A randomized controlled trial of fresh frozen plasma for treating venom-induced consumption coagulopathy in cases of Australian snakebite (ASP-18)

[A global core outcome measurement set for snakebite clinical trials]

Background

Snakebite clinical trials have often used heterogeneous outcome measures and there is an urgent need for standardisation.

Method

A globally representative group of key stakeholders came together to reach consensus on a globally relevant set of core outcome measurements. Outcome domains and outcome measurement instruments were identified through searching the literature and a systematic review of snakebite clinical trials. Outcome domains were shortlisted by use of a questionnaire and consensus was reached among stakeholders and the patient group through facilitated discussions and voting.

Results

Five universal core outcome measures should be included in all future snakebite clinical trials: mortality, WHO disability assessment scale, patient-specific functional scale, acute allergic reaction by Brown criteria, and serum sickness by formal criteria. Additional syndrome-specific core outcome measures should be used depending on the biting species.

Conclusion

This core outcome measurement set provides global standardisation, supports the priorities of patients and clinicians, enables meta-analysis, and is appropriate for use in low-income and middle-income settings.

Mechanical ventilation in snake envenomation of dogs and cats

Envenomation by snakes in Elapidae and Viperidae families have been associated with respiratory failure in dogs and cats. Mechanical ventilation may be required for hypoventilation due to neuromuscular paralysis or hypoxemia due to pulmonary hemorrhage or aspiration pneumonia. Median incidence of dogs and cats with snake envenomation that require mechanical ventilation is 13% (0.06-40%). Standard treatment of snake envenomation in dogs and cats includes prompt administration of appropriate antivenom and management of envenomation complications such as coagulopathy, rhabdomyolysis and acute kidney injury. When mechanical ventilation is required, overall prognosis is good with appropriate treatment. Standard anesthetic protocols and mechanical ventilator settings are generally appropriate, with lung protective ventilation strategies typically reserved for patients with pulmonary disease. Median survival to discharge for cats and dogs with elapid envenomation is 72% (76-84%) with 33 h (19.5-58 h) median duration of mechanical ventilation and 140 h (84-196 h) median hospitalization. This article reviews indications for mechanical ventilation in cats and dogs with snake envenomation, and discusses ventilator settings, anesthetic and nursing considerations, complications and outcomes specific to this disease.

Clinical aspects of snakebite envenoming and its treatment in low-resource settings

There is increasing recognition of the public health importance of snakebite envenoming. Worldwide annual incidence is likely to be 5 million bites, with mortality exceeding 150 000 deaths, and the resulting physical and psychological morbidity leads to substantial social and economic repercussions. Prevention through community education by trained health workers is the most effective and economically viable strategy for reducing risk of bites and envenoming. Clinical challenges to effective treatment are most substantial in rural areas of low-resource settings, where snakebites are most common. Classic skills of history taking, physical examination, and use of affordable point-of-care tests should be followed by monitoring of evolving local and systemic envenoming. Despite the profusion of new ideas for interventions, hyperimmune equine or ovine plasma-derived antivenoms remain the only specific treatment for snakebite envenoming. The enormous interspecies and intraspecies complexity and diversity of snake venoms, revealed by modern venomics, demands a radical redesign of many current antivenoms.

A global core outcome measurement set for snakebite clinical trials

Snakebite clinical trials have often used heterogeneous outcome measures and there is an urgent need for standardisation. A globally representative group of key stakeholders came together to reach consensus on a globally relevant set of core outcome measurements. Outcome domains and outcome measurement instruments were identified through searching the literature and a systematic review of snakebite clinical trials. Outcome domains were shortlisted by use of a questionnaire and consensus was reached among stakeholders and the patient group through facilitated discussions and voting. Five universal core outcome measures should be included in all future snakebite clinical trials-mortality, WHO disability assessment scale, patient-specific functional scale, acute allergic reaction by Brown criteria, and serum sickness by formal criteria. Additional syndrome-specific core outcome measures should be used depending on the biting species. This core outcome measurement set provides global standardisation, supports the priorities of patients and clinicians, enables meta-analysis, and is appropriate for use in low-income and middle-income settings.

Outcomes in intervention research on snakebite envenomation: a systematic review

INTRODUCTION

A core outcome set (COS) is a minimal list of consensus outcomes that should be used in all intervention research in a specific domain. COS enhance the ability to undertake meaningful comparisons and to understand the benefits or harms of different treatments. A first step in developing a COS is to identify outcomes that have been used previously. We did this global systematic review to provide the foundation for development of a region-specific COS for snakebite envenomation.  Methods: We searched 15 electronic databases, eight trial registries, and reference lists of included studies to identify reports of relevant trials, protocols, registry records and systematic reviews. We extracted verbatim data on outcomes, their definitions, measures, and time-points. Outcomes were classified as per an existing outcome taxonomy, and we identified unique outcomes based on similarities in the definition and measurement of the verbatim outcomes.

RESULTS

We included 107 records for 97 studies which met our inclusion criteria. These reported 538 outcomes, with a wide variety of outcome measures, definitions, and time points for measurement. We consolidated these into 88 unique outcomes, which we classified into core areas of mortality (1, 1.14 %), life impact (6, 6.82%), resource use (15, 17.05%), adverse events (7, 7.95%), physiological/clinical (51, 57.95%), and composite (8, 9.09%) outcomes. The types of outcomes varied by the type of intervention, and by geographic region. Only 15 of the 97 trials (17.04%) listed Patient Related Outcome Measures (PROMS).

CONCLUSION

Trials evaluating interventions for snakebite demonstrate heterogeneity on outcomes and often omit important information related to outcome measurement (definitions, instruments, and time points). Developing high quality, region-specific COS for snakebite could inform the design of future trials and improve outcome reporting. Measurement of PROMS, resource use and life impact outcomes in trials on snakebite remains a gap.

