Chapter 18: Immunologic Emergencies

Transcription

1 Chapter 18 Immunologic Emergencies Unit Summary After students complete this chapter and the related course work, they will understand the anatomy, physiology, and pathophysiology of hypersensitivity disorders and anaphylactic reactions. Additionally, students will have the knowledge and skills to recognize and manage hypersensitivity disorders and anaphylactic reactions. National EMS Education Standard Competencies Medicine Applies fundamental knowledge to provide basic emergency care and transportation based on assessment findings for an acutely ill patient. Immunology Recognition and management of shock and difficulty breathing related to: Anaphylactic reactions (pp ) Anatomy, physiology, pathophysiology, assessment, and management of: Hypersensitivity disorders and/or emergencies (pp ) Anaphylactic reactions (pp ) Knowledge Objectives 1. Understand and define the terms allergic reaction and anaphylaxis. (p 647) 2. Explain the difference between a local and a systemic response to allergens. (pp ) 3. Differentiate the primary assessment for a patient with a systemic allergic or anaphylactic reaction and a local reaction. (pp ) 4. Describe the five categories of stimuli that could cause an allergic reaction or an extreme allergic reaction. (pp ) 5. Discuss the steps in the primary assessment that are specific to a patient who is having an allergic reaction. (pp ) 6. Explain the importance of managing the ABCs of a patient who is having an allergic reaction. (pp ) 7. Explain the factors involved when making a transport decision for a patient having an allergic reaction. (pp ) 2011 Jones & Bartlett Learning, LLC ( 1

2 8. Explain the rationale, including communication and documentation considerations, when determining whether to administer epinephrine to a patient who is having an allergic reaction. (pp ) 9. Review the process for providing emergency medical care to a patient who is experiencing an allergic reaction. (pp ) 10. Describe some age-related contraindications to using epinephrine to treat an allergic reaction in a geriatric patient. (p 650) Skills Objectives 1. Demonstrate how to remove the stinger from a honeybee sting and proper patient management following its removal. (p 649) 2. Demonstrate how to use an EpiPen auto-injector. (pp , Skill Drill 18-1) 3. Demonstrate how to use a Twinject. (pp , Skill Drill 18-2) Readings and Preparation Review all instructional materials including Emergency Care and Transportation of the Sick and Injured, Tenth Edition, Chapter 18, and all related presentation support materials. Review local protocols regarding EMT assistance with epinephrine auto-injectors. Support Materials Lecture PowerPoint presentation Case Study PowerPoint presentation Skill Drill PowerPoint presentations - Skill Drill 18-1, Using an EpiPen Auto-injector PowerPoint presentation - Skill Drill 18-2, Using a Twinject Auto-injector PowerPoint presentation Equipment needed to perform the psychomotor skills presented in this chapter. Skill Evaluation Sheets - Skill Drill 18-1, Using an EpiPen Auto-injector - Skill Drill 18-2, Using a Twinject Auto-injector Enhancements Direct students to visit the companion website to the Tenth Edition at for online activities Jones & Bartlett Learning, LLC ( 2

3 Provide students with copies of local and state protocols regarding the EMT assisting with epinephrine auto-injectors. Content connections: Discuss the importance of practicing the assessment and management skills that are covered in Chapter 9, Airway Management. Remind students that they should be prepared to use standard airway procedures and positivepressure ventilation (for those experiencing anaphylaxis) according to the principles identified in Chapter 9. Teaching Tips Review and present local protocols for the EMT scope of practice in relation to epinephrine administration. Unit Activities Writing assignments: Instruct each student to choose an allergy (eg, allergy to bee stings, allergy to peanuts) and write a brief, one-page report summarizing the physiology, occurrence, and management of the allergy. Group activities: Divide the class into groups of three or four, and instruct each group to create a brief scenario depicting an anaphylactic emergency and perform the scenario for the others in the class. Medical terminology review: Ask students to research epinephrine to determine its class, mechanism of action, indications, contraindications, adverse reactions, how it is supplied, dosage and administration, duration of action, and any special considerations of the medication. Visual thinking: Prepare handouts or slides to project on-screen depicting miniscenarios (such as in the You are the Provider sections of the chapter). Include vital signs, SAMPLE history, and assessment findings. Conduct a class discussion regarding what these findings might indicate and what complications may develop. Pre-Lecture You are the Provider You are the Provider is a progressive case study that encourages critical thinking skills. Instructor Directions 1. Direct students to read the You are the Provider scenario found throughout Chapter You may wish to assign students to a partner or a group. Direct them to review the discussion questions at the end of the scenario and prepare a response to each question. Facilitate a class dialogue centered on the discussion questions and the Patient Care Report Jones & Bartlett Learning, LLC ( 3

