The Epidemiology, Clinical Course, and Management of Snakebites in the North American Snakebite Registry

Platelet and Red Cell Responses to Three North American Pit Vipers

We investigated the hemotoxic effects of three North American pit vipers in healthy human donor blood. Using experiments focusing on platelet and red blood cell activity, we found differential effects of these venoms on these cellular components. Platelet aggregation was most induced by C. adamanteus. Platelet activation was highest with C. atrox. Red blood cells had calcium expression and erythrocyte formation most induced by C. adamanteus and A. piscivorus. These results demonstrate the complex interplay of individual cellular effects with clinical presentations seen in envenomings from these species.

Fab Antivenom Reversal of Neurotoxicity Caused by a Juvenile Crotalus horridus Lacking Canebrake Toxin

We present a case of neurotoxic effects in a pediatric patient after envenomation by a timber rattlesnake (Crotalus horridus) in the Appalachian upstate of South Carolina. Though some members of this species are capable of primarily neurotoxic envenomation, there is heterogeneity in venom composition, and neurotoxic timber rattlesnakes are not endemic to the Appalachian region. However, neurotoxic effects caused by C horridus species lacking typical neurotoxins have been suspected, though not previously confirmed in the medical literature. This case presents a patient who was envenomated by a genotypically confirmed non-neurotoxic C horridus but who nevertheless presented with symptoms consistent with primary neurotoxicity. Neurotoxic effects can be variable in their response to traditional antivenom, though this patient demonstrated rapid response to treatment, representing a novel case in the literature of neurotoxic effects from a snake lacking typical neurotoxins with documented improvement with traditional antivenom.

Ruthenium-based antivenom attenuates Crotalus atrox venom mediated coagulopathy in rabbits

BACKGROUND

The Western diamondback rattlesnake ( Crotalus atrox ) is a medically important venomous snake in the Southwestern United States, injuring humans, and their companion animals. The goals of this investigation were to utilize a rabbit model of subcutaneous envenomation to assess Crotalus atrox venom coagulopathy and determine the efficacy of a ruthenium-containing antivenom (RA) in attenuating it.

METHODS

Sedated New Zealand White rabbits had viscoelastic measurements of whole blood coagulation kinetics obtained from ear artery samples. Crotalus atrox venom (4 mg/kg) was injected subcutaneously and changes in coagulation determined over three hours and compared to samples obtained prior to envenomation. Other rabbits had site-directed RA injected 5 min after venom injection.

RESULTS

A significant decrease in the velocity of clot growth and thrombus strength was observed in animals injected with venom alone. Site-directed administration of RA resulted in no change in coagulation over the 3 h following venom injection. The interaction of antivenom administration and time was significantly different in the cases of clot growth velocity and strength.

CONCLUSIONS

A novel rabbit model was used to define the toxicodynamic profile of coagulopathy of Crotalus atrox venom and demonstrate the efficacy of RA. Future investigation is planned involving other medically important venoms and RA administration.

Fasciotomy following North American pit viper envenomation in Texas 2004-2021

INTRODUCTION

North American pit viper envenomation occurs over 4,000 times annually in the United States, with polyvalent Fab antivenom being the primary treatment. Fasciotomy is occasionally performed due to concerns about compartment syndrome. We utilized our direct access to Texas Poison Center Network data to create a new snakebite abstraction form and database on relevant available information between 2004 and 2021 and to identify, describe, and estimate the incidence of fasciotomy following pit viper envenomation in Texas.

METHODS

We searched the Texas Poison Center Network database for cases during 2004-2021 using keywords such as fasciotomy, surgery, compartment pressure, and compartment syndrome. Descriptive statistics summarized the data.

RESULTS

Of 16,911 reported envenomations, 0.69 percent involved fasciotomies (n = 117). Most common bite sites were digits/hands and lower extremities. Patients who underwent fasciotomy were typically male, aged 20-59, and 10 years younger than the total snakebite population. Only 6 percent of reported compartment syndrome cases had a compartment pressure measurement. Antivenom was administered in 101 (86.3 percent) cases, 92 (91.1 percent) of which received only Fab antivenom product. Patients with bites from rattlesnakes (47.9 percent) were associated with most fasciotomies.

DISCUSSION

Our findings suggest a potential increase in snakebite exposures, accompanied by a decrease in fasciotomies. Overall, copperheads constituted the majority of snakebites, but most fasciotomies were from rattlesnake envenomations (47.9 percent). In this cohort, compartment syndrome diagnosis and decisions regarding fasciotomy were primarily based on clinical evaluation/surgeon expertise without compartment pressure measurements. Despite the efficacy of antivenom, only 86.3 percent of patients in our study received antivenom.

CONCLUSIONS

Fasciotomy after North American pit viper envenomation in Texas is uncommon (0.69 percent) and has decreased over time, possibly due to increased antivenom use or surgeon comfort with nonsurgical management.

Snakebite-Associated Infections: A Systematic Review and Meta-Analysis

Snakebites still constitute a significant public health problem in developing countries and are considered a neglected tropical condition by the WHO. Snake accidents are associated with substantial morbidity and mortality and may produce secondary complications, such as severe infections. The objective of this systematic review was to determine the prevalence of snakebite infections and characterize the bacteria isolated from these infections. A systematic literature review in five databases was carried out to assess the prevalence of snakebite infection. A meta-analysis was performed using a random-effects model to calculate the pooled prevalence and 95% CIs. Cochran's Q test and the I2 statistic were used to assess between-study heterogeneity. The pooled prevalence of infection due to snakebite was 27.0% (95% CI: 22.0-32.0%), with high heterogeneity among studies (I2 = 99.7%). The prevalence was higher in Asia (32%) than in the Americas (21%). Snakebite infections required surgical interventions in 68% (95% CI: 37.0-98.0%). The leading group of pathogens identified corresponded to Gram-negative bacteria (63%), particularly Morganella morganii (32%), but also, Gram-positive cocci (40%), especially Enterococcus spp. (23%) and Staphylococcus aureus (15%). However, multiple other pathogens, including anaerobes, were found. A high prevalence of snakebite-associated infection has been described, primarily due to M. morganii, with the corresponding implications for empirical therapy. Rational use of antimicrobials is recommended, and this should guide initial empirical treatment. Moreover, isolation and identification of the possible bacteria present in snakebite wounds is recommended in all cases to confirm or rule out associated infection.

Snakebite envenoming: A systematic review and meta-analysis of global morbidity and mortality

BACKGROUND

Snakebite envenoming represents a significant and often neglected public health challenge, particularly in rural communities across tropical and subtropical regions. An estimated 1.2-5.5 million people are envenomed by snakebites annually. More than 125,000 of these bites are fatal, and 3-4 times as many results in disability/disfigurement. Despite its prevalence, collecting accurate epidemiological data on snakebite is challenging. This systematic review and meta-analysis collates global epidemiology data on snakebite morbidity and mortality.

METHODS

Medline, Embase, Cochrane and CINAHL Plus databases were searched for articles published between 2001-2022. Pooled incidence and mortality were obtained using random effects modelling, heterogeneity (I2) was tested, and sensitivity analyses performed. Newcastle-Ottawa Scale assessed study quality.

