Viper Snakebite Research Articles

FabAV antivenin use after copperhead snakebite: clinically indicated or knee-jerk reaction?

BackgroundCrotalidae Polyvalent Immune Fab (Ovine) (FabAV) antivenin is commonly recommended after pit viper snakebites. Because copperhead envenomations are usually self-limited, some physicians are reluctant to use this costly treatment routinely, while others follow a more liberal approach. We hypothesized that, in practice, only patients with evidence of significant (moderate or severe) copperhead envenomation [those with snakebite severity score (SSS) > 3] receive FabAV and examined a large cohort to determine the relationship between clinical findings and FabAV administration.MethodsAll data from patients evaluated for copperhead snakebite at a rural tertiary referral center from 5/2002 to 10/2013 were compiled. Demographics, transfer status, antivenin use, and clinical findings were collected; SSS was calculated. The relationships among FabAV use, clinical findings, and SSS were analyzed using t-test, chi-square, and Pearson’s coefficient (p < 0.05 was significant).ResultsDuring the study period, 318 patients were treated for copperhead snakebite; 44 (13.8 %) received antivenin. Median dose was four vials (range: 1–10; IQR: 4,6). There were no deaths. Most patients receiving FabAV (63.6 %) were admitted. With regard to demographics and symptoms, only the degree of swelling (moderate vs. none/mild; p < 0.01) and bite location (hand/arm vs. leg: p < 0.0001) were associated with FabAV use. A SSS > 3, indicating moderate or severe envenomation, was only very weakly correlated with antivenin use (r = 0.217; p < 0.0001). The majority of patients with SSS > 3 (65.8 %) did not receive antivenin while most patients who did receive antivenin (70.5 %) had SSS ≤ 3 (indicating mild envenomation).ConclusionsConsiderable variation occurs in antivenin administration after copperhead snakebite. Use of FabAV appears poorly correlated with patients’ symptoms. This practice may expose patients to the risks of antivenin and increasing costs of medical care without improving outcomes. Guidelines used for treating other pit viper strikes, such as rattlesnake or cottonmouth snakebite may be too liberal for copperhead envenomations. Our data suggests that most patients with mild or moderate envenomation appear to do well independent of FabAV use. We suggest, for patients with copperhead snakebite, that consideration be given to withholding FabAV for those without clinical evidence of severe envenomation until prospective randomized data are available.

Acute Cerebral Infarct on Evolution in Middle Cerebral Artery Following Viper Snake Bite

Acute Cerebral Infarct on Evolution in Middle Cerebral Artery Following Viper Snake Bite

Viper snake bite with cellulitis

Viper snake bite with cellulitis

Rebound Coagulopathy in Patients With Snakebite Presenting With Marked Initial Coagulopathy

An estimated 70% of patients with pit viper snakebites require antivenom to treat serious complications such as coagulopathy. Evidence-based guidance is limited for the appropriate administration of Crotalinae Polyvalent Immune Fab (FabAV) and the duration of laboratory follow-up. The objective of our study was to assess the incidence of marked and recurrent envenomation coagulopathy at our trauma center and identify practice patterns that may prevent serious complications. A retrospective case review was conducted over a 3-year period on patients treated for symptomatic snakebite injury. Case records were reviewed for the inclusion criteria of international normalized ratio (INR) greater than 2.0. The exclusion criterion was limited to patients receiving anticoagulant therapy. In all, 61 patients were identified on retrospective chart review and 3 patients (4.9%) met inclusion criteria. Two of the 3 patients had marked rebound coagulopathy requiring readmission and additional treatment. In our small series, 2 patients presenting after crotaline envenomation with increased INR (>6.0), decreased fibrinogen (<60 mg/dL), and decreased platelet count (<100,000/mL) had recurrent coagulopathy and were asymptomatic, and recurrence was noted only with follow-up laboratory testing. All patients responded positively within a matter of hours to repeat FabAV administration, with resolution of rebound coagulopathy. We recommend periodic monitoring of patients with increased INR, decreased fibrinogen, and decreased platelet count. Patients should be monitored for 10 to 14 days after envenomation to identify asymptomatic rebound coagulopathy. Prompt readministration of FabAV appears to correct the coagulopathy.