4 3. You may also use this as an individual activity and ask students to turn in their comments on a separate piece of paper. Lecture I. Introduction A. At least 1,000 Americans per year die of allergic reactions. 1. Allergy-related emergencies may involve: a. Acute airway obstruction b. Cardiovascular collapse 2. You must be able to treat these life-threatening complications. 3. You must also be able to distinguish between the body s usual response to an allergen and an allergic reaction. B. This chapter describes immunology, which is the study of the body s immune system, and the five categories of stimuli that may provoke an allergic reaction. II. Anatomy and Physiology A. The immune system protects the body from foreign substances and organisms. B. When a foreign substance invades the body: 1. The body goes on alert. 2. The body initiates a series of responses to inactivate the invader. III. Pathophysiology A. An allergic reaction is an exaggerated immune response to any substance. 1. It is not caused directly by an outside stimulus, such as a bite or sting. 2. Rather, it is caused by the body s immune system, which releases chemicals to combat the stimulus. a. The chemicals include histamines and leukotrienes, both of which contribute to an allergic reaction. b. An allergic reaction may be: i. Mild and local, involving hives, itching, and tenderness ii. Severe and systemic, resulting in shock and respiratory failure B. Anaphylaxis is an extreme, life-threatening allergic reaction. 1. Involves multiple organ systems 2011 Jones & Bartlett Learning, LLC ( 4

5 2. In severe cases, it can rapidly result in death. 3. Wheezing is one of the most common signs. a. Wheezing is a high-pitched, whistling breath sound that is typically heard on expiration. b. Results from bronchospasm/bronchoconstriction and increased mucus production 4. Urticaria (hives) is also present. a. Consists of small areas of generalized itching or burning that appear as multiple, small, raised areas on the skin 5. You may also note hypotension as a result of hypovolemic shock due to increased capillary permeability. C. The most common allergens fall into five general categories. 1. Insect bites and stings a. When an insect bites and injects the bite with its venom, this is called envenomation, or more commonly, a sting. b. The reaction can be local, causing swelling and itchiness in the surrounding tissue, or it may be systemic, involving the entire body (anaphylactic reaction). 2. Medications a. Penicillin injection may cause an immediate (within 30 minutes) and severe allergic reaction. b. Oral penicillin may take longer but causes an equally severe reaction. c. A person will typically experience an allergic reaction after becoming sensitized by the first exposure. 3. Plants a. Dusts, pollens, and other plant materials can cause a rapid and severe allergic reaction. 4. Food a. Reaction can be relatively slow (more than 30 minutes). b. Examples: shellfish, nuts 5. Chemicals a. Examples: makeup, soap, latex IV. Insect Stings A. Death from stinging insects far outnumber deaths from snakebites. 1. The stinging organ of most insects is a small hollow spine projecting from the abdomen. 2. Venom can be injected through this spine directly into the skin. 3. Honeybees cannot withdraw their stinger. a. The honeybee flies away and dies Jones & Bartlett Learning, LLC ( 5

