without fatalities decreased from 4.16 to 2.15. Antivenin-related acute reactions occurred in 6 dogs (6%), and no serum sickness occurred within the 95 cases contacted at the 2-week posttreatment follow-up. CONCLUSIONS In the first randomized trial in dogs of antivenin in the United States, OPCA effectively stabilized or terminated venom effects. There were no statistical differences detected between treatment groups within the study time frame.
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Lavonas EJ, Ruha AM, Banner W, Bebarta V, Bernstein JN, Bush SP, Kerns WP, Richardson WH, Seifert SA, Tanen DA, Curry SC, Dart RC. Unified treatment algorithm for the management of crotaline snakebite in the United States: results of an evidence-informed consensus workshop. BMC Emerg Med 2011; 11:2. [PMID: 21291549 PMCID: PMC3042971 DOI: 10.1186/1471-227x-11-2] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 02/03/2011] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Envenomation by crotaline snakes (rattlesnake, cottonmouth, copperhead) is a complex, potentially lethal condition affecting thousands of people in the United States each year. Treatment of crotaline envenomation is not standardized, and significant variation in practice exists. METHODS A geographically diverse panel of experts was convened for the purpose of deriving an evidence-informed unified treatment algorithm. Research staff analyzed the extant medical literature and performed targeted analyses of existing databases to inform specific clinical decisions. A trained external facilitator used modified Delphi and structured consensus methodology to achieve consensus on the final treatment algorithm. RESULTS A unified treatment algorithm was produced and endorsed by all nine expert panel members. This algorithm provides guidance about clinical and laboratory observations, indications for and dosing of antivenom, adjunctive therapies, post-stabilization care, and management of complications from envenomation and therapy. CONCLUSIONS Clinical manifestations and ideal treatment of crotaline snakebite differ greatly, and can result in severe complications. Using a modified Delphi method, we provide evidence-informed treatment guidelines in an attempt to reduce variation in care and possibly improve clinical outcomes.
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Affiliation(s)
- Eric J Lavonas
- Rocky Mountain Poison and Drug Center, Denver Health and Hospital Authority, Denver, Colorado, USA
- Division of Medical Toxicology, Department of Emergency Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
- Department of Emergency Medicine, Wilford Hall Medical Center, San Antonio, Texas, USA
| | - Anne-Michelle Ruha
- Department of Medical Toxicology, Banner Good Samaritan Medical Center, Phoenix, Arizona, USA
| | - William Banner
- Oklahoma Poison Center, College of Pharmacy, University of Oklahoma, Oklahoma City, Oklahoma, USA
- Pediatric Intensive Care Unit, Integris Baptist Medical Center, Oklahoma City, Oklahoma, USA
| | | | - Jeffrey N Bernstein
- Florida Poison Information Center, Miami, Florida, USA
- Emergency Care Center, Jackson Memorial Hospital, Miami, Florida, USA
| | - Sean P Bush
- Department of Emergency Medicine, Loma Linda University School of Medicine, Loma Linda, California USA
| | - William P Kerns
- Division of Medical Toxicology, Department of Emergency Medicine and Carolinas Poison Center, Carolinas Medical Center, Charlotte, North Carolina, USA
| | - William H Richardson
- Department of Emergency Medicine, Palmetto Health Richland, Columbia, South Carolina, USA
- Palmetto Poison Center, University of South Carolina, Columbia, South Carolina, USA
| | - Steven A Seifert
- New Mexico Poison and Drug Information Center, College of Pharmacy, University of New Mexico, Albuquerque, New Mexico, USA
- Department of Emergency Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA
| | - David A Tanen
- Naval Medical Center, San Diego, California, USA
- Division of Medical Toxicology, Department of Emergency Medicine, University of California at San Diego, San Diego, California, USA
| | - Steve C Curry
- Department of Medical Toxicology, Banner Good Samaritan Medical Center, Phoenix, Arizona, USA
| | - Richard C Dart
- Rocky Mountain Poison and Drug Center, Denver Health and Hospital Authority, Denver, Colorado, USA
- Division of Medical Toxicology, Department of Emergency Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
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Yin S, Kokko J, Lavonas E, Mlynarchek S, Bogdan G, Schaeffer T. Factors associated with difficulty achieving initial control with crotalidae polyvalent immune fab antivenom in snakebite patients. Acad Emerg Med 2011; 18:46-52. [PMID: 21166732 DOI: 10.1111/j.1553-2712.2010.00958.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The prescribing information for Crotalidae Fab antivenom (FabAV) instructs clinicians to administer FabAV until initial control of the envenomation syndrome is achieved. Risk factors for difficulty achieving initial control are not known. OBJECTIVES The study aim was to identify factors present before administration of antivenom associated with difficulty achieving initial control. METHODS The authors conducted a retrospective study of all patients presenting to any one of 17 centers and receiving FabAV from 2002 to 2004. Demographic and historical information, as well as data about nine specific venom effects, were collected prior to the administration of antivenom. An expert panel used standard criteria to determine if initial control was achieved. The patient group that had difficulty achieving initial control was compared to the group that achieved initial control, and adjusted odds ratios were calculated using stepwise logistic regression. RESULTS A total of 247 patients were included in the final analysis. The majority of patients were envenomated on the upper extremity and were young males. A total of 203 patients (82.2%) achieved initial control. In univariate analysis, thrombocytopenia, bleeding, neurologic effects, and a severe bite were significantly associated with difficulty achieving initial control. After logistic regression, the presence of neurologic effects and thrombocytopenia remained significantly associated with difficulty achieving initial control. When both factors were present, the patient was 13.8 times more likely to have difficulty achieving initial control. CONCLUSIONS A number of factors were present before the administration of FabAV that were independently associated with difficulty achieving initial control of the envenomation syndrome. Predicting which patients will have difficulty achieving initial control has important ramifications for patient disposition and may provide insight into the mechanisms for lack of antivenom efficacy.
