Environmental Emergencies

chapter 17 Environmental Emergencies Susan Fuchs, MD, FAAP, FACEP Dee Hodge III, MD, FAAP Objectives 1 Identify the early manifestations of a 8 Identify three types of minor serious pit viper envenomation, the heat illness and describe their appropriate supportive care, and the management. appropriate use of antivenin. 9 Differentiate between heat 2 Describe coral snake envenomation, exhaustion and heat stroke and evaluation, and management. discuss their management. 3 Describe black widow and brown 10 Discuss the management of mild, recluse spider bite recognition and moderate, and severe hypothermia. management. 11 Describe illnesses that occur at high 4 Describe scorpion bite envenomation, altitudes. evaluation, and management. 12 Identify the factors responsible for 5 Describe marine envenomations and most submersion injuries. management. 13 Describe the primary and secondary 6 Identify seafood-associated foodborne pathophysiologic changes that occur illnesses. after submersion injuries. 7 Describe basic physiology of 14 Discuss the major management temperature regulation. principles of submersion injuries in the out-of-hospital and hospital setting. Copyright © 2012 by the American Academy of Pediatrics and the American College of Emergency Physicians Chapter Outline Introduction Body Temperature Disturbances Envenomations Hyperthermia Snake Bites Minor Heat Illnesses Spider Bites Major Heat Illnesses Scorpion Bites Hypothermia Marine Envenomations High-Altitude Illness Seafood-Associated Foodborne Illnesses Submersion Injury A 4-year-old boy is brought to the emergency department (ED) after being bitten by a spider a few hours previously at his family’s campsite. The child says that the spider was dark but cannot 1 remember any identifying marks. On examination, his respiratory rate is 26/min, heart rate is 130/ min, blood pressure is 100/60 mm Hg, and temperature is 37°C (98.6°F). He is calm but experiencing pain in the bite area. His right forearm is swollen and erythematous, with two small marks at the center of the wound. His hand is pink, pulses are 2+ and strong, and he is able to move his fingers. The results of the remainder of the examination are normal. 1. What is the differential diagnosis of this spider bite? 2. What signs or symptoms would help distinguish the type of spider bite? 3. What studies are needed? CASE SCENARIO SCENARIO CASE 4. What treatment is necessary? 17-3 Copyright © 2012 by the American Academy of Pediatrics and the American College of Emergency Physicians Introduction A Environmental emergencies have become more common as children and adults participate in outdoor activities, such as camping, mountain climbing, skiing or snowboarding, hiking, and just enjoying nature. Unfortunately, some of these activities can result in injuries, such as envenomations by snakes, spiders, and scorpions, or body temperature disturbances, including hyperthermia and hypothermia, high-altitude illness and submersion injuries. In addition, submersion injuries, which in- B clude drowning, have been the second leading cause of unintentional death in young children for a number of years. This chapter addresses the diagnosis and treatment of these problems. Envenomations Snake Bites In 2008, more than 6,000 snake bites were re- ported to the American Association of Poison Control Centers, with 29% of them occurring in children.1 The bites causing the most concern in the United States are those that involve the ven- omous snakes, such as those in the Crotalidae C (pit vipers) and Elapidae (coral snakes) families. Pit Vipers Pit viper (Crotalidae) envenomation is a rare but important cause of disease and death in the United States (Figure 17.1). The pit viper family includes rattlesnakes, cottonmouth (water moccasins), and copperheads. Pit vipers have a heat-sensing pit between the eyes and nostril. They also have a triangular head and elliptical or slitlike pupils, and rattlesnakes have tail rattles Figure 17.1 Pit vipers. A. Cottonmouth. B. Rattlesnake. 2 and a single row of ventral anal scales. C. Copperhead. The severity of envenomation varies widely with the species and the location of the bite; these differences, clinical presentations can vary. however, any member of the pit viper family Envenomation results in extensive capillary leak, found in North America is capable of inflicting abnormal clotting, and local tissue necrosis.3 significant damage that requires treatment. After a major envenomation, the release of Clinical Features vasodilatory compounds, hypovolemia from the Pit viper venoms differ in the relative amounts of loss of integrity of the capillary endothelium, their component parts, including proteolytic en- and bleeding can all contribute to the rapid de- zymes, hemotoxins, and neurotoxins. Because of velopment of circulatory shock. 