6 b. The implanted stinger remains and keeps delivering toxin. c. Because they fly away, it is difficult to identify which species is responsible. 4. Wasps, hornets, and fire ants can sting multiple times. a. They do not die after stinging. 5. Some ants, especially the fire ant, also strike repeatedly, often injecting a particularly irritating toxin at the bite sites. B. Signs and symptoms include: 1. Sudden pain 2. Swelling 3. Localized heat 4. Redness in light-skinned individuals 5. Itching and possibly a wheal (raised, swollen, well-defined area on the skin) 6. There is no specific treatment for these injuries, although applying ice sometimes makes them less irritating. a. The swelling associated with an insect bite may be dramatic and sometimes frightening. b. These local manifestations are usually not serious. C. The stinger of the honeybee can continue to inject venom for up to 20 minutes after the bee has flown away. 1. Gently attempt to remove the stinger and attached muscle by scraping the skin with the edge of a sharp, stiff object such as a credit card. 2. Do not use tweezers or forceps. a. Squeezing may cause the stinger to inject still more venom into the wound. 3. Gently wash the area with soap and water or a mild antiseptic. 4. Try to remove any jewelry from the area before swelling begins. 5. Position the injection site slightly below the level of the heart, and apply ice or cold packs to the area. 6. Be alert for vomiting or any signs of shock or allergic reaction. 7. Do not give the patient anything by mouth. 8. Place the patient in the shock position, and give oxygen if needed. 9. Monitor the patient s vital signs, and be prepared to provide further support as needed. D. Anaphylactic reaction to stings 1. About 5% of people may have anaphylactic reactions from: a. Bees b. Hornets c. Yellow jackets 2011 Jones & Bartlett Learning, LLC ( 6

7 d. Wasps 2. This type of allergy accounts for about 200 deaths per year and can cause anaphylaxis. 3. Patients may experience: a. Generalized itching and burning b. Widespread urticaria c. Wheals d. Swelling of the lips and tongue e. Bronchospasm and wheezing f. Chest tightness and coughing g. Dyspnea h. Anxiety i. Abdominal cramps j. Hypotension k. Occasionally, respiratory failure 4. If untreated, an anaphylactic reaction can proceed rapidly to death. a. More than two thirds of patients who die of anaphylaxis do so within the first half hour. b. Speed on your part is essential. V. Patient Assessment of an Immunologic Emergency A. Scene size-up 1. Scene safety a. Identify and address any environmental hazards. b. The patient s environment or activity may indicate the source of the allergic reaction. i. Sting or bite from an insect ii. Food allergy at a restaurant iii. New medication regimen c. A respiratory problem reported by dispatch may be an allergic reaction. d. If many people are affected, however, it could be: i. Inhaled poison ii. Terrorist event e. Never enter a scene where more than one person is experiencing the same symptoms with similar onset. f. Follow standard precautions, with a minimum of gloves and eye protection. g. Consider the need for additional or specialized resources. h. Call for additional resources earlier rather than later. 2. Mechanism of injury (MOI)/nature of illness (NOI) a. May not be an allergic reaction 2011 Jones & Bartlett Learning, LLC ( 7

8 b. Trauma may have occurred because of a medical incident. c. Determine the MOI/NOI. d. Look for bee stingers or contact with chemicals and other indications of a reaction. B. Primary assessment 1. Perform a rapid scan of the patient to identify and treat any immediate or potential life threats. 2. Form a general impression. a. Allergic reactions may present as respiratory or as cardiovascular distress in the form of shock. b. Patients experiencing a severe allergic reaction will often be very anxious and feel like they are going to die. c. Call for advanced life support (ALS) backup if available. d. Some patients will be wearing a medical identification tag. e. Try to get information on the chief complaint from a conscious patient. f. If the patient is unresponsive or has a decreased level of consciousness, immediately evaluate and treat the airway, breathing, and circulation. 3. Airway and breathing a. Anaphylaxis can cause rapid swelling of the upper airway. i. You may have only a few minutes to assess the airway and provide lifesaving measures. b. Not all allergic reactions are anaphylactic reactions. i. Work quickly to assess the patient to determine the severity of the symptoms. c. Position the conscious patient in a tripod position, and listen to the lungs on each side of the chest. i. If wheezing or a silent chest is encountered, the lower airways are also closing. d. Do not hesitate to initiate high-flow oxygen therapy. e. In severe situations, the definitive care needed is an injection of epinephrine. f. If necessary, be prepared to use standard airway procedures and positive-pressure ventilation. 4. Circulation a. Some patients in anaphylaxis may not present with severe respiratory symptoms but primarily with signs and symptoms of circulatory distress, such as hypotension. b. Palpate for a radial pulse. c. If the patient is unresponsive and without a pulse, begin basic life support (BLS) measures or use an automated external defibrillator. d. If the patient has a pulse, assess for a rapid pulse; pale, cool cyanotic or red, moist skin; and delayed capillary refill times that indicate hypoperfusion. e. Your initial treatment for shock should include: i. Oxygen ii. Positioning iii. Maintaining normal body temperature 2011 Jones & Bartlett Learning, LLC ( 8

