Does the traditional snakebite severity score correctly classify envenomated patients?

The association between the neutrophil lymphocyte ratio and local edema after viper snake envenomation in South Korea

The role of the inflammatory process in the pathogenesis of local edema-related envenomation has not been explored with endemic venomous snakebites in Korea. Gloydius species are responsible for most snakebites in South Korea. In this study we aimed to investigate whether the neutrophil-lymphocyte ratio is relevant to snake envenomation-induced local edema in South Korea. This retrospective study divided 126 patients into two groups according to local edema severity at presentation. Logistic regression models were used to investigate the association between the neutrophil-lymphocyte ratio and local edema. Sixty-one (48.4%) patients had grade 2 or higher local edema at presentation despite 21 of them being given antivenom before presentation. During hospitalization, local edema progressed in 61 patients 48 (11.5-48) hours after presentation, and 54 patients demonstrated grade 3 or higher local edema. A higher neutrophil-lymphocyte ratio at presentation after adjustment for factors related to envenomation and antivenom administration and factors influencing the neutrophil-lymphocyte ratio were associated with both a higher grade of local edema at presentation and a higher peak local edema grade during hospitalization. The delta neutrophil-lymphocyte ratio during the first 24 h after presentation was related to the local edema progression after presentation. The neutrophil-lymphocyte ratio at presentation is associated with the severity of local edema-related envenomation. Furthermore, the change in the neutrophil-lymphocyte ratio during the first 24 h is related to the risk of local edema progression. Further clinical and experimental research aimed at investigating the role of inflammation on the pathogenesis of local edema should be conducted. This study may suggest the introduction of short-term anti-inflammatory agents considering the failure of antivenom to curb local edema.

Snakebite victim profiles and treatment-seeking behaviors in two regions of Kenya: results from a health demographic surveillance system

INTRODUCTION

Snakebites are a major cause of permanent injury and death among poor, rural populations in developing countries, including those in East Africa. This research characterizes snakebite incidence, risk factors, and subsequent health-seeking behaviors in two regions of Kenya using a mixed methods approach.

METHODS

As a part of regular activities of a health demographic surveillance system, household-level survey on snakebite incidence was conducted in two areas of Kenya: Kwale along the Kenyan Coast and Mbita on Lake Victoria. If someone in the home was reported to have been bitten in the 5 years previous to the visit, a survey instrument was administered. The survey gathered contextual information on the bite, treatment-seeking behavior and clinical manifestations. To obtain deeper, contextual information, respondents were also asked to narrate the bite incident, subsequent behavior and outcomes.

RESULTS

8775 and 9206 households were surveyed in Kwale and Mbita, respectively. Out of these, 453 (5.17%) and 92 (1.00%) households reported that at least one person had been bitten by a snake in the past 5 years. Deaths from snakebites were rare (4.04%), but patterns of treatment seeking varied. Treatment at formal care facilities were sought for 50.8% and at traditional healers for 53.3%. 18.4% sought treatment from both sources. Victims who delayed receiving treatment from a formal facility were more likely to have consulted a traditional healer (OR 8.8995% CI [3.83, 20.64]). Delays in treatment seeking were associated with significantly increased odds of having a severe outcome, including death, paralysis or loss of consciousness (OR 3.47 95% CI [1.56; 7.70]).

CONCLUSION

Snakebite incidence and outcomes vary by region in Kenya, and treatment-seeking behaviors are complex. Work needs to be done to better characterize the spatial distribution of snakebite incidence in Kenya and efforts need to be made to ensure that victims have sufficient access to effective treatments to prevent death and serious injury.

A simple mortality risk prediction score for viper envenoming in India (VENOMS): A model development and validation study

BACKGROUND

Snakebite is a neglected problem with a high mortality in India. There are no simple clinical prognostic tools which can predict mortality in viper envenomings. We aimed to develop and validate a mortality-risk prediction score for patients of viper envenoming from Southern India.

METHODS

We used clinical predictors from a prospective cohort of 248 patients with syndromic diagnosis of viper envenoming and had a positive 20-minute whole blood clotting test (WBCT 20) from a tertiary-care hospital in Puducherry, India. We applied multivariable logistic regression with backward elimination approach. External validation of this score was done among 140 patients from the same centre and its performance was assessed with concordance statistic and calibration plots.

FINDINGS

The final model termed VENOMS from the term "Viper ENvenOming Mortality Score included 7 admission clinical parameters (recorded in the first 48 hours after bite): presence of overt bleeding manifestations, presence of capillary leak syndrome, haemoglobin <10 g/dL, bite to antivenom administration time > 6.5 h, systolic blood pressure < 100 mm Hg, urine output <20 mL/h in 24 h and female gender. The lowest possible VENOMS score of 0 predicted an in-hospital mortality risk of 0.06% while highest score of 12 predicted a mortality of 99.1%. The model had a concordance statistic of 0·86 (95% CI 0·79-0·94) in the validation cohort. Calibration plots indicated good agreement of predicted and observed outcomes.

