Chapter 18

Chapter 18Chapter 18Chapter 18Chapter 18

Immunologic Emergencies

National EMS Education National EMS Education Standard Competencies Standard Competencies (1 of 2)(1 of 2)


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

• Anatomy, physiology, pathophysiology, assessment, and management of:– Hypersensitivity disorders and/or emergencies

– Anaphylactic reactions

Introduction (1 of 2)Introduction (1 of 2)

• At least 1,000 Americans per year die of allergic reactions.

• Allergy-related emergencies may involve:– Acute airway obstruction

– Cardiovascular collapse

Introduction (2 of 2)Introduction (2 of 2)

• You must be able to treat these life-threatening complications.

• Immunology is the study of the body’s immune system.

Anatomy and PhysiologyAnatomy and Physiology

• Immune system protects the body from foreign substances and organisms.

• When a foreign substance invades the body:– Body goes on alert.

– Body initiates a series of responses to inactivate the invader.

Pathophysiology: Allergic Reaction (1 of 2)


• An allergic reaction is an exaggerated immune response to any substance.

• Not caused directly by an outside stimulus

• Caused by the body’s immune system– Releases chemicals to combat stimulus

– Include histamines and leukotrienes



• Caused by the body’s immune system– Releases chemicals to combat stimulus

– Include histamines and leukotrienes

• Allergic reaction may be mild and local, or severe and systemic.

Pathophysiology: Anaphylaxis (1 of 3)


• Anaphylaxis is an extreme, life-threatening allergic reaction.– Involves multiple

organ systems

– Wheezing is one of the most common signs.



• Urticaria (hives) is also present.– Consists of small

areas of generalized itching or burning that appear as multiple, small, raised areas on the skin

Source: © Chuck Stewart, MD



• You may also note hypotension as a result of hypovolemic shock.

Common Allergens (1 of 3)Common Allergens (1 of 3)

• Insect bites and stings– When an insect bites

and injects the bite with its venom, this is called envenomation.

– The reaction may be local (swelling and itchiness) or systemic (involving the entire body).


• Medications– Penicillin injection

may cause an immediate and severe reaction.

– Oral penicillin may take longer.

– A person will typically experience an allergic reaction after becoming sensitized.

Source: Courtesy of Carol B. Guerrero


• Plants– Dusts, pollens, other plant materials

• Food– Reaction can be relatively slow

– Shellfish, nuts

• Chemicals– Makeup, soap, latex

Insect Stings (1 of 11)Insect Stings (1 of 11)

• Death from stinging insects far outnumber deaths from snakebites.– Stinging organ of most insects is a small hollow

spine projecting from the abdomen.

– Venom can be injected directly into skin.


• Honeybees cannot withdraw their stinger.– Fly away and die

• Wasps, hornets, and fire ants can sting multiple times.

Source: B. © Heintje Joseph T. Lee/ShutterStock, Inc.

Source: A. © manfredxy/ShutterStock, Inc.


• Some ants, especially the fire ant, also strike repeatedly.– Often inject a particularly irritating toxin at the

bite sites

Source: B. © Chris Harvey/ShutterStock, Inc.

Source: A. Courtesy of Scott Bauer/USDA


• Signs and symptoms include:– Sudden pain

– Swelling

– Localized heat

– Redness in light-skinned individuals

– Itching and possibly a wheal

Source: © Simon Krzic/ShutterStock, Inc.


• There is no specific treatment for these injuries.– Applying ice sometimes helps.

– Swelling may be dramatic and frightening.

– Local manifestations are not serious.


• Stinger of the honeybee can continue to inject venom for up to 20 minutes.

• Attempt to remove the stinger by scraping the skin with the edge of a sharp, stiff object such as a credit card.


• Do not use tweezers or forceps.

• Wash the area with soap and water.

• Remove any jewelry from the area.

• Be alert for vomiting or signs of shock.

• Give oxygen if needed.

• Monitor the patient’s vital signs.


• About 5% of people may have anaphylactic reactions from:– Bees

– Hornets

– Yellow jackets

– Wasps

• Account for 200 deaths per year.



• Patients may experience:– Generalized itching and burning

– Widespread urticaria

– Wheals

– Swelling of the lips and tongue

– Bronchospasm and wheezing

– Chest tightness and coughing

– Dyspnea


• Patients may experience (cont’d):– Anxiety

– Abdominal cramps

– Hypotension

– Occasionally, respiratory failure

• If untreated, anaphylactic reaction can proceed rapidly to death.