9 f. The definitive treatment for anaphylactic shock is epinephrine. g. Trauma is unlikely, but if it has occurred, bandage all bleeding sites and take spinal precautions when appropriate. 5. Transport decision a. Always provide prompt transport for any patient who may be having an allergic reaction. b. Take along all medications and auto-injectors the patient has at the time. c. Make your transport decision based on findings in the primary assessment. C. History taking 1. Identify the chief complaint or history of present illness, associated signs and symptoms, and pertinent negatives. 2. SAMPLE history a. If the patient is conscious, ask him or her the following questions specific to an allergic reaction: i. Have any interventions already been completed? ii. Do you have any prescribed, preloaded medications for allergic reactions? iii. Do you have any respiratory symptoms? iv. Do you have other symptoms such as itching, rash, hives, pallor, or bite or sting marks, or have you experienced any confusion? v. Have you had previous allergic reactions, asthma, or hospitalizations? vi. What were you doing or what were you exposed to before the onset of symptoms? D. Secondary assessment 1. Physical examinations a. The secondary assessment should include a systematic head-to-toe or focused assessment to determine hidden trauma or other unrelated medical problems. b. Thoroughly assess breathing, including: i. Increased work of breathing ii. Use of accessory muscles iii. Head bobbing iv. Tripod positioning v. Nostril flaring vi. Grunting c. Auscultate both the trachea and the chest. d. Wheezing occurs because of narrowing of the air passages, which is mainly the result of contraction of muscles around the bronchioles in reaction to the allergen. i. Exhalation becomes harder. ii. Breathing rapidly becomes more difficult, and the patient may even stop breathing. iii. Prolonged respiratory difficulty can cause a rapid heartbeat (tachycardia), shock, and even death Jones & Bartlett Learning, LLC ( 9

10 iv. Stridor, a harsh, high-pitched inspiratory sound, occurs when swelling in the upper airway closes off the airway; the swelling can eventually lead to total obstruction. e. Assess the circulatory system. i. The presence of hypoperfusion or respiratory distress indicates that the patient is having a severe enough allergic reaction that it can lead to death. f. Assess the skin for swelling, rash, hives, or signs of the source of the reaction: bite, sting, or contact marks. i. A rapidly spreading rash or red, hot skin may indicate a systemic reaction. ii. Red, hot skin may also indicate a systemic reaction. g. If reaction continues, the body will have difficulty supplying blood and oxygen to organs. i. One of the first signs will be an altered mental status. 2. Vital signs a. Assess baseline vital signs, including pulse, respirations, blood pressure, skin, pupils, and oxygen saturation. b. Rapid respiratory rate indicates airway obstruction. c. Rapid respiratory and pulse rates may indicate respiratory distress or systemic shock. d. Fast pulses and hypotension are ominous signs indicating systemic vascular collapse and shock. e. Monitoring devices i. In a patient experiencing an allergic reaction, pulse oximetry is a useful method that you can use to assess the patient s perfusion status. E. Reassessment 1. Repeat the primary assessment and reassess the patient s vital signs. a. The patient experiencing a suspected allergic reaction should be monitored with vigilance because deterioration of the patient s condition can be rapid and fatal. b. Special attention should be given to any signs of airway compromise. c. Monitor the patient s anxiety level. d. Watch the skin for signs of shock. 2. Interventions a. You must first identify how much distress the patient is in. i. Epinephrine and ventilatory support are required for severe reactions. ii. Milder reactions may only require supportive care, such as oxygen. iii. In either case, the patient should be transported to a medical facility for further evaluation. b. Recheck your interventions. i. You may need to give more than one injection of epinephrine. ii. Be sure to consult medical control first. 3. Communication and documentation a. When to contact medical control depends on your assessment findings and the urgency of care required Jones & Bartlett Learning, LLC ( 10