RESULTS

Out of the four databases, 5,312 articles were found. After removing duplicates, 3,953 articles were screened by title and abstract and 65 articles containing information on snakebite epidemiology, encompassing 663,460 snakebites, were selected for analysis. The people most at risk for snakebite were men (59%), engaged in agricultural labour (27.5%), and residing in rural areas (66.7%). More than half (57%) of the reported bites resulted in envenoming. Incidents occurred frequently in the summer season (38.5%), during daytime (56.7%), and bites were most often to the lower limb (56.4%). Envenoming severity was frequently mild (46.7%), treated in hospital (68.3%), and was treated with anti-venom (64.7%). The pooled global incidence and mortality was 69.4 /100,000 population (95%CI: 36.8 to 101.9) and 0.33/100,000 population (95%CI, 0.14 to 0.52) per year, respectively. Stratified by continents, Asia had the highest incidence of 130.7/100,000 population (95%CI: 48.3 to 213.1) while Europe has the lowest with 0.7/100,000 population (95%CI: -0.2 to 1.5). The highest mortality was reported in Asia at 0.96/100,000 population (95% CI: 0.22 to 1.70), and Africa 0.44/100,000 population (95%CI: -0.03 to 0.84). Incidence was highest among inhabitants of lower-middle-income countries 132.7/100,000 population (95%CI: 55.4 to 209.9) while mortality was highest in low-income countries at 0.85/100,000 population (95% CI: -0.06 to 2.31).

CONCLUSION

Incidence and mortality rates noted here highlight the global impact of snakebite and underscore the critical need to address the burden of snakebite envenoming. It also reveals that while reported snakebite incidence was higher in lower-middle-income countries, the burden of mortality was greatest among inhabitants of low-income countries, again emphasising the need for greater efforts to tackle this neglected tropical disease.

Geographic variation in the clinical features of Mohave rattlesnake (Crotalus scutulatus) envenomations reported to the North American Snakebite Registry

The geographic variation of Mohave rattlesnake (Crotalus scutulatus) venom is well established. We reviewed all the Mohave rattlesnake bites reported to the Toxicology Investigators Consortium's North American Snakebite Registry between January 1, 2015 and 12/31/2021. Data reviewed for this study included details regarding the snake encounter, patient demographics, signs and symptoms, treatment, and outcomes. Our objective was to describe the epidemiology, clinical manifestations, and management of Mohave rattlesnake envenomations using prospective data from two geographically distinct sites. There were 20 subjects, including eight nonpregnant females. Ages ranged from seven to 75 years, median age 48. Nine of the bites were managed in Arizona and 11 in California. In Arizona, all envenomated patients had local swelling. None had neurological toxicity. In California, swelling was present in nine patients. Neurological effects were observed in five subjects. Four Arizona patients and one California patient had hypotension requiring treatment. Each site had one patient with thrombocytopenia. An Arizona patient who sustained a bite to the face was intubated. Rhabdomyolysis occurred in two California patients. All envenomated patients received antivenom. Mohave rattlesnakes have the potential to cause significant local and/or systemic toxicity. Neurotoxicity was not observed in envenomations from Mohave rattlesnakes that presumably lack Mohave toxin, but hypotension and gastrointestinal signs were more common than in bites from snakes believed to possess Mohave toxin. Neurological toxicity was limited to paresthesias and fasciculations. Significant skeletal or respiratory muscle weakness was not observed in our study population.

Neurological and neuro-ophthalmological manifestations of snake bite: a systematic review

Objective

Snakebites, a major health concern in developing countries, affect rural farming communities. Venom, primarily neurotoxin, injected during a snake bite disrupts the nervous system, causing symptoms like muscle weakness, paralysis, altered sensation, and coordination issues. This review focuses on evaluating neurological and neuro-ophthalmological manifestations associated with snakebites.

Methods

A database search was conducted in EMBASE and PubMed for studies published from 2000 to 2023. The investigation centered on examining neurological and neuro-ophthalmological symptoms and signs, treatment approaches, treatment outcomes, and long-term complications of snake bites.

Results

Neurological and neuro-ophthalmological symptoms were common in both neurotoxic and hemotoxic snake bites, especially in neurotoxic cases. Ptosis was a prevalent manifestation across various snake bites, along with respiratory paralysis, limb weakness, dysphasia, and visual disturbances in some instances. However, most patients improved without residual neurological symptoms after treatment.

Conclusions

Understanding patterns of neurological manifestations contributes valuable insights for the comprehensive management of snakebite.

Compartment Syndrome after Crotalid Envenomation in the United States: A Review of the North American Snakebite Registry from 2013 to 2021 on Behalf of the ToxIC Snakebite Study Group

INTRODUCTION

Compartment syndrome (CS) is a rare but serious complication after crotalid envenomation in the United States. Few data are available regarding the epidemiology and management of these cases. Significant controversy and misunderstanding over best practices, including measurement of compartment pressures and use of fasciotomy, exist for this syndrome. This study aims to describe presentation and management of suspected CS cases after native snakebite reported to the North American Snakebite Registry (NASBR).

METHODS

This is an analysis of snakebite cases reported to the Toxicology Investigators Consortium NASBR between January 1, 2013 and December 31, 2021. Cases of native snakebite with documented concern for CS were included.

RESULTS

Over an 8-y period, 22 cases of suspected CS were identified, representing 1% of all cases reported to the NASBR. Fasciotomies were performed in 41% (n=9) of these cases, most commonly to the upper extremity (67%, n=6). In cases of suspected CS, intracompartmental pressures (ICPs) were rarely measured (23%, n=5) and fasciotomies were performed without measurement of ICPs frequently (56%, n=5). In 1 case, ICPs were measured and found to be low (8 mm Hg) and fasciotomy was avoided.

CONCLUSIONS

Measurement of compartment pressures in cases of suspected CS was uncommon in cases reported to the NASBR. Fasciotomy was commonly performed without measurement of compartment pressures.

A review of 95 pit viper envenomations in Northcentral Florida (2018-2020)

The medical records of 95 pit viper envenomations in client-owned dogs presented to an academic emergency hospital in the Southeastern United States during the period spanning 2018 and 2020 were retrospectively examined. This study's primary objectives were to record the clinical abnormalities and treatment responses associated with envenomation and their relation to outcome. Approximately 80% of the bites involved the head region associated with varying degrees of hemorrhagic lymphedema. Some of the most common additional symptoms observed were; hypotension (10%), cardiac dysrhythmias (17%), and coagulopathy (21%). Treatment in most cases consisted of intravenous fluids, antivenom, and analgesic drugs. Blood products were used as indicated for anemia and persistent bleeding. The average dose of the F('ab')₂ was 1-2 vials. Additional vials (3-22) were administered as needed to counteract persistent or recurrent coagulopathy and hemolysis. Only 3% of the dogs had mild clinical signs of Type 1 hypersensitivity during their treatment period. Antihistamine use at the tertiary hospital was restricted to the three dogs showing signs of a suspected allergic reaction in response to antivenom administration; these patients received diphenhydramine intramuscularly. A glucocorticoid drug was used in only one dog prior to referral but not subsequently. Ninety dogs had a good outcome, while five died. Historically, pit viper envenomation in dogs in the southeastern United States has been a potentially life-threatening problem. Most dogs will survive if treated promptly and appropriately with adequate amounts of intravenous fluids, and antivenom titrated on severity of clinical presentation.

Total CroFab and Anavip Antivenom Vial Administration in US Rattlesnake Envenomations: 2019-2021

INTRODUCTION

In 2018, Anavip became available for the treatment of rattlesnake envenomations in the USA. No comparisons between the treatment characteristics of patients have been made since Anavip and CroFab have both been widely available. The objective of this study was to compare the number of antivenom vials administered of CroFab and Anavip during the treatment of rattlesnake envenomations in the USA.

