Children are frequently victims of terrestrial animal and insect bites and stings. While the majority of these bites or stings are nondangerous, pediatric patients occasionally encounter a venomous animal. In such cases, children may present to the emergency department for evaluation and management. This review presents the basic epidemiology of bites and stings of spiders, bees and wasps, fire ants, scorpions, and snakes, but it primarily focuses on the underlying pathophysiology and clinical presentation of the envenomated patient. While the pathophysiology and much of the presentation and treatment are the same for both children and adults, there are occasionally subtle differences, which will be highlighted. The management and disposition of pediatric patients for each type of bite or sting will also be discussed.
A 7-year-old boy presents to the ED after being bitten on the right ankle by a rattlesnake while walking along a trail at sunset. The patient developed pain nearly immediately. Upon examination in the ED, he is noted to have edema extending from the midfoot up to proximal to the knee. Ecchymosis is noted as well as oozing from the 2 puncture wounds. The calf compartments are soft. You order labs and try to recall if there is an antidote for this type of envenomation…
Introduction for Pediatric Envenomations
Children are frequently bitten or stung by various terrestrial and aquatic animals. In 2012, the American Association of Poison Control Centers received > 20,500 calls for bites and stings involving patients aged ≤ 19 years.1 Due to underreporting, it is commonly believed that these numbers significantly underestimate the true prevalence of the problem. Additionally, because of the relative rarity of these events, and the occasional misidentification of the animal, the exact prevalence may not be known. While many of these incidents involve relatively minor symptoms, severe toxicity and hospitalization are certainly not uncommon.
Neither the underlying mechanisms of action of the toxin nor the treatment recommendations differ substantially between pediatric and adult patients. However, due to their size, children may be more susceptible to some of the effects of the venom and consequently experience more severe envenomations, especially in the case of scorpions. This review will focus on the mechanism of action of the various toxins, along with the clinical evaluation and management strategies for pediatric patients who have been envenomated by snakes, scorpions, spiders, and various insects. Because aquatic envenomations are not particularly common in this age group, they will not be discussed in this review.
Risk Management Pitfalls For Pediatric Envenomations
“The patient had an anaphylactoid reaction to the Latrodectus antivenom.” Reserve black widow (Latrodectus mactans) antivenom for individuals with end-organ dysfunction or those who are failing conservative management with opioids and benzodiazepines. Antivenom should not be a first-line therapy.
“The patient was bitten by a black widow, but the symptoms did not improve after calcium administration.” Do not administer calcium to patients with black widow bites, as data have demonstrated its lack of efficacy.
“This patient who resides in the Northeast was diagnosed with a brown recluse bite 2 days ago. However, on examination today, there appears to be significant cellulitis around the bite.” Be extremely cautious about making the diagnosis of a brown recluse bite in patients who live in areas outside the typical geographic distribution of the brown recluse spider. In such situations, the lesions are much more likely to be an abscess than a brown recluse bite. Do not mistake a necrotizing soft tissue infection for a brown recluse bite.
“We removed 200 bee stingers from the child, but he remains hypotensive.” Do not delay the initial resuscitation of a patient who presents following a massive Hymenoptera envenomation to remove the stingers. Research has demonstrated that 90% of a bee’s venom is injected within the first 20 seconds after a sting, and virtually 100% is injected at 1 minute. Consequently, the initial management of victims of massive hymenoptera envenomations should not focus on removal of the stinger.
“The patient was stung by 200 bees, but he looked good after 4 hours, so we sent him home. I don’t understand why he returned in renal failure 2 days later.” Observe pediatric patients with > 50 bee stings in a monitored setting for 24 hours, as many complications may have delayed onset.
“The patient looks like he has a classic anaphylactic reaction, but he has never been stung before.” Anaphylactic reactions to venom have preformed antibodies, while massive envenomations can result in anaphylactoid reactions without any prior exposure. However, the treatment is the same, and it should focus on ensuring airway patency and using epinephrine, fluid boluses, H1 and H2 antagonists, and corticosteroids.
“We applied a tight tourniquet to the arm of this rattlesnake bite victim to reduce absorption of venom.” Do not apply ice, tourniquets, suction devices or other similar objects to the skin of a rattlesnake bite, as systemic absorption may be increased. The envenomated limb should be splinted in extension and elevated.
“The patient was bitten by a rattlesnake, but he only had minor pain, so we gave him ibuprofen." Avoid the use of nonsteroidal anti-inflammatory drugs for the treatment of pain associated with pit viper envenomation due to their antiplatelet effects.
