Vials Of Antivenom Research Articles

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

To describe the clinicopathological characteristics of dogs that develop acute kidney injury (AKI) secondary to pit viper envenomation, and to describe the association between development of AKI and clinical course and outcome. Retrospective study. University teaching hospital. Client-owned dogs treated with at least 1 vial of antivenom following pit viper envenomation and that had at least 2 plasma creatinine concentrations measured during the course of hospitalization. None. Sixty-three dogs met the inclusion criteria. One was excluded due chronic kidney disease, and 6 were excluded due to nonsteroidal anti-inflammatory drug administration. Of the 56 dogs included in the study, 16 developed AKI (29%). Dogs with AKI received a significantly higher dose of antivenom, 8.7 ± 6.8 total vials versus dogs in the non-AKI group that received 4.2 ± 2.6 vials (P=0.006). Dogs in the AKI group were significantly more tachycardic (P=0.028), hypotensive (P=0.002), had a higher shock index (P=0.012), and were more likely to receive transfusions with packed red blood cells (P=0.042) than dogs in the non-AKI group. No significant association was identified between the development of AKI and length of hospitalization. The only factors that were significantly associated with degree of severity of AKI included the receipt of blood transfusion (P=0.006) and number of vials of antivenom administered (P=0.03). The development of AKI was significantly associated with outcome (P<0.001), with 5 of 16 (31%) dogs in the AKI group surviving to discharge, 7 of 16 (44%) dying, and 4 of 16 (25%) being euthanized versus 39 of 40 (98%) surviving to discharge in the non-AKI group and 1 of 40 (2%) dying in hospital. Development of AKI in dogs following pit viper envenomation carries an increased risk of mortality that is associated with severity of shock at presentation and increased doses of antivenom administration.

Toxicity and cross-neutralization of snake venoms from two lesser-known arboreal pit vipers in Southeast Asia: Trimeresurus wiroti and Trimeresurus puniceus

The lesser-known Sundaic lance-headed pit vipers Trimeresurus wiroti (Malaysia) and Trimeresurus puniceus (Indonesia) contribute to the disease burden of snakebite envenomation in Southeast Asia, but their venom toxicity and neutralization remain insufficiently investigated. This study demonstrated that both venoms were procoagulant (involving thrombin-like activity), hemorrhagic, and lethal to mice, with T. wiroti venom being more lethal (LD50 = 0.78 μg/g c.f. 1.21 μg/g). The hetero-specific antivenom from Thailand, Green Pit Viper Antivenom (GPVAV, raised against Trimeresurus albolabris) cross-reacted with T. wiroti and T. puniceus venoms with a higher efficacy of immunological binding activity for the latter. The antivenom was also effective in cross-neutralizing the procoagulant, hemorrhagic and lethal effects of the venoms. In lethality neutralization, GPVAV showed a potency of 0.79–1.05 mg venom per mL antivenom, corresponding to the complete neutralization of approximately 8–10 mg venom per unit vial of antivenom for T. wiroti and T. puniceus venoms. Taken together, it was inferred that T. wiroti, T. puniceus, and T. albolabris venoms share common toxin epitopes, thus enabling the cross-neutralization observed. These findings suggest that GPVAV may be potentially useful in the management of envenomation by T. wiroti and T. puniceus while awaiting clinical trial and validation.

Descending Cervical-Sacral Pain after the Administration of Antivenom to the Scorpion Sting Poisoning: A Case Report

Introduction. Scorpion stings occur mainly in spring and summer, with an estimate of 1.2 million cases per year worldwide. About 300,000 poisonings occur within a year, primarily affecting children and adults older than 65 years. In 2019, Guanajuato (Mexico) ranked third in poisoning by scorpion sting with a total of 43,913 cases. The intoxication grades are three where the signs and symptoms are varied. There are two types of antivenom in the Mexican market, and we use Alacramyn® in our case. Case presentation. A 70-year-old female —with grade 1 scorpion sting poisoning, 30 minutes of evolution, with type 2 diabetes and high blood pressure— received two vials of antivenom according to current regulations. She presented transient vagal reaction and subsequent transient pain in the cervical region that radiates to the sacral region. At discharge, there are no data compatible with scorpion sting poisoning. Conclusions. Transient pain in the cervical region to the sacral region may be secondary to an anxiety crisis, hypersensitivity to IgG, or secondary reaction to administration in less time than recommended by the provider. The benefit was greater than the reactions that occurred.