Tratamiento de la mordedura por víbora en España

Viper snake bite is, by far, the most common ophidian accident in Spain. It is responsible for between 100 and 150 hospitalizations per year in this country, although it is difficult to determine the frequency of emergency admissions due to this cause. The cornerstone to their approach rests on the correct evaluation of the possible effects derived from envenomation and the use of anti-venoms. In spite of all the controversies surrounding the use of anti-venoms, they have become a powerful therapeutic weapon ever since the serum has been highly purified and the great decrease of related anaphylactic reactions.The aim of this article is to update the emergency room procedures when viper bites are suspected, and to clarify the main therapeutic recommendations.

Coral Snake Bites and Envenomation in Children

North America is home to 2 families of venomous snakes, Crotalinae (pit viper family) and Elapidae (coral snake family). Although there are several published reports describing and reviewing the management of pit viper snakebites in children, there are no recent similar publications detailing the clinical course and management of coral snake envenomation. Our case series describes the hospital course of children with coral snake bites admitted to our regional pediatric intensive care. We also reviewed prior published case reports of coral snake bites in the United States. We identified 4 patients with either confirmed or suspected coral snake envenomation from our hospital's records. In 2 cases, the snakebite occurred after apparent provocation. Antivenom was administered to 3 patients. The regional venom response team was consulted for management advice and supplied the antivenom. One patient had a prolonged hospital course, which was complicated by respiratory failure, bulbar palsy, and ataxia. All survived to discharge. Admission to pediatric intensive care is warranted after all Eastern coral snake bites. A specialized regional or national venom response team can be a useful resource for management advice and as a source of antivenom.

Dosage comparison of snake anti-venomon coagulopathy.

This study was done to determine whether high or low dose ofanti-snake venom (ASV) is better incoagulopathy invictims of envenoming by vipers. This retrospective study was conducted on the 154 patients (Mean age ± SD, Range) of viper snake bites who were referred to the emergency ward of Razi Hospital, Ahvaz, Iran over 2 years period (2004-2006).According to the treatment dosage the patients were divided in two groups include group 1(78 cases), low dose regimen and group 2 (76 cases), high dose one. In group 1, the treatment was performed by administration of 4 to 6 vials of ASV through intravenous infusion.In group 2, the patients were given 5 to 10 vials of ASV as an initial dose. In low dose regimen, the number of received packed red blood cell was higher (14 vs. 3) in comparison with high dose group. The number of ASV vials the patients received was 5.5and 21.06 in group 1 and 2, respectively (5.5±1.7 vs. 21.06±10.89; p < 0.01).The difference in frequency of coagulopathy complications, and need for using packed red blood cell were statistically significant(96.2% and 17.9% in group 1 vs. 34.2% and 3.9% in group 2, p < 0.01).It seems that cautious usage of high dose of ASV (10-20 vials) without very special concerns about the cost, dose, and without hazardous side effects is essential for the routine management of sever snake envenoming.

Snake Envenomation Causing Distant Tracheal Myonecrosis

Snakebites are often believed to be poisonous. However, this is not always the case. In fact, each bite differs from snake to snake, depending on if the snake is poisonous and if there is envenomation. Venom in pit viper snakebites is often associated with local necrosis. The abundant literature selections and research articles justify local myonecrosis due to envenomation, but there is not much in the literature regarding myonecrosis at a site distant from the snakebite. We hereby present a case of a 42-year-old man who was transferred to our emergency department after a rattlesnake bit him twice. The patient, besides developing local myonecrosis at the site of the snakebite, developed necrosis of the scrotum as well as tracheal pressure myonecrosis at the site of the endotracheal tube balloon. In this review, we will attempt to discuss the myonecrosis pathophysiology and management related to the rattle snakebite.