“The snake had a combination of black, red, and yellow bands, and the patient didn’t have any symptoms, so we assumed it was a king snake even though we never saw the snake.” Do not mistake a coral snake bite for a king snake simply because of a lack of symptoms during the initial emergency department evaluation. If there is concern that a snake may have been an elapid and the patient was in an area where neurotoxic coral snakes reside, prolonged observation may be required to ensure that delayed neurotoxicity does not develop.
Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.
To help the reader judge the strength of each reference, pertinent information about the study will be included in bold type following the reference, where available.
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Vetter RS, Isbister GK. Medical aspects of spider bites. Annu Rev Entomol. 2008;53:409-429. (Review)
Levine M, Canning J, Chase R, et al. Cardiomyopathy following latrodectus envenomation. West J Emerg Med. 2010;11(5):521-523. (Case report; 1 patient)
Henkel AW, Sankaranarayanan S. Mechanisms of alphalatrotoxin action. Cell Tissue Res. 1999;296(2):229-233. (Review)
Levine M, Ruha AM, Graeme K, et al. Toxicology in the ICU: part 3: natural toxins. Chest. 2011;140(5):1357-1370. (Review)
Murphy CM, Hong JJ, Beuhler MC. Anaphylaxis with Latrodectus antivenin resulting in cardiac arrest. J Med Toxicol. 2011;7(4):317-321. (Review)
Quan D, Ruha AM. Priapism associated with Latrodectus mactans envenomation. Am J Emerg Med. 2009;27(6):759.e1-2. (Case report; 1 patient)
Clark RF, Wethern-Kestner S, Vance MV, et al. Clinical presentation and treatment of black widow spider envenomation: a review of 163 cases. Ann Emerg Med. 1992;21(7):782- 787. (Retrospective chart review: 163 patients)
Furbee RB, Kao LW, Ibrahim D. Brown recluse spider envenomation. Clin Lab Med. 2006;26(1):211-226. (Review)
Peterson ME. Brown spider envenomation. Clin Tech Small Anim Pract. 2006;21(4):191-193. (Review)
Rhoades RB, Stafford CT, James FK. Survey of fatal anaphylactic reactions to imported fire ant stings. Report of the Fire Ant Subcommittee of the American Academy of Allergy and Immunology. J Allergy Clin Immunol. 1989;84(2):159-162. (Survey)
deShazo RD, Kemp SF, deShazo MD, et al. Fire ant attacks of patients in nursing homes; an increasing problem. Am J Med. 2004;116(12):843-846. (Case reports and review; 6 patients)
Lockey RF. The imported fire ant: immunopathological sig nificance. Hosp Pract (Off Ed). 1990;25(3):109-124. (Review)
30. O’Connor A, Ruha AM. Clinical course of bark scorpion envenomation managed without antivenom. J Med Toxicol. 2012;8(3):258-262. (Retrospective chart review; 88 patients)
31. World Health Organization. Venomous snakes distribution and species risk categories. Available at: http://apps.who. int/bloodproducts/snakeantivenoms/database. Accessed June 3, 2014. (Government report)
32. Cruz LS, Vargas R, Lopes AA. Snakebite envenomation and death in the developing world. Ethn Dis. 2009;19(1 Suppl 1):S1-42-46. (Review)
33. Lavonas EJ, Ruha AM, Banner W, et al. Unified treatment algorithm for the management of crotaline snakebite in the United States: results of an evidence-informed consensus workshop. BMC Emerg Med. 2011;11:2. (Database review and consensus statement)
Cetaruk EW. Rattlesnakes and other crotalids. In: Critical Care Toxicology: Diagnosis And Management Of The Critically Poisoned Patient. Philadelphia: Elsevier-Mosby; 2005:1075- 1090. (Textbook chapter)
Ownby CL, Bjarnason J, Tu AT. Hemorrhagic toxins from rattlesnake (Crotalus atrox) venom. Pathogenesis of hemorrhage induced by three purified toxins. Am J Pathol. 1978;93(1):201-218. (Animal study)
Tanen DA, Ruha AM, Graeme KA, et al. Rattlesnake envenomations: unusual case presentations. Arch Intern Med. 2001;161(3):474-479. (Case series; 4 patients)
Kitchens CS, Van Mierop LH. Envenomation by the eastern coral snake (Micrurus fulvius fulvius). A study of 39 victims. JAMA. 1987;258(12):1615-1618. (Retrospective chart review; 39 patients)
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