Allergic Reactions and Anaphylaxis
Help Questions
NREMT: AEMT Level › Allergic Reactions and Anaphylaxis
An AEMT administers 0.5 mg of IM epinephrine to a 200-lb male in anaphylactic shock. What is the most important parameter to reassess within five minutes of administration?
The size and redness of the cutaneous urticaria.
The patient's core body temperature and skin signs.
Blood pressure and the quality of breathing.
The patient's subjective level of anxiety and fear.
Explanation
The primary purpose of epinephrine in anaphylaxis is to reverse life-threatening hypotension (via alpha-1 vasoconstriction) and respiratory compromise (via beta-2 bronchodilation and reduced edema). Therefore, the most critical parameters to reassess are the blood pressure and the patient's respiratory status (rate, effort, lung sounds) to determine if the intervention was effective. Skin signs (B) and anxiety (A) resolve more slowly and are not immediate life threats.
You arrive at a home for a 50-year-old female with a new medication reaction. She began a new pain medication today after dental work. She has a diffuse rash, feels lightheaded, and reports shortness of breath. A medical alert bracelet indicates “Opioid allergy.” She is sitting on the floor supported by family. Lung sounds reveal mild wheezes; she is speaking in full sentences but appears fatigued. Vitals: BP 98/64, HR 112, RR 22, SpO2 95% on room air. Family has opened windows, stopped the medication, and called 911. No epinephrine has been administered.
Based on the scenario, what is the recommended dosage of epinephrine for this patient?
Epinephrine 1:1,000, 0.3 mg IM in the lateral thigh
Epinephrine 1:1,000, 1 mg IM repeated every two minutes
Epinephrine 1:10,000, 1 mg IV push as a single dose
Epinephrine 1:1,000, 0.1 mg IM in the deltoid muscle
Explanation
This question tests the management of allergic reactions and anaphylaxis at the AEMT level. Allergic reactions and anaphylaxis involve hypersensitivity to allergens, requiring prompt identification and intervention. Common symptoms include hives, respiratory distress, and hypotension. In this scenario, the patient's symptoms and history indicate anaphylaxis, necessitating immediate administration of epinephrine. The correct answer is choice A because it aligns with AEMT guidelines for immediate management of anaphylaxis, ensuring rapid symptom relief with the standard adult dose. Choice B is incorrect because it suggests an inappropriate sequence of interventions, which can delay critical treatment and worsen patient outcomes. To help students: Emphasize the importance of recognizing signs of anaphylaxis and following established protocols. Practice scenarios should include identifying critical symptoms and correctly administering emergency medications. Watch for common errors such as confusing symptom severity and misapplying intervention sequences.
A 4-year-old child weighing 33 lbs is stung by a wasp and develops stridor and hypotension. The AEMT has an epinephrine auto-injector that delivers 0.15 mg. What is the most appropriate action?
Administer the 0.15 mg autoinjector into the anterolateral thigh.
Withhold epinephrine and transport, as the dose may be too high.
Attempt to administer only half the contents of the 0.15 mg autoinjector.
Request orders from medical control to administer the adult 0.3 mg dose.
Explanation
The patient's weight is 33 lbs, which is 15 kg. The standard pediatric dose of epinephrine for anaphylaxis is 0.01 mg/kg. For this child, the calculated dose is 15 kg * 0.01 mg/kg = 0.15 mg. Therefore, the 0.15 mg auto-injector is the correct dose. Withholding treatment (B) or giving an incorrect dose (C, D) would be dangerous.
You respond to a home for a 36-year-old female with a reaction after taking a new over-the-counter supplement. She has a diffuse rash and reports dizziness and shortness of breath. She is wearing a medical alert bracelet that states “Anaphylaxis risk.” Lung sounds reveal wheezes; she is speaking in short phrases. Vitals: BP 94/58, HR 120, RR 26, SpO2 92% on room air. Family has stopped the supplement, called 911, and placed her supine with legs elevated. No epinephrine has been given.
Based on the scenario, what is the recommended dosage of epinephrine for this patient?