Patient Assessment (1 of 3)Patient Assessment (1 of 3)

• Scene size-up

• Scene safety– Identify and address environmental hazards.

– Patient’s environment or activity may indicate source of reaction.

– Never enter a scene where more than one person is experiencing same symptoms.


• Scene safety (cont’d)– Follow standard precautions, with a minimum of

gloves and eye protection.

– Consider the need for additional or specialized resources.

– Call for additional resources earlier rather than later.


• Mechanism of injury/nature of illness– May not be an allergic reaction

– Trauma may have occurred.

– Determine the MOI/NOI.

– Look for bee stingers or chemicals and other indications of a reaction.

Primary Assessment (1 of 5)Primary Assessment (1 of 5)

• Perform a rapid scan of the patient.

• Form a general impression.– May present as respiratory or cardiovascular

distress in the form of shock

– Patients will be very anxious.

– Call for ALS backup if available.

– Try to get information on the chief complaint.


• Airway and breathing– Anaphylaxis can

cause rapid swelling of the upper airway.

– Only a few minutes to assess the airway and provide lifesaving measures

– Work quickly to determine the severity of the symptoms.


• Airway and breathing (cont’d)– Position conscious patients in tripod position

and listen to the lungs.

– Do not hesitate to initiate high-flow oxygen.

– In severe situations, the definitive care is an injection of epinephrine.


• Circulation– May present with hypotension

– Palpate for radial pulse.

• If the patient is unresponsive and without a pulse, begin BLS or use an AED.

• If pulse is present, assess for a rapid pulse, and check skin condition and capillary refill.


• Initial treatment – Oxygen

– Positioning

– Maintaining normal body temperature

• Transport decision– Always provide prompt transport for any patient

who may be having an allergic reaction.

– Take along all medications and auto-injectors the patient has at the time.

History Taking (1 of 4)History Taking (1 of 4)

• Identify:– Chief complaint

– History of present illness

– Associated signs and symptoms

– Pertinent negatives



• SAMPLE history

• If the patient is conscious, ask the following questions:– Have any interventions already been

completed?

– Do you have any prescribed, preloaded medications for allergic reactions?


• Ask the following questions (cont’d):– Do you have any respiratory symptoms?

– Do you have other symptoms?

– Have you had previous allergic reactions, asthma, or hospitalizations?

– What were you doing or what were you exposed to before the onset of symptoms?

Secondary Assessment (1 of 4)Secondary Assessment (1 of 4)

• Physical examinations– Includes a systemic head-to-toe or focused

assessment

– Thoroughly assess breathing, including:

• Increased work of breathing

• Use of accessory muscles

• Head bobbing, nostril flaring, grunting

• Tripod positioning


• Physical examinations (cont’d)– Auscultate both the trachea and the chest.

– Wheezing may occur because of narrowing of the air passages.

– Assess the circulatory system.

– Assess the skin for swelling, rash, hives, or signs of the source of the reaction.


• Vital signs– Assess baseline vitals:

• Pulse

• Respirations

• Blood pressure

• Skin

• Pupils

• Oxygen saturation


• Vital signs (cont’d)– Rapid respiratory rate indicates airway

obstruction.

– Rapid respiratory and pulse indicate respiratory distress or systemic shock.

– Pulse oximetry is a useful method to assess the patient’s perfusion status.

Reassessment (1 of 3)Reassessment (1 of 3)

• Repeat the primary assessment and reassess the patient’s vital signs.– Deterioration of the patient’s condition could be

rapid and fatal.

– Give special attention to any signs of airway compromise.

– Monitor the patient’s anxiety level.

– Watch for signs of shock.


• Interventions– Identify how much distress the patient is in.

– Severe reactions require epinephrine and ventilatory support.

– Milder reactions require supportive care such as oxygen.

– Transport to a medical facility.

– Recheck your interventions.


• Communication and documentation– When to contact medical control depends on

your assessment findings.

– Documentation should include:

• Signs and symptoms

• Reasons for choosing to provide the care you did

• Patient’s response to your treatment

Emergency Medical Care (1 of 9)Emergency Medical Care (1 of 9)

• If patient appears to be having a severe allergic (or anaphylactic) reaction:– Administer BLS, including oxygen.

