Crotalidae polyvalent immune Fab for the treatment of pediatric crotaline envenomation

Pit viper envenomation in pediatric dogs: 5 cases

Treatment of pit viper envenomated puppies (≤6  months old) with antivenom was well tolerated, similar to adult dogs. However, therapeutic guidelines should be established to direct use and prove efficacy in this population.

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

CONTEXT

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

AIM

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

Management of pediatric snake bites: are we doing too much?

BACKGROUND

The optimal management of children with snake bite injuries is not well defined. The purpose of this study was to review the use of antivenom, diagnostic tests, and antibiotics in children bitten by venomous snakes in a specific geographic region (Southeast Texas).

METHODS

This is a retrospective single-center review of all patients with snake bite injury from 1/2006 to 6/2012. An envenomated bite was defined as causing edema, discoloration of the skin, necrosis, or systemic effects. The severity of injury was scored using a novel 4-point scale based on initial physical examination alone.

RESULTS

One hundred fifty-one children (mean age 8.4±4.3years) were treated for a snake bite. There were no mortalities. Lower extremity injuries were most common (60%). Most bites were from copperheads (43%). Envenomation was evident in 82% (average wound score: 2.61±0.81). The median hospital stay for admitted patients (79%) was 2days (range 1-7). Four patients required surgery for complications of the snake bite. Fifty-two children (34%) received CroFab, with one allergic reaction. 22/135 (16%) had evidence of coagulopathy. Seventy-two children (48%) received IV antibiotics.

CONCLUSION

Despite a high rate of envenomated bites in Southeast Texas, significant morbidity is rare. Children with an envenomation score of 1 or 2 are unlikely to be coagulopathic, suggesting that laboratory investigation should be reserved for patients with higher scores. The indications for the administration of CroFab deserve further prospective study.

Facial diplegia, pharyngeal paralysis, and ophthalmoplegia after a timber rattlesnake envenomation

The timber rattlesnake, also known as Crotalus horridus, is well known to cause significant injury from toxins stored within its venom. During envenomation, toxic systemic effects immediately begin to cause damage to many organ systems including cardiovascular, hematologic, musculoskeletal, respiratory, and neurologic. One defining characteristic of the timber rattlesnake is a specific neurotoxin called crotoxin, or the "canebrake toxin," which is a potent β-neurotoxin affecting presynaptic nerves that can cause paralysis by inhibiting appropriate neuromuscular transmission. We present an unusual case of an 8-year-old boy bitten twice on his calf by a timber rattlesnake, who presented with a life-threatening envenomation and suffered multisystem organ failure as well as a prominent presynaptic neurotoxicity resulting in facial diplegia, pharyngeal paralysis, and ophthalmoplegia.

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

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

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Crotalidae polyvalent immune Fab: in patients with North American crotaline envenomation

Crotalidae polyvalent immune Fab is an antivenom comprising purified, sheep-derived, Fab IgG fragments and is indicated for use in patients with North American crotaline envenomation. Crotalidae polyvalent immune Fab is produced using four North American snake venoms: Crotalus atrox, Crotalus adamanteus, Crotalus scutulatus, and Agkistrodon piscivorus. Intravenous crotalidae polyvalent immune Fab was effective in patients aged ≥10 years who had minimal or moderate envenomation by a North American crotaline, who presented within 6 hours of the snakebite, and who had progression of the envenomation syndrome, according to the results of two prospective trials. One trial was a noncomparative, multicenter pilot study and the other trial was a randomized, open-label, multicenter trial in which patients received scheduled or 'as needed' administration of crotalidae polyvalent immune Fab after initial control had been achieved. A prospective, postmarketing trial demonstrated the efficacy of crotalidae polyvalent immune Fab in confirmed Crotalus viridis helleri envenomation (indicating cross-protection against a venom not used in its production). Results of these prospective trials are supported by the findings of additional (mainly retrospective) studies demonstrating the efficacy of crotalidae polyvalent immune Fab in patients with crotaline envenomation, including patients with severe envenomation, pediatric patients, and patients with symptoms of neurotoxicity. Despite treatment with crotalidae polyvalent immune Fab, patients may experience delayed-onset or recurrent venom effects (e.g. coagulopathy). Intravenous crotalidae polyvalent immune Fab was generally well tolerated; acute hypersensitivity reactions (e.g. urticaria, rash, pruritus) were the most commonly occurring adverse event.

Unified treatment algorithm for the management of crotaline snakebite in the United States: results of an evidence-informed consensus workshop

BACKGROUND

Envenomation by crotaline snakes (rattlesnake, cottonmouth, copperhead) is a complex, potentially lethal condition affecting thousands of people in the United States each year. Treatment of crotaline envenomation is not standardized, and significant variation in practice exists.

METHODS

A geographically diverse panel of experts was convened for the purpose of deriving an evidence-informed unified treatment algorithm. Research staff analyzed the extant medical literature and performed targeted analyses of existing databases to inform specific clinical decisions. A trained external facilitator used modified Delphi and structured consensus methodology to achieve consensus on the final treatment algorithm.

RESULTS

A unified treatment algorithm was produced and endorsed by all nine expert panel members. This algorithm provides guidance about clinical and laboratory observations, indications for and dosing of antivenom, adjunctive therapies, post-stabilization care, and management of complications from envenomation and therapy.

CONCLUSIONS

Clinical manifestations and ideal treatment of crotaline snakebite differ greatly, and can result in severe complications. Using a modified Delphi method, we provide evidence-informed treatment guidelines in an attempt to reduce variation in care and possibly improve clinical outcomes.