Epinephrine 1:10,000, 0.3 mg IV push over 30 seconds
Epinephrine 1:1,000, 0.5 mg IM in the forearm near the rash
Epinephrine 1:1,000, 0.03 mg IM in the lateral thigh
Epinephrine 1:1,000, 0.3 mg IM in the lateral thigh
Explanation
This question tests the management of allergic reactions and anaphylaxis at the AEMT level. Allergic reactions and anaphylaxis involve hypersensitivity to allergens, requiring prompt identification and intervention. Common symptoms include hives, respiratory distress, and hypotension. In this scenario, the patient's symptoms and history indicate anaphylaxis, necessitating immediate administration of epinephrine. The correct answer is choice D because it aligns with AEMT guidelines for immediate management of anaphylaxis, ensuring rapid symptom relief with the standard adult dose. Choice C is incorrect because it suggests an inappropriate sequence of interventions, which can delay critical treatment and worsen patient outcomes. To help students: Emphasize the importance of recognizing signs of anaphylaxis and following established protocols. Practice scenarios should include identifying critical symptoms and correctly administering emergency medications. Watch for common errors such as confusing symptom severity and misapplying intervention sequences.
An AEMT administers diphenhydramine to a patient having an allergic reaction. How does this medication primarily work to alleviate symptoms like urticaria and pruritus?
It stabilizes mast cells, preventing them from releasing more histamine.
It provides a beta-2 adrenergic effect, causing bronchodilation.
It competitively blocks H1 histamine receptors on target cells.
It causes systemic vasoconstriction through alpha-1 adrenergic effects.
Explanation
Diphenhydramine is a first-generation antihistamine. Its primary mechanism of action is to competitively block H1 histamine receptors, preventing histamine released from mast cells from binding and causing symptoms like hives, itching, and vasodilation. It does not prevent histamine release (A). Beta-2 effects (C) are characteristic of albuterol, and alpha-1 effects (D) are characteristic of epinephrine.
You are dispatched to a food court for a 19-year-old female with known peanut allergy. She accidentally eats a dessert labeled “may contain nuts” and quickly develops hives, lip swelling, and shortness of breath. A friend reports, “I used her EpiPen about 10 minutes ago, but she’s getting worse again.” The patient is upright, anxious, and speaking in short phrases with audible wheezing. Vitals: BP 88/52, HR 136, RR 30, SpO2 88% on room air. The friend has already called 911 and moved her away from the vendor; mall security has brought an AED and oxygen. You note persistent respiratory distress and hypotension despite the initial auto-injector.
Which intervention should follow the administration of epinephrine?
Administer 0.1 mg epinephrine IM to minimize tachycardia risk
Give antihistamine first because epinephrine has already been used once
Observe on scene until hives resolve before initiating transport
Reassess and administer a repeat IM epinephrine dose per protocol if symptoms persist
Explanation
This question tests the management of allergic reactions and anaphylaxis at the AEMT level. Allergic reactions and anaphylaxis involve hypersensitivity to allergens, requiring prompt identification and intervention. Common symptoms include hives, respiratory distress, and hypotension. In this scenario, the patient's symptoms and history indicate anaphylaxis, necessitating immediate administration of epinephrine. The correct answer is choice C because it aligns with AEMT guidelines for immediate management of anaphylaxis, ensuring rapid symptom relief through reassessment and repeat epi if needed. Choice D is incorrect because it suggests an inappropriate sequence of interventions, which can delay critical treatment and worsen patient outcomes. To help students: Emphasize the importance of recognizing signs of anaphylaxis and following established protocols. Practice scenarios should include identifying critical symptoms and correctly administering emergency medications. Watch for common errors such as confusing symptom severity and misapplying intervention sequences.
A 44-year-old male presents with urticaria and pruritus on his arms 10 minutes after a bee sting. His vital signs are within normal limits and he denies any difficulty breathing. Which additional finding would be the clearest indication to treat for anaphylaxis with epinephrine?
Development of swelling and redness localized to the sting site.
A complaint of abdominal cramping and sudden nausea.
A complaint of significant anxiety and a feeling of impending doom.
A history of a previous severe allergic reaction to bee stings.