– Provide prompt transport to the hospital.

– Reassess vital signs every 5 minutes (unstable patient) or 15 minutes (stable patient).


– Place hypotensive or shock patients in the appropriate position.

– Request ALS backup if you work in a tiered response system.

– Be prepared to maintain the airway or administer cardiopulmonary resuscitation.


– If a stinger is present, scrape away with a credit card.

– Applying ice may help.

– In some areas, you may be allowed to administer epinephrine or assist the patient with epinephrine administration.


• Epinephrine– Mimics the sympathetic (fight-or-flight) response

– Causes the blood vessels to constrict

– Reverses vasodilation and hypotension

– Increases cardiac contractility and relieves bronchospasm

– Rapidly reverses the effects of anaphylaxis


• Indications include:– A severe allergic reaction

– Hypersensitivity to an exposed substance

• Remember that your EMS service may or may not allow you to assist the patient in the administration of epinephrine. Call medical control!


• All kits should contain a prepared, auto-injectable syringe of epinephrine.Source: Courtesy of Shionogi Pharma, Inc.


• The adult EpiPen delivers 0.3 mg of epinephrine; the infant-child system delivers 0.15 mg.

• The Twinject auto-injector contains two doses of epinephrine.

• See Skill Drills 18-1 and 18-2.


• Side effects include:– High blood pressure

– Increased pulse rate

– Anxiety

– Cardiac arrhythmias

– Pallor

– Dizziness


• Side effects include (cont’d):– Chest pain

– Headache

– Nausea

– Vomiting

Summary Summary (1 of 7)(1 of 7)Summary Summary (1 of 7)(1 of 7)

• An allergic reaction is a response to chemicals the body releases to combat certain stimuli, called allergens.

• Allergic reactions occur most often in response to five categories of stimuli: insect bites and stings, medications, food, plants, and chemicals.


• The reactions may be mild and local, involving itching, redness, and tenderness, or they may be severe and systemic, including shock and respiratory failure.


• Anaphylaxis is a life-threatening allergic reaction mounted by multiple organ systems, which must be treated with epinephrine.

• Wheezing and skin wheals can be signs of anaphylaxis.


• People allergic to bee, hornet, yellow jacket, or wasp venom often carry a kit that contains epinephrine in an auto-injector.

• All patients with suspected anaphylaxis require oxygen.


• 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.


• 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.


• Carefully monitor the patient’s vital signs en route; be especially alert for airway compromise.

ReviewReview

1. The signs and symptoms of an allergic reaction are caused by the release of:

A. histamine.

B. adrenalin.

C. epinephrine.

D. glucagon.

ReviewReview

Answer: A

Response: The two chief chemicals released by the body that result in the signs and symptoms of an allergic reaction are histamines and leukotrienes. Epinephrine (adrenalin) is used to treat allergic reactions.

Review (1 of 2)Review (1 of 2)


A. histamine.Rationale: Correct answer

B. adrenalin.Rationale: Adrenalin is also called epinephrine and, along with Benadryl, is used to treat anaphylaxis.



C. epinephrine.Rationale: Epinephrine is used to treat anaphylaxis.

D. glucagon. Rationale: Glucagon is a hormone produced by the pancreas that helps in the control of metabolism.

ReviewReview

2. The negative effects associated with anaphylactic shock are the result of:

A. severe internal fluid loss.

B. inadequate pumping of the heart.

C. vasodilation and bronchoconstriction.

D. the nervous system’s release of adrenalin.

ReviewReview

Answer: C

Rationale: Anaphylaxis is an extreme allergic reaction that is life threatening and involves multiple organ systems. In severe cases, anaphylaxis can rapidly result in death. One of the most common signs of anaphylaxis is wheezing, a high-pitched, whistling breath sound that is typically heard on expiration, usually resulting from bronchospasm/ bronchoconstriction and increased mucus production.



A. severe internal fluid loss. Rationale: The body does not lose fluid; blood pools in the dilated circulatory system and causes less blood flow back to the heart.

B. inadequate pumping of the heart. Rationale: Inadequate pumping is not the problem; the cardiac output is decreased due to poor return to the heart.



