North American snake envenomation: diagnosis, treatment, and management

Clinical features and management of snake bites in 70 dogs in Korea

BACKGROUND

Snakebites remain a devastating and life-threatening environmental hazard. While the management of snakebites has been well described in humans, few clinical data and guidelines exist for dogs, especially in Korea.

OBJECTIVES

This retrospective study evaluated the clinical features of 70 dogs with snakebite wounds in Korea.

METHODS

The medical records of 72 dogs that presented to three animal hospitals from June 2008 to July 2021 were reviewed; among these, 70 dogs that met the inclusion criteria were enrolled. Their signalment, history, clinical signs, physical examination, blood analysis, treatment, and prognosis were also evaluated.

RESULTS

Of 70 dog owners, 35 (50%) witnessed the bite, with a mean time between bite and hospital presentation of 9.7 ± 4.1 h in 58 dogs. Blood smears were evaluated in 45 dogs, of which 28 (62%) showed echinocytosis. Anemia and acute kidney injury were found in 21 (29%) and 2 dogs (3%), respectively. A total of 37 dogs (53%) were hospitalized, 5 (7%) of which died.

CONCLUSIONS

The most significant finding was the high prevalence of echinocytosis. The data from this retrospective study could inform the management of dogs bitten by snakes in Korea.

Cerebral Complications of Snakebite Envenoming: Case Studies

There are an estimated 5.4 million snakebite cases every year. People with snakebite envenoming suffer from severe complications, or even death. Although some review articles cover several topics of snakebite envenoming, a review of the cases regarding cerebral complications, especially rare syndromes, is lacking. Here, we overview 35 cases of snakebite by front-fanged snakes, including Bothrops, Daboia, Cerastes, Deinagkistrodon, Trimeresurus, and Crotalus in the Viperidae family; Bungarus and Naja in the Elapidae family, and Homoroselaps (rare cases) in the Lamprophiidae family. We also review three rare cases of snakebite by rear-fanged snakes, including Oxybelis and Leptodeira in the Colubridae family. In the cases of viper bites, most patients (17/24) were diagnosed with ischemic stroke and intracranial hemorrhage, leading to six deaths. We then discuss the potential underlying molecular mechanisms that cause these complications. In cases of elapid bites, neural, cardiac, and ophthalmic disorders are the main complications. Due to the small amount of venom injection and the inability to deep bite, all the rear-fanged snakebites did not develop any severe complications. To date, antivenom (AV) is the most effective therapy for snakebite envenoming. In the six cases of viper and elapid bites that did not receive AV, three cases (two by viper and one by elapid) resulted in death. This indicates that AV treatment is the key to survival after a venomous snakebite. Lastly, we also discuss several studies of therapeutic agents against snakebite-envenoming-induced complications, which could be potential adjuvants along with AV treatment. This article organizes the diagnosis of hemotoxic and neurotoxic envenoming, which may help ER doctors determine the treatment for unidentified snakebite.

Arabian Levantine viper bite induces thrombocytopenia - a case report

Snakebites have been reported to induce hematological complications. Thrombocytopenia usually occurs secondary to disseminated intravascular coagulation (DIC) and coagulopathy induced by the snake bite. However, thrombocytopenia can develop after the snake bite, even in the absence of significant coagulopathy. We reported the case of a 36-year-old Jordanian male patient who was bitten by Arabian Macrovipera Lebetina Obtusa (Levantine viper), which developed venom-induced severe thrombocytopenia without coagulopathy. A progressive drop in platelet count was observed during his admission. His condition improved after anti-venom therapy, and he was discharged after 4 weeks of treatment for a full recovery. This case supports that snake venom can produce severe thrombocytopenia without significant coagulopathy, which can be treated successfully with anti-venom and the best supportive care.

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.

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.

Myalgia as a Symptom of Envenomation by the Eastern Coral Snake, Micrurus Fulvius: A Case Report

We present the case of a patient who developed myalgia as the primary symptom of envenomation by the eastern coral snake, Micrurus fulvius. The patient was evaluated and treated in the emergency department. Physical examination did not demonstrate any neuromuscular abnormalities. On consultation with the poison control center, the patient's myalgia was determined to be an effect of envenomation, and 5 vials of North American coral snake antivenin were administered. The patient was admitted to the intensive care unit where his symptoms resolved. He was discharged the following day after remaining asymptomatic for 24 h.

Antivenin plants used for treatment of snakebites in Uganda: ethnobotanical reports and pharmacological evidences

Snakebite envenomation is a serious public health concern in rural areas of Uganda. Snakebites are poorly documented in Uganda because most occur in rural settings where traditional therapists end up being the first-line defense for treatment. Ethnobotanical surveys in Uganda have reported that some plants are used to antagonize the activity of various snake venoms. This review was sought to identify antivenin plants in Uganda and some pharmacological evidence supporting their use. A literature survey done in multidisciplinary databases revealed that 77 plant species belonging to 65 genera and 42 families are used for the treatment of snakebites in Uganda. The majority of these species belong to family Fabaceae (31%), Euphorbiaceae (14%), Asteraceae (12%), Amaryllidaceae (10%) and Solanaceae (10%). The main growth habit of the species is shrubs (41%), trees (33%) and herbs (18%). Antivenin extracts are usually prepared from roots (54%) and leaves (23%) through decoctions, infusions, powders, and juices, and are administered orally (67%) or applied topically (17%). The most frequently encountered species were Allium cepa, Carica papaya, Securidaca longipedunculata, Harrisonia abyssinica, and Nicotiana tabacum. Species with global reports of tested antivenom activity included Allium cepa, Allium sativum, Basella alba, Capparis tomentosa, Carica papaya, Cassia occidentalis, Jatropa carcus, Vernonia cinereal, Bidens pilosa, Hoslundia opposita, Maytensus senegalensis, Securinega virosa, and Solanum incanum. There is need to identify and evaluate the antivenom compounds in the claimed plants.