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Affiliation(s)
- Shan Yin
- Denver Health Hospital Authority, Rocky Mountain Poison and Drug Center, Denver, CO, USA.
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Ruha AM, Curry SC, Albrecht C, Riley B, Pizon A. Late hematologic toxicity following treatment of rattlesnake envenomation with crotalidae polyvalent immune Fab antivenom. Toxicon 2010; 57:53-9. [PMID: 20920516 DOI: 10.1016/j.toxicon.2010.09.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 08/27/2010] [Accepted: 09/25/2010] [Indexed: 10/19/2022]
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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Affiliation(s)
- Anne-Michelle Ruha
- Department of Medical Toxicology, Banner Good Samaritan Medical Center, Phoenix, AZ, United States.
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Recurrent coagulopathy and thrombocytopenia in children treated with crotalidae polyvalent immune fab: a case series. Pediatr Emerg Care 2010; 26:576-82. [PMID: 20693856 DOI: 10.1097/pec.0b013e3181ea722b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Recurrent signs and symptoms after initial treatment and control of coagulopathy and thrombocytopenia after American pit viper (crotaline) envenomations have been previously described in patients treated with Crotalidae polyvalent immune Fab antivenom (FabAV). The significance and necessity of treatment of these recurrent abnormalities are uncertain. Our goal was to further characterize recurrent coagulopathy or thrombocytopenia in pediatric patients. METHODS All cases presenting to our Toxicology Consult Service, which covers 6 hospitals in a metropolitan area, from May 2007 to April 2008 with recurrent coagulopathy after initial control with FabAV were included and retrospectively reviewed. RESULTS Four cases of pediatric patients are presented who presented with recurrent coagulopathy and/or thrombocytopenia after initial control with FabAV. The patients were all treated with delayed administration of FabAV with variable results. Blood products administered without concurrent FabAV were of limited use. The laboratory abnormalities took up to 18 days to resolve in one case. One patient developed hemodynamically significant spontaneous bleeding. CONCLUSIONS The cases presented here suggest administration of FabAV may correct delayed coagulopathy associated with crotaline envenomations. The first 3 cases illustrate that in the face of severe derangements in laboratory values, most envenomated patients treated with FabAV do not develop significant bleeding. These cases may respond to additional antivenom alone. However, case 4 illustrates that hemodynamically significant spontaneous bleeding can occur. Until more data are available, readministration of FabAV is a reasonable first-line therapy for delayed coagulopathy associated with crotaline envenomations.
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Abubakar IS, Abubakar SB, Habib AG, Nasidi A, Durfa N, Yusuf PO, Larnyang S, Garnvwa J, Sokomba E, Salako L, Theakston RDG, Juszczak E, Alder N, Warrell DA. Randomised controlled double-blind non-inferiority trial of two antivenoms for saw-scaled or carpet viper (Echis ocellatus) envenoming in Nigeria. PLoS Negl Trop Dis 2010; 4:e767. [PMID: 20668549 PMCID: PMC2910709 DOI: 10.1371/journal.pntd.0000767] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Accepted: 06/16/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND In West Africa, envenoming by saw-scaled or carpet vipers (Echis ocellatus) causes great morbidity and mortality, but there is a crisis in supply of effective and affordable antivenom (ISRCTN01257358). METHODS In a randomised, double-blind, controlled, non-inferiority trial, "EchiTAb Plus-ICP" (ET-Plus) equine antivenom made by Instituto Clodomiro Picado was compared to "EchiTAb G" (ET-G) ovine antivenom made by MicroPharm, which is the standard of care in Nigeria and was developed from the original EchiTAb-Fab introduced in 1998. Both are caprylic acid purified whole IgG antivenoms. ET-G is monospecific for Echis ocellatus antivenom (initial dose 1 vial) and ET-Plus is polyspecific for E. ocellatus, Naja nigricollis and Bitis arietans (initial dose 3 vials). Both had been screened by pre-clinical and preliminary clinical dose-finding and safety studies. Patients who presented with incoagulable blood, indicative of systemic envenoming by E. ocellatus, were recruited in Kaltungo, north-eastern Nigeria. Those eligible and consenting were randomly allocated with equal probability to receive ET-Plus or ET-G. The primary outcome was permanent restoration of blood coagulability 6 hours after the start of treatment, assessed by a simple whole blood clotting test repeated 6, 12, 18, 24 and 48 hr after treatment. Secondary (safety) outcomes were the incidences of anaphylactic, pyrogenic and late serum sickness-type antivenom reactions. FINDINGS Initial doses permanently restored blood coagulability at 6 hours in 161/194 (83.0%) of ET-Plus and 156/206 (75.7%) of ET-G treated patients (Relative Risk [RR] 1.10 one-sided 95% CI lower limit 1.01; P = 0.05). ET-Plus caused early reactions on more occasions than did ET-G [50/194 (25.8%) and 39/206 (18.9%) respectively RR (1.36 one-sided 95% CI 1.86 upper limit; P = 0.06). These reactions were classified as severe in 21 (10.8%) and 11 (5.3%) of patients, respectively. CONCLUSION At these doses, ET-Plus was slightly more effective but ET-G was slightly safer. Both are recommended for treating E. ocellatus envenoming in Nigeria. TRIAL REGISTRATION Current Controlled Trials ISRCTN01257358.