Australian snake antivenom dosing: What is scientific and safe?

Because the median dose of one vial 'clears the blood of circulating venom', the authors of the Australian Snakebite Project recommend restriction of antivenom to one vial for all envenomated victims. This is neither scientific nor safe. Methodological flaws in the case series include limited detection of venom toxins and misinterpretation of data. The recommendation fails to consider larger doses of venom than that neutralised by one vial of antivenom. Although one vial may be adequate for minor envenomation, the initial dose should be two vials with more on a clinical basis.

Acute adverse events associated with the administration of Crotalidae polyvalent immune Fab antivenom within the North American Snakebite Registry

Background: Crotalidae Polyvalent Immune Fab (Fab Antivenom) is the primary Viperid antivenom used in the United States since 2000. Adverse event data associated with its use are limited. The purpose of this study is to describe the prevalence of acute adverse events associated with the use of Fab antivenom.Methods: The American College of Medical Toxicology’s Toxicology Investigators Consortium maintains a prospective case registry of poisoned and envenomated patients managed by medical toxicologists at the bedside. This registry includes the North American Snakebite sub-registry. We performed a review of 438 cases entered into the Snakebite sub-registry.Results: A total of 373 (85.2%) received at least one vial of Fab Antivenom. Forty percent were children. Adverse events occurred in 10 patients (2.7%) of whom six were adults. Rash was the most common adverse event. More severe adverse events (hypotension, bronchospasm, and/or angioedema) occurred in four (1.1%) patients. Prophylaxis was administered prior to Fab antivenom in 4.0%. Eight patients received various treatments for their adverse events. Neither the initial number of Fab antivenom vials, atopic history, nor prior envenomation correlated with the prevalence of adverse events.Discussion: This prevalence of adverse events was lower than in previous studies and in a meta-analysis of 11 studies. The types of adverse events and treatments used are consistent with those in previous reports. There were no prior reports of prophylaxis use with which to compare.Conclusion: The prevalence of Fab antivenom adverse events in the North American Snakebite Registry was 2.7%.

Second Dose of Scorpion Antivenom in Children with Indian Red Scorpion (Mesobuthus tamulus) Sting Envenomation

To study the effect of the second dose of scorpion antivenom in children with non-resolving or worsening scorpion sting envenomation. 72 children aged ≤12 years with scorpion sting envenomation grade 2 and above were enrolled. 61 received the first dose of three vials of antivenom at admission (group A). Children with persistent/worsening envenomation at 6 hours received the second dose (group B). The time required for resolution of autonomic symptoms, myocardial dysfunction, predictors of the second dose and side effects were studied. The mean time taken for resolution of autonomic symptoms were similar in GroupA and B (4.1 vs. 5.3 hours, P=0.452), and of myocardial dysfunction was shorter in Group A (10.8 vs. 37.6 hours, P=0.019). On regression analysis, abnormal echocardiography at admission was found to be a significant predictor of the second dose (OR=27.6, 95% CI, 4.7-162.5; P=<0.001). Children with severe scorpion sting envenomation with abnormal echocardiography may require a higher dose of scorpion antivenom.

Elapid snake envenomation in horses: 52 cases (2006-2016).