11 b. Your documentation should include: i. Signs and symptoms found during your assessment ii. Reasons for choosing to provide the care you did iii. Patient s response to your treatment VI. Emergency Medical Care of Immunologic Emergencies A. If the patient appears to be having a severe allergic (or anaphylactic) reaction: 1. Administer BLS at once, including high-flow, high-concentration oxygen. 2. Provide prompt transport to the hospital. 3. Reassess vital signs every 5 minutes (for an unstable patient) or 15 minutes (for a stable patient). 4. Place shock patients in the appropriate position. 5. Request ALS backup if you work in a tiered response system. 6. Be prepared to maintain the airway or administer cardiopulmonary resuscitation. 7. If a stinger is present, scrape it away with a hard object such as a credit card. a. Do not use tweezers to remove the stinger. 8. Applying ice may help. a. Do not apply directly to the skin. 9. In some areas, you may be allowed to administer epinephrine or assist the patient with epinephrine administration. B. Epinephrine 1. Epinephrine is a sympathomimetic. a. It mimics the sympathetic (fight-or-flight) response. 2. It has various properties that cause the blood vessels to constrict, which reverses vasodilation and hypotension. 3. Other properties of epinephrine increase cardiac contractility and relieve bronchospasm in the lungs. 4. It can rapidly reverse the effects of anaphylaxis. 5. The indications include: a. A severe allergic reaction b. Hypersensitivity to an exposed substance 6. All allergic emergency kits should contain a prepared, auto-injectable syringe of epinephrine. 7. If the patient is known to have an allergy, he or she may carry a kit. 8. Your EMS service may or may not allow you to assist the patient in the administration of his or her medication Jones & Bartlett Learning, LLC ( 11

12 9. Contact medical control and follow standard precautions. 10. The adult EpiPen and Twinject systems deliver 0.3 mg of epinephrine via an automatic needle and syringe system; the infant-child system delivers 0.15 mg. 11. The Twinject auto-injector contains two doses of epinephrine. 12. See Skill Drill 18-1 to use an EpiPen auto-injector. 13. See Skill Drill 18-2 to use a Twinject auto-injector. 14. Because epinephrine constricts blood vessels, it may cause the patient s blood pressure to rise significantly. 15. Other side effects include: a. Increased pulse rate b. Anxiety c. Cardiac arrhythmias d. Pallor e. Dizziness f. Chest pain g. Headache h. Nausea i. Vomiting VII. Summary A. An allergic reaction is a response to chemicals the body releases to combat certain stimuli, called allergens. B. Allergic reactions occur most often in response to five categories of stimuli: insect bites and stings, medications, food, plants, and chemicals. C. The reactions may be mild and local, involving itching, redness, and tenderness, or they may be severe and systemic, including shock and respiratory failure. D. Anaphylaxis is a life-threatening allergic reaction mounted by multiple organ systems; it must be treated with epinephrine. E. Wheezing and skin wheals can be signs of anaphylaxis. F. People allergic to bee, hornet, yellow jacket, or wasp venom often carry a kit that contains epinephrine in an auto-injector. You may help to administer this medication in this form with authorization from medical control. G. All patients with suspected anaphylaxis require oxygen. H. Check patients who may be having an allergic reaction for flushing, itching, and swelling skin, hives, wheezing and stridor, persistent cough, decrease in blood pressure, weak pulse, dizziness, abdominal cramps, and headache Jones & Bartlett Learning, LLC ( 12