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Affiliation(s)
- Isa S. Abubakar
- Department of Community Medicine, Bayero University of Kano, Kano, Nigeria
| | | | | | | | - Nandul Durfa
- Special Projects Unit, Federal Ministry of Health, Abuja, Nigeria
| | - Peter O. Yusuf
- Faculty of Veterinary Medicine, Ahmadu Bello University, Zaria, Nigeria
| | | | - John Garnvwa
- Alistair Reid Venom Research Unit, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Elijah Sokomba
- Department of Pharmacology, University of Jos, Jos, Nigeria
| | - Lateef Salako
- Department of Pharmacology and Therapeutics, University of Ibadan, Ibadan, Nigeria
| | - R. David G Theakston
- Alistair Reid Venom Research Unit, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Ed Juszczak
- Centre for Statistics in Medicine, University of Oxford, Oxford, United Kingdom
| | - Nicola Alder
- Centre for Statistics in Medicine, University of Oxford, Oxford, United Kingdom
| | - David A. Warrell
- Nuffield Department of Clinical Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
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Janes DN, Bush SP, Kolluru GR. Large Snake Size Suggests Increased Snakebite Severity in Patients Bitten by Rattlesnakes in Southern California. Wilderness Environ Med 2010; 21:120-6. [DOI: 10.1016/j.wem.2010.01.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
Snake bite is a common and frequently devastating environmental and occupational disease, especially in rural areas of tropical developing countries. Its public health importance has been largely ignored by medical science. Snake venoms are rich in protein and peptide toxins that have specificity for a wide range of tissue receptors, making them clinically challenging and scientifically fascinating, especially for drug design. Although the full burden of human suffering attributable to snake bite remains obscure, hundreds of thousands of people are known to be envenomed and tens of thousands are killed or maimed by snakes every year. Preventive efforts should be aimed towards education of affected communities to use proper footwear and to reduce the risk of contact with snakes to a minimum through understanding of snakes' behaviour. To treat envenoming, the production and clinical use of antivenom must be improved. Increased collaboration between clinicians, epidemiologists, and laboratory toxinologists should enhance the understanding and treatment of envenoming.
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Affiliation(s)
- David A Warrell
- Nuffield Department of Clinical Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK.
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Camilleri C, Offerman S, Gosselin R, Albertson T. Conservative Management of Delayed, Multicomponent Coagulopathy Following Rattlesnake Envenomation. Clin Toxicol (Phila) 2009. [DOI: 10.1081/clt-53339] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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70
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Walter FG, Stolz U, Shirazi F, McNally J. Epidemiology of severe and fatal rattlesnake bites published in the American Association of Poison Control Centers’ Annual Reports. Clin Toxicol (Phila) 2009; 47:663-9. [DOI: 10.1080/15563650903113701] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Abstract
OBJECTIVES Report of delayed significant coagulopathy, thrombocytopenia, and bleeding after Crotaline envenomation. METHODS Recurrent coagulopathy and thrombocytopenia have been described after treatment of Crotaline envenomation with Crotalidae polyvalent immune Fab (CroFab). Until now, there have been no reports of significant spontaneous bleeding despite these abnormalities. RESULTS Crotalidae polyvalent immune Fab has a relatively short half-life compared with previous antivenoms used to treat snake bite. This shorter half-life allows for recurrence of venom effects. Therefore, patients with Crotaline envenomation should undergo close monitoring for recurrence of coagulopathy or thrombocytopenia after treatment with CroFab. CONCLUSIONS If coagulopathy or thrombocytopenia recurs, retreatment with CroFab should be considered to prevent significant bleeding.
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73
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Seifert SA, Boyer LV, Benson BE, Rogers JJ. AAPCC database characterization of native U.S. venomous snake exposures, 2001-2005. Clin Toxicol (Phila) 2009; 47:327-35. [PMID: 19514880 DOI: 10.1080/15563650902870277] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BACKGROUND Differences in victim demographics, clinical effects, managements, and outcomes among native viperid (rattlesnake, copperhead, and cottonmouth) and elapid (coral snake) species have not been systematically characterized. METHODS The database of the American Association of Poison Control Centers from 2001 through 2005 was analyzed. RESULTS Between 2001 and 2005, there were 23,676 human exposures (average = 4,735/year) to native venomous snakes in the United States reported to U.S. poison centers in all states except Hawaii: 98% were to viperid snakes and 2% to elapids. Overall, 77% of victims were male, 70% were adults >20 years, and 12% were aged less than 10 years. Sixty-five cases involved pregnant women, with rattlesnake bites resulting in moderate or greater effects in over 70%. The overall hospital admission rate was 53%. Outcomes were generally more severe with rattlesnake and copperhead envenomations and in children <6 years of age. The fatality rate of reported cases was 0.06%. CONCLUSIONS Native U.S. venomous snakebite results in considerable morbidity and mortality. Rattlesnake and copperhead envenomations, and those in children <6 years of age, produce the most severe outcomes, but coral snakebites result in similar hospital admission rates.
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Affiliation(s)
- Steven A Seifert
- New Mexico Poison and Drug Information Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131-0001, USA.