Venom composition of adult Western Diamondback Rattlesnakes (Crotalus atrox) maintained under controlled diet and environmental conditions shows only minor changes

Many species of snakes produce venom as a chemical means of procuring potentially fractious prey. Studies have increasingly focused on venom compositional variation between and within individual snakes of the same species/subspecies, with significant differences often being observed. This variation in composition has been attributed to differences in age, season, diet, and environment, suggesting that these factors could help explain the inter- and intra-specific variation found in some snake venoms, perhaps via some type of feedback mechanism(s). To address several of these possible sources of variation, this study utilized wild-caught Western Diamondback Rattlesnakes (Crotalus atrox) from Cochise Co., AZ. Sixteen adult C. atrox were maintained in the lab on a diet of NSA mice for eight months to determine whether venom composition changed in captivity under a static diet in a stable environment. Reducing 1-D SDS-PAGE, fibrinogen degradation assays, reversed-phase HPLC, and MALDI-TOF mass spectrometry revealed only minor differences over time within individuals. Venom L-amino acid oxidase (LAAO) and phosphodiesterase activities significantly increased over the course of captivity, with no changes occurring in azocasein metalloproteinase, kallikrein-like serine proteinase (KLSP), or thrombin-like serine proteinase (TLSP) activities. Snake total length was positively correlated with TLSP activity and negatively correlated with LAAO and KLSP activity. There was typically a much higher degree of variation between individuals than within individuals for all analyses performed and measurements collected. Because the overall "fingerprint" of each snake's venom remained more/less constant, it is concluded that biologically significant changes in venom composition did not occur within individual C. atrox as a function of captivity/diet. However, this study does indicate that differences in activity levels do occur in minor venom enzyme components, but the differences observed are likely to be of minimal significance to the production of antivenom or to subsequent treatment of human envenomations.

Snake Eyes: Coral Snake Neurotoxicity Associated With Ocular Absorption of Venom and Successful Treatment With Exotic Antivenom

BACKGROUND

Coral snake bites from Micrurus fulvius and Micrurus tener account for < 1% of all snake bites in North America. Coral snake envenomation may cause significant neurotoxicity, including respiratory insufficiency, and its onset may be delayed up to 13 h.

CASE REPORT

We present a unique patient encounter of M. tener venom exposure through the ocular mucous membranes and a small cutaneous bite, resulting in neurotoxicity. To our knowledge, this is the first reported case of systemic neurotoxicity associated with ocular contact with coral snake venom. Our patient developed rapid-onset skeletal muscle weakness, which is very uncommon for M. tener, along with cranial nerve deficits. Acquisition of antivenom was challenging, but our patient provides a rare report of resolution of suspected M. tener neurotoxicity after receiving Central American coral snake (Micrurus nigrocinctus) antivenom. Our patient subsequently developed serum sickness, a known delayed complication of antivenom. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: The emergency physician should be aware that coral snake venom may be absorbed through different routes. Neurotoxicity and respiratory insufficiency may be fatal and onset may be delayed up to 13 h. North American Coral Snake Antivenom is in very limited supply, so non-Food and Drug Administration-approved alternative coral snake antivenoms may be used for patients demonstrating neurotoxicity. Emergency physicians should be proactive in contacting a toxicologist to procure antivenom, as well as consideration of adjunctive treatments, such as neostigmine. Furthermore, whole immunoglobulin G products, such as antivenom, may result in immediate and delayed reactions.

Venomous Snakebites in Canada: A National Review of Patient Epidemiology and Antivenom Usage

INTRODUCTION

There are 3 pit viper species in Canada. Limited Canadian literature exists on the epidemiology of venomous snakebites and the treatment patterns with antivenom. This study described the epidemiology, the utilization of antivenom, and estimated expenditures due to forfeited antivenom for pit viper envenomations in Canada.

METHODS

A retrospective review of the Health Canada Special Access Program records to generate descriptive statistics. Data are presented as mean±SD (range), as appropriate.

RESULTS

The geographic distribution of Canadian pit viper species is presented. There were 99 envenomations reported in Canada from January 2009 to December 2015. The number of envenomations per year was 14±6 (6-21). CroFab and Antivipmyn are used in Canada to treat envenomations. The number of vials for patient treatment was 17±12 (3-66) and 16±9 (6-42) for CroFab and Antivipmyn, respectively. Antivenom stock usage for patient treatment varied across the country with provincial means reported for British Columbia (33%), Alberta (37%), Saskatchewan (27%), and Ontario (71%). The costs incurred secondary to forfeited stock where estimated as: $1,280,000 USD in British Columbia, $255,000 in Alberta, $60,000 in Saskatchewan, and $0 in Ontario.