Effect of purified Russell’s viper venom-factor X activator (RVV-X) on renal hemodynamics, renal functions, and coagulopathy in rats

Acute renal failure (ARF) is the most frequent and a serious complication in victims of Russell’s viper snakebites. Russell’s viper venom-factor X activator (RVV-X) has been identified as a main procoagulant enzyme involving coagulopathy, which might be responsible for changes in renal hemodynamics and renal functions. Here, we purified RVV-X from crude Russell’s viper venom to study renal hemodynamics, renal functions, intravascular clot, and histopathological changes in Sprague–Dawley rats. Changes in renal hemodynamics and renal functions were evaluated by measuring the mean arterial pressure, glomerular filtration rate (GFR), effective renal plasma flow (ERPF), effective renal blood flow (ERBF), renal vascular resistance (RVR), and fractional excretion of electrolytes. After 10 min, rats receiving both crude venom and purified RVV-X decreased GFR, ERPF, and ERBF and increased RVR. These changes correlated to renal lesions. Along with the determination of intravascular clot, rats injected with purified RVV-X increased the average D-dimer level and reached a peak at 10 min, declined temporarily, and then reached another peak at 30 min. The temporal association between clots and renal dysfunction was observed in rats within 10 min after the injection of purified RVV-X. These findings suggested RVV-X as a major cause of renal failure through intravascular clotting in the renal microcirculation.

Exotropia caused by pit viper snakebite

Pit viper snake venom exerts a mildly neurotoxic effect that may rarely lead to neurotoxic complications, such as paralytic strabismus. Extraocular muscles are known to be particularly susceptible to this complication. In previously reported cases, the medial rectus muscle has been the most frequently involved. We report the first case of a pit viper snakebite resulting in comitant exotropia without obvious paralytic features.

Novel role of antiplatelet agents (aspirin plus clopidogrel) in an incoagulable blood of a victim of russell's viper snakebite

Snake antivenom is a specific antidote to the venom action, neutralizing the circulating venom. However, it fails to neutralize the venom fixed to target organs such as platelets, renal tubules, etc. Russell's viper venom initiates rapid coagulation in a victim by activating blood platelets, factors V, X, and anticoagulant cofactors. Activation of thrombin, resulting in formation of micro-thrombi, fibrinolysis, and a vicious cascade, sets in. Inhibition of activated platelets by aspirin (cyclooxygenase inhibitor) and clopidogrel (ADP receptor inhibitor) helps to break this vicious circle induced by Russell's venom and may initiate the natural physiological clotting mechanism. They can be utilized as an adjuvant treatment.

Antivenom treatment and renal dysfunction in Russell's viper snakebite in Taiwan: a case series

Formosan Russell's viper (Daboia russelli siamensis) is the sixth most frequent cause of snakebites in Taiwan. Its bite induces greater kidney injury than other Russell's vipers in Southeast Asia. Poor availability of antivenom might be the major reason. To enhance treatment, we supplied the antivenom to the teaching hospitals that are near the areas where D. r. siamensis is found. We also used an ELISA in diagnosis. From June 1999 to December 2001, a total of 13 cases of D. r. siamensis snakebite were diagnosed with serum venom level of 10-98 ng/ml, 1-6 hours after being envenomed. Abnormal coagulation function and acute renal failure occurred early and were the two most important clinical features. Early specific antivenom treatment, 3-6 hours after systemic envenoming, restored the coagulation function in 1-2 days and seemed to be statistically effective in reducing the severity of renal damage compared with the historical and delayed group by the Wilcoxon rank-sum test. Two to four vials of antivenom were needed to block the systemic toxicity and produced few side effects. The antivenom should be administered as early as possible to prevent systemic dysfunction.