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74
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Lavonas EJ, Schaeffer TH, Kokko J, Mlynarchek SL, Bogdan GM. Crotaline Fab antivenom appears to be effective in cases of severe North American pit viper envenomation: an integrative review. BMC Emerg Med 2009; 9:13. [PMID: 19545426 PMCID: PMC2713980 DOI: 10.1186/1471-227x-9-13] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Accepted: 06/22/2009] [Indexed: 01/21/2023] Open
Abstract
Background In 2000, the United States Food and Drug Administration approved Crotalidae Polyvalent Immune Fab (Ovine) (hereafter, FabAV), "for the management of patients with minimal to moderate North American Crotalid envenomation." Because whole-IgG pit viper antivenom is no longer available in the United States, FabAV is currently the only specific treatment option available to United States clinicians treating snakebite victims of any severity. No clinical trial data are available concerning the effectiveness of FabAV for treatment of severe snakebite, but several published articles describe its use in this setting. Methods We performed a comprehensive review of the English-language medical literature to identify all publications (1996 to July, 2008) containing data about the administration of FabAV. Two trained reviewers separately extracted case-level data concerning the administration of FabAV to patients with severe envenomation by North American crotaline snakes to a standardized form. Descriptive statistics were used. In addition, we hand-searched the US National Poison Data System reports for the years 2000–2006 to identify and describe any reports of death that occurred after FabAV administration. Results The literature review found 147 unique publications regarding FabAV. Twenty-four evaluable cases of severe human envenomation treated with FabAV were identified in 19 publications. Seven cases were described in five cohort studies, and 17 cases were described in 14 single patient case reports or non-cohort case series. Sixty-five specific severe venom effects were reported in these 24 patients, of which 50 effects (77%) improved or resolved after FabAV therapy. Initial control of all severe venom effects was achieved in 12 patients (50%). The rate at which initial control was achieved was significantly higher among patients reported in the cohort series than in the case series and non-cohort reports (100% vs. 29%, P = 0.005). The median dose of FabAV used to obtain initial control was 6 vials (range: 4 – 18 vials). Nine patients had severe venom effects that persisted despite FabAV therapy. Recurrent and/or delayed-onset severe defibrination syndrome occurred in 12 patients, most of whom did not receive recommended maintenance FabAV dosing. No patient developed systemic bleeding. Conclusion In this structured literature review, FabAV appears to be effective in the management of severe crotaline snake envenomation. Incomplete response to therapy, recurrence of venom effects, and delayed-onset venom effects were reported in case reports, but not reported in cohort studies.
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Affiliation(s)
- Eric J Lavonas
- Rocky Mountain Poison & Drug Center, Denver Health Hospital Authority, 777 Bannock St, MC 0180, Denver, CO 80204, USA.
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75
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Abstract
Crotaline snakebites occur frequently in children, often resulting in significant morbidity. Crotalidae Polyvalent Immune Fab antivenom (FabAV) became available for clinical use in the US in 2000 and is currently the standard of care for the treatment of crotaline envenomation. The pediatric emergency care provider should be familiar with FabAV because its judicious use in affected children can greatly decrease morbidity caused by crotaline snakebites. This article will review the use of FabAV for the treatment of pediatric crotaline envenomation.
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Fazelat J, Teperman SH, Touger M. Recurrent hemorrhage after western diamondback rattlesnake envenomation treated with crotalidae polyvalent immune fab (ovine). Clin Toxicol (Phila) 2008; 46:823-6. [DOI: 10.1080/15563650701753849] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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77
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Abstract
Snakebites are common among the rural population of developing countries. The severity of venomous snakebites depends on several factors, including the location of the bite, the amount of venom injected, and the effectiveness of the initial therapy. Snakebites frequently occur in the extremities with approximately two thirds of envenomations occurring in the upper extremities. In this study, we presented 12 cases of hand reconstruction after Vipera snakebites and discussed how to minimize functional loss and maximize hand rehabilitation. Twelve patients bitten by Vipera between 2001 and 2006 were included in this study. Groin flaps were performed in three cases, full-thickness grafts in two cases, thenar flaps in three cases, and cross finger flaps in three cases. With medical management, spontaneous healing occurred in one case. We prefer to use flaps on the volar site of the hand and, if the bone is not exposed, full-thickness grafts on the dorsal site of the hand. We also recommend starting rehabilitation of the hand early.
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Kitchens C, Eskin T. Fatality in a case of envenomation by Crotalus adamanteus initially successfully treated with polyvalent ovine antivenom followed by recurrence of defibrinogenation syndrome. J Med Toxicol 2008; 4:180-3. [PMID: 18821492 DOI: 10.1007/bf03161198] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
INTRODUCTION Recurrences of clinical or laboratory manifestations of North American pit viper envenomation may happen despite control of the envenomation syndrome by prompt and adequate antivenom therapy. Recurrences of coagulopathy in victims of Eastern diamondback rattlesnake envenomation are generally regarded as benign. The vast majority suffer no actual bleeding despite florid coagulation laboratory abnormalities due to selective defibrinogenation. CASE REPORT We report what we believe to be the first fatality following successful control of the envenomation syndrome following ovine antivenom treatment resulting from envenomation by a bite from the Eastern diamondback rattlesnake. This case raises the question of whether such recurrences are in fact benign, causal, or coincidental. This patient sustained significant brain hemorrhage and death ensued due to generalized cerebral edema. Defibrinogenation occurred 4 days after treatment with ovine antivenom. DISCUSSION Coagulation abnormalities following Eastern diamondback rattlesnake envenomation are due to selective defibrinogenation. This is separate from disseminated intravascular coagulation (DIC). Thrombin generation, thus hemostasis, are generally considered normal. This case may cause reexamination of this belief.
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Affiliation(s)
- Craig Kitchens
- Department of Medicine, Division of Hematology/Oncology, University of Florida College of Medicine, Gainesville, FL, USA.
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79
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Reuter-Rice K. Bites that bleed: crotalid envenomation. J Pediatr Health Care 2008; 22:258-61. [PMID: 18590872 DOI: 10.1016/j.pedhc.2008.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2008] [Revised: 02/14/2008] [Accepted: 02/16/2008] [Indexed: 11/26/2022]
Affiliation(s)
- Karin Reuter-Rice
- Division of Pediatric Critical Care, MC 5065, San Diego, California, USA.
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80
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Santos-Soares PC, Bacellar A, Povoas HP, Brito AF, Santana DLP. Stroke and snakebite: case report. ARQUIVOS DE NEURO-PSIQUIATRIA 2008; 65:341-4. [PMID: 17607441 DOI: 10.1590/s0004-282x2007000200030] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Accepted: 12/08/2006] [Indexed: 11/22/2022]
Abstract
Snakebites are common and lead to potential complications like neuromyopathies and strokes, these last associated with disturbances of blood coagulation. We report on a 65 years old woman of cerebral intraparenchymal hemorrhage associated with snakebite by a Bothrops jararaca that occurred in the Reconcavo of Bahia, BA, Brazil. The patient was submitted to a surgical evacuation of the hematoma, with a good result. This report is accompanied by a revision about the association among snakebite and neurological complications, emphasizing strokes. Statistics reveal a high incidence of snakebite in the world, mainly in tropical countries and gets attention for his socioeconomic impact. The clinical and laboratory characteristics to identify the victims that present a high risk of presenting strokes are discussed in order to identify early those patients, so that they may be treated in a more precocious and effective way.