CONCLUSIONS

The absolute number of annual envenomations is small and the 3 Crotalinae species are limited to relatively narrow geographic areas in British Columbia, Alberta, Saskatchewan, and Ontario. The utilization of antivenom in the treatment of patients revealed that regions where the western and prairie rattlesnake reside forfeited a substantial amount of antivenom from 2009 to 2015. Organizations responsible for maintaining antivenom supplies on a provincial or regional level could use these data to guide antidote stocking and reduce costs.

Snakebites in Africa and Europe: a military perspective and update for contemporary operations

Snakebite envenoming is rare among military patients, with few cases reported in recent years. Increasingly, however, military operations are taking place in remote parts of Africa, which are inhabited by numerous species of venomous snake, and in Europe, where dangerous species exist but are less common. Bites from a venomous snake may prove fatal, and therefore military medics must be adequately prepared to manage them. This paper reviews the most medically significant species of venomous snake present in Africa and Europe, before suggesting an evidence-based approach to snakebite prevention and management, including possible changes to the UK's Clinical Guidelines for Operations.

Snakebites Treated in North Carolina Emergency Departments, October 2013-September 2015

INTRODUCTION

North Carolina (NC) is home to more than 30 species of indigenous venomous and nonvenomous snakes. Snakebites can cause debilitating and potentially fatal injuries. However, there is a lack of current information available describing the incidence of snakebites in NC. Therefore, we performed this study of snakebites treated in NC emergency departments (EDs) using the statewide syndromic surveillance system, the North Carolina Disease Event Tracking and Epidemiologic Collection Tool (NC DETECT).

METHODS

This was a descriptive epidemiologic study characterizing NC ED visits collected by NC DETECT between October 1, 2013 and September 30, 2015 with an assigned International Classification of Diseases, 9th Revision, Clinical Modification code or keyword indicating a snakebite.

RESULTS

Over the 2-year period, the absolute count of snakebite-related ED visits was 2080 visits with an incidence rate of 10.4 visits per 100 000 person-years (95% confidence interval: 10.0-10.9). The frequency of snakebite was highest during the summer months and evening hours. Men had higher incidence rates of snakebite-related ED visits than women, and residents of the Coastal Plain geographic region of NC had higher incidence rates than persons in other regions.

CONCLUSIONS

The current study indicated that snakebites are common injuries treated at NC EDs, with a strong seasonal and geographic component. Additional research is needed to further characterize the circumstances associated with snakebites for the development of preventive measures and public health education.

Suspected anaphylaxis and lack of clinical protection associated with envenomation in two dogs previously vaccinated with Crotalus atrox toxoid

OBJECTIVE

to describe the clinical presentation of two canines present in anaphylactic shock secondary to rattlesnake envenomation. In both cases, there was no previous documented previous envenomation event and the initial sensitization required for anaphylactic response is believed to be secondary to Crotalus atrox toxoid vaccine.

CASE DESCRIPTION

In the first case, a 12-year-old golden retriever present for collapse, severe hematochezia, and vomiting after first time envenomation from a suspected western diamondback rattlesnake. The patient presented in severe hypovolemic shock and required aggressive fluid therapy, antivenom, anti-emetics, and pain management. The patient made a full recovery within 24 hours. In the second case, an 8-year old English setter presented for acute collapse, vomiting, and facial swelling after suspected first time envenomation from a suspected Prairie rattlesnake. The patient presented in severe hypovolemic shock with cardiac arrhythmias and required aggressive fluid therapy, antivenom, pain control, anti-emetics, and antibiotics. The patient made a full recovery after three days of hospitalization. Both patients had been previously vaccinated with the C. atrox vaccine.

CONCLUSION

This case report documents suspected anaphylaxis in two canine patients after first time envenomation by a rattlesnake. Both patients were previously vaccinated by the Crotalus atrox toxoid, which is hypothesized to be the initial inciting trigger.

Efficacy and Safety of Snake Antivenom Therapy: Experience of a Regional Hospital

Introduction

Snakebite is a commonly encountered envenomation emergency in the rural areas of Hong Kong. The majority of cases do not warrant antivenom therapy. We looked into those receiving antivenom to enhance the understanding of the results of antivenom therapy.

Methods

This was a retrospective review of the snakebite cases treated with antivenom in Tuen Mun Hospital from 1st January 2000 to 31st August 2005, focusing on both the therapeutic and side effects of the antivenom.

Results

Twelve patients were identified. All had local symptoms of swelling or numbness. Two of them subsequently developed skin necrosis requiring operative treatment. Thrombocytopenia was less amenable to correction than prolonged INR. No early or late allergic reactions were observed.

Conclusion

Because of the small number of cases, the apparent safety of the antivenoms in the current review warrants larger trials in future.