CONCLUSIONS

The VENOMS score is a good predictor of the mortality in viper envenoming in southern India where Russell's viper envenoming burden is high. The score may have potential applications in triaging patients and guiding management after further validation.

Snakebite Envenomation and Heart: Systematic Review

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

Snakebite envenomings in the Republic of Korea from the 1970s to the 2020s: A review

Snakebite envenomings remain a neglected disease across the globe causing severe injuries and death. An understanding of regional snakebite patterns is a necessary prerequisite for public health programs aimed at reducing snakebite risks. However, such regional knowledge is poorly documented or lacking in many countries where the risk of snakebite envenomings receive little medical attention, and the Republic of Korea is one of these countries. Here, we reviewed the literature on snakebites published between 1970 and 2020 as well as public healthcare data recorded between 2010 and 2019 to determine the patterns of snakebite envenomings in the Republic of Korea. Our results, based on literature data, show Gangwon province as a hotspot of snakebite occurrences and identify middle-aged males living in rural areas as the demographic group at highest risk of venomous snakebites. We also highlight major limitations for further understanding snakebite patterns in the country, most notably the lack of proper species identification for snakes and conflicting patterns of envenomings revealed by different sources of data. Our study provides baseline information on venomous snakebites occurring in the Republic of Korea, thereby filling a gap in the knowledge of snakebite trends in the country.

Vipers of Major clinical relevance in Europe: Taxonomy, venom composition, toxicology and clinical management of human bites

Snakebites in Europe are mostly due to bites from Viperidae species of the genus Vipera. This represents a neglected public health hazard with poorly defined incidence, morbidity and mortality. In Europe, fourteen species of "true vipers" (subfamily Viperinae) are present, eleven of which belong to the genus Vipera. Amongst these, the main medically relevant species due to their greater diffusion across Europe and the highest number of registered snakebites are six, namely: Vipera ammodytes, V. aspis, V. berus, V. latastei, V. seoanei and V. ursinii. Generally speaking, viper venom composition is characterised by many different toxin families, like phospholipases A2, snake venom serine proteases, snake venom metalloproteases, cysteine-rich secretory proteins, C-type lectins, disintegrins, haemorrhagic factors and coagulation inhibitors. A suspected snakebite is often associated with severe pain, erythema, oedema and, subsequently, the onset of an ecchymotic area around one or two visible fang marks. In the field, the affected limb should be immobilised and mildly compressed with a bandage, which can then be removed once the patient is being treated in hospital. The clinician should advise the patient to remain calm to reduce blood circulation and, therefore, decrease the spread of the toxins. In the case of pain, an analgesic therapy can be administered, the affected area can be treated with hydrogen peroxide or clean water. However, anti-inflammatory drugs and disinfection with alcohol or alcoholic substances should be avoided. For each patient, clinical chemistry and ECG are always a pre-requisite as well as the evaluation of the tetanus immunisation status and for which immunisation may be provided if needed. The treatment of any clinical complication, due to the envenomation, does not differ from treatments of emergency nature. Antivenom is recommended when signs of systemic envenomation exist or in case of advanced local or systemic progressive symptoms. Recommendations for future work concludes. The aim of this review is to support clinicians for the clinical management of viper envenomation, through taxonomic keys for main species identification, description of venom composition and mode of action of known toxins and provide a standardised clinical protocol and antivenom administration.

Vipera snakebite in Europe: a systematic review of a neglected disease

In 2009, snakebites were included in the list of the World Health Organization (WHO) neglected diseases. Dermatological literature lacks current and up-to-date articles about snakebites and their management, despite the fact that dermatologists, especially from rural hospitals, can be called into the emergency room to consult the management of suspected snakebites. In this systematic review, we highlighted the main clinical and laboratory aspects of snakebites from Vipera spp. in Europe, by reviewing 3574 studies initially retrieved from PubMed, Embase and Cochrane CENTRAL databases. Of these, 78 were finally included in the systematic review. We found that the most involved taxon was V. berus in 63.3% and the most involved anatomic site of the bite was the upper limbs 53.1% with fang marks reported in 90.5%. The mean age of the patients was 32.9 years, and bites were slightly more common among males (58.2%). A wound washing was performed in 86.9% of cases before the hospitalization. The most frequently reported grade of envenomation was G2 (42.2%). In addition to local dermatological symptoms (extended erythema, oedema, cutaneous necrosis, hives, purpura, petechiae, acute compartment syndrome), numerous systemic symptoms have also been reported, including fatigue (14.4%), pain (75.3%), fever (49.2%), direct anaphylactoid reaction (5.3%), anxiety (60.8%), cranial nerve neurotoxicity (14.8%), dysesthesia/paraesthesia (7.9%), vomiting (33.7%), abdominal pain (23.3%), diarrhoea (15.4%), dyspnoea (6.3%), proteinuria (10.6%) and haematuria (9.3%). Secondary infections were present in 3.5% and disseminated intravascular coagulation in 3.1% of cases, and fasciotomy was performed in 4.2% cases, while an amputation in 6.9%. Only 0.9% of patients died. Antivenom was administered in 3053 cases. In conclusion, there is a pressing need for robust multi-centre randomized control trials, standardized protocol for snakebite management and antivenom administration across Europe and a National snakebite register for each European country.