METHODS

This was a secondary analysis of rattlesnake envenomations utilizing the North American Snakebite Registry (NASBR) from 2019 through 2021. Frequencies and proportions were used to summarize demographics and baseline clinical characteristics. The primary outcome was total antivenom vials administered during treatment. Secondary outcomes included the number antivenom administration events, total treatment time, and hospital length of stay.

RESULTS

Two hundred ninety-one rattlesnake envenomations were analyzed; most occurred in the Western USA (n = 279, 96 %). One hundred one patients (35%) received only CroFab, 110 (38%) received Anavip only, and 80 (27%) received both products. The median number of vials used was 10 for CroFab, 18 for Anavip, and 20 for both antivenoms. More than one antivenom administration was necessary in thirty-nine (39%) patients that received only CroFab and 76 (69%) patients that received Anavip only. The median total treatment time was 5.5 hours for CroFab, 6.5 for Anavip, and 15.5 hours when both antivenoms were administered. All antivenom groups had a median hospital length of stay of 2 days.

CONCLUSIONS

Rattlesnake envenomated patients in the Western USA treated with CroFab had fewer antivenom vials and fewer antivenom administrations compared to patients treated with Anavip.

Clinical Presentations, Treatments, and Outcomes of Non-native Snake Envenomations in the United States Reported in the North American Snakebite Registry

BACKGROUND

Non-native snake envenomations in the United States are uncommon with much unknown about a patient's presenting signs and symptoms. Antivenoms for non-native snake envenomations are not typically available in hospital pharmacies which may limit their administration. What are the clinical presentations, treatments, and outcomes of non-native snake envenomation cases reported to the North American Snakebite Registry (NASBR) of the Toxicology Investigators Consortium (ToxIC)?

METHODS

This is a descriptive review of all non-native envenomations reported to the NASBR from 2013 to March 2022. Data abstracted included snake species, patient history, clinical signs, diagnostics, treatment (including antivenom usage), follow-up, and final outcome.

RESULTS

We identified 19 non-native snake envenomations resulting from encounters with eleven different species, eight of which belonged to the Viperidae family. The most common presenting symptoms were edema (18 patients), ecchymosis (seven patients), and necrosis (six patients). Systemic effects and hematologic abnormalities were less common. The most common treatments were extremity elevation and analgesia, with two patients receiving mechanical ventilation. Ten patients received antivenom. No patients died. Three patients had loss of mobility in a digit at the last follow-up visit. One patient had permanent tissue loss of a small area on a finger.

CONCLUSIONS

The results of this study suggest that non-native snake envenomations in the United States frequently cause local soft tissue effects and less frequently cause systemic or hematologic effects. Most patients received antivenom, although several patients envenomated by snakes for which a specific antivenom exists did not receive any. Sequelae at the last follow-up of such encounters consisted of local mobility deficits.

Delayed Recognition of Severe Systemic Envenomation after Copperhead Bite: A Case Report

Introduction

We report a case of severe systemic copperhead, Agkistrodon contortrix, envenomation that resulted in long-term sequelae.

Case Report

A 72-year-old man presented to the emergency department after suffering a copperhead snakebite. He developed severe systemic toxicity before local tissue injury developed. Clinicians did not initially recognize his envenomation syndrome and sought alternative explanations for his systemic symptoms before polyvalent immune fab (ovine) antivenom was administered. Although the patient improved, he was discharged with new stage three chronic kidney disease.

Conclusion

Although rare, copperhead envenomation can cause severe systemic toxicity. Envenomation should be promptly treated with antivenom.

Emergency Department Visits by Pediatric Patients for Snakebites

OBJECTIVES

Few studies have examined pediatric emergency department (ED) visits for snakebites. This study sought to examine characteristics of pediatric patients presenting to EDs nationally in the United States for snakebites.

METHODS

This retrospective cohort study obtained data from the Nationwide Emergency Department Sample for 2006 to 2014. Pediatric patients sustaining a snakebite were identified with International Classification of Diseases, Ninth Revision, E-codes E905.0 or E906.2. Data extracted included age, sex, insurance, disposition, hospital trauma designation, ED charges, and geographic region. Comparative analyses were performed for patients younger than 10 years and aged 10 to 17 years.

RESULTS

There were 24,388 ED visits from 2006 to 2014 by pediatric patients for snakebites: 10,554 were younger than 10 years, and 13,834 were aged 10 to 17 years. Males comprised 62% and 67% of the respective age cohorts. Most patients (younger than 10 years, 68%; aged 10-17 years, 63%) experienced snakebites in the South. Only 14% of those younger than 10 years and 10% of those aged 10 to 17 years were treated at a level 1 trauma center, whereas 50% and 54%, respectively, were treated at hospitals with no trauma designation. The majority of patients were discharged from the ED (younger than 10 years, 72%; aged 10-17 years, 80%). The mean ED charges for snakebite victims younger than 10 years were $5363 and for those aged 10 to 17 years were $4618. Medicaid was the primary insurer of younger patients, whereas private insurance was more common in older patients.

CONCLUSIONS

Most pediatric snakebites are seen in nontrauma centers and in the South region and are more commonly male. Most patients were discharged from the ED, with a small percentage being admitted or transferred to another facility.

Control of venom-induced tissue injury in copperhead snakebite patients: a post hoc sub-group analysis of a clinical trial comparing F(ab')2 to Fab antivenom

INTRODUCTION

Fab antivenom (FabAV) halts progression of tissue injury and improves recovery in copperhead snakebite. It is unknown if F(ab')2AV does as well. The objective of this study was to compare control of tissue injury in copperhead snakebite patients treated with F(ab')2AV versus FabAV.

METHODS

We performed a post hoc analysis of copperhead envenomated patients in a clinical trial comparing F(ab')2AV to FabAV. The outcomes for this analysis are the number of repeat doses required to obtain initial control, the number of patients requiring unscheduled doses during maintenance, and the time from antivenom administration to initial control.

RESULTS

Twenty-one (13 F(ab')2AV, 8 FabAV) were copperhead patients. Median age was 46 years with a male predominance. Baseline severity was similar. One (8%) F(ab')2AV and 2(25%) FabAV patients required repeat initial dosing, difference = 17%, (95%CI -18, 57%). One (8%) F(ab')2AV and 1(13%) FabAV patients required additional doses after maintenance, difference = 5%, (95%CI -27, 45%). Median time to initial control was 2.7 range (2.0, 9.3) hours and 3.5 range (2.0, 7.4) for F(ab')2AV and FabAV respectively, difference -0.8 h (95% CI -2.6, 0.9).

CONCLUSIONS

This exploratory analysis suggests that the available measures of the control of venom-induced tissue injury are similar between antivenom subgroups.

Snakebite envenomation in children: An ongoing burden in Morocco

Introduction

Snakebites are a leading cause of mortality and permanent disabilities especially among children in tropical countries and rural areas such as Morocco. Thus, a nationwide management protocol including specific antivenom therapy along with prevention strategies was implemented to reduce the overall snakebites morbimortality.

Patients and methods

Our retrospective study aimed to describe the clinical aspects of snakebite envenomation before and after the implementation of this protocol in children admitted to the pediatric intensive care unit (PICU) in Marrakesh-Morocco for a period of 11 years.