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Affiliation(s)
- Paulo César Santos-Soares
- Adult ICU, Hospital Santo Amaro, José Oliveira Foundation, and Universidade Federal da Bahia, Salvador, BA, Brazil.
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81
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Seifert SA, Oakes JA, Boyer LV. Toxic Exposure Surveillance System (TESS)-based characterization of U.S. non-native venomous snake exposures, 1995-2004. Clin Toxicol (Phila) 2007; 45:571-8. [PMID: 17558631 DOI: 10.1080/15563650701382748] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND Non-native (exotic) snake exposures in the United States have not been systematically characterized. METHODS The Toxic Exposure Surveillance System (TESS) database of the American Association of Poison Control Centers was analyzed to quantify the number and types, demographic associations, clinical presentations, managements and outcomes, and the health resource utilization of non-native snake exposures. RESULTS From 1995 through 2004, there were 399 non-native exposures in the TESS database. Of these, 350 snakes (87%) were identified by genus and species, comprising at least 77 different varieties. Roughly equal percentages of snakes originated in Asia, Africa and Latin America, with a smaller number from the Middle-East, Australia, and Europe. Nearly half were viperids and a little more than a third were elapids. The vast majority of exposed individuals were adults. However, almost 15% were aged 17 years or less, and almost 7% were children aged 5 years or younger. Eighty-four percent were males. The vast majority of exposures occurred at the victim's own residence. Over 50% were evaluated at a healthcare facility, with 28.7% admitted to an ICU. Overall, 26% of patients were coded as receiving antivenom treatment. Coded outcomes were similar between viperid and elapid envenomations. There were three deaths, two involving viperid snakes and one elapid. Enhancements to the TESS database are required for better precision in and more complete characterization of non-native snake envenomations.
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Affiliation(s)
- Steven A Seifert
- Nebraska Regional Poison Center, University of Nebraska Medical Center, Omaha, Nebraska, USA.
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82
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Vázquez H, Chávez-Haro A, García-Ubbelohde W, Mancilla-Nava R, Paniagua-Solís J, Alagón A, Sevcik C. Pharmacokinetics of a F(ab')2 scorpion antivenom in healthy human volunteers. Toxicon 2005; 46:797-805. [PMID: 16197974 DOI: 10.1016/j.toxicon.2005.08.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Accepted: 08/18/2005] [Indexed: 10/25/2022]
Abstract
This paper presents the first study of F(ab')2 scorpion antivenom pharmacokinetics in humans. We have studied the pharmacokinetics of an antiscorpion venom preparation (Alacramyn) in eight human healthy volunteers. The fabotherapic was administered as a 47.5 mg i.v. bolus. Blood samples were drawn at 0, 5, 15, 30, 45, 60, 90, 120, 180 and 360 min after antivenom administration. Subsequently, the volunteers made seven visits to the hospital. Four of them at 24 h intervals, one at day 10, and one at day 21. We measured antivenom plasmatic concentrations using a specific high sensitivity ELISA method for F(ab')2. The time course of F(ab')2 in serum of seven subjects was well described by a lineal combination of three exponential components; a four exponential component model was necessary to fit the eighth subject. The most significant antivenom pharmacokinetic parameters determined were: AUC(infinity)=596.9 (369.3, 891.2) mg h l(-1); V(c) = 3.1 (2.3, 4.3)l; V(ss) = 15.4 (12.8, 39.9)l; MRT = 250.0 (218.8, 310.2) h; CL = 96.6 (58.0, 139.2) ml h(-1); t(1/2,tau1) (also called t(1/2,alpha)) = 0.25 (0.13, 0.37) h; t(1/2,tau(z)) (corresponding to the slowest component) = 161.3 (141.0, 212.0) h.
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Affiliation(s)
- H Vázquez
- Laboratorios Silanes S.A. de C.V., México, México
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83
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Abstract
In the US, two antivenins are marketed for the treatment of snake envenomation. The horse-derived serum-globulin-based Antivenin (Crotalidae) Polyvalent (ACP) has been available since 1954. There are few data on the efficacy and incidence of adverse events that occur following the administration of ACP. Most of the data are retrospective, anecdotal, or case reports. In 2000, ovine-derived serum-globulin-based ACP (Crofab) became available. Crofab is said to cause fewer reactions than ACP, but there are few comparative data to substantiate this claim. Although both antivenins ameliorate the systemic symptoms following snake envenomation, the efficacy of either antivenin in decreasing oedema and swelling is unknown for a number of reasons. Clinical trials are small and have not included control arms. The degree of oedema, as well as the efficacy of the antivenin in decreasing oedema, may depend on the genera of the snake (usually unknown) that envenomated the patient. This article compares available data on clinical aspects of the two antivenins. More prospective data are needed to determine the comparative efficacy of the two antivenins, or the efficacy of Crofab in preventing tissue oedema. There are still unanswered questions regarding the optimal dosing regimen of Crofab.