C. vasodilation and bronchoconstriction. Rationale: Correct answer

D. the nervous system’s release of adrenalin. Rationale: Adrenalin is the treatment for anaphylaxis.

ReviewReview

3. You are called to a local baseball park for a 23-year-old man with difficulty breathing. He states that he ate a package of peanuts approximately 30 minutes ago and denies any allergies or past medical history. Your assessment reveals widespread urticaria, tachycardia, and a BP of 90/60 mm Hg. You can hear him wheezing, even without a stethoscope. You should be MOST suspicious of a(n):

A. acute asthma attack.

B. mild allergic reaction.

C. severe allergic reaction.

D. moderate allergic reaction.

ReviewReview

Answer: C

Rationale: The patient’s signs and symptoms indicate a severe allergic reaction, which is rapidly progressing to anaphylactic shock. Signs and symptoms of a severe allergic reaction include difficulty breathing, urticaria (hives) over large parts of the body, and signs of shock (eg, tachycardia, hypotension). Certain foods, such as shellfish and nuts, may result in a relatively slow onset of symptoms, but the symptoms can become just as severe.


3. You are called to a local baseball park for a 23-year-old man with difficulty breathing. He states that he ate a package of peanuts approximately 30 minutes ago, and denies any allergies or past medical history. Your assessment reveals widespread urticaria, tachycardia, and a BP of 90/60 mm Hg. You can hear him wheezing, even without a stethoscope. You should be MOST suspicious of a(n):

A. acute asthma attack.Rationale: Asthma presents with difficulty breathing, but patients will not have urticaria (hives).


3. You are called to a local baseball park for a 23-year-old man with difficulty breathing. He states that he ate a package of peanuts approximately 30 minutes ago, and denies any allergies or past medical history. Your assessment reveals widespread urticaria, tachycardia, and a BP of 90/60 mm Hg. You can hear him wheezing, even without a stethoscope. You should be MOST suspicious of a(n):

B. mild allergic reaction.Rationale: Mild reactions usually appear with urticaria, itching, and some swelling, but not hypotension and breathing difficulties.



C. severe allergic reaction.Rationale: Correct answer



D. moderate allergic reaction.Rationale: The designation is mild or severe—not moderate.

ReviewReview

4. What is a wheal?

A. a raised, swollen, well-defined area on the skin

B. a poison

C. small areas of generalized itching or burning that appear as multiple, small, raised areas on the skin

D. an exaggerated immune response to any substance

ReviewReview

Answer: A

Rationale: Insect stings and bites can cause a wheal, which is a raised, swollen, well-defined area on the skin. There is no specific treatment for these injuries, although applying ice sometimes makes them less irritating.


4. What is a wheal?

A. a raised, swollen, well-defined area on the skinRationale: Correct answer

B. a poisonRationale: This is the definition of a toxin.


4. What is a wheal?

C. small areas of generalized itching or burning that appear as multiple, small, raised areas on the skinRationale: This is the definition of urticaria.

D. an exaggerated immune response to any substanceRationale: This is the definition of an allergic reaction.

ReviewReview

5. You are treating a woman who was stung numerous times by hornets. On assessment, you note that some of the stingers are still imbedded in her skin. You should:

A. leave the stingers in place.

B. scrape the stingers from her skin.

C. pull the stingers out with tweezers.

D. cover the stings with tight dressings.

ReviewReview

Answer: B

Rationale: Because of the venom left in the sac located at the end of the stinger, you should not grab the stingers in an attempt to remove them. Instead, scrape them off with a rigid object such as a credit card.


5. You are treating a woman who was stung numerous times by hornets. On assessment, you note that some of the stingers are still imbedded in her skin. You should:A. leave the stingers in place.

Rationale: A stinger will continue to inject venom even when the stinger is no longer attached to the insect.

B. scrape the stingers from her skin.Rationale: Correct answer


5. You are treating a woman who was stung numerous times by hornets. On assessment, you note that some of the stingers are still imbedded in her skin. You should:C. pull the stingers out with tweezers.

Rationale: Using tweezers may squeeze more venom into the patient.

D. cover the stings with tight dressings.Rationale: Remove the stingers—do not leave them in place.

ReviewReview

6. A young male is experiencing signs and symptoms of anaphylactic shock after being stung by a scorpion. His level of consciousness is diminished, his breathing is severely labored, you can hear inspiratory stridor, and his face is cyanotic. The patient has a prescribed epinephrine auto-injector. What should you do first?