Results

A total of 75 cases were included and were mostly male (70%) with a mean age of 10 years old. Most envenomations were mild or severe (75%) and often occurred during outdoor activities in limb extremities. Altered hemostasis frequently occurred in 67% of cases but was rarely associated with severe exteriorized hemorrhage. Moderate anemia and PNN- predominant leukocytosis were often observed at admission (52.2% and 58%) but quickly tended to normalize before 48 h. Local symptoms were the main dread as they quickly evolve to a compartment syndrome and necrosis in the absence of antivenom therapy. Fasciotomy was performed in 33% of cases while 5 children required limb amputation. Antivenom administration (n = 39) was statistically significant for rapid improvement in hemostasis disorders, reduced blood transfusions and fasciotomy for compartment syndrome as well as a shortened length of stay in PICU. The onset of acute kidney injury was observed in 18 cases but restored in most patients within 48 h (77%). Five children died of which only two had received delayed antivenom immunotherapy due to its unavailability and deferred hospital admission.

Conclusion

The advent of specific serotherapy has made it possible to optimize the management of patients and to prevent and treat local and systemic complications thus improving the overall prognosis; nevertheless, primary prevention remains the key to reducing snakebites morbimortality.

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Snakebites are a leading cause of mortality and permanent disabilities especially among children.

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Morocco represents a hot spot in northern Africa for venomous snakes where there is a wide variety of species.

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The clinical presentation is widely variable and may rapidly evolve in time.

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Snakebites are eminently preventable and manageable through community awareness and unified therapeutic action.

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The inaccessibility to healthcare structures and the occasional availability of immunotherapy continue to be the main limitation.

Treatment outcomes among snakebite patients in north-west Ethiopia-A retrospective analysis

BACKGROUND

Millions of people are bitten by venomous snakes annually, causing high mortality and disability, but the true burden of this neglected health issue remains unknown. Since 2015, Médecins Sans Frontières has been treating snakebite patients in a field hospital in north-west Ethiopia. Due to the poor market situation for effective and safe antivenoms for Sub-Saharan Africa, preferred antivenom was not always available, forcing changes in choice of antivenom used. This study describes treatment outcomes and the effectiveness and safety of different antivenoms used.

METHODOLOGY / PRINCIPAL FINDINGS

This retrospective observational study included 781 snakebite patients presenting at the field hospital between 2015 and 2019. Adjusted odds ratios, 95%-CI and p-values were used to compare the treatment outcome of patients treated with Fav-Afrique (n = 149), VacSera (n = 164), and EchiTAb-PLUS-ICP (n = 156) antivenom, and to identify the risk of adverse reactions for each antivenom. Whereas only incidental snakebite cases presented before 2015, after treatment was made available, cases rapidly increased to 1,431 in 2019. Envenomation was mainly attributed to North East African saw-scaled viper (Echis pyramidum) and puff adder (Bitis arietans). Patients treated with VacSera antivenom showed lower chance of uncomplicated treatment outcome (74.4%) compared to Fav-Afrique (93.2%) and EchiTAb-PLUS-ICP (90.4%). VacSera and EchiTAb-PLUS-ICP were associated with 16- and 6-fold adjusted odds of treatment reaction compared to Fav-Afrique, respectively, and VacSera was weakly associated with higher odds of death.

CONCLUSIONS / SIGNIFICANCE

Snakebite frequency is grossly underreported unless treatment options are available. Although EchiTAb-PLUS-ICP showed favorable outcomes in this retrospective analysis, prospective randomized trials are needed to evaluate the effectiveness and safety of the most promising antivenoms for Sub-Saharan Africa. Structural investment in sustained production and supply of antivenom is urgently needed.

Predictors of FabAV use in copperhead envenomation

CONTEXT

Crotaline snake envenomation is a serious medical condition affecting thousands of Americans each year. Variation in the treatment of Crotaline snakebites exists among physicians in the United States. Management of copperhead snakebites is controversial with some experts advocating minimal intervention, rarely necessitating antivenom use and, even more rarely, surgical intervention. This study assessed the use of Crotaline Polyvalent Immune Fab antivenom (Ovine) (FabAV) and explored factors influencing the decision to prescribe antivenom for copperhead envenomation in patients in Northeastern Oklahoma.

METHODS

A retrospective cohort study examining electronic medical records of patients with copperhead snakebites from July 1, 2014 to August 31, 2019. Data collected included: patient demographics, transfer information, snake species, bite site, progression of local tissue effects, additional clinical and lab results, patient comorbidities, and treatment strategy. Associations between patient variables and treatment were evaluated using the chi-square test of independence, median test, and logistic regression analysis. Associations were statistically significant if p < 0.05.

DISCUSSION

Of the 130 patients bitten by a copperhead, a majority (75%) received FabAV. Symptoms of copperhead envenomation were mostly limited to the progression of tissue damage. Predictors of treatment with FabAV included progression of venom effects across major joints, younger age, comorbidities, and upper extremity bites.

CONCLUSIONS

Patients who have multiple comorbidities, upper extremity bites and progression of venom effects across major joints are more likely to be treated with FabAV. The high usage of FabAV at the study site underscores the need for continued work to optimize the use of antivenom for copperhead envenomations.

Case Report: Safe Tourniquet Removal in Black Mamba (Dendroaspis polylepis) Bites

The black mamba is known for its notorious potent neurotoxic venom. For this reason, their bites are often erroneously treated in the field with the application of a tourniquet in the hope of delaying systemic spread of the venom. Observational studies have shown that inappropriate tourniquet application is a common, harmful practice. An arterial tourniquet is not a recommended first aid measure because of the risk of limb ischemia and gangrene. When inappropriately applied, the rapid removal of the tourniquet in the emergency department may precipitate a life-threatening venom and metabolic toxin rush, leading to respiratory arrest. We present two cases of black mamba bites in Gauteng, South Africa, where gradual tourniquet removal was used to avoid a venom rush and rapid respiratory paralysis. Venom and metabolic toxin rush with potentially fatal respiratory muscle paralysis may be averted by gradual, cautious removal of field-applied tourniquets with concomitant antivenom administration.

A Strategy for Efficient Preparation of Genus-Specific Diagnostic Antibodies for Snakebites

As said by former United Nations Secretary-General Kofi Annan, "Snakebite is the most important tropical disease you've never heard of." Listed as a priority neglected tropical disease by the World Health Organization, snakebite envenoming (SBE) kills in excess of 125,000 people per year. However, due to the complexity and overlap of snake venom compositions, few reliable venom diagnostic methods for genus-/species-specific identification, which is crucial for successful SBE therapy, are available. Here, we develop a strategy to select and prepare genus-specific snake venom antibodies, which allows rapid and efficient clinical diagnosis of snakebite. Multi-omics approaches are used to choose candidate antigens from snake venoms and identify genus-specific antigenic epitope peptide fragments (GSAEPs) with ideal immunogenicity, specificity, and spatial accessibility. Double-antibody sandwich ELISA kit was established by matching a polyclonal antibody against a natural antigen and a monoclonal antibody that was prepared by natural protein as antigen and can specifically target the GSAEPs. The kit shows the ability to accurately identify venoms from similar genera of Trimeresurus and Protobothrops with a detection limit of 6.25 ng/ml on the snake venoms and a little cross-reaction, thus proving high feasibility and applicability.