Contributing Factors for Complications and Outcomes in Patients With Snakebite: Experience in a Medical Center in Southern Taiwan

OBJECTIVES

Snakebite usually results in various complications, such as significant soft tissue damage, infection, hematological, and neurological deficit. Surgical intervention, usually, is indicated in patients with tissue necrosis, infection, and compartment syndrome. To identify the contributing factors for complications and outcomes in different patients with snakebite so that outcomes can be evaluated and treatment of such patients can be initiated at the earliest.

METHODS

Information was collected regarding age, sex, underlying disease, species of snake, and the course of treatment of the victims of snakebite who visited the emergency department of a medical center in southern Taiwan between 2004 and 2014. The data obtained were analyzed using SPSS 20.0.

RESULTS

The bites from Taiwan cobra (Naja naja atra) significantly resulted in more complications than those from other snakes and required surgical intervention. The use of antivenin and antibiotics, immediate presentation to the hospital, and the location of the bite also were significant contributing factors.

CONCLUSIONS

Taiwan cobra significantly results in higher possibility of prolonged hospitalization, operation, tissue necrosis, infection, and necrotizing fasciitis. Location of the bite, immediate presentation to the hospital, and use of antivenin and antibiotics affect the outcome of snakebite. Knowledge of these factors will help in a better management of patients with snakebite.

Resource Utilization After Snakebite Severity Score Implementation into Treatment Algorithm of Crotaline Bite

BACKGROUND

Crotaline envenomation clinical manifestations vary considerably among patients. Current recommendations for treatment with Crotalidae polyvalent immune Fab require assessment of envenomation control. Determining control of envenomation, particularly when patients are evaluated by different providers in separate clinical settings, can be difficult.

OBJECTIVE

To determine if a difference in total vials of Crotalidae antivenin therapy exists between pre-protocol and post-Snakebite Severity Score (SSS) protocol.

METHODS

Retrospective medical record review at an academic medical and regional Level I trauma center. Resource utilization in patients with a diagnosis of "snakebite" was compared between patients treated pre- and post-SSS protocol implementation.

RESULTS

One hundred forty-six patients were included in the evaluation. One hundred twenty-seven (87.0%) patients received antivenin, n = 80 (90.9%) in the pre-protocol group and n = 47 (81.0%) in the post-protocol group. Median total number of antivenin vials per patient was lower in the post-protocol group than the pre-protocol group, 16 (10-24 interquartile range) vs. 12 (10-16 interquartile range), p = 0.006. This decreased utilization correlates to an approximate $13,200 savings per patient. Hospital and intensive care unit length of stay, opioid use, incidence of blood product transfusion, need for surgical intervention, or need for intubation were not different between groups.

CONCLUSIONS

A snakebite protocol with SSS utilization to guide antivenin administration results in significantly decreased antivenin therapy in snakebite patients without increase in other health care utilization.

Reversible atrial fibrillation following Crotalinae envenomation

Background

Cardiotoxicity is a documented complication of Crotalinae envenomation. Reported cardiac complications following snake envenomation have included acute myocardial infarction, electrocardiogram abnormalities and arrhythmias. Few reports exist describing arrhythmia induced by viper envenomation and to our knowledge none describe arrhythmia induced by Crotalinae envenomation. This report concerns the first known case of atrial fibrillation precipitated by rattlesnake bite.

Case presentation

A 73-year-old Caucasian man with a past medical history of hypertension, hyperlipidemia, type 1 diabetes mellitus, and a baseline first-degree atrioventricular block presented to the emergency department following a rattlesnake bite to his left lower leg. He developed pain and swelling in his left leg two-hour post-envenomation and subsequently received four vials of Crotalidae polyvalent immune fab (ovine). At three-hour post-envenomation following transfer to the intensive care unit, an electrocardiogram revealed new-onset atrial fibrillation. An amiodarone drip was started and the patient successfully converted to normal sinus rhythm approximately six hours after he was found to be in atrial fibrillation. A transthoracic echocardiogram revealed mild concentric left ventricular hypertrophy and an ejection fraction of 72%. He was discharged the following day with no hematological abnormalities and a baseline first-degree atrioventricular block.

Conclusion

This is the first documented case of reversible atrial fibrillation precipitated by Crotalinae envenomation. In patients with pertinent risk factors for developing atrial fibrillation, physicians should be aware of the potential for this arrhythmia. Direct toxic effects of venom or structural and electrophysiological cardiovascular abnormalities may predispose snakebite patients to arrhythmia, warranting extended and attentive cardiac monitoring.

Administration of CroFab Antivenom by a Helicopter Emergency Medical Service Team

The case presented here highlights an unconventional use of a helicopter emergency medical service (HEMS) to provide a specialized medication to a critically ill patient when definitive transport was delayed. A 39-year-old man presented to a rural hospital 1 hour after sustaining a copperhead envenomation. He developed severe symptoms and was intubated. Arrangements were made for transfer to a tertiary referral center by HEMS, but because of incoming weather conditions, the team would not be able to make the return flight safely. The decision was made for the HEMS team to fly antivenom to the patient, administer the medication, and then transport the patient by ground to the tertiary medical center. This plan was executed, and the patient was safely transported to the accepting facility. Antivenom is most effective when administered early because this will halt the progression of edema and may reverse the systemic effects of envenomation. In this case, HEMS transport of antivenom to the patient with severe toxicity prevented a delay to administration and likely improved the patient's outcome. Although the traditional role of HEMS is to provide rapid transport to critically ill patients, HEMS teams can also function to deliver specialized medications to remote settings.