A. Assist him in administering his epinephrine.

B. Apply high-flow oxygen via nonrebreathing mask.

C. Provide ventilatory assistance with a bag-mask device.

D. Elevate his legs and cover him with a warm blanket.

ReviewReview

Answer: C

Rationale: The patient is not breathing adequately, as noted by his decreased level of consciousness, severely labored breathing, inspiratory stridor, and cyanosis. Therefore, you should first assist his ventilations with a bag-mask device. He clearly requires epinephrine, but not before restoring adequate breathing first. Regardless of the situation, a patient’s airway must be patent and his or her breathing must remain adequate at all times.



A. Assist him in administering his epinephrine.Rationale: This is part of the treatment, but only after the breathing has been addressed.

B. Apply high-flow oxygen via nonrebreathing mask.Rationale: Respirations need assistance due to diminished breathing.



C. Provide ventilatory assistance with a bag-mask device. Rationale: Correct answer

D. Elevate his legs and cover him with a warm blanket. Rationale: You should treat for shock, but breathing is the first priority.

ReviewReview

7. The MOST reliable indicator of upper airway swelling during a severe allergic reaction is:

A. stridor.

B. anxiety.

C. cyanosis.

D. wheezing.

ReviewReview

Answer: A

Rationale: Stridor is a high-pitched sound that is most often heard during inhalation. It indicates swelling of the upper airway. Wheezing, a whistling sound, is caused by narrowed bronchioles; it indicates narrowing or swelling of the lower airway. Anxiety and cyanosis can occur from a variety of causes; they are not exclusive to airway swelling.



A. stridor. Rationale: Correct answer

B. anxiety.Rationale: This is typically a symptom of hypoxia or decreased oxygenation to the brain.



C. cyanosis. Rationale: This is a sign of hypoxia and inadequate tissue perfusion.

D. wheezing. Rationale: This is a sign of lower airway constriction or narrowing.

ReviewReview

8. What is the best tool or method for assessing a patient’s perfusion status?

A. small-volume nebulizer

B. bag-mask device

C. pulse oximetry

D. auto-injector

ReviewReview

Answer: C

Rationale: In a patient experiencing an allergic reaction, pulse oximetry is a useful method that you can use to assess the patient’s perfusion status. By using pulse oximetry, you can determine the percentage of oxygen saturation in the bloodstream, which will assist in identifying the degree of respiratory distress.



A. small-volume nebulizerRationale: This device holds liquid medicine that is turned into a fine mist. It treats conditions like asthma.

B. bag-mask deviceRationale: This device delivers supplemental oxygen.



C. pulse oximetryRationale: Correct answer

D. auto-injectorRationale: This device is designed to deliver a single dose of a particular drug, such as epinephrine.

ReviewReview

9. The adult EpiPen system delivers _____ mg of epinephrine, and the infant-child system delivers _____ mg.

A. 0.15, 0.3

B. 0.3, 0.15

C. 0.15, 0.5

D. 0.5, 0.2

ReviewReview

Answer: B

Rationale: The adult EpiPen system delivers 0.3 mg of epinephrine via an automatic needle and syringe system; the infant-child system delivers 0.15 mg.

ReviewReview

9. The adult EpiPen system delivers _____ mg of epinephrine, and the infant-child system delivers _____ mg.A. 0.15, 0.3

Rationale: This is not the correct dosage.

B. 0.3, 0.15Rationale: Correct answer

C. 0.15, 0.5Rationale: This is not the correct dosage.

D. 0.5, 0.2Rationale: This is not the correct dosage.

ReviewReview

10. When administering epinephrine by auto-injector, the EMT should hold the injector in place for:

A. 5 seconds.

B. 10 seconds.

C. 20 seconds.

D. 30 seconds.

ReviewReview

Answer: B

Rationale: When administering epinephrine via auto-injector, push the injector firmly against the thigh until it activates. Hold the injector in place for 10 seconds to ensure that all the medication is injected.



A. 5 seconds.Rationale: The injector should be held in place for 10 seconds.

B. 10 seconds.Rationale: Correct answer



C. 20 seconds.Rationale: The injector should be held in place for 10 seconds.

D. 30 seconds.Rationale: The injector should be held in place for 10 seconds.

CreditsCredits

• Background slide images: © Jones & Bartlett Learning. Courtesy of MIEMSS.

Chapter 18

Documents

insect stings

insect bites

indicatesource of reaction

leukotrienes allergic

severe reaction

patient assessment

local swelling

physiology immune system