In cold blood: Observational descriptive review of Eastern Massasauga rattlesnake bites reported to a single poison center over time

The Eastern Massasauga rattlesnake (Sistrurus catenatus catenatus) is a pit viper indigenous to the Great Lakes region and the only venomous snake native to Michigan. It is small-to-medium, thick-bodied with dark brown, bow-tie shaped blotches. Its behavior is described as reclusive and docile and it prefers damp habitats. The venom of the Eastern Massasauga is primarily cytotoxic and hemotoxic. Previous literature describes severe coagulopathies following Eastern Massasauga envenomings, with some resulting in death. The objective of this study was to characterize Eastern Massasauga envenomings in humans reported to the Michigan Poison & Drug Information Center from 2003 to 2020, including a description of clinical manifestations, incidence and characterization of coagulopathies, and medical outcome severities. This was a retrospective review of Eastern Massasauga snakebites reported to our state poison center over time. Coagulopathies were classified according to previous toxicological snakebite literature. The degree of envenoming was scored using an institutional guideline, representing a modified version of validated snakebite severity score system. Our longitudinal review demonstrated Eastern Massasauga bites led to clinically significant toxicity, including persistent, recurrent, and late coagulopathies, though with low incidence of bleeding events. Cases typically resolved with use of antivenom. This, to our knowledge, is the largest descriptive case series characterizing Eastern Massasauga snakebites.

Association of daily high temperatures with increased snake envenomations: A case-crossover study

The prevention of snake envenomations in North America often focuses on avoiding interactions between humans and snakes. Previous strategies have focused on the influence of geography, type of habitat, and time of year, though a detailed analysis of weather patterns on snakebite envenomation behavior is lacking. We present a case-crossover study of non-pregnant adults (n = 489) who reported snake envenomations to a single state's poison control center from 2014 to 2018. Age and gender of the individual, as well as the date, time, zip code associated with the envenomation, and snake descriptions were collected. Information regarding barometric pressure, actual temperature, high and low daily temperature, and weather condition (fair, cloudy, or rain/precipitation) was collected and compared to the same zip code, date, and time exactly one week and one year prior to the envenomation using historical data from the Weather Underground database. Paired t-tests and Stuart-Maxwell tests were used to determine differences in weather conditions during the study period. This study was IRB-approved. At the time of envenomation, the weather was most often fair (52.2%), followed by cloudy (44%), and least frequently demonstrated rain/precipitation (3.9%). Snake envenomations increased significantly (p < 0.0001) on days with an elevated daily high temperature. There were statistical differences in the distribution of weather conditions (fair, cloudy, or rain/precipitation) on the day of envenomation compared to one week prior (p < 0.0001) and one year prior (p < 0.0008). Comparisons based on both control groups indicated that envenomations were significantly less likely to occur during rain/precipitation and cloudy weather than during fair weather. Limitations include its retrospective nature and low total number of envenomations. In our single-center study, snake envenomation behavior as it relates to readily reportable weather measurements, appears to be associated with the warmer days, the overall high temperature on the day of envenomation, and fair weather conditions. Actual temperature at the time of envenomation, low temperature, barometric pressure, and precipitation at the time of envenomation do not appear to be associated with an increased risk of envenomation. Additional studies to determine the cause of these associations would be beneficial in further delineating the findings of this study.

Practical Review of the Management of Animal Bites

Animal bites are common worldwide. Due to the plethora of animals, there are diverse pathogens with specific associated risks and treatment algorithms. It is crucial to understand these to develop and execute appropriate management plans. This practical review was designed to amalgamate the most common bites worldwide and synthesize data to help guide treatment plans.

METHODS

A PubMed literature search was performed focusing on the major animal bites. High-level studies were preferred and analyzed but lower-level studies were also used if high-level studies did not exist.

RESULTS

The tables presented in this article cover the pertinent information regarding the incidence, common presentation, initial treatment, and potential complications associated with bites from dogs, cats, horses, rodents, snakes, marine life, and spiders. Many of the pathogens associated with the bites are treatable with various and somewhat common antimicrobials, though some are less easy to access. Basic irrigation, debridement, and wound culture are common to almost every animal and should be the first step in treatment.

CONCLUSIONS

Based on the current studies, the most important factor in treating animal bites is timely presentation to a medical facility and/or physician. It is critical that the offending animal be accurately identified to help guide medical and surgical algorithms, including specific antimicrobial treatment guided by the most commonly presenting pathogens specific to certain animals.

Simultaneous open fracture and rattlesnake bite on the same extremity

Open fractures and rattlesnake envenomations are two emergencies that each require emergent intervention and treatment. While each is common, when they occur simultaneously on the same extremity, it creates a syndrome that is quintessential Central Texas. We present the case of a 13-year-old boy who sustained a lower-extremity rattlesnake envenomation with concomitant open tibia and fibula fractures after being thrown from an all-terrain vehicle. The envenomation from the snake bite compelled us to first treat his developing coagulopathy with a delayed operative management of his fractures.

A symphony of destruction: Dynamic differential fibrinogenolytic toxicity by rattlesnake (Crotalus and Sistrurus) venoms

What factors influence the evolution of a heavily selected functional trait in a diverse clade? This study adopts rattlesnakes as a model group to investigate the evolutionary history of venom coagulotoxicity in the wider context of phylogenetics, natural history, and biology. Venom-induced clotting of human plasma and fibrinogen was determined and mapped onto the rattlesnake phylogenetic tree to reconstruct the evolution of coagulotoxicity across the group. Our results indicate that venom phenotype is often independent of phylogenetic relationships in rattlesnakes, suggesting the importance of diet and/or other environmental variables in driving venom evolution. Moreover, the striking inter- and intraspecific variability in venom activity on human blood highlights the considerable variability faced by physicians treating envenomation. This study is the most comprehensive effort to date to describe and characterize the evolutionary and biological aspects of coagulotoxins in rattlesnake venom. Further research at finer taxonomic levels is recommended to elucidate patterns of variation within species and lineages.

Citizen science and online data: Opportunities and challenges for snake ecology and action against snakebite

The secretive behavior and life history of snakes makes studying their biology, distribution, and the epidemiology of venomous snakebite challenging. One of the most useful, most versatile, and easiest to collect types of biological data are photographs, particularly those that are connected with geographic location and date-time metadata. Photos verify occurrence records, provide data on phenotypes and ecology, and are often used to illustrate new species descriptions, field guides and identification keys, as well as in training humans and computer vision algorithms to identify snakes. We scoured eleven online and two offline sources of snake photos in an attempt to collect as many photos of as many snake species as possible, and attempt to explain some of the inter-species variation in photograph quantity among global regions and taxonomic groups, and with regard to medical importance, human population density, and range size. We collected a total of 725,565 photos-between 1 and 48,696 photos of 3098 of the world's 3879 snake species (79.9%), leaving 781 "most wanted" species with no photos (20.1% of all currently-described species as of the December 2020 release of The Reptile Database). We provide a list of most wanted species sortable by family, continent, authority, and medical importance, and encourage snake photographers worldwide to submit photos and associated metadata, particularly of "missing" species, to the most permanent and useful online archives: The Reptile Database, iNaturalist, and HerpMapper.

[Incidence of venomous snakebite accidents by snake species in Brazilian biomes]

The supply of antidotes for the treatment of venomous snakebite accidents, as well as the training of the care team, should be structured according to the frequency and risks by geographical areas. The scope of this article is to analyze the trend of the incidence of snakebite accidents in Brazilian biomes between 2003 and 2012. It involved the ecological study by means of Prais-Winsten regression of the incidence of snakebites by the Bothrops, Crotalus, Lachesis and Micrurus species for the Brazilian biomes in the period from 2003 to 2012. The research revealed that the number of accidents increased from 26,082 in 2003 to 27,870 in 2012 with an increased demand for antidotes. The trend analysis of the incidence showed a stationary trend, except for the Crotalus species with an upward trend in the Brazilian aggregate. An upward trend was found in the Cerrado for the Crotalus, Lachesis and Micrurus species: in the Pampa for Crotalus; in the Caatinga for Lachesis and in the Atlantic Forest for Micrurus. The conclusion drawn is that the stationary trend observed for snakebite accidents in Brazil is due to the fact that the majority of these (87%) are caused by snakes of the Bothrops species. However, it should be stressed that there is an increased risk of accidents with snakes of the Crotalus, Lachesis and Micrurus species.