Effectiveness of clotting factor replacement therapy after antivenom treatment on coagulopathic envenomation following green pit viper bites: a retrospective observational study

Background

Green pit vipers (GPVs), namely Trimeresurus albolabris and Trimeresurus stejnegeri accounts for most snakebites in Southern China. Green pit viper venom contains thrombin-like enzymes, resulting in defibrination syndrome. Using of clotting factor replacement after antivenom administration is controversial. The objective of this study was to investigate the effects of clotting factor replacement in coagulopathic patients with T. albolabris and T. stejnegeri bites after antivenom administration.

Methods

We retrospectively reviewed 123 patients who were bitten by T. albolabris and T. stejnegeri and were admitted to the Emergency Department of a hospital in Guangzhou, Southern China, from 2013 to 2019. Recovery of prothrombin time (PT) and fibrinogen level were compared among (1) fresh-frozen plasma (FFP) group; (2) cryoprecipitate (cryo) group; (3) FFP and cryo group; and (4) control group after antivenom administration.

Results

The incidence of coagulopathy was 31%. Persistent and late coagulopathy were the most common patterns among four groups. The median reduction in PT was 20.1 ± 31.2 s for FFP and cryo group. The median increase in fibrinogen level was very small: 0.05 ± 0.20 g/L for FFP group, 0.09 ± 0.37 g/L for cryo group and 0.07 ± 0.31 g/L for FFP and cryo group, respectively. The percentage of unimproved PT was markedly higher in the FFP and cryo group than the control group (P = 0.01 by log-rank test, P = 0.02 by Gehan-Breslow-Wilcoxon test). The percentage of unimproved fibrinogen level tended to be worse in the FFP and cryo group than the control group, but the different was marginal (P = 0.05 by Gehan-Breslow-Wilcoxon test, P = 0.07 by log-rank test). A total of 7.8% (7/90) of the patients in the clotting factor replacement groups developed anaphylaxis and heart failure.

Conclusion

There is no improvement in coagulopathy profile in patients with T. albolabris and T. stejnegeri bites who received clotting factor replacement after antivenom administration. But the results from GPVs may not be generalized to other species of venomous snakes.

Retrospective review of case records of snakebite presenting to a single tertiary care centre over a 5-year period

Background Snakebite is a disease of the poor, and hospitals catering to these individuals are often resource-constrained. Lack of electronic medical records in these resource-limited settings makes the capture of data even harder. Methods Before establishing a snakebite registry in the region, we did a retrospective case record review of all snakebite victims (n=3229) over 5 years who presented to a single tertiary care centre, catering to one of the largest number of snakebite victims in the country. Results Of the 451 cases, 262 (58.1%) presented to the emergency department within 2 hours of the bite. In 170 instances, the snake was brought along and the species of the snake was recorded. Russell's viper was the most common (130; 76.5%). Blood products were used in 237 (52.5%) patients. Acute kidney injury occurred in 165 (36.6%) patients, of whom 37 (8.2%) required dialysis. The mean (SD) duration of hospital admission was 10.5 (7.4) days. There was a significant correlation between number of snakebites with rainfall and humidity. One hundred and seven cases (3.3%) of snakebite resulted in mortality. A majority of mortality records were not available (88%; 94/107), rendering us incapable of doing reliable mortality data correlations or interpretation. Conclusion Viperidae bites predominate in the region, with renal injury being the most common cause for morbidity. Region-specific, prospective snakebite mapping could be a cost-effective strategy that might help in vulnerability analysis of the region. A multi-centric region-specific snakebite registry encompassing not just the clinico-epidemiological characteristics of snakebite victims, but also the demographic data, the pre-hospital care and local remedial practices, geospatial distribution, anti-snake venom and blood product usage, will help in developing better healthcare strategies for snakebite victims in India.

Hemothorax after snake bite

Hemothorax after snake bite is very rare and unusual presentation. Administration of antivenom with supportive measures and close monitoring can prevent further deterioration. Delays in the transportation of patients to health facilities where antivenom and other therapeutic resources are provided can lead to devastating consequences.

Clinical outcomes and outcome measurement tools reported in randomised controlled trials of treatment for snakebite envenoming: A systematic review

BACKGROUND

Snakebite is a priority neglected tropical disease and causes a range of complications that vary depending on the snake species. Randomised clinical trials have used varied outcome measures that do not allow results to be compared or combined. In accordance with the Core Outcomes Measurements in Effectiveness Trials (COMET) initiative, this systematic review aims to support the development of a globally relevant core outcome set for snakebite.

METHODS

All randomised controlled trials, secondary analyses of randomised controlled trials and study protocols investigating the efficacy of therapeutics for human snakebite envenoming were eligible for inclusion. Study screening and data extraction were conducted in duplicate by two independent reviewers. All primary and secondary outcome measures were extracted and compiled, as were adverse event outcome measures. Similar outcome measures were grouped into domains. The study was prospectively registered with PROSPERO: CRD42020196160.

RESULTS

This systematic review included 43 randomised controlled trials, two secondary analyses and 13 study protocols. A total of 382 outcome measures were extracted and, after duplicates were merged, there were 153 unique outcomes. The most frequently used outcome domain ('venom antigenaemia') was included in less than one third of the studies. The unique outcomes were classified into 60 outcome domains. Patient-centred outcomes were used in only three of the studies.

DISCUSSION

Significant heterogeneity in outcome measures exists in snakebite clinical trials. Consensus is needed to select outcome measures that are valid, reliable, patient-centred and feasible. The results of this systematic review strongly support the development of a core outcome set for use in snakebite clinical trials.

The study of clinical profile and outcome of patients with snakebite in a rural community

Context:

Snakebite remains an underrated cause of accidental death in modern India, primarily in rural India, where people fail to reach out to modern medicine and fall victim to the handful of quacks using traditional healing methods. If promptly diagnosed and treated based on various clinical determinants like mode of presentation, time of medical intervention, recognition of the species, and analysis of a series of reliably identified bites, the treatment outcome would be more promising. We aimed to study snakebite patients' clinical profile and treatment outcome in a rural tertiary care setup.

Materials and Method:

This is a retrospective study in which the data evaluated from an epidemiological viewpoint; gender and age of the snake bite victim, time when bitten, interval between the bite and medical consultation, pattern of toxicity, and response to anti-snake venom (ASV).