17-4 Environmental Emergencies Copyright © 2012 by the American Academy of Pediatrics and the American College of Emergency Physicians Assessment raised to the level of the heart.2 Transportation As in all emergencies, the respiratory and circula- for definitive medical care should be accom- tory systems (airway, breathing, and circulation plished as soon as possible. Venom extraction, [ABCs]) must first be considered. In the absence incision of the wound, local ice, electric shock of immediate life-threatening symptoms, demo- therapy, and venous or arterial tourniquets are graphic variables and physical findings should not recommended. The caregivers will be anx- be considered to assess the severity of the bite. ious even if the child has no envenomation. Information regarding the size and species of the For many snake bites in children, reassurance, snake (if possible), circumstances related to the careful observation, serial measurements, and bite, number of bites inflicted, first aid methods supportive care are all that is necessary.2 used, time of the bite, and transport time required An intravenous (IV) catheter should be should be obtained. The severity of the bite should placed, and correction of hypovolemia with 20 be staged (Table 17-1). In as many as 25% of bites, mL/kg of crystalloid should be initiated. A sec- there is no venom injected (dry bites).2 ond saline bolus of 20 mL/kg should be given Management if needed. The persistence of hypotension man- First aid includes reassurance of the child and dates invasive monitoring and inotropic support caregivers. If the child can be kept quiet, the in addition to administration of antivenin. spread of toxins throughout the body can be Basic and advanced life support should lessened. If possible, keep the affected extremity be instituted as indicated. Obtain appropriate laboratory studies, including a complete blood TABLE 17-1 Envenomation Staging cell (CBC) count, prothrombin time, fibrino- gen degradation products, platelet count, blood No Occurs in approximately 25% Envenomation of strikes; no venom has been urea nitrogen (BUN) measurement, creatinine released, and only fang marks phosphokinase measurement, and urinalysis. are present. For moderate to severe bites, a second IV cath- Mild Fang mark or marks are eter should be placed, blood should be obtained Envenomation present, with edema, pain, and for transfusion, and cross-matching should be ecchymosis confined to the performed before starting infusion of antivenin. surrounding area. No clinical or In all snake bites, the wound area should be laboratory evidence of systemic cleansed and tetanus prophylaxis guidelines fol- effects is present. lowed. There is a low incidence of infection after Moderate Edema, bullae, or ecchymoses pit viper bites, and current evidence does not Envenomation extending beyond the support the use of prophylactic antibiotics.2,3,5 immediate area of the bite to include a large part of the Analgesia should be administered as needed extremity. Tender adenopathy for pain. Sedatives, ice, tourniquets, or aspirin might be present, depending on should not be used. the site of the bite. Clinical or The extremity circumference should be laboratory evidence of systemic measured at a marked location and rechecked venom effects might be present, every 15 to 20 minutes for progression of swell- depending on the species. ing and tenderness to grade the bite severity as Severe Rapid extension of edema, minimal, moderate, or severe.2,4 The laboratory Envenomation bullae, or ecchymoses involving studies should be repeated every 2 to 6 hours; the entire extremity; systemic signs, including hypotension, if significant changes occur, the patient should 2 respiratory insufficiency, change be treated with antivenin. in level of consciousness, or Use of Crotalidae Antivenin abnormal results on clotting In moderate to severe envenomations, antivenin studies, are present.4 Bites on the thorax, the head, and neck should be administered (Figure 17.2). Copper- should be assumed to be severe. head bites are often treated without antivenin, but diamondback rattlesnake envenomations Envenomations 17-5 Copyright © 2012 by the American Academy of Pediatrics and the American College of Emergency Physicians are very dangerous and require antivenin thera- TABLE 17-2 Pit Viper Envenomation: How py. There are currently two antivenins available. to Use Crotalidae Polyvalent Immune Fab The older polyvalent antivenin, antivenin (Cro- Antivenin talidae) polyvalent, is derived from horse serum. Acute and delayed hypersensitivity reactions are • Initial dosing: administer four to six vials IV for 1 hour a risk when using antivenin (Crotalidae) polyva- (reconstitute

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