16: Allergic Reactions and Envenomations

4-5.1 Recognize the patient experiencing an allergic reaction.

4-5.2 Describe the emergency medical care of the patient with an allergic reaction.

4-5.3 Establish the relationship between the patient with an allergic reaction and airway management.

4-5.4 Describe the mechanisms of allergic response and the implications for airway management.

Cognitive Objectives (1 of 2)

Cognitive Objectives (2 of 2)

4-5.5 State the generic and trade names, medication forms, dose, administration, action, and contraindications for the epinephrine auto-injector.

4-5.6 Evaluate the need for medical direction in the emergency medical care of the patient with an allergic reaction.

4-5.7 Differentiate between the general category of those patients having an allergic reaction, and those patients having an allergic reaction and requiring immediate medical care, including immediate use of an epinephrine auto-injector.

4-5.8 Explain the rationale for administering epinephrine using an auto-injector.

Affective Objectives

Psychomotor Objectives

4-5.9 Demonstrate the emergency medical care of the patient experiencing an allergic reaction.

4-5.10 Demonstrate the use of an epinephrine auto-injector.

4-5.11 Demonstrate the assessment and documentation of patient response to an epinephrine injection.

4-5.12 Demonstrate proper disposal of equipment. 4-5.13 Demonstrate completing a prehospital care

report for patients with allergic emergencies.

Allergic Reactions

• Allergic reaction– Exaggerated immune response to

any substance• Histamines and leukotrienes

– Chemicals released by the immune system

Anaphylaxis

• Extreme allergic reaction• Involves multiple organs• Can rapidly result in death• Most common signs:

– Wheezing – Urticaria (hives)

Severe Allergic Reaction

Five General Allergen Categories

• Insect bites and stings

• Medications

• Plants

• Food

• Chemicals

Insect Bites and Stings

• Death from insect stings outnumber those from snakebites.

• Venom is injected through stinging organ.

• Some insects and ants can sting repeatedly.

Signs and Symptoms

• Sudden pain, swelling, and redness at site

• Itching and sometimes a wheal

• Sometimes dramatic swellings

Removing Stingers

Anaphylactic Reactions to Stings

• 5% of all people are allergic to bee, hornet, yellow jacket, and wasp stings.

• Anaphylaxis accounts for approximately 200 deaths a year.

• Most deaths occur within half an hour of being stung.

Signs and Symptomsof Allergic Reaction

• Itching and burning• Widespread urticaria• Wheals• Swelling of the lips and

tongue• Bronchospasm and

wheezing

• Chest tightness and coughing

• Dyspnea

• Anxiety

• Abdominal cramps

• Hypotension

You are the Provider

• You are dispatched to a park for a possible allergic reaction.

• You arrive to find a crowd of onlookers around a 25-year-old man.

• He appears very anxious and has hives all over his chest and arms. He thinks he was stung.

• He says it is hard to breathe, and is dizzy.

You are the Provider (continued)

• What type of reaction is this man having?• What vital signs would you expect?• What is your next step?

Scene Size-up

• Remember crew safety.• Check environment for source of the reaction—

insects, foods, medications.• Call ALS immediately if reaction is serious, as in

this case.

You are the Provider (continued)

• Vital signs are:– BP 94/56 mm Hg– Pulse 130 beats/min– Respirations 42 breaths/min– Pulse oximetry 90%

• You explain that you need to administer epinephrine, then administer it.

• Your partner administers high-flow oxygen and removes the stinger.

• You have patient lie down with feet propped up.

Initial Assessment

• General impression– May present as respiratory distress and/or

cardiac distress in the form of shock. – Patients may feel sense of impending doom.– Check carefully for medical identification tags.– See what treatment has been administered prior

to your arrival.– If unresponsive, immediately evaluate and treat

life threats.

Airway and Breathing

• You may only have a few minutes to assess the airway and provide lifesaving measures.

• Place conscious patient in tripod position.

• Quickly listen to lungs for wheezing.

• Provide high-concentration oxygen via nonrebreathing mask, but be prepared to assist with ventilations if necessary.

Circulation

• Look for indications of circulatory distress.• If unresponsive without a pulse, begin CPR and

AED resuscitation.• Rapid heart rate; cool, moist skin; and delayed

capillary refill times indicate hypoperfusion.

Transport Decision

• Transport promptly.• Take patient medications and auto-injectors

with you.• Treat respiratory distress and shock, then

transport immediately.

Focused History and Physical Exam

• Unresponsive patients receive a rapid physical exam.

• For responsive patients, obtain a SAMPLE history.• SAMPLE history helps determine:

– History of specific allergies– If patient carries medication for an allergy– If reaction is related to food or environment

Focused Physical Exam

• Evaluate respiratory system, circulatory system, mental status, and skin.