Explanation
Anaphylaxis is defined by the involvement of two or more body systems. The patient already has skin involvement (urticaria). The development of gastrointestinal symptoms (abdominal cramping, nausea) indicates a second system is involved, meeting the criteria for anaphylaxis and warranting epinephrine. A history of severe reactions (A) is a risk factor but does not define the current event. Anxiety (B) is a common symptom but is less objective than GI distress. Localized swelling (C) is an expected finding of a simple allergic reaction, not systemic anaphylaxis.
An 88-pound adult female is experiencing anaphylaxis with severe respiratory distress and hypotension. According to standard AEMT protocols for weight-based dosing (0.01 mg/kg), what is the correct initial dose and administration of epinephrine?
0.5 mg of 1:10,000 solution administered intramuscularly.
0.4 mg of 1:1,000 solution administered intramuscularly.
0.3 mg of 1:1,000 solution administered subcutaneously.
0.4 mg of 1:1,000 solution administered intravenously.
Explanation
First, convert the patient's weight: 88 lbs / 2.2 lbs/kg = 40 kg. The correct dose is 0.01 mg/kg, so 40 kg * 0.01 mg/kg = 0.4 mg. The correct concentration for intramuscular injection is 1:1,000. Intravenous administration of this concentration is dangerous (A). The 1:10,000 concentration is for IV/IO use in cardiac arrest, not IM administration (B). The subcutaneous route is no longer recommended due to less reliable absorption compared to IM (D).
A 68-year-old male with a history of COPD is in anaphylaxis with severe respiratory distress. After IM epinephrine, he remains tachypneic and is using accessory muscles, with an SpO2 of 88% and diffuse wheezing. The patient is conscious and maintaining his airway. Which intervention is most appropriate to improve oxygenation and reduce the work of breathing?
Administration of a nebulized bronchodilator.
Application of continuous positive airway pressure (CPAP).
Insertion of a supraglottic airway.
Initiating assisted ventilations with a bag-valve mask.
Explanation
This patient is showing signs of impending respiratory failure (accessory muscle use, tachypnea, hypoxia) despite initial treatment. CPAP is an excellent intervention in this scenario. It helps to stent open the smaller airways, improves gas exchange, and significantly reduces the work of breathing, potentially preventing the need for intubation. A nebulizer (B) is also helpful but does less to support the patient's ventilatory effort. A supraglottic airway (A) or BVM (D) are incorrect as the patient is still conscious and breathing spontaneously.
Which sequence of interventions is most appropriate for this patient?
Apply CPAP, administer nebulized albuterol, and then give IM epinephrine.
Administer IV diphenhydramine, apply high-flow oxygen, and transport rapidly.
Establish IV access, administer a fluid bolus, then give IM epinephrine.
Administer IM epinephrine, apply high-flow oxygen, establish IV access, and prepare for airway management.
Explanation
When you encounter a patient with signs of anaphylaxis—urticaria, angioedema, stridor, hypotension, and altered mental status—time is critical. The priority is immediate epinephrine administration followed by supportive airway and circulatory management.
Answer A provides the correct sequence: IM epinephrine first (the definitive treatment for anaphylaxis), high-flow oxygen for hypoxemia, IV access for additional medications and fluids, and airway preparation since stridor indicates upper airway compromise that could progress to complete obstruction.
Answer B delays epinephrine by prioritizing IV access and fluids first. While IV access is important, epinephrine is the life-saving intervention that must be given immediately. Fluid resuscitation alone won't reverse the underlying anaphylactic process causing vasodilation and increased capillary permeability.
Answer C suggests CPAP and albuterol, but this patient's respiratory distress is from upper airway swelling (evidenced by stridor), not bronchospasm. CPAP could worsen upper airway obstruction, and delaying epinephrine is dangerous. Albuterol may help with any bronchospasm component but isn't the primary treatment.
Answer D omits epinephrine entirely, relying only on diphenhydramine (an antihistamine). While antihistamines are adjunctive therapy for anaphylaxis, they work too slowly for life-threatening presentations. This patient needs immediate epinephrine to counteract the severe cardiovascular and respiratory compromise.
Remember: In anaphylaxis, epinephrine is always first-line treatment. Don't let other interventions delay this critical medication—every minute counts when airway compromise and shock are present.