An Analysis of Media-Reported Venomous Snakebites in the United States, 2011-2013

BACKGROUND

Venomous snakebite is a widespread natural hazard in the United States. A common perception exists that the majority of these snakebites are "illegitimate," resulting from deliberate interaction with snakes (such as attempting to move or kill the animal), but there is little quantitative information available regarding the conditions under which bites occur.

METHODS

To better understand the circumstances under which victims are bitten, we compiled a dataset of media-reported snakebites in the United States between 2011 and 2013. A total of 332 reported snakebites were recorded. Of these, 307 were from snakes encountered under natural circumstances and 25 were under captive-care conditions.

RESULTS

Most reported victims were adult males. Although some bites occurred during intentional handling of snakes and such activity may relate to bite severity, the majority of victims reported being unaware of the snake before they were bitten. Accidentally stepping on or placing the hands near an unseen snake were the activities most frequently associated with bites under natural conditions.

CONCLUSIONS

Although bias in snakebite reporting patterns by the media is likely, across the United States "legitimate" bites from unseen snakes appear to be the norm.

Benefits of using heterologous polyclonal antibodies and potential applications to new and undertreated infectious pathogens

BACKGROUND

Passive immunotherapy using polyclonal antibodies (immunoglobulins) has been used for over a century in the treatment and post-exposure prophylaxis of various infections and toxins. Heterologous polyclonal antibodies are obtained from animals hyperimmunised with a pathogen or toxin.

AIMS

The aims of this review are to examine the history of animal polyclonal antibody therapy use, their development into safe and effective products and the potential application to humans for emerging and neglected infectious diseases.

METHODS

A literature search of OVID Medline and OVID Embase databases was undertaken to identify articles on the safety, efficacy and ongoing development of polyclonal antibodies. The search contained database-specific MeSH and EMTREE terms in combination with pertinent text-words: polyclonal antibodies and rare/neglected diseases, antivenins, immunoglobulins, serum sickness, anaphylaxis, drug safety, post marketing surveillance, rabies, human influenza, Dengue, West Nile, Nipah, Hendra, Marburg, MERS, Hemorrhagic Fever Virus, and Crimean-Congo. No language limits were applied. The final search was completed on 20.06.2015. Of 1960 articles, title searches excluded many irrelevant articles, yielding 303 articles read in full. Of these, 179 are referenced in this study.

RESULTS

Serum therapy was first used in the 1890s against diphtheria. Early preparation techniques yielded products contaminated with reactogenic animal proteins. The introduction of enzymatic digestion, and purification techniques substantially improved their safety profile. The removal of the Fc fragment of antibodies further reduces hypersensitivity reactions. Clinical studies have demonstrated the efficacy of polyclonal antibodies against various infections, toxins and venoms. Products are being developed against infections for which prophylactic and therapeutic options are currently limited, such as avian influenza, Ebola and other zoonotic viruses.

CONCLUSIONS

Polyclonal antibodies have been successfully applied to rabies, envenomation and intoxication. Polyclonal production provides an exciting opportunity to revolutionise the prognosis of both longstanding neglected tropical diseases as well as emerging infectious threats to humans.

Ethnopharmacological survey on medicinal plants used in snakebite treatments in Western and Sabaragamuwa provinces in Sri Lanka

ETHNOPHARMACOLOGICAL RELEVANCE

Sri Lanka has a great diversity of snake species. In this relation, over 40,000 cases of snakebite accidents are reported annually from different agro-ecological regions of the country. Since more than 95% of victims rely on traditional treatments, there is an urgent necessity to improve the system. Traditional knowledge on snakebite treatments has been passed on from generation to generation within families. Unfortunately, there has been a limited update of information on pertinent issues related to this subject. In the present study we conducted a comprehensive survey on the types of medicinal plant materials, including the specific plant parts that are available for this purpose. In addition, various treatment types, frequency index, heavily used and rare materials, family wise distribution, challenges faced by traditional practitioners and future prospects were also explored.

MATERIALS AND METHODS

The present survey covered two provinces with a high population of traditional practitioners for snakebites treatment in Sri Lanka.Information was gathered from a total of seventy-four (74) traditional practitioners from the Sabaragamuwa and Western provinces. A questionnaire was prepared and pre-tested by 10-15 respondents prior to the survey. Actual data were gathered through face-to-face interviews. Collected data were tabulated and analyzed.

RESULTS

A total of 341 different plant species belonging to 99 families were documented. The highest number of plants was reported from the family Fabaceae (32 species). This was followed by Malvaceae (16 species), Asteraceae (15 species), Rutaceae (13 species Apocyanaceae (14 species), Lamiaceae (11 species), Poaceae, Euphorbaceae and Phyllanthaceae (10 species per each) respectively. Different parts of the plant such as leaves (53.67%), barks (26.10%), entire plant (14.08%), roots (10.26%), bulbs (8.80%), seeds (7.62%), fruits (6.45%), buds (5.87%), flowers (3.23%) stems (2.93%) and latex (2.05%) were used for the preparation of nine different types of formulae. These formulae include oral administration (172 plant species), external bandaging (167 plant species), oiling for external application (34 plant species), steaming (33 plant species), creaming for wounds (6 plant species), nasal treatments (40 plant species), head treatments (23 plant species), treatment for eyes (4 plant species) and washing of wounds (9 plant species). Moreover, plants used for the different snake types, constraints faced by traditional practitioners, and their constructive suggestions were also discussed.