Snake envenomation is a cause of morbidity and mortality in domestic animals worldwide. The clinical features of crotalid snake (pit viper) envenomation are widely reported and well described in horses but elapid snake envenomation is poorly characterised. To describe the presentation, clinical and laboratory findings, treatment and outcome of horses with a diagnosis of elapid snake envenomation in Australia. Retrospective case series. Medical records of horses with a diagnosis of elapid snake envenomation (2006-2016) at several university and private veterinary practices were reviewed. Inclusion criteria comprised one or more of the following: 1) observed snakebite, 2) positive snake venom detection kit (SVDK) result, 3) appropriate clinical response to treatment with antivenom or 4) supportive post-mortem findings. Fifty-two cases met the inclusion criteria. Most cases (94%) demonstrated clinical signs of neurotoxicity, characterised by generalised neuromuscular weakness. Associated neurologic signs included staggering gait, muscle fasciculations, recumbency, mydriasis, ptosis and tongue paresis. Concurrent clinically important conditions included rhabdomyolysis (50%) and haemolysis (19%). Of 18 urine samples evaluated with a SVDK, only three (17%) were positive. Overall survival was favourable (86%) among 49 horses who received antivenom. Eighteen surviving horses (43%) required more than one vial of antivenom. Possible cases within the searchable database were not included if horses died acutely or responded to symptomatic treatment without receiving antivenom. Elapid snake envenomation is primarily a syndrome of neuromuscular weakness. Supportive anamnesis or an obvious bite site is rarely encountered. In endemic areas, this diagnosis should be considered for horses with generalised neuromuscular weakness, altered mentation, rhabdomyolysis and/or haemolysis; especially during spring and summer months. Diagnostic suspicion is best confirmed by response to treatment with antivenom.

Clinical and Laboratory Parameters Associated with Acute Kidney Injury in Viper Envenomed Cases

Viper species are distributed allover Egypt. Venomous bites by Viperidae snakes are associated with local and systemic manifestations and may be exacerbated by the development of acute kidney injury (AKI). THE AIM of the study was to assess acute renal injury in cases of envenomations by locally prevalent vipers as regards incidence, clinical and laboratory parameters and final outcome. METHODS: The current study was conducted on all patients, of both sex, admitted in Poison Control Center of Ain Shams University hospitals following envenomation by Viperidae snakes during 2014, 2015, and 2016. Diagnosis was based on history of snake bite with suggestive clinical data. Recorded data included patient characteristics (age, gender, delay time), vital data (heart rate, blood pressure), presence of local signs, bleeding manifestations, laboratory parameters (INR, platelet count, hemoglobin level, BUN and serum creatinine), number of antivenom vials used , duration of hospital stay and survival. Cases were sub-grouped to group I with AKI and group II without AKI. RESULTS: A total of 120 cases of venomous bites by Viperidae snakes were recorded during the study period with mortality of 4.2%. Cases were predominantly males with mean age of 35 +/-14.7years. A subset of 5.8% cases developed AKI which statistically was related to older age, longer delay time, increased incidence of bleeding manifestations and tachycardia, higher values of INR, serum creatinine, and blood urea nitrogen, lower platelet count, higher number of used antivenom vials and longer duration of hospital stay. Gender, hypotension, presence of local manifestations and hemoglobin level were insignificant among AKI. Mortality among AKI cases was statistically linked to old age, prolonged delay time, increased incidence of bleeding manifestations, higher INR values, low platelet count and low hemoglobin level and increased number of used antivenom vials and duration of hospital stay. The incidence of tachycardia, hypotension and local manifestations, serum creatinine and blood urea nitrogen levels were not statistically different among non- survivors. CONCLUSION: Acute renal injury may complicate the course of viper envenomations. Venom hemotoxicity is related to morbidity and mortality especially with older age and longer time between bite to antivenom therapy.

Bungarus multicinctus multicinctus Snakebite in Taiwan.

AbstractAlthough specific antivenom is available in Taiwan, respiratory failure and general pain frequently accompany Bungarus multicinctus envenomation and there have been few reports on the management of B. multicinctus envenomation. We retrospectively analyzed 44 cases of B. multicinctus bite admitted to Taichung Veterans General Hospital (VGH) or to Taipei VGH. Demographic data, treatment, and outcome of patients with and without respiratory failure were compared. In this study, 20.5% patients had bites without noticeable signs or symptoms of significant envenoming, 27.3% developed respiratory failure, and 27.3% experienced general pain. Bivalent specific antivenom for B. multicinctus and N. atra was administered in all envenomed cases. Respiratory failure occurred 1.5-6.5 hours post-bite and general pain occurred 1-12 hours post-bite. Specific antivenom for B. multicinctus and N. atra at the recommended dose (i.e., 2-4 vials) might not effectively prevent respiratory failure and pain. Respiratory failure, general pain, and autonomic effects after B. multicinctus bite were probably caused, at least partly, by β-bungarotoxin. Although general weakness, ptosis, dysarthria, and dilated pupils were significantly associated with respiratory failure, their predictive value could not be accurately determined in such a retrospective study. Due to the rapid onset of respiratory failure, every suspected envenomed case thus should be closely monitored in the first few hours. We recommend the initial administration of four vials of antivenom in all envenomation cases, and a subsequent four vials be considered if the patient's condition is deteriorating. Prospective evaluation of the antivenom dosing regimen is urgently needed to improve B. multicinctus envenomation treatment.