Snakebites Reported to the Kentucky Regional Poison Control Centers for the Years 2012-2016

INTRODUCTION

Snake envenomations cause significant morbidity and mortality. The goals of this study were to assess the epidemiology of snakebites in Kentucky and treatment strategies used by physicians reporting to the Kentucky Regional Poison Control Centers.

METHODS

This was a descriptive epidemiologic study compiling clinical data on snakebites reported to the Kentucky Regional Poison Control Centers from 2012 to 2016. We built a database of the patient demographics, treatment, and clinical course of each snakebite reported in the study period. Attention was paid to all antivenom interventions and use of contraindicated therapies.

RESULTS

We compiled 674 total records. Patient age was 34±18 y (mean±SD), with males (71%) predominating. Most (97%) bites were to a distal upper or lower extremity. The majority (78%) occurred at a private residence. Most reports came between May and September (88%). Of the 674 patients, 24% (n=159) were classified as moderate or severe. Two hundred thirty (34%) patients were admitted to the hospital. Forty-six patients (7%) received surgical consultation, and 12 (2%) underwent surgical intervention. One hundred fifty-three patients received antivenom, with 6±3 vials used per patient. Length of stay was 3±2 d when antivenom was administered and 2±2 d when not administered. Six cases of coagulopathy were noted. Multiple contraindicated therapies were noted.

CONCLUSIONS

Snake envenomations are a prevalent public health concern for residents of Kentucky, chiefly during summer months. Significant medical intervention is being performed for many patients, with a high prevalence of contraindicated therapies. More data are needed to fully characterize the epidemiologic impact and appropriateness of the interventions being applied.

Snake Bite Management: A Scoping Review of the Literature

Background:

Around the world, snake bite envenomation remains an underreported human health hazard. Envenomation can cause local and systemic complications, especially when there is a lack of antivenom availability. Although there are established guidelines regarding snake bite management acute care, there is a paucity of data regarding surgical intervention and the plastic surgeon’s role treating this unique patient population.

Methods:

A review was conducted identifying relevant published articles involving snake bite management and treatment in PubMed and EMBASE.

Results:

One hundred ten articles were identified and 77 met inclusion criteria. Snake bite envenomation can result in complications that are dependent upon a variety of variables. The literature has shown the best field treatment to be timely transportation to the nearest medical facility, along with antivenom administration. The cytotoxic, hemotoxic, and neurotoxic effects of venom can cause a variety of local soft tissue and systemic complications. Surgical interventions such as fasciotomies, wound debridements, skin grafts, and tissue flaps may be necessary in these patients to optimize functional and aesthetic outcomes. Disparities in access to care in resource limited settings are discussed.

Conclusions:

Global health disparities and insufficient antivenom distribution create an inequality of care in snake bite patients. Plastic surgeons have an important role in managing acute and chronic complications of snake bite envenomations that can lead to improved patient outcomes.

Supervised Learning Computer Vision Benchmark for Snake Species Identification From Photographs: Implications for Herpetology and Global Health

We trained a computer vision algorithm to identify 45 species of snakes from photos and compared its performance to that of humans. Both human and algorithm performance is substantially better than randomly guessing (null probability of guessing correctly given 45 classes = 2.2%). Some species (e.g., Boa constrictor) are routinely identified with ease by both algorithm and humans, whereas other groups of species (e.g., uniform green snakes, blotched brown snakes) are routinely confused. A species complex with largely molecular species delimitation (North American ratsnakes) was the most challenging for computer vision. Humans had an edge at identifying images of poor quality or with visual artifacts. With future improvement, computer vision could play a larger role in snakebite epidemiology, particularly when combined with information about geographic location and input from human experts.

Snakebite Envenomation and Heart: Systematic Review

Snakebite envenomation is a neglected tropical disease which can result in morbidity and mortality. Cardiac implications are poorly understood due to the low frequency of cardiotoxicity combined with a lack of robust information, as snakebites commonly occur in remote and rural areas. This review aims to assess cardiovascular implications of snakebite envenoming and proposes an algorithm for screening of cardiovascular manifestations. A systematic review was performed and 29 articles relating to cardiovascular involvement in snakebite envenomation were selected. Cardiovascular involvement seems to be rare and includes a wide spectrum of outcomes, such as myocardial infarction, ventricular dysfunction, hypotension, cardiac arrest, and myocarditis. In a significant proportion of the cases analyzed (24.39%), the cardiovascular manifestations had major consequences (cardiac arrest, myocardial infarction, malignant ventricular arrhythmias, or death). Clinical monitoring, physical examination, and early electrocardiogram should be considered as key measures to detect cardiovascular involvement in patients with evidence of systemic illness.

Use of Crotalidae equine immune F(ab')2 antivenom for treatment of an Agkistrodon envenomation

INTRODUCTION

Anavip (F(ab')₂AV) is a lyophilized F(ab')₂ immunoglobulin fragment derived from horses immunized with venom from Bothrops asper and Crotalus durissus. It was approved by the FDA in 2015 for treatment of North American rattlesnake envenomation but not for Agkistrodon envenomation. Published data regarding the efficacy and safety of Anavip in treating Agkistrodon envenomations is limited. We present a case of a patient treated with Anavip after confirmed Agkistrodon laticinctus envenomation.

CASE DETAILS

A 77 year-old man was bitten on his fifth finger by a captive A. laticinctus. He was taken to a local emergency department where he received a 10 vial initial dose of F(ab')₂AV for pain and swelling and was transferred. At the receiving facility, his pain had improved and his swelling had not progressed. Over the next 30 h, his platelets declined to 132,000/mm³ and he received an additional 4 vials of F(ab')₂AV. The remainder of his course was unremarkable with complete recovery by 3 months.

DISCUSSION

This case provides an additional published datapoint on the use of this F(ab')₂AV in the treatment of envenomation by Agkistrodon.

A Clot Twist: Extreme Variation in Coagulotoxicity Mechanisms in Mexican Neotropical Rattlesnake Venoms