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Affiliation(s)
- Donna Seger
- Tennessee Poison Center, Nashville, 37232, USA
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84
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Ertem K. Venomous Snake Bite in Turkey: First Aid and Treatment. ELECTRONIC JOURNAL OF GENERAL MEDICINE 2004. [DOI: 10.29333/ejgm/82236] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Gutiérrez JM, León G, Lomonte B. Pharmacokinetic-pharmacodynamic relationships of immunoglobulin therapy for envenomation. Clin Pharmacokinet 2004; 42:721-41. [PMID: 12846594 DOI: 10.2165/00003088-200342080-00002] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Parenteral administration of horse- and sheep-derived antivenoms constitutes the cornerstone in the therapy of envenomations induced by animal bites and stings. Depending on the type of neutralising molecule, antivenoms are made of: (i) whole IgG molecules (150 kDa), (ii) F(ab')(2) immunoglobulin fragments (100 kDa) or (iii) Fab immunoglobulin fragments (50 kDa). Because of their variable molecular mass, these three types of antivenoms have different pharmacokinetic profiles. Fab fragments have the largest volume of distribution and readily reach extravascular compartments. They are catabolised mainly by the kidney, having a more rapid clearance than F(ab')(2) fragments and IgG. On the other hand, IgG molecules have a lower volume of distribution and a longer elimination half-life, showing the highest cycling through the interstitial spaces in the body. IgG elimination occurs mainly by extrarenal mechanisms. F(ab')(2) fragments display a pharmacokinetic profile intermediate between those of Fab fragments and IgG molecules. Such diverse pharmacokinetic properties have implications for the pharmacodynamics of these immunobiologicals, since a pronounced mismatch has been described between the pharmacokinetics of venoms and antivenoms. Some venoms, such as those of scorpions and elapid snakes, are rich in low-molecular-mass neurotoxins of high diffusibility and large volume of distribution that reach their tissue targets rapidly after injection. In contrast, venoms rich in high-molecular-mass toxins, such as those of viperid snakes, have a pharmacokinetic profile characterised by a rapid initial absorption followed by a slow absorption process from the site of venom injection. Such delayed absorption has been linked with recurrence of envenomation when antibody levels in blood decrease. This heterogeneity in pharmacokinetics and mechanism of action of venom components requires a detailed analysis of each venom-antivenom system in order to determine the most appropriate type of neutralising molecule for each particular venom. Besides having a high affinity for toxicologically relevant venom components, an ideal antivenom should possess a volume of distribution as similar as possible to that of the toxins being neutralised. Moreover, high levels of neutralising antibodies should remain in blood for a relatively prolonged time to assure neutralisation of toxins reaching the bloodstream later in the course of envenomation, and to promote redistribution of toxins from extravascular compartments to blood. Additional studies are required on different venoms and antivenoms in order to further understand the pharmacokinetic-pharmacodynamic relationships of antibodies and their fragments and to optimise the immunotherapy of envenomations.
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Affiliation(s)
- José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica.
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86
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Lalloo DG, Theakston RDG. Snake antivenoms. JOURNAL OF TOXICOLOGY. CLINICAL TOXICOLOGY 2003; 41:277-90; 317-27. [PMID: 12807311 DOI: 10.1081/clt-120021113] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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87
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Arce V, Rojas E, Ownby CL, Rojas G, Gutiérrez JM. Preclinical assessment of the ability of polyvalent (Crotalinae) and anticoral (Elapidae) antivenoms produced in Costa Rica to neutralize the venoms of North American snakes. Toxicon 2003; 41:851-60. [PMID: 12782085 DOI: 10.1016/s0041-0101(03)00043-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Polyvalent (Crotalinae) and anticoral (Elapidae) antivenoms produced by Instituto Clodomiro Picado, Costa Rica, were assessed for their ability to neutralize various toxic activities of the venoms of North American snakes of the genera Crotalus, Agkistrodon and Micrurus, in assays involving preincubation of venom and antivenom. When the intraperitoneal route of injection was utilized, polyvalent (Crotalinae) antivenom was effective in the neutralization of the venoms of Crotalus atrox, Crotalus adamanteus, Crotalus viridis viridis, Crotalus horridus atricaudatus, Agkistrodon contortrix contortrix and Agkistrodon piscivorus piscivorus, whereas the venom of Crotalus scutulatus was not neutralized. When the intravenous route was used, results differed depending on the "challenge dose" of venom employed. Polyvalent antivenom neutralized all venoms when mice were challenged with 2 LD(50)s of venom. When 5 LD(50)s were used, antivenom neutralized the venoms of C. atrox, C. adamanteus, C. v. viridis and C. h. atricaudatus, being ineffective in the neutralization of C. scutulatus, A. c. contortrix and A. p. piscivorus. Polyvalent antivenom was effective in the neutralization of hemorrhagic and myotoxic activities of all venoms studied. It also neutralized coagulant activity of C. adamanteus venom, whereas most of the venoms were devoid of clotting activity on plasma in vitro. Moreover, it neutralized defibrinating activity of the only three venoms that induced this effect (i.e. C. adamanteus, A. c. contortrix and A. p. piscivorus). Anticoral (Elapidae) antivenom neutralized lethality induced by the venom of Micrurus fulvius, using either the intravenous or the intraperitoneal routes of injection. Moreover, it neutralized myotoxic effect of this venom as well. It is concluded that polyvalent antivenom neutralizes lethality and other activities of most of the crotaline venoms tested. However, since it is ineffective in neutralizing the lethal effect of C. scutulatus venom, it is suggested that a venom containing presynaptically-active neurotoxic phospholipases A(2) related to "mojave toxin" needs to be introduced in the immunizing mixture in order to increase the neutralizing scope of this product in North America. Anticoral antivenom is highly effective in the neutralization of the venom of M. fulvius.
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Affiliation(s)
- Viviana Arce
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
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88
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Abstract
Bleeding diathesis is a cardinal feature of viperine bite, which has been thought to last not more than 24 hours. There is scarcity of literature about prolonged bleeding disorder in snake envenomation. Various explanations suggested in the literature include-temporary decrease in antivenin levels, rapid elimination of antivenin from circulation or continuous release of unneutralised venom from the envenomated site. Two children with prolonged coagulopathy lasting for more than a week, correction of which required more than 300 ml of antisnake venom are reported here.
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Affiliation(s)
- Alka Khadwal
- Department of Pediatrics, Government Medical College and Hospital, Chandigarh, India.