Results:

Of a total of 200 patients bitten by a snake, 121 were males, with 77% adults. In nearly all cases, the type of snake was unknown; however, most of the bites were poisonous, showing one or the other type of toxicity. One hundred seventy-one patients survived the snake bite, and 29 succumbed. When Logistic regression was done with Death/discharge as the dependent variable and “Time to bite and reaching hospital, Age, Sex, number of ASV given, Ventilation needed or not, pack cell volume (PCV) numbers, Fresh Frozen Plasma (FFP) numbers, Dialysis and presence or absence of toxicity” as the independent variables, the model developed did not account for any respectable amount of variation in the outcome. The only variable found to be predicting the outcome significantly was FFP.

Conclusion:

It is often difficult to identify the type of snake, and thus polyvalent antisnake venom remains the only available treatment resource. Readily available treatment resources, timely intervention, appropriate referral, and close ICU will alleviate mortality.

Successful treatment of a potentially fatal eastern brown snake (Pseudonaja textilis) envenomation in a dog with tiger-brown snake antivenom with serial quantification of venom antigen and antivenom concentrations in serum and urine

CASE REPORT

A successfully treated case of eastern brown snake (Pseudonaja textilis) envenomation in a Jack Russel Terrier dog is described with measurement of venom and antivenom concentration pre- and post-treatment. Early presentation, prompt administration of tiger-brown snake antivenom, hospitalisation and critical care monitoring lead to low morbidity and rapid recovery from a potentially fatal envenomation. Retrospective measurement of urine and serum venom and antivenom provided insight into the potential severity of the case and rapid efficacy of antivenom.

CLINICAL SIGNIFICANCE

Potentially fatal brown snakebite cases may initially present with only mild clinical signs despite having high concentrations of venom and potential for fatal outcome. Prompt treatment with antivenom is essential to prevent the development of progressive and fatal coagulopathy and paralysis.

Development of a Treatment Protocol for Cobra (Naja naja) Bite Envenoming in Dogs

There is limited information on clinical profiles, treatment, and management aspects of Indian cobra (Naja naja) bite envenoming in dogs in Sri Lanka. Dogs with cobra bites presented to the Veterinary Teaching Hospital (VTH), University of Peradeniya, were prospectively studied over a period of 72 months; local and systemic clinical manifestations and hematological abnormalities were recorded. We studied 116 cobra bite envenomings in dogs. A grading system was established using a combination of anatomical site of fang marks, as well as local and systemic clinical manifestations. Accordingly, treatment strategies were established using Indian polyvalent antivenom (AVS). Pain and swelling at the bite site were major clinical signs observed, while neurotoxic manifestations (mydriasis, wheezing, and crackles) were detected in most dogs. Leukocytosis was observed in 78% of them. Statistical analysis revealed that the grading scores obtained were compatible to initiate AVS administration according to the severity. The minimum number required was 2 AVS vials (range 2-12). Almost 20% of the dogs developed wheezing, crackles, hypersalivation, restlessness, and dyspnea as adverse reactions to AVS treatment. Necrotic wounds on bitten anatomical sites developed in 19% of the dogs and 2.5% developed acute kidney injuries as a consequence of envenoming crisis. Despite treatment, 3% of dogs died. No dry bites were recorded.

Snakebites in Suriname: Evaluation of the Protocolled Administration of Anti-Snake Venom in a Tertiary Care Setting

Venomous snakebites regularly occur in Suriname, a middle-income country located on the north coast of South America. Officially reported data on incidence and mortality are lacking. The aim of this retrospective study was to assess whether the use of our national snakebite protocol with selective administration of anti-snake venom (ASV) in patients with signs of snakebite envenoming improved clinical outcome as measured by mortality and length of stay (LOS) in the hospital. Medical records of all patients admitted at the Academic Hospital Paramaribo from 2013 to 2015, before and after the introduction of the protocol, with signs of snakebite envenoming, were reviewed for demographics, snakebite characteristics, mortality, length of hospital stay, administration of ASV, and occurrence of complications. Secondary outcome measures were the development of late complications due to a snakebite. Sixty-eight and 76 patients in 2013 and 2015, respectively, with venomous or potentially venomous snakebites were identified. One patient (1.5%) in 2013 and 29 patients (38.2%) in 2015 received ASV. In 2013 one patient died: deterioration of renal function occurred before protocolled ASV administration. No deaths were reported in 2015. There was no difference in the overall length of hospital stay between 2013 and 2015 or in the total number of late complications. In 2015, the mean LOS (±SD) for patients who did not receive ASV (n = 47) was significantly lower than that for patients who received ASV (n = 29), 2.15 ± 2.27 versus 5.31 ± 5.53 days, respectively (P = 0.001). The mean LOS (±SD) for patients who did not receive ASV in 2013 (n = 67) and 2015 (n = 47) was 4.06 ± 5.44 and 2.15 ± 2.27 days, respectively, which also differed significantly (P = 0.025). The protocolled evaluation of snakebite victims resulted in more patients being admitted to the intensive care unit and receiving ASV and a shorter length of hospital stay for the patients who did not receive ASV, and no difference in the occurrence of complications was observed in Suriname's largest hospital responsible for the acute care of snakebite victims.

Failure of a Mexican antivenom on recovery from snakebite-related coagulopathy in French Guiana

INTRODUCTION

In French Guiana, most snakebites are caused by crotalids, with the main signs being tissue damage and bleeding due to venom-induced coagulopathy. Since December 2014 the Western Guiana Hospital (WGH) has used Antivipmyn Tri ^TM, a Mexican polyvalent antivenom. The aim of the study was to assess its benefit on the correction of snakebite-related coagulopathy.

METHODS

This retrospective study included patients hospitalized at the WGH with snakebite and a coagulopathy defined by: a prothrombin rate (PR) lower than 45%, an activated partial thromboplastin time ratio (aPTTr) greater than 2 or a fibrinogen lower than 100 mg.dL^-1. The antivenom group included patients receiving Antivipmyn Tri ^TM from December 2014 to September 2017. The control group included patients admitted between January 2013 and November 2014 (when antivenom was unavailable) or admitted between December 2014 and September 2017 during times of antivenom shortage. We graphically compared the time courses of PR, aPTTr and fibrinogen between groups. Other endpoints were the length of hospital stay and the need for surgery or dialysis.