Rattlesnakes are a diverse clade of pit vipers (snake family Viperidae, subfamily Crotalinae) that consists of numerous medically significant species. We used validated in vitro assays measuring venom-induced clotting time and strength of any clots formed in human plasma and fibrinogen to assess the coagulotoxic activity of the four medically relevant Mexican rattlesnake species Crotalus culminatus, C. mictlantecuhtli, C. molossus, and C. tzabcan. We report the first evidence of true procoagulant activity by Neotropical rattlesnake venom in Crotalus culminatus. This species presented a strong ontogenetic coagulotoxicity dichotomy: neonates were strongly procoagulant via Factor X activation, whereas adults were pseudo-procoagulant in that they converted fibrinogen into weak, unstable fibrin clots that rapidly broke down, thereby likely contributing to net anticoagulation through fibrinogen depletion. The other species did not activate clotting factors or display an ontogenetic dichotomy, but depleted fibrinogen levels by cleaving fibrinogen either in a destructive (non-clotting) manner or via a pseudo-procoagulant mechanism. We also assessed the neutralization of these venoms by available antivenom and enzyme-inhibitors to provide knowledge for the design of evidence-based treatment strategies for envenomated patients. One of the most frequently used Mexican antivenoms (Bioclon Antivipmyn®) failed to neutralize the potent procoagulant toxic action of neonate C. culminatus venom, highlighting limitations in snakebite treatment for this species. However, the metalloprotease inhibitor Prinomastat substantially thwarted the procoagulant venom activity, while 2,3-dimercapto-1-propanesulfonic acid (DMPS) was much less effective. These results confirm that venom-induced Factor X activation (a procoagulant action) is driven by metalloproteases, while also suggesting Prinomastat as a more promising potential adjunct treatment than DMPS for this species (with the caveat that in vivo studies are necessary to confirm this potential clinical use). Conversely, the serine protease inhibitor 4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride (AEBSF) inhibited the direct fibrinogen cleaving actions of C. mictlantecuhtli venom, thereby revealing that the pseudo-procoagulant action is driven by kallikrein-type serine proteases. Thus, this differential ontogenetic variation in coagulotoxicity patterns poses intriguing questions. Our results underscore the need for further research into Mexican rattlesnake venom activity, and also highlights potential limitations of current antivenom treatments.

Pan-American Lancehead Pit-Vipers: Coagulotoxic Venom Effects and Antivenom Neutralisation of Bothrops asper and B. atrox Geographical Variants

The toxin composition of snake venoms and, thus, their functional activity, can vary between and within species. Intraspecific venom variation across a species’ geographic range is a major concern for antivenom treatment of envenomations, particularly for countries like French Guiana that lack a locally produced antivenom. Bothrops asper and Bothrops atrox are the most medically significant species of snakes in Latin America, both producing a variety of clinical manifestations, including systemic bleeding. These pathophysiological actions are due to the activation by the venom of the blood clotting factors Factor X and prothrombin, thereby causing severe consumptive coagulopathy. Both species are extremely wide-ranging, and previous studies have shown their venoms to exhibit regional venom variation. In this study, we investigate the differential coagulotoxic effects on human plasma of six venoms (four B. asper and two B. atrox samples) from different geographic locations, spanning from Mexico to Peru. We assessed how the venom variation of these venom samples affects neutralisation by five regionally available antivenoms: Antivipmyn, Antivipmyn-Tri, PoliVal-ICP, Bothrofav, and Soro Antibotrópico (SAB). The results revealed both inter- and intraspecific variations in the clotting activity of the venoms. These variations in turn resulted in significant variation in antivenom efficacy against the coagulotoxic effects of these venoms. Due to variations in the venoms used in the antivenom production process, antivenoms differed in their species-specific or geographical neutralisation capacity. Some antivenoms (PoliVal-ICP, Bothrofav, and SAB) showed species-specific patterns of neutralisation, while another antivenom (Antivipmyn) showed geographic-specific patterns of neutralisation. This study adds to current knowledge of Bothrops venoms and also illustrates the importance of considering evolutionary biology when developing antivenoms. Therefore, these results have tangible, real-world implications by aiding evidence-based design of antivenoms for treatment of the envenomed patient. We stress that these in vitro studies must be backed by future in vivo studies and clinical trials before therapeutic guidelines are issued regarding specific antivenom use in a clinical setting.

Use of both Fab and F(ab')2 fragment antivenom in a pediatric patient for treatment of a North American Crotalidae envenomation

Crotalidae envenomation has been managed successfully in emergency departments across the world with antivenom. Over the years, antivenom has evolved and newer agents have been studied with the possibility of eliminating maintenance antivenom therapy. Here we report a patient who had worsening platelet and fibrinogen concentrations, as well as complaints of swelling and pain at the site of a rattlesnake envenomation following an initial dose of F(ab')₂AV (Crotalidae immune F(ab')₂ (equine) [ANAVIP®]) Crotalidae antivenom. The patient was subsequently transferred to a tertiary children's hospital for a higher level of care and received FabAV (Crotalidae polyvalent immune Fab (ovine) [CroFab®]) Crotalidae antivenom. The details of this patient's treatment course highlight the possibility that patients who receive F(ab')₂AV, may require additional antivenom treatment. Furthermore, it appears that based on our single patient experience, giving FabAV after F(ab')₂AV is safe and effective.

Cytoprotective effects of creosote bush (Larrea tridentata) and Southern live oak (Quercus virginiana) extracts against toxicity induced by venom of the black-tailed rattlesnake (Crotalus ornatus)

The venom of Crotalus ornatus (vCo) poses a threat to human health, as it contains a mixture of toxins that can cause cytotoxic, necrotic, and hemolytic effects. The present study assessed methanolic and acetone extracts from leaves and flowers of Larrea tridentata, as well as the bark of Quercus virginiana as potential suppressors of the toxic effects of vCo in vitro. The content of total phenols, flavonoids, and tannins of the plant extracts were quantified for the suppression of vCo cytotoxicity in two cell culture models, human lymphocytes and porcine aortic endothelial (PAE) cells. Extracts from Q. virginiana displayed a greater concentration of total phenols, flavonoids, and tannins. Co-incubation of lymphocytes and PAE cells with fixed concentrations of vCo and plant extracts resulted in decreased vCo-induced cytotoxicity. A 24-hour co-incubation of lymphocytes with vCo (2.36 ± 0.17 µg/mL) and 0.5 µg/mL of methanolic leaf extract from L. tridentata (LLM) significantly suppressed the venom-induced cytotoxicity by 37.33 ± 8.33%. Similarly, the LLM extract (4 µg/mL) caused a significant decrease in vCo cytotoxicity after 24 hours in PAE cells. In contrast, while the acetone extract of Q. virginiana bark (QA) suppressed cytotoxicity by 29.20 ± 3.51% (p < 0.001) in lymphocytes, it failed to protect PAE cells against vCo after 24 hours. In PAE cells, a shorter 4-hour co-incubation showed significant suppression of cytotoxicity with both extracts. Our results collectively suggest that LLM and QA possess cytoprotective properties against the in vitro toxic effects of vCo, and thus establish extracts from these plants as potential therapeutic interventions against Crotalus envenomation.

Review of North American pit viper antivenoms

PURPOSE

For the first time in nearly 20 years, 2 antigen-binding fragment (Fab) antivenoms are available to treat patients who incur North American pit viper snakebites: Crotalidae polyvalent immune Fab (ovine), or simply FabAV; and Crotalidae immune F(ab')2 (equine), or simply F(ab')2. Pharmacists are in a key position for the selection, dosing, reconstitution, administration, and monitoring of antivenom therapy; however, they encounter inconsistent exposure and experience with these drugs. Thus, an updated review of the literature is necessary.

METHODS

The search strategy and selection incorporated both controlled vocabulary terms and keywords to describe concepts relevant to the search. Retrieval was limited to literature published from 1997 to the present in English, Portuguese, or Spanish.

RESULTS

Given the paucity of available prospective literature, the authors elected to include all prospective evidence to best describe the role of antivenom. For the primary literature review, manuscripts were excluded if they were observational studies, conference abstracts, narrative or opinion articles, letters to the editor, or in-progress studies.

CONCLUSION

While there is limited evidence-based guidance on the superiority of F(ab')2 to FabAV, or vice versa, individual and regional considerations should contribute to formulary decisions. Pharmacists must play a role in the development of clinical pathways to ensure appropriate evaluation, supportive care, and antivenom procurement, administration, and monitoring.