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89
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Abstract
Thrombocytopenia is a common occurrence in moderate to severe crotaline envenomation. The exact mechanism by which rattlesnake venom leads to thrombocytopenia is unclear, but aggressive treatment with crotaline-specific antivenom often leads to resolution of this disorder. Crotalinae Polyvalent Immune Fab (CroFab(TM), Protherics Inc., Nashville, TN) (crotaline Fab) is now available for the treatment of symptomatic rattlesnake envenomation. Although recurrence of thrombocytopenia has been reported in patients after envenomation treated with crotaline Fab, cases refractory to this therapy have not been described. We report a case of severe crotaline envenomation that appears to have exhibited two separate episodes of thrombocytopenia, only one of which responded to antivenom. The second, later phase was refractory to both crotaline Fab as well as traditional Antivenin (Crotalinae) Polyvalent (Wyeth-Ayerst Pharmaceuticals, Philadelphia, PA) (ACP). By reviewing the literature regarding venom-induced thrombocytopenia, we attempt to explain this "biphasic" phenomenon and the inability of crotaline Fab to reverse this toxic effect.
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Affiliation(s)
- Steven R Offerman
- Division of Medical Toxicology, San Diego Regional Poison Center, University of California-San Diego, 200 West Arbor Drive #8925, San Diego, CA 92103-8925, USA
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90
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Sánchez EE, Galán JA, Perez JC, Rodríguez-Acosta A, Chase PB, Pérez JC. The efficacy of two antivenoms against the venom of North American snakes. Toxicon 2003; 41:357-65. [PMID: 12565759 DOI: 10.1016/s0041-0101(02)00330-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mortality due to snake envenomation is not a major problem in the United States with approximately 8-12 deaths per year, but envenomation is a serious problem that can result in functional disability, loss of extremities, and a costly recovery. Physicians encounter different clinical situations with each new snakebite victim because of the geographical variations in snake venoms. The best and most acceptable form of treatment is the use of antivenom; however, it must be administered as soon as possible since it is not so effective at reducing local signs of envenomation such as necrosis. The antivenom in the United States is in short supply, expensive and may not even be the most effective for neutralizing all North American snake venoms. In this study, we tested two antivenoms. The first was a Crotalidae Polyvalent Fab fragment with Ovine origin (FabO) manufactured in London, and the second was Antivipmyn, a Mexican manufactured antivenom that is F(ab')(2) fragment produced in horse (Fab(2)H). The efficacy of the two antivenoms was tested with 15 different snake venoms found in North America. Three different assays were used to test the efficacy of the antivenoms, the in vivo serum protection test (ED(50)), antihemorrhagic and anticoagulant. The Fab(2)H antivenom was most effective in neutralizing the hemorrhagic activity of 78% of the hemorrhagic venoms used in this study. In the ED(50) assay, the Fab(2)H antivenom was effective in neutralizing all venoms used in this study, while FabO neutralized all but C. m. molossus venom. However, in most cases, FabO required less antivenom than Fab(2)H antivenom to neutralize three LD(50).
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Affiliation(s)
- Elda E Sánchez
- Department of Biology, Natural Toxins Research Center (NTRC), Texas A&M University-Kingsville, MSC 158, Kingsville, TX 78363-8202, USA
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91
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Offerman SR, Bush SP, Moynihan JA, Clark RF. Crotaline Fab antivenom for the treatment of children with rattlesnake envenomation. Pediatrics 2002; 110:968-71. [PMID: 12415038 DOI: 10.1542/peds.110.5.968] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE There is little data regarding safety or efficacy of Crotalinae polyvalent immune Fab (ovine) antivenom (crotaline Fab) in pediatric patients. Our objective was to provide the first information regarding safety and effectiveness of this new drug in children. METHODS Data were collected prospectively and retrospectively for all consecutive pediatric patients bitten by rattlesnakes and treated at 2 urban hospitals during 2001. Cases were included if there were signs of envenomation at presentation, patient age was 13 years or less, and there was administration of crotaline Fab. Cases were excluded if antivenin (Crotalidae) polyvalent (equine origin, the conventional antivenom) was given. Primary outcome variables were snakebite severity scores throughout the course of therapy, number of vials of crotaline Fab administered, occurrence of allergic reactions, adjunct surgical therapy, and the presence of permanent sequelae or serum sickness identified at follow-up. RESULTS In the 12 cases studied, ages ranged from 14 months to 13 years (mean: 6.9; standard deviation: 4.2). Presentation snakebite severity scores ranged from 2 to 9 (mean: 5.3; standard deviation: 2.3). Total crotaline Fab doses ranged from 4 to 22 vials (mean: 12.7; standard deviation: 5.4). Initial control of symptoms was achieved with 4 to 16 vials (mean: 7.7; standard deviation: 3.7), and severity scores stabilized or improved within 24 hours in all patients. Recurrence of local swelling occurred in 1 case despite scheduled repeat doses of antivenom. No cases required surgical intervention, and no permanent sequelae were identified. No immediate or delayed hypersensitivity reactions occurred. CONCLUSION In this group of pediatric patients treated for rattlesnake envenomation, crotaline Fab antivenom was safe and seemed to be effective.