RESULTS

84 patients were included: 42 in the antivenom group, 42 in the control group. Both groups were similar for age, sex-ratio, proportion of bleedings, necrosis, and severity. Most patients in the antivenom group received 3 vials. There were no significant differences in recovery of PR, aPTTr and fibrinogen through the first 24 h. Fibrinogen declined again in the control group at 30 h and showed a slower rise to normal concentration. There were no significant differences in any secondary endpoint.

CONCLUSION

Antivipmyn Tri ^TM as currently used did not show any benefit in recovery from coagulopathy.

Novel Treatment Strategy for Patients with Venom-Induced Consumptive Coagulopathy from a Pit Viper Bite

Pit viper venom commonly causes venom-induced consumptive coagulopathy (VICC), which can be complicated by life-threatening hemorrhage. VICC has a complex pathophysiology affecting multiple steps of the coagulation pathway. Early detection of VICC is challenging because conventional blood tests such as prothrombin time (PT) and activated partial thromboplastin time (aPTT) are unreliable for early-stage monitoring of VICC progress. As the effects on the coagulation cascade may differ, even in the same species, the traditional coagulation pathways cannot fully explain the mechanisms involved in VICC or may be too slow to have any clinical utility. Antivenom should be promptly administered to neutralize the lethal toxins, although its efficacy remains controversial. Transfusion, including fresh frozen plasma, cryoprecipitate, and specific clotting factors, has also been performed in patients with bleeding. The effectiveness of viscoelastic monitoring in the treatment of VICC remains poorly understood. The development of VICC can be clarified using thromboelastography (TEG), which shows the procoagulant and anticoagulant effects of snake venom. Therefore, we believe that TEG may be able to be used to guide hemostatic resuscitation in victims of VICC. Here, we aim to discuss the advantages of TEG by comparing it with traditional coagulation tests and propose potential treatment options for VICC.

Venom-Induced Consumption Coagulopathy Following Hump-Nosed Pit Viper (Genus: Hypnale) Envenoming in Sri Lanka: Uncertain Efficacy of Fresh Frozen Plasma

INTRODUCTION

Hump-nosed pit vipers (Hypnale spp) cause the highest number of venomous snakebites in Sri Lanka. Bites commonly cause local envenoming leading to local pain, swelling, and necrosis of the site of the bite. Acute kidney injury is the most common systemic manifestation, and some patients develop venom-induced consumption coagulopathy (VICC). Genus Hypnale comprises 3 species. Of them, H hypnale is found in Sri Lanka and the Western Ghats region of India. The other 2 (H nepa and H zara) are endemic species in Sri Lanka.

METHODS

This study included 500 patients with hump-nosed viper bites studied prospectively over 4.5 y starting June 2014. All patients were assessed and the data were collected by the principal investigator (primary data). A subgroup of patients who developed VICC is described. There were 2 groups, including proven (patients with the specimen of the snake) and probable (specimen of snake not available) bites.

RESULTS

Thirty (n=500; 6%) patients developed VICC; of them, 17 (3%) were proven cases, and 13 (2%) were probable cases. In both groups, 24 (80%) recovered, 2 (7%) progressed to chronic kidney disease, 1 (3%) died of severe hemostatic dysfunction, and 3 (10%) were lost to follow-up. Systemic bleeding was observed in 16 patients (53%), including hematuria (microscopic and gross) in 8 (27%) and venipuncture bleeding in 5 (17%). Eleven (37%) developed local bleeding at the site of the bite. Fresh frozen plasma was administered to 20 patients (67%), among whom only 11 (55%) experienced early correction of VICC. In both groups, 15 (50%) developed acute kidney injury, and 2 (7%) progressed to chronic kidney disease. Microangiopathic hemolysis was observed in 18 patients (60%) and thrombocytopenia in 16 (53%). Thrombotic microangiopathy was detected in 13 patients (43%), of whom 10 (33%) developed hemolytic uremic syndrome and 2 (7%) had thrombotic thrombocytopenic purpura. Of patients with VICC in the proven group, 94% (n=16) was caused by H hypnale and 1 (6%) was caused by H zara. In the proven group, median international normalized ratio was 3.7 (interquartile range 1.6-5.0); in the probable group, it was 5.0 (interquartile range 2.1-5.4).

CONCLUSIONS

We found that 6% of patients develop hemostatic dysfunction after hump-nosed viper bites. However, which patients will develop coagulopathy or die of envenoming is unpredictable. Reliable and accessible treatments are unmet essential needs because antivenoms for these bites are currently not available in the country. Therapy with fresh frozen plasma has doubtful efficacy in early correction of VICC and needs further evaluation.

Bite by a juvenile Bothrops venezuelensis (Venezuelan lancehead) resulting in severe envenomation: A case report

Bothrops venezuelensis is a venomous snake of the Viperidae family. It is associated with a high snakebite-related morbidity and mortality in Venezuela, although clinical case descriptions are scarce. Bites by other Bothrops sp. can result in coagulopathy and acute kidney injury. We describe a bite by a captive juvenile B. venezuelensis that caused local swelling, severe pain, endothelial damage, excessive fibrinolysis (INR >12, aPTT 136s, fibrinogen 0.3g/l) and incoagulable blood within 1.5 hours after the bite. The patient was treated with prothrombin complex factors concentrate, fibrinogen and antivenom (Antivipmyn®, Instituto Bioclon, Mexico) 4.5 h after the bite, which improved coagulation parameters progressively. Subsequently signs of compensated disseminated intravascular coagulation manifested and the patient received fresh frozen plasma and erythrocyte concentrate. The patient developed acute kidney injury with macroscopic hematuria. Fluid overload resulted in pulmonary edema requiring intermittent ventilation and diuretic treatment with furosemide. He was discharged with moderately elevated creatinine 16 days after hospitalization. Creatinine level normalized within another week. This case displays the life-threatening toxicity even after juvenile B. venezuelensis bites and the comparability to bites by other Bothrops sp.