When It Comes to Snakebites, Kids Are Little Adults: a Comparison of Adults and Children with Rattlesnake Bites

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.

Retrospective evaluation of acute kidney injury in dogs with pit viper envenomation (2008-2017): 56 cases

OBJECTIVES

To describe the clinicopathological characteristics of dogs that develop acute kidney injury (AKI) secondary to pit viper envenomation, and to describe the association between development of AKI and clinical course and outcome.

DESIGN

Retrospective study.

SETTING

University teaching hospital.

ANIMALS

Client-owned dogs treated with at least 1 vial of antivenom following pit viper envenomation and that had at least 2 plasma creatinine concentrations measured during the course of hospitalization.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Sixty-three dogs met the inclusion criteria. One was excluded due chronic kidney disease, and 6 were excluded due to nonsteroidal anti-inflammatory drug administration. Of the 56 dogs included in the study, 16 developed AKI (29%). Dogs with AKI received a significantly higher dose of antivenom, 8.7 ± 6.8 total vials versus dogs in the non-AKI group that received 4.2 ± 2.6 vials (P = 0.006). Dogs in the AKI group were significantly more tachycardic (P = 0.028), hypotensive (P = 0.002), had a higher shock index (P = 0.012), and were more likely to receive transfusions with packed red blood cells (P = 0.042) than dogs in the non-AKI group. No significant association was identified between the development of AKI and length of hospitalization. The only factors that were significantly associated with degree of severity of AKI included the receipt of blood transfusion (P = 0.006) and number of vials of antivenom administered (P = 0.03). The development of AKI was significantly associated with outcome (P < 0.001), with 5 of 16 (31%) dogs in the AKI group surviving to discharge, 7 of 16 (44%) dying, and 4 of 16 (25%) being euthanized versus 39 of 40 (98%) surviving to discharge in the non-AKI group and 1 of 40 (2%) dying in hospital.

CONCLUSION

Development of AKI in dogs following pit viper envenomation carries an increased risk of mortality that is associated with severity of shock at presentation and increased doses of antivenom administration.

Development a national minimum data set for poisoning registry in Iran

OBJECTIVES

In the developing countries with high mortality rates, poisoning is considered to be one of the most common causes of admission to emergency wards. Given the importance of registering data on poisoned patients, it is very important to have a complete poisoning Minimum Data Set (MDS). Therefore, the purpose of this study was to determine an MDS for poisoning registry in Iran.

METHODS

This applied and cross-sectional study was conducted through of Delphi technique in the poisoning ward of Imam Reza Hospital (northeastern Iran) in 2019. Literature reviews were initially carried out on such databases as PubMed, Web of Sciences, Scopus, and Embase. Then, Google search was done to retrieve poisoning forms and poisoning registry websites. Also, we considered International Classification of Diseases, 10th Revision coding guidelines of poisoning. Then, a questionnaire containing data elements of poisoning was developed.

RESULTS

In total, 558 data elements were developed during two rounds of Delphi technique. The MDS was divided into 10 categories including patient and communication data, encounter data, diagnostic data and medical history, exposure data, clinical data, treatment data, complications, paraclinical tests, biobank, and discharge data.

CONCLUSIONS

Establishing an MDS as the first and most important step towards implementing poisoning registry can be the standard basis for collecting poisoned patient data. The data registered in the poisoning registry can be used for planning, policy-making, prevention, and control purposes.

Epidemiology of fatal snakebites in the United States 1989-2018

BACKGROUND

There are 5000-10,000 snake envenomations annually in the United States. Fortunately, few are fatal. In this study we review the epidemiology of fatal snakebites.

METHODS

Native snakebite cases from the American Association of Poison Control Centers (AAPCC) National Poison Data System from 1989 to 2018 were reviewed. Additional cases that were not reported to the AAPCC were identified by reviewing Wikipedia and by searching PubMed and online news outlets using various combinations of relevant keywords.

RESULTS

We identified 101 fatal bites from native snakes. Rattlesnakes accounted for 74 (90.2%) of the 82 deaths for which the species was known or which occurred where rattlesnakes are the only native crotalids. There were five fatalities attributed to copperheads, two due to cottonmouths, and one caused by an eastern coral snake. Males were disproportionately affected. The median age for victims was 40 years old. In cases for which data were available, many of the snake interactions were intentional, e.g. religious services, animal husbandry, and attempting to kill the snake.

CONCLUSIONS

Death following envenomation from a native U.S. snake is unlikely, particularly if medical attention is sought promptly. Rattlesnake envenomations are more likely to be fatal than bites from other species. Intentionally engaging with a venomous snake raises the risk of incurring a fatal bite, as does concurrent alcohol or drug use. Age less than 12 years old does not appear to be a risk factor for a fatal outcome, while elderly patients may have a slightly increased risk of death.

One Bite, Two Patients: Disparate Clinical Courses Following Simultaneous Crotalus oreganus abyssus Envenomation

A number of crotaline species have been associated with neurotoxic envenomation in North America. One clinical sign that can occur is myokymia: fine, involuntary, wave-like muscle movements occurring at regular intervals. We report an unusual scenario in which a single snakebite resulted in simultaneous envenomation of 2 patients. Both developed myokymia, with 1 having respiratory compromise. One patient also developed a hypersensitivity reaction to antivenom. Envenomation by the Grand Canyon rattlesnake, Crotalus oreganus abyssus, can produce significant neurotoxicity and resultant respiratory compromise. Antivenom may be helpful but can produce hypersensitivity reactions.

Epidemiology, Clinical Features, and Management of Texas Coral Snake (Micrurus tener) Envenomations Reported to the North American Snakebite Registry

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.

Sex Differences in Pediatric Poisonings by Age Group: a Toxicology Investigators' Consortium (ToxIC) Analysis (2010-2016)

OBJECTIVE

To review pediatric poisonings evaluated at the bedside by medical toxicologists and reported in the ToxIC registry, by sex and age group.

METHODS

Pediatric poisoning cases age ≤18 years, reported between January 2010 and December 2016, were reviewed. Descriptive statistics were used to describe study variables by age group and sex.

RESULTS

A total of 12,699 cases were analyzed. There were 7517 females and 5182 males. Those < 2 years old represented 12.5% of the study group (n = 1584), 17.2% were 2-6 years old (n = 2178), 8.6% were 7-12 years old (n = 1097), and 61.7% were 13-18 years old (n = 7840). The most common primary reasons for encounter were intentional pharmaceutical with 4900 females and 1836 males; intentional non-pharmaceutical with 952 females and 1213 males; unintentional pharmaceutical with 539 females and 644 males; and unintentional non-pharmaceutical with 435 females and 593 males. Overall, pharmaceuticals were the most commonly involved agents, including analgesics (20.9% of cases) and antidepressants (11% of cases): 27.8% of females and 10.7% of males were reportedly exposed to an analgesic.13.7% of females and 7.0% of males were reportedly exposed to an antidepressant. Among 1584 cases under 2 years, there were 747 females and 837 males; among 2178 cases aged 2-6 years, there were 954 females and 1224 males; among 1097 cases aged 7-12 years, there were 555 females and 542 males; and among 7840 cases aged 13-18 years, there were 5261 females and 2579 males. Death was reported in 0.7% of the cases: 20 females and 18 males. 6.1% of cases were managed with intubation: 421 females and 351 males.

CONCLUSIONS

Sex-based characteristics of poisonings varied by age group among pediatric poisoning presentations reported to the ToxIC registry and further research is needed to determine implications for education and prevention efforts.