CONCLUSION

A pioneering attempt was made to exploit local knowledge on snakebite treatments for the conservation of valued medicinal plants and to promote primary health care needs in Sabaragamuwa and Western provinces in Sri Lanka. The documented plants together with the traditional knowledge could be effectively utilized for the isolation and characterization of antivenom for different snake species.

Hyperglycemia is a risk factor for high-grade envenomations after European viper bites (Vipera spp.) in children

CONTEXT

Hyperglycemia has been described in severe scorpion envenomation, we wanted to analyze if it was applicable to viper bites in children.

AIM

To describe clinical, biological, and therapeutic characteristics of 83 children bitten by European viper (Vipera spp.) and to confirm that hyperglycemia is a risk factor for high-grade envenomation.

MATERIAL AND METHODS

A retrospective study was conducted between 2001 and 2014 in the pediatric emergency department of a tertiary level children's hospital. Collected data were: age and sex of children; day and time of admission; day, time and circumstances of the accident; snake identification; bite location; envenomation severity; presence of fang marks; prehospital care; laboratory abnormalities, use of specific immunotherapy, associated treatments; length of stay; hospital course.

RESULTS

Eighty-three children were included (62 boys, 21 girls). The mean age was 7.4 ± 3.9 years. Bites were most often located on the lower extremities (66%). The classification of envenomation was: 83% low grade (absent or minor envenomation) and 17% high grade (moderate to severe envenomation). All high-grade envenomations received specific immunotherapy (Viperfav(TM), (Aventis Pasteur, MSD, Lyon, France). Being bitten on an upper extremity (odds ratio [OR] 51.1 95% class interval [CI] [6.1-424], p < 0.0001), during the afternoon (OR 13.4 95% CI [1.7-107.9], p = 0.015), feeling violent pain (OR 4.2 95% CI [1.1-16.5], p = 0.023), and high initial plasma glucose level (6.5 ± 1.7 mmol/L versus 5.0 ± 0.9 mmol/L, p = 0.027) were associated with a significant risk of high-grade envenomation.

CONCLUSION

We have confirmed a potential link between initial hyperglycemia and the risk of progression to high-grade envenomation as well as its association with other published predictive factors.

Severe Pit Viper Envenomation with Extended Clinical Signs and Treatment Complications in a Dog

This manuscript describes the extended clinical abnormalities that can occur in severe snake envenomation and the clinical signs associated with antivenom hypersensitivity in a 3 yr old dog. Treatment consisted of IV fluid therapy, analgesics, a vasopressor, cardiac antiarrhythmia drugs, and polyvalent pit viper antivenom. Following initial response to treatment, relapse of clinical signs occurred. Most interesting was the recrudescence of clinical signs on day 7 that may have been caused by the release of deposited venom during surgical debridement of necrotic skin. The resulting extensive clinical signs required multiple vials of antivenom (22 vials over a 7 day period). Both F(ab′)2 antivenom and antivenin (Crotalidae) polyvalent were used in this dog because of availability logistics. It is thought that this large amount of antivenom resulted in type I (anaphylaxis) and type III hypersensitivity (serum sickness) reactions. The dog made a complete clinical recovery. This description of extended, fluctuating clinical abnormalities that were associated with envenomation together with the development of hypersensitivity reactions that were presumably secondary to antivenom administration is information that can be useful for the management of patients afflicted with severe pit viper envenomation.

Coral snake bites and envenomation in children: a case series

OBJECTIVE

North America is home to 2 families of venomous snakes, Crotalinae (pit viper family) and Elapidae (coral snake family). Although there are several published reports describing and reviewing the management of pit viper snakebites in children, there are no recent similar publications detailing the clinical course and management of coral snake envenomation.

METHODS

Our case series describes the hospital course of children with coral snake bites admitted to our regional pediatric intensive care. We also reviewed prior published case reports of coral snake bites in the United States.

RESULTS

We identified 4 patients with either confirmed or suspected coral snake envenomation from our hospital's records. In 2 cases, the snakebite occurred after apparent provocation. Antivenom was administered to 3 patients. The regional venom response team was consulted for management advice and supplied the antivenom. One patient had a prolonged hospital course, which was complicated by respiratory failure, bulbar palsy, and ataxia. All survived to discharge.

CONCLUSIONS

Admission to pediatric intensive care is warranted after all Eastern coral snake bites. A specialized regional or national venom response team can be a useful resource for management advice and as a source of antivenom.

Wilderness medicine

BACKGROUND

Human activity in wilderness areas has increased globally in recent decades, leading to increased risk of injury and illness. Wilderness medicine has developed in response to both need and interest.

METHODS

The field of wilderness medicine encompasses many areas of interest. Some focus on special circumstances (such as avalanches) while others have a broader scope (such as trauma care). Several core areas of key interest within wilderness medicine are discussed in this study.