• Be alert for altered mental status.• Thoroughly assess breathing and auscultate.• Check for wheezing and stridor.

Signs and Symptoms (1 of 2)

• Sneezing or itchy, runny nose• Tightness in chest or throat• Irritating, persistent dry cough• Hoarseness• Rapid, labored, or noisy

respirations• Wheezing and/or stridor• Decreased blood pressure• Increased pulse• Pale skin, dizziness

Signs and Symptoms (2 of 2)

• Loss of consciousness, coma

• Flushing, itching, or burning skin

• Urticaria• Swelling• Warm, tingling feeling in

the face, mouth, chest, feet, hands

• Anxiety• Abdominal cramps• Headache• Itchy, watery eyes• Decreasing mental

status

Baseline Vital Signs

• Assess pulse, respirations, blood pressure, skin, and pupils.

• Watch for shock.• Fast pulses and hypotension are ominous signs.• Skin signs may be unreliable due to rashes or

swelling.

Interventions

• Severe reactions require epinephrine and ventilatory support.

• Milder reactions may only require oxygen.• In either case, transport.

You are the Provider (continued)

• A few moments after EpiPen administration, the patient is breathing more easily.

• Blood pressure and pulse oximetry values have risen; respirations have decreased.

• The paramedics arrive and begin to administer IV fluids.

Detailed Physical Exam

• Consider if:– Complaint or history is confusing.– There is extended transport time.– You need to clarify findings.

• In severe reactions, exam may be omitted.

Ongoing Assessment

• Monitor with vigilance; deterioration can be rapid and fatal.

• Note the effect of epinephrine. Consider second dose.

• If you are unsure whether to administer epinephrine, contact medical control.

• Document the patient’s response.

Emergency Medical Care

• In addition to providing oxygen, be prepared to maintain airway or give CPR.

• Placing ice over injury site may slow absorption of toxin, but may also freeze skin and cause more damage.

• You may or may not be allowed to assist with epinephrine depending on local protocols.

• Adult dose is 0.3 mg; pediatric dose is 0.15 mg.

Using an Auto-Injector

• Receive order from medical direction.

• Follow BSI precautions.• Make sure the prescription

is for the patient.• Make sure the medication is

not discolored or expired.

Auto-Injector

Administering an Auto-Injector

• Remove safety cap.• Place tip of injector against

lateral side of patient’s thigh.

• Push injector firmly and hold until all medication is injected.

• Remove injector.• Record time and dose.• Reassess and record vital

signs.

Using an AnaKit (1 of 2)

• Follow the same preliminary steps.• Prepare injection site.• Hold syringe upright so that air rises to base of

needle.• Turn plunger one quarter turn.

Using an AnaKit (2 of 2)

• Insert needle quickly.• Push plunger until it stops.• Have the patient chew and swallow Chlo-Amine

tablets.• Apply a cold pack.

Review

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

A. histamine.

B. adrenalin.

C. epinephrine.

D. glucagon.

Review

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

A. histamine.

Rationale: Correct answer

B. adrenalin.

Rationale: Adrenalin is also called epinephrine and is used to treat anaphylaxis along with benedryl.

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.

Review

2. You are called to a local baseball park for a 23-year-old man with difficulty breathing. The 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/an:

A. acute asthma attack.

B. mild allergic reaction.

C. severe allergic reaction.

D. moderate allergic reaction.

Review

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.

Review (1 of 2)

2. You are called to a local baseball park for a 23-year-old man with difficulty breathing. The 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/an:

A. acute asthma attack.

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

B. mild allergic reaction.

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

Review (2 of 2)

2. You are called to a local baseball park for a 23-year-old man with difficulty breathing. The 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/an:

C. severe allergic reaction.

Rationale: Correct answer

D. moderate allergic reaction.

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

Review

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

A. 5 seconds.

B. 10 seconds.

C. 20 seconds.

D. 30 seconds.

Review

Answer: B

Rationale: When administering epinephrine via auto injector, the EMT-B should 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.

Review

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

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

Review

4. 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. You should:

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.

ReviewAnswer: 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.

Review4. 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. You should:

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

Review

5. You are treating a man who was bitten on the leg by a rattlesnake. The patient complains of generalized weakness and is diaphoretic. There is a large, swollen area on his left lower leg with two obvious puncture wounds. In addition to high-flow oxygen, appropriate treatment for this patient includes:

A. applying a proximal tourniquet and elevating the leg.

B. applying ice to the wound to help decrease pain and swelling.

C. encouraging the patient to walk to help decrease venom spread.

D. splinting the extremity and keeping it below the level of the heart.

Review

Answer: D

Rationale: Appropriate treatment for a pit viper bite includes supplemental oxygen (or assisted ventilation if needed), covering the wound with a sterile dressing, splinting the affected extremity, and keeping the extremity below the level of the heart. NEVER apply ice to a snakebite; doing so constricts the blood vessels and may only push the venom further into the bloodstream.