Australian taipan (Oxyuranus spp.) envenoming: clinical effects and potential benefits of early antivenom therapy – Australian Snakebite Project (ASP-25)

Context: Taipans (Oxyuranus spp.) are medically important venomous snakes from Australia and Papua New Guinea. The objective of this study was to describe taipan envenoming in Australian and its response to antivenom.Methods: Confirmed taipan bites were recruited from the Australian Snakebite Project. Data were collected prospectively on all snakebites, including patient demographics, bite circumstances, clinical effects, laboratory results, complications and treatment. Blood samples were taken and analysed by venom specific immunoassay to confirm snake species and measure venom concentration pre- and post-antivenom.Results: There were 40 confirmed taipan bites: median age 41 years (2–85 years), 34 were males and 21 were snake handlers. Systemic envenoming occurred in 33 patients with neurotoxicity (26), complete venom induced consumption coagulopathy (VICC) (16), partial VICC (15), acute kidney injury (13), myotoxicity (11) and thrombocytopenia (7). Venom allergy occurred in seven patients, three of which had no evidence of envenoming and one died. Antivenom was given to 34 patients with a median initial dose of one vial (range 1–4), and a median total dose of two vials (range 1–9). A greater total antivenom dose was associated with VICC, neurotoxicity and acute kidney injury. Early antivenom administration was associated with a decreased frequency of neurotoxicity, acute kidney injury, myotoxicity and intubation. There was a shorter median time to discharge of 51 h (19–432 h) in patients given antivenom <4 h post-bite, compared to 175 h (27–1104 h) in those given antivenom >4 h. Median peak venom concentration in 25 patients with systemic envenoming and a sample available was 8.4 ng/L (1–3212 ng/L). No venom was detected in post-antivenom samples, including 20 patients given one vial initially and five patients bitten by inland taipans.Discussion: Australian taipan envenoming is characterised by neurotoxicity, myotoxicity, coagulopathy, acute kidney injury and thrombocytopenia. One vial of antivenom binds all measurable venom and early antivenom was associated with a favourable outcome.

A Retrospective Study on Snakebite Victims in a Tertiary Referral Center

Background: Snakebite is a serious public health problem in the world. The annual incidence of snakebites ranges from 4.5-9.1 in 100,000 population in Iran. With regard to diversity of envenomation profiles in different geographical parts of Iran, the aim of this study was to determine the demographical data, clinical and laboratory findings, and the outcome of the snakebite victims referred to a tertiary referral hospital. Methods: In this retrospective, cross-sectional study in Loghman Hakim Hospital Poisoning Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran, during a four-year period from March 2007 to March 2011. The demographic data, clinical manifestations, paraclinical findings, treatments performed before hospital admission, time elapsed between the bite and hospital admission, total dose of antivenom and the patients’ outcomes were investigated. Results: Seventy cases (58 males, 12 females) were evaluated. Most of the cases (79%) were older than 20 year old. The most common bite site was upper extremity (67%). Most of the patients were admitted within 5 h after the snakebite. The most common local and systemic manifestations were swelling (90%), pain (81.4%), nausea and vomiting (24.3%). Leukocytosis (35.7%) and thrombocytopenia (25.7%) were the most common laboratory abnormalities. Most of the patients (97.1%) were treated with antivenom. Fifty percent of the patients only received 3-5 vials of antivenom. The mortality rate was 1.4%. Necrosis of the toes and compartment syndrome were the only serious complications. Conclusion: The findings emphasize the importance of early admission to the hospital and treatment with antivenom to avoid morbidity and mortality.