RESULTS

Wilderness medicine is characterized by remote and improvised care of patients with routine or exotic illnesses or trauma, limited resources and manpower, and delayed evacuation to definitive care. Wilderness medicine is developing rapidly and draws from the breadth of medical and surgical subspecialties as well as the technical fields of mountaineering, climbing, and diving. Research, epidemiology, and evidence-based guidelines are evolving. A hallmark of this field is injury prevention and risk mitigation. The range of topics encompasses high-altitude cerebral edema, decompression sickness, snake envenomation, lightning injury, extremity trauma, and gastroenteritis. Several professional societies, academic fellowships, and training organizations offer education and resources for laypeople and health care professionals.

CONCLUSIONS

THE FUTURE OF WILDERNESS MEDICINE IS UNFOLDING ON MULTIPLE FRONTS: education, research, training, technology, communications, and environment. Although wilderness medicine research is technically difficult to perform, it is essential to deepening our understanding of the contribution of specific techniques in achieving improvements in clinical outcomes.

Development of a double sandwich fluorescent ELISA to detect rattlesnake venom in biological samples from horses with a clinical diagnosis of rattlesnake bite

Rattlesnake bites in horses are not uncommon and the clinical outcomes are widely variable. Treatment of horses with anti-venom is often cost prohibitive and could have negative consequences; therefore, the development of a quantitative test to determine if anti-venom therapy is indicated would be valuable. The objective of this study was to develop an ELISA to detect rattlesnake venom in biological samples from clinically bitten horses. Nineteen horses were enrolled in the study. Urine was available from 19 horses and bite site samples were available from 9 horses. A double sandwich fluorescent ELISA was developed and venom was detected in 5 of 9 bite site samples and 12 of 19 urine samples. In order to determine if this assay is useful as a guide for treatment, a correlation between venom concentration and clinical outcome needs to be established. For this, first peak venom concentration needs to be determined. More frequent, consistent sample collection will be required to define a venom elimination pattern in horses and determine the ideal sample collection time to best estimate the maximum venom dose. This report describes development of an assay with the ability to detect rattlesnake venom in the urine and at the bite site of horses with a clinical diagnosis of rattlesnake bite.

Isolation, characterization, cloning and expression of an alpha-neurotoxin from the venom of the Mexican coral snake Micrurus laticollaris (Squamata: Elapidae)

A new member of short chain α-neurotoxic protein family from venom of the Mexican coral snake, Micrurus laticollaris, was characterized. This protein, named MlatA1, possesses 61 amino acids with 8 conserved cysteine residues, sharing 30-91% sequence identity with other fully sequenced Micrurus toxins. MlatA1 (LD50i.v. = 0.064 mg/kg) antagonizes with both fetal and adult nicotinic acetylcholine receptor (nAChR) as well as α-7 neuronal nAChR in a dose-dependent way. Specific rabbit anti-Mlat serum (titer higher than 18,000) does not show any protective ability against this toxin, nevertheless it was able to recognize protein bands in six out of twelve Micrurus venoms showing the existence of two distinct antigenic groups for α-neurotoxins in North American coral snakes species. The MlatA1 gene was cloned and used to produce recombinant toxin (rMlatA1) that was recognized by rabbit anti-native toxin but was depleted of toxic activity.

The use and tolerability of Crotalidae Polyvalent Immune FAB (Ovine) in pediatric envenomations

There are limited data on the use of Crotalidae Polyvalent Immune FAB-Ovine (CroFab) in the management of crotalid envenomations in children. Thus, the primary objective of this retrospective chart review was to evaluate the safety and tolerability of CroFab in a pediatric population. Over an 8-year time period at this institution, there were 204 admissions for snakebite of which 82 received CroFab. Children who received CroFab were more often associated with bites to the hands and fingers and tended to have more significant envenomations as indicated by longer hospital stays, greater tissue injury, and a tendency to require surgery more often. Six (7.3%) of the 82 patients who received CroFab experienced an adverse drug reaction. Reactions consisted of allergic symptoms that were mild, responded to minimal interventions, and did not limit the subsequent use of CroFab. It is concluded that CroFab use is typically well tolerated in pediatric patients.

Risk factors for high-grade envenomations after French viper bites in children

BACKGROUND

Viper bites and subsequent evolution to severe envenomations are more frequent in children.

AIM

The aims of this study were to describe the clinical, biological, and therapeutic characteristics of children bitten by vipers in France and to identify risk factors associated with severe envenomations.

METHODS

A retrospective study was conducted between 2001 and 2009 in the pediatric emergency department of a tertiary-level children hospital. Collected data were age and sex of children; day and time of admission; day, time, and circumstances of the accident; snake identification; bite location; envenomation severity; presence of fang marks; prehospital care; use of specific immunotherapy and associated treatments; length of stay; and hospital course.