Review article: Let us talk about snakebite management: A discussion on many levels

We want to discuss antivenom use in snakebite clinical practice guidelines. Coronial reviews in Victoria of two cases of snakebite envenomation, one described in detail below, prompted us to submit this paper for a wider audience and debate. Venom and antivenom levels were measured in the case detailed below, but not in the other. The coroner received conflicting and varied advice from experts regarding the dose of antivenom. The Victorian Department of Health and Human Services and the Australasian College for Emergency Medicine were instructed to review snakebite management guidelines, particularly with respect to antivenom dosage. The discussion that took place among medical experts led to considerable media attention. We discuss the potential fallout when there is no consensus among medical experts.

The validity, reliability and minimal clinically important difference of the patient specific functional scale in snake envenomation

Objective

Valid, reliable, and clinically relevant outcome measures are necessary in clinical studies of snake envenomation. The aim of this study was to evaluate the psychometric (validity and reliability) and clinimetric (minimal clinically important difference [MCID]) properties of the Patient-Specific Functional Scale (PSFS) in snakebite envenomation.

Methods

We performed a secondary analysis of two existing snakebite trials that measured clinical outcomes using the PSFS as well as other quality of life and functional assessments. Data were collected at 3, 7, 10, and 17 days. Reliability was determined using Cronbach’s alpha for internal consistency and the intraclass correlation coefficient (ICC) for temporal stability at 10 and 17 days. Validity was assessed using concurrent validity correlating with the other assessments. The MCID was evaluated using the following criteria: (1) the distribution of stable patients according to both standard error of measurement (SEM) and responsiveness techniques, and (2) anchor-based methods to compare between individuals and to detect discriminant ability of a positive change with a receiver operator characteristic (ROC) curve and optimal cutoff point.

Results

A total of 86 patients were evaluated in this study. The average PSFS scores were 5.37 (SD 3.23), 7.95 (SD 2.22), and 9.12 (SD 1.37) at 3, 7, and 10 days, respectively. Negligible floor effect was observed (maximum of 8% at 3 days); however, a ceiling effect was observed at 17 days (25%). The PSFS showed good reliability with an internal consistency of 0.91 (Cronbach’s alpha) (95% CI 0.88, 0.95) and a temporal stability of 0.83 (ICC) (95% CI 0.72, 0.89). The PSFS showed a strong positive correlation with quality of life and functional assessments. The MCID was approximately 1.0 for all methods.

Conclusions

With an MCID of approximately 1 point, the PSFS is a valid and reliable tool to assess quality of life and functionality in patients with snake envenomation.

Acute Kidney Injury Induced by Bothrops Venom: Insights into the Pathogenic Mechanisms

Acute kidney injury (AKI) following snakebite is common in developing countries and Bothrops genus is the main group of snakes in Latin America. To evaluate the pathogenic mechanisms associated with Bothrops venom nephrotoxicity, we assessed urinary and blood samples of patients after hospital admission resulting from Bothrops snakebite in a prospective cohort study in Northeast Brazil. Urinary and blood samples were evaluated during hospital stay in 63 consenting patients, divided into AKI and No-AKI groups according to the KDIGO criteria. The AKI group showed higher levels of urinary MCP-1 (Urinary monocyte chemotactic protein-1) (median 547.5 vs. 274.1 pg/mgCr; p = 0.02) and urinary NGAL (Neutrophil gelatinase-associated lipocalin) (median 21.28 vs. 12.73 ng/mgCr; p = 0.03). Risk factors for AKI included lower serum sodium and hemoglobin levels, proteinuria and aPTT (Activated Partial Thromboplastin Time) on admission and disclosed lower serum sodium (p = 0.01, OR = 0.73, 95% CI: 0.57–0.94) and aPTT (p = 0.031, OR = 26.27, 95% CI: 1.34–512.11) levels as independent factors associated with AKI. Proteinuria showed a positive correlation with uMCP-1 (r = 0.70, p < 0.0001) and uNGAL (r = 0.47, p = 0.001). FE_Na (Fractional Excretion of sodium) correlated with uMCP-1 (r = 0.47, P = 0.001) and uNGAL (r = 0.56, p < 0.0001). sCr (serum Creatinine) showed a better performance to predict AKI (AUC = 0.85) in comparison with new biomarkers. FE_K showed fair accuracy in predicting AKI (AUC = 0.92). Coagulation abnormality was strongly associated with Bothrops venom-related AKI. Urinary NGAL and MCP-1 were good biomarkers in predicting AKI; however, sCr remained the best biomarker. FE_K (Fractional Excretion of potassium) emerged as another diagnostic tool to predict early AKI. Positive correlations between uNGAL and uMCP-1 with proteinuria and FE_Na may signal glomerular and tubular injury. Defects in urinary concentrations highlighted asymptomatic abnormalities, which deserve further study.

Thromboelastographic study of the snakebite-related coagulopathy in Djibouti

: Hemostasis disorders are one of the major clinical conditions of snakebites and are because of mechanisms which may disrupt vessels, platelets, clotting factors and fibrinolysis. Thromboelastography (TEG) could help to understand these effects in the clinical practice. A retrospective study reports a series of patients presenting a snakebite-related coagulopathy, treated with antivenom and monitored with conventional tests and TEG in a French military treatment facility (Republic of Djibouti, East Africa) between August 2011 and September 2013. Conventional coagulation assays (platelets, prothrombin time, activated partial thromboplastin time, fibrinogen) and TEG measurements were taken on arrival and at various times during the first 72 h of hospitalization, at the discretion of the physician. The study included 14 patients (median age 28 years). Bleedings were present in five patients. All patients received antivenom. A coagulopathy was present in all patients and was detected by both conventional assays and TEG. None exhibited thrombocytopenia. Prothrombin time and fibrinogen remained abnormal for most of patients during the first 72 h. The TEG profiles of 11 patients (79%) showed incoagulability at admission (R-time > 60 min). TEG distinguished 10 patients with a generalized clotting factor deficiency and 4 patients with an isolated fibrinogen deficiency after an initial profile of incoagulability. Hyperfibrinolysis was evident for 12 patients (86%) after Hour 6. Snake envenomations in Djibouti involve a consumption coagulopathy in conjunction with delayed hyperfibrinolysis. TEG could improve medical management of the condition and assessment of additional therapeutics associated with the antivenom.