Estimating the Burden of Snakebite on Public Hospitals in KwaZulu Natal, South Africa

We propose a formula as a means to estimate the number and incidence of snakebites treated per annum in KwaZulu Natal (KZN), South Africa. Using an unvalidated formula that includes an antivenom ratio, we crudely estimated the total number of snakebite presentations in KZN. Using antivenom supply data from the central pharmacy, we stratified a sample of 6 hospitals that were surveyed to establish an antivenom ratio, that is, the total number of patients receiving antivenom to the total number of snakebite presentations at hospitals. The antivenom ratio and the average number of antivenom vials for treated snakebites were incorporated into a formula to crudely estimate the number of snakebite presentations. This was then applied to all public hospitals and districts in the region. Seventy-eight percent of public hospitals were included. The mean antivenom ratio derived from the sample hospitals indicated that 12% (95% CI, 10-14%) of snakebite presentations received antivenom. We estimated an annual total of 1680 (95% CI, 1193-2357) snakebite presentations to hospitals. Two thirds of cases (1109 of 1680) were in the low-lying subtropical coastal region. Few cases were in the higher, cooler regions of KZN (87 of 1680) or the metropolitan city of Durban (93 of 1680). The overall incidence for KZN was 16/100,000. The estimated cost of snakebite in KZN was between $1,156,930 and $2,827,848. We propose an alternative method to estimate the annual number of snakebite presentations to hospitals.

An investigation of snakebite antivenom usage in Taiwan.

Four types of antivenom are used to treat snakebites by the six species of venomous snakes native to Taiwan. Research into antivenom use in Taiwan and its outcomes, as well as the utility of current Taiwan Poison Control Center guidelines for antivenom use, has been limited. We aimed to provide increased understanding by investigating the treatment and outcomes of patients treated for snakebite in Taiwan. On the basis of data collected from the 2009 Taiwan National Health Insurance database, patients with snakebites were identified and categorized into two sets of groups according to types of antivenom administered. The relationships between antivenom types, dosage and the variables of antibiotic use, surgical intervention, acute respiratory failure acute, renal failure, antivenom-related allergic reaction, mortality, need for hospital admission, and length of hospitalization were analyzed by multivariate logistic regression and the Kruskal-Wallis test. The majority of patients were successfully treated by administration of 1 vial of antivenom and discharged without complications. However, patients treated for neurotoxic-type venom snakebite required administration of larger doses of antivenom and > 30% required surgical intervention, particularly those treated for Chinese cobra snakebite. Approximately 10% of patients were administered two types of antivenom. The results partially support Taiwan Poison Control Center guidelines for treating the hemorrhagic-type venom snakebite. However, deficit in the guidelines for treatment of neurotoxic-type venom snakebite is obvious and new guidelines for treatment of neurotoxic-type venom snakebite and diagnosis should be developed.

A chance to cut is not always a chance to cure- fasciotomy in the treatment of rattlesnake envenomation: A retrospective poison center study.

Fasciotomy has been described in the treatment of rattlesnake-envenomation. We sought to compare the characteristics of patients undergoing fasciotomy with those where fasciotomy was discussed but not performed. A retrospective case-series constructed from a single-statewide-poison-system electronic database for cases of fasciotomy discussion or completion in rattlesnake-envenomation between January 2001 and May 2012. Age, gender, bite location, antivenom administered, compartment pressure measurements, Snakebite Severity Score (SSS) and length of hospitalization (LOS) were recorded. Comparisons were made between fasciotomy completed and where fasciotomy was only discussed. One-hundred-five cases of fasciotomy discussion or completion were identified. Fasciotomy was performed in 28 cases (27%). There was no statistically significant difference (p>0.05) between groups in age, gender, bite site, SSS, and total number of vials of antivenom administered. Only 2 of 28 (7%) had compartment pressure measurements. Patients undergoing fasciotomy spent an additional 2 days in the hospital. Fasciotomies continue to take place, without compartment pressure measurements, and without repeat dosing of antivenom. In the absence of clear objective evidence that limb-threatening compartment syndrome occurs despite adequate antivenom administration, fasciotomy does not favorably impact morbidity and may be associated with increased costs for care following rattlesnake envenomation.