RESULTS

Fifty-eight children were included (43 boys, 15 girls). The mean age was 7.8 ± 4.1 years. Bites were most often located on the lower extremities (77%). The classification of envenomation was: 83% low grade (absence or minor envenomation) and 17% high-grade (moderate to severe envenomations). All high-grade envenomations received specific immunotherapy (Viperfav). Being bitten on an upper extremity (P < 0.001), during the afternoon (P = 0.025), feeling violent pain (P = 0.037), and high initial glucose level (P = 0.016) were associated with a significant risk of high-grade envenomation. In the multivariate analysis, 3 factors remained significant: upper-extremity location (relative risk [RR], 60.5 [3.5-1040]; P = 0.005), immediate violent pain (RR, 21.5 [1.3-364.5]; P = 0.03), and female sex (RR, 17.5 [0.9-320.3]; P = 0.053).

CONCLUSIONS

A certain number of criteria seem related to more significant risk of progression to high-grade envenomation. Bites to the upper extremities should be carefully observed because of the risk of evolution to a high-grade envenomation.

A retrospective review of early gastrointestinal symptoms in the prediction of crotaline envenomation severity

OBJECTIVES

Rattlesnake envenomations are cited to cause gastrointestinal (GI) symptoms, which may be indicators of systemic envenomation. We sought to identify whether the presence of early GI symptoms, defined as occurring within 4 hours of the bite, could be used to predict antivenom use or bite severity.

METHODS

We performed a retrospective review of a statewide poison system's database for all cases of rattlesnake envenomation from January 2000 to December 2009. Data collected included presence of GI symptoms and antivenom use. The GI symptoms were further classified as early (within 4 hours) or late. Bite severity was determined using the minimal to moderate to severe scoring system from collected data. Data were then analyzed with a χ(2) test and Fisher's exact test to evaluate for association between early GI symptoms and either antivenom use or bite severity.

RESULTS

There were 2570 reported rattlesnake exposures in the database. Sixty-one (2.4%) of these had GI symptoms reported. Of these, 36 (59%) had symptoms develop within 4 hours of envenomation. A total of 49 patients (80%) received antivenom. Early GI symptoms were seen in 31 (63%) of patients receiving antivenom versus 5 (42%) of patients not receiving antivenom (P = .20). Early GI symptoms were seen in 4 of 6 (66%) of the severe group, 19 of 29 (66%) of the moderate group, and 13 of 26 (50%) of the minimal group (P = .47).

CONCLUSIONS

Gastrointestinal symptoms after rattlesnake envenomations were rarely reported in this poison center study, and the presence of early GI symptoms did not predict bite severity or the use of antivenom.

Commentary: pressure bandaging for North American snake bite? No!

This issue of The Journal of Medical Toxicology includes a position statement regarding the use of pressure immobilization for the pre-hospital treatment of North American Crotalinae envenomation. This commentary discusses the background behind the creation of the position statement and explores the issues involved in applying science to real-world public health recommendations and practice.

Safety and cost-effectiveness of a clinical protocol implemented to standardize the use of Crotalidae polyvalent immune Fab antivenom at an academic medical center

STUDY OBJECTIVE

To evaluate the safety and cost-effectiveness of a clinical protocol adopted in June 2006 that included a comprehensive, objective assessment of snake bite envenomations and standardized the use of Crotalidae polyvalent immune Fab antivenom (FabAV).

DESIGN

Retrospective medical record review.

SETTING

Academic medical center that serves as the regional level I trauma center.

PATIENTS

Seventy-five adults treated with FabAV for snake envenomations in the emergency department between June 1, 2003, and June 1, 2009; 30 patients received treatment according to the protocol (treatment group), and 45 patients received treatment that did not adhere to the protocol (control group).

MEASUREMENTS AND MAIN RESULTS

Demographic and envenomation characteristics, as well as treatment details, were collected for all patients. In addition, information on quantity of FabAV vials required, length of hospital stay, and length of intensive care unit stay were compared between the treatment and control groups. In the treatment group, significantly fewer vials of FabAV were used (2.5 vs 4.727 vials, p=0.007). This decreased in usage correlated to a cost savings of approximately $2000/patient. Despite no significant difference in the severity of the envenomations between the two groups (p=0.379), the treatment group experienced a significantly shorter hospital length of stay (1.933 vs 2.791 days, p=0.030). No significant difference in the progression to fasciotomy or the development of allergic reactions was noted between the two groups.

CONCLUSION

Use of a clinical protocol related to snake envenomations resulted in approximately two fewer vials of FabAV required for each patient. In addition, the treatment group experienced a shorter hospital length of stay without a corresponding increase in adverse events or envenomation progression. Data show that use of the protocol was cost-effective. The development of institution-specific multidisciplinary protocols regarding snake bite envenomations is recommended. Clinical pharmacists can play a vital role in the protocol development to ensure that optimal care is provided for this distinct patient population.

Toxicology in the ICU: part 3: natural toxins

This is the third article of a three-part series that reviews the care of poisoned patients in the ICU. This article focuses on natural toxins, such as heavy metals and those produced by plants, mushrooms, arthropods, and snakes. The first article discussed the general approach to the patient, including laboratory testing; the second article focused on specific toxic agents, grouped into categories.

Pressure bandaging for North American snake bite? No!

This issue of Clinical Toxicology includes a Position Statement regarding the use of pressure immobilization for the pre-hospital treatment of North American Crotalinae envenomation. This Commentary discusses the background behind the creation of the Position Statement and explores the issues involved in applying science to real world public health recommendations and practice.