Review (1 of 2)

5. You are treating a man who was bitten on the leg by a rattlesnake. The patient complains of generalized weakness and is diaphoretic. There is a large, swollen area on his left lower leg with two obvious puncture wounds. In addition to high-flow oxygen, appropriate treatment for this patient includes:

A. applying a proximal tourniquet and elevating the leg.

Rationale: Tourniquets are not used, but a proximal constricting band may be indicated.

B. applying ice to the wound to help decrease pain and swelling.

Rationale: Ice causes vasoconstriction and may push venom into the bloodstream.

Review (2 of 2)

5. You are treating a man who was bitten on the leg by a rattlesnake. The patient complains of generalized weakness and is diaphoretic. There is a large, swollen area on his left lower leg with two obvious puncture wounds. In addition to high-flow oxygen, appropriate treatment for this patient includes:

C. encouraging the patient to walk to help decrease venom spread.

Rationale: Walking only increases the movement of circulation, so the patient should be instructed to remain seated or lying down.

D. splinting the extremity and keeping it below the level of the heart.

Rationale: Correct answer

Review

6. Approximately 3 days after removing a tick from his leg, a 35-year-old man presents with a local rash that resembles a “bulls-eye.” His BP is 110/68 mm Hg, pulse is 100 beats/min, and respirations are 22 breaths/min with adequate air exchange. The MOST likely cause of this patient’s symptoms is:

A. Lyme disease.

B. an allergic reaction.

C. a systemic infection.

D. Rocky mountain spotted fever.

Review

Answer: A

Rationale: Lyme disease, which is transmitted by an infected tick, presents approximately 2 to 3 days after exposure, and includes a rash that appears to have a “bulls-eye” in the center. Within a few more days (in some cases, up to a week), the patient typically begins experiencing joint pain—especially in the knees.

Review6. Approximately 3 days after removing a tick from his leg, a 35-year-old

man presents with a local rash that resembles a “bulls-eye.” His BP is 110/68 mm Hg, pulse is 100 beats/min, and respirations are 22 breaths/min with adequate air exchange. The MOST likely cause of this patient’s symptoms is:

A. Lyme disease.Rationale: Correct answerB. an allergic reaction. Rationale: An allergic reaction presents with urticaria (hives), itching,

and tenderness.C. a systemic infection. Rationale: A systemic infection presents with redness, swelling, and

warm or hot skin at bite site.D. Rocky mountain spotted fever. Rationale: Rocky mountain spotted fever is caused by a tick bite,

symptoms are fever, nausea, vomiting, headache, and muscle pain.

Review

7. 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.

Review

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.

Review7. 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 answerC. 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.

Review

8. The adult epinephrine auto-injector delivers _____ mg of a _________ solution via the ______________ route.

A. 0.15, 1:2,000, subcutaneous

B. 0.3, 1:1,000, intramuscular

C. 0.15, 1:2,000, subcutaneous

D. 0.3, 1:2,000, intramuscular

Review

Answer: B

Rationale: The adult epinephrine auto-injector deliver 0.3 mg of a 1:1,000 solution via the intramuscular route. The pediatric auto-injector delivers 0.15 mg of a 1:2,000 via the same route. The EMT-B should be thoroughly familiar with the dose and administration route for any drug he or she gives or assists the patient with.

Review8. The adult epinephrine auto-injector delivers _____ mg of a

_________ solution via the ______________ route.

A. 0.15, 1:2,000, subcutaneousRationale: This is a pediatric dose, but it is not delivered

subcutaneously.B. 0.3, 1:1,000, intramuscularRationale: Correct answerC. 0.15, 1:2,000, subcutaneousRationale: This is a pediatric dose, but it is not delivered

subcutaneously.D. 0.3, 1:2,000, intramuscularRationale: This is the correct number of milligrams (mg), but it is

the incorrect solution, it should be 1:1000.

Review

9. The negative affects 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.

Review

Answer: C

Rationale: Anaphylactic shock is associated with two negative effects: breathing impairment and hypotension. These effects are the result of bronchoconstriction and vasodilation in response to a massive release of histamines and leukotrienes from the immune system.

Review

9. The negative affects associated with anaphylactic shock are the result of:

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 deceased due to poor return back 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.

Review

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

A. stridor.

B. anxiety.

C. cyanosis.

D. wheezing.

Review

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.

Review

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

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.