13 I. Always provide prompt transport to the hospital for any patient who is having an allergic reaction. Remember that signs and symptoms can rapidly become more severe. J. Carefully monitor the patient s vital signs en route; be especially alert for airway compromise. Post-Lecture This section contains various student-centered end-of-chapter activities designed as enhancements to the instructor s presentation. As time permits, these activities may be presented in class. They are also designed to be used as homework activities. Assessment in Action This activity is designed to assist the student in gaining a further understanding of issues surrounding the provision of prehospital care. The activity incorporates both critical thinking and application of basic EMT knowledge. Instructor Directions 1. Direct students to read the Assessment in Action scenario located in the Prep Kit at the end of Chapter Direct students to read and individually answer the quiz questions at the end of the scenario. Allow approximately 10 minutes for this part of the activity. Facilitate a class review and dialogue of the answers, allowing students to correct responses as may be needed. Use the quiz question answers noted below to assist in building this review. Allow approximately 10 minutes for this part of the activity. 3. You may wish to ask students to complete the activity on their own and turn in their answers on a separate piece of paper. Answers to Assessment in Action Questions 1. Answer: C urticaria. 2. Answer: A scraping the skin with the edge of a credit card. 3. Answer: A Histamine 4. Answer: B Epinephrine 5. Answer: A wheezing. 6. Answer: C Shellfish 7. Answer: Epinephrine is the drug of choice when treating a severe allergic reaction because it blocks the allergic reaction, opens up the bronchioles, and raises the blood pressure. 8. Answer: The use of epinephrine is relatively contraindicated for patients who have a history of cardiac problems, such as a previous heart attack, because it 2011 Jones & Bartlett Learning, LLC ( 13

14 causes increased myocardial oxygen demand and increased workload on the heart. Calling for medical direction is recommended when treating such patients. 9. Answer: Epinephrine stimulates the body s stress response, and therefore causes an increased heart rate, increased workload on the heart, and increased demand for oxygen by the heart. 10. Answer: Yes! The child is experiencing signs and symptoms of severe respiratory distress and may progress to respiratory failure without immediate intervention. Assignments A. Review all materials from this lesson and be prepared for a lesson quiz to be administered (date to be determined by instructor). B. Read Chapter 19, Toxicology, for the next class session Jones & Bartlett Learning, LLC ( 14

15 Unit Assessment Keyed for Instructors 1. What is an allergic reaction? Answer: An exaggerated immune response p What are the two most common signs of anaphylaxis? Answer: Wheezing and urticaria p What is the medical term for hives? Answer: Urticaria p List five common allergens. Answer: Insect bites and stings, medications, plants, food, chemicals pp Which insects can sting repeatedly? Answer: Wasps, hornets, and fire ants p How should a honeybee stinger be removed? Answer: By scraping the skin with a stiff object p What causes wheezing? Answer: Muscles around the bronchioles tighten in reaction to the allergen, and airways are constricted, making breathing more difficult. Fluid in the air passages and constricted bronchi together produce the wheezing sound. p Epinephrine is a sympathomimetic, which means it mimics. Answer: the sympathetic (fight-or-flight) response p What are the epinephrine doses for adult and pediatric anaphylactic patients? Answer: Adult = 0.3 mg, pediatric = 0.15 mg p What are the steps in using an EpiPen auto-injector? Answer: Remove cap; place against lateral thigh; press and hold for 10 seconds; remove; record the time and dose; reassess and record p Jones & Bartlett Learning, LLC ( 15

16 Unit Assessment 1. What is an allergic reaction? 2. What are the two most common signs of anaphylaxis? 3. What is the medical term for hives? 4. List five common allergens. 5. Which insects can sting repeatedly? 6. How should a honeybee stinger be removed? 7. What causes wheezing? 8. Epinephrine is a sympathomimetic, which means it mimics. 9. What are the epinephrine doses for adult and pediatric anaphylactic patients? 10. What are the steps in using an EpiPen auto-injector? 2011 Jones & Bartlett Learning, LLC ( 16