Intermittent exotropia as the presenting sign of pit viper snakebite to an extremity: a case report

Snake venom can cause various local and systemic signs and symptoms. The most common complication is local tissue destruction, which often results in a loss of function. However, neurotoxicity is uncommon. The unique structure of the extraocular muscles makes them particularly susceptible to neurotoxins. The clinical effects of the neurotoxin to the eye include decreased visual acuity, diplopia, ptosis, and external ophthalmoplegia. We report a patient who had an intermittent exotropia with a mild underaction of medial rectus of the left eye caused by envenomation. CASE REPORT

Russell's viper snakebite in Taiwan: differences from other Asian countries

Formosan Russell's viper ( Daboia russelli siamensis) is the sixth most frequent cause of snakebite in Taiwan. Its venom has been thought to have both neurotoxic and hematoxic properties. This viper's snakebite is rare and thus scarcely subjected to systemic studies. In this paper, we retrospectively analyzed and described 18 cases of viper snakebite from 1987 to 1999. Like that of the Russell's viper snakebite in other South East Asian areas, varied degrees of acute renal failure, incoagulable blood with bleeding diathesis and hemolysis were the major symptoms found in the systemic envenoming patients. Systemic thrombosis seems to be the distinguishing feature in Formosan Russell's viper snakebite. Neither symptoms nor signs of neuromuscular junction blocking effects were observed, which is another difference from symptoms observed after bites of some other Russell's viper subspecies, suggesting a significant geographic variation. These findings confirmed the clinical importance of Russell's viper snakebite in Taiwan.

Pit Viper Snakebite Envenomation in the United States

AbstractPit viper snakebite is a relatively uncommon medical emergency which must be adequately diagnosed and treated to minimize local tissue destruction and systemic complications and to prevent death. Severity is highly variable and may range from minimal local pain and swelling to marked pain, edema, tissue necrosis, hemorrhage, shock, and death within one hour. By far, the most common complication is local tissue destruction often resulting in loss of function. Pit viper venom is extremely complex, containing factors which directly destroy muscle, blood vessels, and renal tissues. Other components anticoagulate blood and cause hypotension, local edema, and pain. Neurotoxicity is unusual, but respiratory paralysis may follow Mojave rattlesnake bites. Proper first aid consists of a proximal mildly constricting tourniquet, superficial incision at fang marks, and constant suction. Medical management consists of early intravenous antivenin in adequate dosage, after hypersensitivity testing. Other measures...

Pit Viper Snakebite Envenomation

AbstractPit viper snakebite is a relatively uncommon medical emergency which must be adequately diagnosed and treated to minimize local tissue destruction and systemic complications and to prevent death. Severity is highly variable and may range from minimal local pain and swelling to marked pain, edema, tissue necrosis, hemorrhage, shock, and death within one hour. By far, the most common complication is local tissue destruction often resulting in loss of function. Pit viper venom is extremely complex, containing factors which directly destroy muscle, blood vessels, and renal tissues. Other components anticoagulate blood and cause hypotension, local edema, and pain. Neurotoxicity is unusual, but respiratory paralysis may follow Mojave rattlesnake bites. Proper first aid consists of a proximal mildly constricting tourniquet, superficial incision at fang marks, and constant suction. Medical management consists of early intravenous antivenin in adequate dosage, after hypersensitivity testing. Other measures...

Histological and ultrastructural changes of the kidney in renal failure after viper envenomation

Forty experimental animals injected with lethal doses of Russell's viper venom and seven human victims of viper snake bite were studied in order to elucidate the pathogenesis of renal tubular necrosis due to viper envenomation. Autopsy, light and electron microscopic examinations were performed on animals and on 4 patients that died; renal biopsy studies were also carried out on the 3 patients that recovered. General features of disseminated intravascular coagulation, consumption coagulopathy and paradoxic haemorrhage were seen as a result of the strong coagulant effects of the venom. The salient features in the kidney are intraglomerular deposition of fibrin, fibrin degradation products and coagulation. The obstruction of glomerular capillaries by coagulated material is the most likely cause of reduction of blood supply to the renal tubules. This tubular ischemia results in tubular necrosis and subsequent renal failure.