Comparative therapeutic index, lethal time and safety margin of various toxicants and snake antivenoms using newly derived and old formulas

OBJECTIVE

The assessment of clinical efficacy and toxicity is very important in pharmacology and toxicology. The effects of psychostimulants (e.g. amphetamine), psychotomimetics (e.g. Cannabis sativus) and snake antivenoms are sometimes unpredictable even at lower doses, leading to serious intoxication and fatal consequences. Hence, there is need to re-assess some formulas for calculation of therapeutic index, lethal time and safety margin with a view to identifying therapeutic agents with remarkable toxicity potentials.

RESULTS

The therapeutic index formula [Formula: see text] was derived from T1 = LD50/ED50 and ED50 = [Formula: see text]. Findings have shown that, therapeutic index is a function of death reversal (s), safety factor (10-4) and weight of animal (Wa). However, the new safety margin formula [Formula: see text] derived from LT50 = [Formula: see text] and MS = [Formula: see text] shows that safety margin is a function of cube root of ratio between LT50 and LD50 and ED100th. Concentration (k) of toxicant at the receptor [Formula: see text] derived from D1 × Tn = K and LD1 = [Formula: see text] shows that therapeutic index, lethal time and safety margin is a function of drug or toxicant concentration at the receptor, the drug-receptor interaction and dose of toxicant or drug administered at a particular time.

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.

Epidemiological profile and outcomes of snakebite injuries treated in emergency departments in South Korea, 2011–2016: a descriptive study

Background

Snakebite is a global public health crisis, but there are no nationwide data on snakebite in South Korea. The aim of this study was to describe the epidemiological profile and outcomes of snakebite cases in South Korea seasonally.

Methods

The selected subjects were patients of all ages with a chief complaint of snakebite who presented to participating emergency departments (EDs) between 1 January 2011 and 31 December 2016.

Results

A total of 1335 patients were eligible for the study. There were an average of 223 snakebite cases reported each year. Most snakebites occurred during the summer months (55.9%) in patients aged 40–59 y (36.3%) and males (61.5%). Snakebites occurred most frequently on Mondays (22.9%) between 12:00 and 17:59 h (42.0%) outdoors (57.9%) and in farm areas (20.7%). Over 82% of the bites were by venomous snakes across all seasons, and 66% of the patients visited EDs without using emergency medical services. Based on the excess mortality ratio-adjusted injury severity score, 88, 9.2 and 2.8% had mild, moderate and severe injuries, respectively. There were 10 fatalities during the study period.

Conclusion

This study provides essential information to understand and assess the burden and distribution of snakebites in South Korea and provides valuable information for developing appropriate prevention and control interventions to address it.

Daboia (Vipera) palaestinae envenomation in horses: Clinical and hematological signs, risk factors for mortality and construction of a novel severity scoring system

Daboia palaestinae is the most common venomous snake in Israel and an important cause of envenomations in humans and animals. Although specific antivenom is produced from horses, little documentation exists regarding the characteristics of envenomed horses. This survey was constructed to describe the clinical, hematological and biochemical characteristics of D. palaestinae envenomation in horses, to identify risk factors for fatality and to construct a prognostic snakebite severity scale (SSS) to be used by veterinarians in the field. Data regarding 123 equine snakebite cases were collected over four years. Clinical signs most frequently described were local swelling (100%), tachycardia (67%), increased respiratory effort (62%), bite marks (44%) and reduced appetite (50%). Blood samples were collected at initial presentation from 23 of these horses. Hematological and biochemical abnormalities described in the majority of the sampled cases included leukocytosis (52%), neutrophilia (78%), increased creatine phosphokinase (77%), hypoproteinemia (50%), decreased total carbon dioxide (54%), and hyperphosphatemia (54%). The overall case fatality rate was 20.3% (25/123 horses). Risk factors associated with increased mortality (P < 0.05) were body weight below 200 kg, hind limb envenomation, severity of local swelling, mental status, respiratory effort, bleeding disorders, dehydration, basophilia, monocytosis, bilirubinemia, hypocalcemia and hyperphosphatemia. These risk factors were used to construct an SSS adapted for the assessment of envenomed horses in the field, consisting of seven dichotomous parameters. A cutoff value of 1.5 predicted mortality with 95% sensitivity and 68% specificity. In the future, this tool could assist clinicians with case management and communication with owners.