Australian elapid snake envenomation in cats: Clinical priorities and approach

Practical relevance: No fewer than 140 species of terrestrial snakes reside in Australia, 92 of which possess venom glands. With the exception of the brown tree snake, the venom-producing snakes belong to the family Elapidae. The venom of a number of elapid species is more toxic than that of the Indian cobra and eastern diamondback rattle snake, which has earned Australia its reputation for being home to the world's most venomous snakes. Clinical challenges: The diagnosis of elapid snake envenomation is not always easy. Identification of Australian snakes is not straightforward and there are no pathognomonic clinical signs. In cats, diagnosis of envenomation is confounded by the fact that, in most cases, there is a delay in seeking veterinary attention, probably because snake encounters are not usually witnessed by owners, and also because of the tendency of cats to hide and seek seclusion when unwell. Although the administration of antivenom is associated with improved outcomes, the snake venom detection kit and antivenom are expensive and so their use may be precluded if there are financial constraints. Evidence base: In providing comprehensive guidance on the diagnosis and treatment of Australian elapid snake envenomation in cats, the authors of this review draw on the published veterinary, medical and toxicology literature, as well as their professional experience as specialists in medicine, and emergency medicine and critical care.

A randomized controlled trial of fresh frozen plasma for coagulopathy in Russell's viper (Daboia russelii) envenoming

Essentials Russell's viper envenoming is a major health issue in South Asia and causes coagulopathy. We studied the effect of fresh frozen plasma and two antivenom doses on correcting coagulopathy. Fresh frozen plasma did not hasten recovery of coagulopathy. Low-dose antivenom did not worsen coagulopathy.

SUMMARY

Background Russell's viper (Daboia russelii) envenoming is a major health issue in South Asia and causes venom-induced consumption coagulopathy (VICC). Objectives To investigate the effects of fresh frozen plasma (FFP) and two antivenom doses in correcting VICC. Methods We undertook an open-label randomized controlled trial in patients with VICC at two Sri Lankan hospitals. Patients with suspected Russell's viper bites and coagulopathy were randomly allocated (1 : 1) to high-dose antivenom (20 vials) or low-dose antivenom (10 vials) plus 4 U of FFP. The primary outcome was the proportion of patients with an International Normalized Ratio (INR) of < 2 at 6 h after antivenom administration. Secondary outcomes included anaphylaxis, major hemorrhage, death, and clotting factor recovery. Results From 214 eligible patients, 141 were randomized: 71 to high-dose antivenom, and 70 to low-dose antivenom/FFP; five had no post-antivenom blood tests. The groups were similar except for a delay of 1 h in antivenom administration for FFP patients. Six hours after antivenom administration, 23 of 69 (33%) patients allocated to high-dose antivenom had an INR of < 2, as compared with 28 of 67 (42%) allocated to low-dose antivenom/FFP (absolute difference 8%; 95% confidence interval - 8% to 25%). Fifteen patients allocated to FFP did not receive it. Severe anaphylaxis occurred equally frequently in each group. One patient given FFP developed transfusion-related acute lung injury. Three deaths occurred in low-dose antivenom/FFP patients, including one intracranial hemorrhage. There was no difference in recovery rates of INR or fibrinogen, but there was more rapid initial recovery of factor V and FX in FFP patients. Conclusion FFP after antivenom administration in patients with Russell's viper bites did not hasten recovery of coagulopathy. Low-dose antivenom/FFP did not worsen VICC, suggesting that low-dose antivenom is sufficient.

Deinagkistrodon acutus envenomation: a report of three cases

Background

Deinagkistrodon acutus envenomation is associated with severe hematological and wound complications but is rarely described.

Case presentation

Herein, we report three cases of victims bitten by D. acutus and indicate that rapid-onset severe coagulopathy and thrombocytopenia are distinct features of D. acutus snakebite, which are not observed in other crotaline snakebites (i.e., Trimeresurus stejnegeri and Protobothrops mucrosquamatus) in Taiwan. The toxic effects could occur as early as 2 to 3 h following D. acutus envenomation and persist if the administration of specific antivenom is delayed or even not commenced. Based on our findings, 2 to 4 vials of specific antivenom as the first dose should be administered to victims and repeated at 6 to 8 h intervals if coagulopathy or thrombocytopenia persists. Fresh frozen plasma or platelet replacement is probably safe as an adjunct therapy for D. acutus bite in the presence of venom-induced consumptive coagulopathy.

Conclusion

Severe coagulopathy and thrombocytopenia could occur as early as 2 to 3 h after D. acutus envenomation. The current recommendation for antivenom is 2 to 4 vials as the first dose and repeated every 6– to 8 h if coagulopathy or thrombocytopenia persists. These cases studied may be helpful to first-line medical personnel in the early diagnosis and management of D. acutus envenomation among other crotaline snakebites in Taiwan.

Neurotoxicity in Russell's viper (Daboia russelii) envenoming in Sri Lanka: a clinical and neurophysiological study

CONTEXT

Russell's viper is more medically important than any other Asian snake, due to number of envenoming's and fatalities. Russell's viper populations in South India and Sri Lanka (Daboia russelii) cause unique neuromuscular paralysis not seen in other Russell's vipers.

OBJECTIVE

To investigate the time course and severity of neuromuscular dysfunction in definite Russell's viper bites, including antivenom response.

METHODOLOGY

We prospectively enrolled all patients (>16 years) presenting with Russell's viper bites over 14 months. Cases were confirmed by snake identification and/or enzyme immunoassay. All patients had serial neurological examinations and in some, single fibre electromyography (sfEMG) of the orbicularis oculi was performed.