Bleeding Following Rattlesnake Envenomation in Patients With Preenvenomation Use of Antiplatelet or Anticoagulant Medications

Rattlesnake envenomations commonly produce coagulopathy and thrombocytopenia, yet clinically significant bleeding is uncommon. It is unknown if patients who use antiplatelet or anticoagulant medications prior to envenomation are at increased risk for bleeding after envenomation. This was a retrospective cohort study of patients age 14 years and older who were admitted to a single academic medical center for rattlesnake envenomation. Patients who reported use of antiplatelet or anticoagulant medications prior to envenomation were compared to patients not on those medications. Severity and timing of bleeding was compared between groups, as was a composite endpoint of major bleeding at any time, shock, readmission, or death. A total of 319 patients met inclusion criteria; 31 (9.7%) were documented to be taking antiplatelet or anticoagulant medications including aspirin, clopidogrel, and/or warfarin. Seventeen of the 319 patients developed bleeding associated with envenomation (major = 9; minor = 4; trivial = 4), with major bleeding occurring in five patients on antiplatelet or anticoagulant medications versus four patients not on antiplatelet or anticoagulant medications (p < 0.001). Seven of the 17 presented with early bleeding. This early bleeding occurred in three of 31 (9.7%) patients on antiplatelet or anticoagulant medications and four of 288 (1.4%) patients not on antiplatelet or anticoagulant medications (relative risk [RR] = 6.9; 95% confidence interval [CI] = 1.6 to 29.4; p = 0.022). Clinical outcome data were available for 300 of the 319 (94%) subjects following discharge. Late bleeding (bleeding after discharge from the index hospitalization) occurred in nine subjects, one of whom also had early bleeding (major = 2, minor = 3, trivial = 4). Three of these nine subjects with late bleeding were on antiplatelet or anticoagulant medications, compared with six not on antiplatelet or anticoagulant medications (p = 0.042). Both cases of late major bleeding occurred in patients on antiplatelet or anticoagulant medications. Therefore, among patients with follow-up data available, the overall rate of bleeding (early and late) was seven of 28 (25%) in patients taking antiplatelet or anticoagulant medications and 10 of 273 (3.7%) in patients not taking antiplatelet or anticoagulant medications (p < 0.001). The use of antiplatelet or anticoagulant medications was also associated with an increased risk of reaching the composite endpoint of major bleeding, shock, readmission, or death (6 of 31, or 19.4% vs. 14 of 288, or 4.9%; RR = 3.98; 95% CI = 1.65 to 9.62; p = 0.008). The risk of developing bleeding following rattlesnake envenomation is increased in patients who use antiplatelet or anticoagulant medications. This risk is greatest early after envenomation during the index hospitalization. However, risk of late, major bleeding appears also to be greatest in patients on antiplatelet or anticoagulant medications. Extra vigilance should be taken in patients on antiplatelet or anticoagulant medications and a careful risk/benefit analysis should be undertaken before continuing these medications in the weeks following the envenomation.

Multicenter evaluation of the administration of crotalid antivenom in cats: 115 cases (2000–2011)