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Affiliation(s)
- Steven R Offerman
- Division of Medical Toxicology, Department of Emergency Medicine UCSD Medical Center, San Diego, California, USA
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92
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Affiliation(s)
- Jason Chu
- Division of Pulmonary, Critical Care, and Sleep Medicine, Tufts-New England Medical Center, Boston, Massachusetts 02111, USA
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93
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Miller MA, Dyer JE, Olson KR. Two cases of rattlesnake envenomation with delayed coagulopathy. Ann Emerg Med 2002; 39:348. [PMID: 11867998 DOI: 10.1067/mem.2002.121998] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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94
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Abroug F, Nouira S. Antagonization of tumor necrosis factor in snake bite. A new approach for an old threat. Intensive Care Med 2001; 27:800-2. [PMID: 11430534 DOI: 10.1007/s001340100928] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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95
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Boyer LV, Seifert SA, Cain JS. Recurrence phenomena after immunoglobulin therapy for snake envenomations: Part 2. Guidelines for clinical management with crotaline Fab antivenom. Ann Emerg Med 2001; 37:196-201. [PMID: 11174239 DOI: 10.1067/mem.2001.113134] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recurrent local and coagulopathic effects (worsening after clinical improvement) have been described after treatment with Fab antivenom for envenomation by North American crotaline snakes. Although similar phenomena have been described previously in snakebite, few studies have examined recurrence or its management. Recurrence is consistent with known venom and antivenom kinetics and dynamics. The clinical significance of late coagulopathy after snakebite is uncertain, but clinically significant bleeding is a possibility. Prevention and treatment of recurrence with Fab antivenom require repeated dosing for at least 18 hours, with close monitoring of at-risk patients in the follow-up period. Duration of therapy depends on individual risk factors and coagulation response.
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Affiliation(s)
- L V Boyer
- Department of Pediatrics and Arizona Poison and Drug Information Center, University of Arizona Health Sciences Center, Tucson, AZ 85724, USA.
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96
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Seifert SA, Boyer LV. Recurrence phenomena after immunoglobulin therapy for snake envenomations: Part 1. Pharmacokinetics and pharmacodynamics of immunoglobulin antivenoms and related antibodies. Ann Emerg Med 2001; 37:189-95. [PMID: 11174238 DOI: 10.1067/mem.2001.113135] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The production of immunoglobulin antivenoms has evolved over the past 50 years, resulting in a choice of source animals and highly purified, target-specific immunoglobulin fragments (IgG, Fab2, and Fab). Differences in pharmacokinetic and pharmacodynamic properties of these fragments may affect clinical efficacy. For example, both local and systemic recurrences (worsening after initial improvement) with intact or fragmented immunoglobulin antivenoms have been observed. Local recurrence may result in greater tissue injury, and coagulopathic recurrence may result in the risk of hemorrhage. The latter is of particular concern because coagulopathic recurrence usually occurs after patient discharge. Similar phenomena of symptom recurrence have been observed with ovine, digoxin-specific Fab, and with Fab2 and IgG antivenoms from a variety of source animals as well. Recurrence of venom effects in Fab-treated patients appears to be the result of a pharmacokinetic and pharmacodynamic mismatch between the antivenom and target venom components. That is, tissue penetration and venom neutralization is incomplete, and clearance of unbound antivenom (antivenom that has not bound its venom target) is significantly faster than the clearance of some venom components, allowing signs and symptoms of envenomation to recur. Understanding the relative kinetics and dynamics of immunoglobulins and their targets may allow the physician to anticipate their clinical implications and may suggest modifications of the drug or dose to produce better clinical results.
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Affiliation(s)
- S A Seifert
- Arizona Poison and Drug Information Center, and the Department of Pediatrics, University of Arizona Health Sciences Center, Tucson, AZ 85724, USA.
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97
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Affiliation(s)
- S M Schexnayder
- Department of Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children's Hospital, Little Rock 72202, USA
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98
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Bush SP, Wu VH, Corbett SW. Rattlesnake venom-induced thrombocytopenia response to Antivenin (Crotalidae) Polyvalent: a case series. Acad Emerg Med 2000; 7:181-5. [PMID: 10691078 DOI: 10.1111/j.1553-2712.2000.tb00524.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To test the hypothesis that rattlesnake venom-induced thrombocytopenia would improve following Antivenin (Crotalidae) Polyvalent administration, and that the degree of platelet increase would correlate with the dosage of antivenom. METHODS The authors conducted a retrospective review of all patients admitted for rattlesnake envenomation at two southern California hospitals between 1980 and 1998. Patients were included if platelet count was less than 150 x 10(9)/L following a rattlesnake bite. Patients were excluded if they received platelet transfusion. The relationship between Antivenin (Crotalidae) Polyvalent administration and venom-induced thrombocytopenia was evaluated by linear regression and paired t-test. RESULTS The authors identified 103 cases of rattlesnake envenomation. Seventeen cases met inclusion criteria for thrombocytopenia. Two patients were excluded because they received platelet transfusions. One additional patient was excluded from paired t-test only because no antivenom was given. Thrombocytopenia usually improved between presentation and discharge (mean difference, 44 x 10(9)/L), although complete resolution was often not achieved. A statistically significant partial improvement in platelet counts immediately after antivenom administration was observed in a subset of patients with severe thrombocytopenia (platelet count <100 x 10(9)/L) (mean difference, 64 x 10(9)/L). Using regression analysis, the authors did not detect a linear relationship between the amount of Antivenin (Crotalidae) Polyvalent administered and the degree of improvement. CONCLUSIONS Although rattlesnake venom-induced thrombocytopenia usually improves immediately after Antivenin (Crotalidae) Polyvalent administration and by the time of discharge, the degree of improvement is frequently incomplete and of uncertain clinical significance in the absence of life-threatening bleeding. The authors found no correlation between the degree of improvement and the dosage of Antivenin (Crotalidae) Polyvalent.
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Affiliation(s)
- S P Bush
- Loma Linda University Medical Center, Department of Emergency Medicine, CA 92354, USA.
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99
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Abstract
Envenomations are uncommon, challenging causes of critical care admissions. This article describes the diagnosis and treatment of envenomations that cause the most critical care admissions in the United States. Most are caused by the following animals: rattlesnakes, copperheads, cottonmouths, coral snakes, brown recluse spiders, and bark scorpions.
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Affiliation(s)
- F G Walter
- Section of Medical Toxicology, University of Arizona College of Medicine, Tucson, USA.
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