RESULTS

245 definite Russell's viper bite patients (median age: 41 years; 171 males) presented a median 2.5 h (interquartile range: 1.75-4.0 h) post-bite. All but one had local envenoming and 199 (78%) had systemic envenoming: coagulopathy in 166 (68%), neurotoxicity in 130 (53%), and oliguria in 19 (8%). Neurotoxicity was characterised by ptosis (100%), blurred vision (93%), and ophthalmoplegia (90%) with weak extraocular movements, strabismus, and diplopia. Neurotoxicity developed within 8 h post-bite in all patients. No bulbar, respiratory or limb muscle weakness occurred. Neurotoxicity was associated with bites by larger snakes (p < 0.0001) and higher peak serum venom concentrations (p = 0.0025). Antivenom immediately decreased unbound venom in blood. Of 52 patients without neurotoxicity when they received antivenom, 31 developed neurotoxicity. sfEMG in 27 patients with neurotoxicity and 23 without had slightly elevated median jitter on day 1 compared to 29 normal subjects but normalised thereafter. Neurological features resolved in 80% of patients by day 3 with ptosis and weak eye movements resolving last. No clinical or neurophysiological abnormality was detected at 6 weeks or 6 months.

CONCLUSION

Sri Lankan Russell's viper envenoming causes mild neuromuscular dysfunction with no long-term effects. Indian polyvalent antivenom effectively binds free venom in blood but does not reverse neurotoxicity.

Detection of Snake Venom in Post-Antivenom Samples by Dissociation Treatment Followed by Enzyme Immunoassay

Venom detection is crucial for confirmation of envenomation and snake type in snake-bite patients. Enzyme immunoassay (EIA) is used to detect venom, but antivenom in samples prevents venom detection. We aimed to detect snake venom in post-antivenom samples after dissociating venom-antivenom complexes with glycine-HCl (pH 2.2) and heating for 30 min at 950 °C. Serum samples underwent dissociation treatment and then Russell’s viper venom or Australian elapid venom measured by EIA. In confirmed Russell’s viper bites with venom detected pre-antivenom (positive controls), no venom was detected in untreated post-antivenom samples, but was after dissociation treatment. In 104 non-envenomed patients (negative controls), no venom was detected after dissociation treatment. In suspected Russell’s viper bites, ten patients with no pre-antivenom samples had venom detected in post-antivenom samples after dissociation treatment. In 20 patients with no venom detected pre-antivenom, 13 had venom detected post-antivenom after dissociation treatment. In another 85 suspected Russell’s viper bites with no venom detected pre-antivenom, 50 had venom detected after dissociation treatment. Dissociation treatment was also successful for Australian snake envenomation including taipan, mulga, tiger snake and brown snake. Snake venom can be detected by EIA in post-antivenom samples after dissociation treatment allowing confirmation of diagnosis of envenomation post-antivenom.

Snake antivenom for snake venom induced consumption coagulopathy

BACKGROUND

Snake venom induced consumption coagulopathy is a major systemic effect of envenoming. Observational studies suggest that antivenom improves outcomes for venom induced consumption coagulopathy in some snakebites and not others. However, the effectiveness of snake antivenom in all cases of venom induced consumption coagulopathy is controversial.

OBJECTIVES

To assess the effect of snake antivenom as a treatment for venom induced consumption coagulopathy in people with snake bite.

SEARCH METHODS

The search was done on 30 January 2015. We searched the Cochrane Injuries Group's Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), Ovid MEDLINE(R), Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily and Ovid OLDMEDLINE(R), Embase Classic+Embase (OvidSP), three other sources, clinical trials registers, and we also screened reference lists.

SELECTION CRITERIA

All completed, published or unpublished, randomised, controlled trials with a placebo or no treatment arm, where snake antivenom was administered for venom induced consumption coagulopathy in humans with snake bites.

DATA COLLECTION AND ANALYSIS

Two authors reviewed the identified trials and independently applied the selection criteria.

MAIN RESULTS

No studies met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

Randomised placebo-controlled trials are required to investigate the effectiveness of snake antivenom for clinically relevant outcomes in patients with venom induced consumption coagulopathy resulting from snake bite. Although ethically difficult, the routine administration of a treatment that has a significant risk of anaphylaxis cannot continue without strong evidence of benefit.

Intracranial haemorrhages associated with venom induced consumption coagulopathy in Australian snakebites (ASP-21)

Intracranial haemorrhage (ICH) is a rare life-threatening consequence of venom induced consumption coagulopathy in snake-bite. It is unclear why certain patients haemorrhage. We aimed to investigate ICH in snake envenoming. Cases of venom-induced consumption coagulopathy from July 2005-June 2014 were identified from the Australian Snakebite Project, a prospective multicentre cohort of snake-bites. Cases with venom-induced consumption coagulopathy were extracted with data on the snake-bite, clinical effects, laboratory investigations, treatment and outcomes. 552 cases had venom-induced consumption coagulopathy; median age, 40 y (2-87 y), 417 (76%) males, 253 (46%) from brown snakes and 17 died (3%). There were 6/552 (1%) cases of ICH; median age, 71 y (59-80 y), three males and five from brown snakes. All received antivenom and five died. All six had a history of hypertension. Time to onset of clinical effects consistent with ICH was 8-12 h in four cases, and within 3 h in two. Difficult to manage hypertension and vomiting were common. One patient had a normal cerebral CT on presentation and after the onset of focal neurological effects a repeat CT showed an ICH. ICH is rare in snake-bite with only 1% of patients with coagulopathy developing one. Older age and hypertension were associated with ICH.