To evaluate use of crotalid antivenom, frequency of hypersensitivity reactions, and risk factors for hypersensitivity reactions and death in envenomed cats. Retrospective multicenter case series. 115 envenomed cats treated with antivenom and 177 envenomed cats treated without antivenom. Procedures-Medical records from 5 institutions were searched by means of a multiple-choice survey with standardized answers for patient data including signalment, diagnosis, antivenom administration criteria, premedication, product, dose, administration rate, hypersensitivity reactions, and mortality rate. 95 of 115 (82.6%) cats received whole IgG antivenom, 11 (9.57%) received F(ab')2 antivenom, and 4 (3.48%) received Fab antivenom. The majority (101/115 [878%]) of cats received 1 vial of antivenom. In all cats, the median dilution of antivenom was 1:60 (range, 1:10 to 1:250) administered over a median period of 2.0 hours (range, 0.3 to 9.0 hours). There was no mortality rate difference between cats that did (6.67%) or did not (5.08%) receive antivenom. A type I hypersensitivity reaction was diagnosed in 26 of 115 (22.6%) cats. The use of premedications did not decrease type I hypersensitivity or improve mortality rate. Cats that had a type I hypersensitivity reaction were 10 times as likely to die as were those that did not have such a reaction. The mortality rate of cats treated with antivenom was low. The administration of premedications did not improve mortality rate or prevent hypersensitivity reactions. The only variable associated with mortality rate was development of a type I hypersensitivity reaction. The rate of antivenom administration should be further evaluated as a possible risk factor for type I hypersensitivity reactions.

Mulga snake (Pseudechis australis) envenoming: a spectrum of myotoxicity, anticoagulant coagulopathy, haemolysis and the role of early antivenom therapy – Australian Snakebite Project (ASP-19)

Context. Mulga snakes (Pseudechis australis) are venomous snakes with a wide distribution in Australia. Objective. The objective of this study was to describe mulga snake envenoming and the response of envenoming to antivenom therapy. Materials and methods. Definite mulga bites, based on expert identification or venom-specific enzyme immunoassay, were recruited from the Australian Snakebite Project. Demographics, information about the bite, clinical effects, laboratory investigations and antivenom treatment are recorded for all patients. Blood samples are collected to measure the serum venom concentrations pre- and post-antivenom therapy using enzyme immunoassay. Results. There were 17 patients with definite mulga snake bites. The median age was 37 years (6–70 years); 16 were male and six were snake handlers. Thirteen patients had systemic envenoming with non-specific systemic symptoms (11), anticoagulant coagulopathy (10), myotoxicity (7) and haemolysis (6). Antivenom was given to ten patients; the median dose was one vial (range, one–three vials). Three patients had systemic hypersensitivity reactions post-antivenom. Antivenom reversed the coagulopathy in all cases. Antivenom appeared to prevent myotoxicity in three patients with high venom concentrations, given antivenom within 2 h of the bite. Median peak venom concentration in 12 envenomed patients with samples was 29 ng/mL (range, 0.6–624 ng/mL). There was a good correlation between venom concentrations and the area under the curve of the creatine kinase for patients receiving antivenom after 2 h. Higher venom concentrations were also associated with coagulopathy and haemolysis. Venom was not detected after antivenom administration except in one patient who had a venom concentration of 8.3 ng/ml after one vial of antivenom, but immediate reversal of the coagulopathy. Discussion. Mulga snake envenoming is characterised by myotoxicity, anticoagulant coagulopathy and haemolysis, and has a spectrum of toxicity that is venom dose dependant. This study supports a dose of one vial of antivenom, given as soon as a systemic envenoming is identified, rather than waiting for the development of myotoxicity.

Tiger snake (Notechis spp) envenoming: Australian Snakebite Project (ASP‐13)

OBJECTIVES: To describe the clinical syndrome associated with definite tiger snake (Notechis spp) envenoming and to examine the ability of tiger snake antivenom (TSAV) to bind free venom in vivo. DESIGN, SETTING AND PARTICIPANTS: We conducted a prospective cohort study within the Australian Snakebite Project, reviewing all definite tiger snake envenoming cases between October 2004 and June 2011. Definite cases were identified by venom-specific enzyme immunoassay or expert snake identification. MAIN OUTCOME MEASURES: Clinical effects of tiger snake envenoming; peak venom concentrations; number of vials of antivenom administered. RESULTS: Fifty-six definite tiger snake envenomings were identified. Clinical effects included venom-induced consumption coagulopathy (VICC) (n = 53), systemic symptoms (n = 45), myotoxicity (n = 11) and neurotoxicity (n = 17). Thrombotic microangiopathy occurred in three patients, all of whom developed acute renal failure. There were no deaths. A bite-site snake venom detection kit test was done in 44 patients, but was positive for tiger snake in only 33 cases. Fifty-three patients received TSAV and eight of these patients had immediate hypersensitivity reactions, severe enough in one case to satisfy diagnostic criteria for severe anaphylaxis. The median peak venom concentration in 50 patients with pretreatment blood samples available was 3.2 ng/mL (interquartile range [IQR], 1-12 ng/mL; range 0.17-152 ng/mL). In 49 patients with post-treatment blood samples available, no venom was detected in serum after the first antivenom dose. Ten patients were given 1 vial of TSAV; the median dose was 2 vials (range, 1-4 vials). Pretreatment serum venom concentrations did not vary significantly between patients given 1 vial of TSAV and those given 2 or more vials. CONCLUSION: Tiger snake envenoming causes VICC, systemic symptoms, neurotoxicity and myotoxicity. One vial of TSAV, the dose originally recommended when the antivenom was first made available, appears to be sufficient to bind all circulating venom. Language: en