Hematologic effects and complications of snake envenoming

Hematologic abnormalities are the most common effects of snake envenoming globally. Venom-induced consumption coagulopathy (VICC) is the commonest and most important. Other hematologic abnormalities are an anticoagulant coagulopathy and thrombotic microangiopathy. Venom-induced consumption coagulopathy is a venom-induced activation of the clotting pathway by procoagulant toxins, resulting in clotting factor consumption and coagulopathy. The type of procoagulant toxin differs between snakes and can activate prothrombin, factor X, and factor V or consume fibrinogen. The most useful investigation in VICC is a prothrombin time/international normalized ratio. The d-dimer may assist in early diagnosis, but fibrinogen levels often add little in the clinical setting. Bedside investigations would be ideal, but point-of-care testing international normalized ratio and whole blood clotting tests have been shown to be unreliable in VICC. The major complication of VICC is hemorrhage, including intracranial hemorrhage which is often fatal. The role of antivenom in VICC is controversial and may only be beneficial for some types of snakes including Echis spp where the duration of abnormal clotting is reduced from more than a week to 24 to 48 hours. In contrast, antivenom does not appear to speed the recovery of VICC in Australian snake envenoming. Other treatments for VICC include factor replacement, observation and prevention of trauma, and heparin. An Australian study showed that fresh-frozen plasma speeds recovery of VICC, but early use may increase consumption. There is no evidence to support heparin.

Current treatment for venom-induced consumption coagulopathy resulting from snakebite

Venomous snakebite is considered the single most important cause of human injury from venomous animals worldwide. Coagulopathy is one of the commonest important systemic clinical syndromes and can be complicated by serious and life-threatening haemorrhage. Venom-induced consumption coagulopathy (VICC) is the commonest coagulopathy resulting from snakebite and occurs in envenoming by Viperid snakes, certain elapids, including Australian elapids, and a few Colubrid (rear fang) snakes. Procoagulant toxins activate the clotting pathway, causing a broad range of factor deficiencies depending on the particular procoagulant toxin in the snake venom. Diagnosis and monitoring of coagulopathy is problematic, particularly in resource-poor countries where further research is required to develop more reliable, cheap clotting tests. MEDLINE and EMBASE up to September 2013 were searched to identify clinical studies of snake envenoming with VICC. The UniPort database was searched for coagulant snake toxins. Despite preclinical studies demonstrating antivenom binding toxins (efficacy), there was less evidence to support clinical effectiveness of antivenom for VICC. There were no placebo-controlled trials of antivenom for VICC. There were 25 randomised comparative trials of antivenom for VICC, which compared two different antivenoms (ten studies), three different antivenoms (four), two or three different doses or repeat doses of antivenom (five), heparin treatment and antivenom (five), and intravenous immunoglobulin treatment and antivenom (one). There were 13 studies that compared two groups in which there was no randomisation, including studies with historical controls. There have been numerous observational studies of antivenom in VICC but with no comparison group. Most of the controlled trials were small, did not use the same method for assessing coagulopathy, varied the dose of antivenom, and did not provide complete details of the study design (primary outcomes, randomisation, and allocation concealment). Non-randomised trials including comparison groups without antivenom showed that antivenom was effective for some snakes (e.g., Echis), but not others (e.g., Australasian elapids). Antivenom is the major treatment for VICC, but there is currently little high-quality evidence to support effectiveness. Antivenom is not risk free, and adverse reactions can be quite common and potentially severe. Studies of heparin did not demonstrate it improved outcomes in VICC. Fresh frozen plasma appeared to speed the recovery of coagulopathy and should be considered in bleeding patients.

Snakebite in Australia: a practical approach to diagnosis and treatment

Snakebite is a potential medical emergency and must receive high-priority assessment and treatment, even in patients who initially appear well. Patients should be treated in hospitals with onsite laboratory facilities, appropriate antivenom stocks and a clinician capable of treating complications such as anaphylaxis. All patients with suspected snakebite should be admitted to a suitable clinical unit, such as an emergency short-stay unit, for at least 12 hours after the bite. Serial blood testing (activated partial thromboplastin time, international normalised ratio and creatine kinase level) and neurological examinations should be done for all patients. Most snakebites will not result in significant envenoming and do not require antivenom. Antivenom should be administered as soon as there is evidence of envenoming. Evidence of systemic envenoming includes venom-induced consumption coagulopathy, sudden collapse, myotoxicity, neurotoxicity, thrombotic microangiopathy and renal impairment. Venomous snake groups each cause a characteristic clinical syndrome, which can be used in combination with local geographical distribution information to determine the probable snake involved and appropriate antivenom to use. The Snake Venom Detection Kit may assist in regions where the range of possible snakes is too broad to allow the use of monovalent antivenoms. When the snake identification remains unclear, two monovalent antivenoms (eg, brown snake and tiger snake antivenom) that cover possible snakes, or a polyvalent antivenom, can be used. One vial of the relevant antivenom is sufficient to bind all circulating venom. However, recovery may be delayed as many clinical and laboratory effects of venom are not immediately reversible. For expert advice on envenoming, contact the National Poisons Information Centre on 13 11 26.

Point-of-care derived INR does not reliably detect significant coagulopathy following Australian snakebite

INTRODUCTION

Point-of-care international normalised ratio (INR) has been suggested as a way to screen for venom-induced consumption coagulopathy following snakebite, but has not been validated for this. This study aimed to assess the diagnostic reliability of point-of-care INR for venom-induced consumption coagulopathy.

METHODS

This was a prospective study of snakebite patients recruited between January 2011 and May 2012 where a point-of-care INR was done and compared to an INR done on a laboratory coagulation analyser, as part of a quality assurance exercise. Data was obtained for each patient, including demographics, information on the snake bite, the point-of-care INR results and any laboratory derived coagulation studies. Snake identification was confirmed by expert identification or venom specific enzyme immunoassay.

RESULTS

There were 15 patients with a median age of 29 years (2 to 68 y) and 13 were male. Four of the 7 patients with venom-induced consumption coagulopathy had an abnormal point-of-care INR (3 false negatives) and 1 of the 7 non-envenomed patients had an abnormal point-of-care INR (1 false positive). The patient with a falsely elevated point-of-care INR was given antivenom prior to formal coagulation studies. The point-of-care INR was also negative in the patient with an anticoagulant coagulopathy.

CONCLUSIONS

The study shows that point-of-care INR testing devices should not be used in suspected snakebite cases in Australia to diagnose venom-induced consumption coagulopathy.