Clinical Effects and Antivenom Dosing in Brown Snake (Pseudonaja spp.) Envenoming — Australian Snakebite Project (ASP-14)

BackgroundSnakebite is a global health issue and treatment with antivenom continues to be problematic. Brown snakes (genus Pseudonaja) are the most medically important group of Australian snakes and there is controversy over the dose of brown snake antivenom. We aimed to investigate the clinical and laboratory features of definite brown snake (Pseudonaja spp.) envenoming, and determine the dose of antivenom required.Methods and FindingThis was a prospective observational study of definite brown snake envenoming from the Australian Snakebite Project (ASP) based on snake identification or specific enzyme immunoassay for Pseudonaja venom. From January 2004 to January 2012 there were 149 definite brown snake bites [median age 42y (2–81y); 100 males]. Systemic envenoming occurred in 136 (88%) cases. All envenomed patients developed venom induced consumption coagulopathy (VICC), with complete VICC in 109 (80%) and partial VICC in 27 (20%). Systemic symptoms occurred in 61 (45%) and mild neurotoxicity in 2 (1%). Myotoxicity did not occur. Severe envenoming occurred in 51 patients (38%) and was characterised by collapse or hypotension (37), thrombotic microangiopathy (15), major haemorrhage (5), cardiac arrest (7) and death (6). The median peak venom concentration in 118 envenomed patients was 1.6 ng/mL (Range: 0.15–210 ng/mL). The median initial antivenom dose was 2 vials (Range: 1–40) in 128 patients receiving antivenom. There was no difference in INR recovery or clinical outcome between patients receiving one or more than one vial of antivenom. Free venom was not detected in 112/115 patients post-antivenom with only low concentrations (0.4 to 0.9 ng/ml) in three patients.ConclusionsEnvenoming by brown snakes causes VICC and over a third of patients had serious complications including major haemorrhage, collapse and microangiopathy. The results of this study support accumulating evidence that giving more than one vial of antivenom is unnecessary in brown snake envenoming.

Venomous Bites and Stings

Fasciotomy has been described in the treatment of rattlesnake-envenomation. We sought to compare the characteristics of patients undergoing fasciotomy with those where fasciotomy was discussed but not performed.A retrospective case-series constructed from a single-statewide-poison-system electronic database for cases of fasciotomy discussion or completion in rattlesnake-envenomation between January 2001 and May 2012. Age, gender, bite location, antivenom administered, compartment pressure measurements, Snakebite Severity Score (SSS) and length of hospitalization (LOS) were recorded. Comparisons were made between fasciotomy completed and where fasciotomy was only discussed.One-hundred-five cases of fasciotomy discussion or completion were identified. Fasciotomy was performed in 28 cases (27%). There was no statistically significant difference (p > 0.05) between groups in age, gender, bite site, SSS, and total number of vials of antivenom administered. Only 2 of 28 (7%) had compartment pressure measurements. Patients undergoing fasciotomy spent an additional 2 days in the hospital.Fasciotomies continue to take place, without compartment pressure measurements, and without repeat dosing of antivenom. In the absence of clear objective evidence that limb-threatening compartment syndrome occurs despite adequate antivenom administration, fasciotomy does not favorably impact morbidity and may be associated with increased costs for care following rattlesnake envenomation.