# A nurse is assessing a 6-month-old infant who received routine immunizations 2 hours ago. Which assessment finding would require immediate nursing intervention?

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> subject: Infectious Diseases

## 문제

A nurse is assessing a 6-month-old infant who received routine immunizations 2 hours ago. Which assessment finding would require immediate nursing intervention?

## 보기

1. Mild erythema and tenderness at the injection site
2. Low-grade fever of 100.2°F (37.9°C)
3. Inspiratory stridor with facial swelling **✔ 정답**
4. Fussiness and decreased appetite

**정답: 3**

## 해설

Inspiratory stridor with facial swelling indicates anaphylaxis, a life-threatening allergic reaction requiring immediate emergency intervention. Other options are expected mild post-vaccination reactions.

## 심화 해설

Understanding the Priority Assessment

When assessing an infant after routine immunization, the nurse must rapidly distinguish between expected, self-limiting side effects and signs of a rare but life-threatening emergency. The primary framework for this clinical decision is the "airway, breathing, circulation" (ABC) priority-setting principle. The correct answer is the finding that signals a potential immediate threat to the airway.

Analysis of the Correct Answer: Inspiratory Stridor with Facial Swelling

Inspiratory stridor is a high-pitched, harsh sound heard during inhalation, indicating a partial obstruction of the upper airway at the level of the larynx or trachea. When this finding appears acutely after an injection, especially when combined with facial swelling (angioedema), it is a cardinal sign of anaphylaxis, a severe systemic hypersensitivity reaction. The underlying pathophysiology involves IgE-mediated mast cell degranulation, releasing histamine and other vasoactive mediators that cause rapid fluid shift from the vasculature into the interstitial tissues, leading to edema in the loose connective tissue of the face and upper airway. This condition can progress to complete airway obstruction, respiratory failure, and death if not immediately recognized and managed. As outlined in the reference on pediatric emergencies, the clinical presentation of anaphylaxis requires immediate recognition and stabilization, with airway management being the absolute first priority [1]. The initial first hour of emergency care for such a presentation is critical to prevent decompensation [1]. A finding of stridor necessitates immediate nursing intervention, including activating the emergency response system, preparing to administer intramuscular epinephrine, and ensuring emergency airway equipment is at the bedside.

Analysis of the Incorrect Answers

The other options represent common, expected, and non-emergent responses to vaccination that do not indicate a threat to airway patency.

- **Option 1: Mild erythema and tenderness at the injection site.** This is a predictable, localized inflammatory response to the vaccine's antigenic components and adjuvant. It is a sign that the immune system is being activated and does not require intervention beyond a cool compress or parental reassurance.

- **Option 2: Low-grade fever of 100.2°F (37.9°C).** A low-grade fever is a common systemic reaction as the body's immune system mounts a response, mediated by endogenous pyrogens like interleukin-1. This is an expected finding and is managed with antipyretics as recommended by a provider and parental education, not as an emergency.

- **Option 4: Fussiness and decreased appetite.** These are non-specific, common behavioral responses in an infant who may be experiencing mild systemic discomfort or localized pain from the injection. While the nurse should provide comfort measures and monitor the infant, these findings do not signal a physiological emergency and are not the priority over an airway-compromising condition.

Clinical Reasoning and Test-Taking Strategy

This question tests the critical NCLEX-RN concept of prioritizing care using the ABC framework and recognizing an emergent versus a non-emergent presentation. A useful strategy is to identify the option that represents a physiological derangement with the highest potential for rapid deterioration. While respiratory diseases are a common reason for pediatric consultation, the acute onset of stridor after an exposure points specifically to a hypersensitivity crisis, not a primary respiratory infection like bronchiolitis or asthma . The key to answering correctly is recognizing that stridor is an airway problem, which always takes precedence over a local reaction (Option 1), a mild systemic symptom (Option 2), or a behavioral change (Option 4). The nurse must immediately intervene to secure the airway, as a patent airway is non-negotiable for survival.References (research sources)

- [1]Emergency MedicineResearch articleNesiama J, McConnell J, Yen K. (2019)

## 임상 시나리오

Clinical Practice Guide: Post-Immunization Anaphylaxis in Infants

Immediate Recognition

Following routine immunization, monitor for any signs of respiratory distress or airway compromise. Inspiratory stridor, a high-pitched sound on inhalation, combined with facial swelling (angioedema) is a cardinal sign of anaphylaxis. This indicates laryngeal edema and potential for rapid, complete airway obstruction. Other signs may include wheezing, cyanosis, hypotonia, or persistent vomiting. Do not dismiss these as normal post-vaccine fussiness.

Emergency Nursing Intervention

Activate the emergency response system immediately. The priority is airway management per ABC principles. Administer intramuscular epinephrine (1:1000 solution, 0.01 mg/kg) into the anterolateral thigh without delay; this is the first-line treatment and should not be postponed for vital sign assessment. Position the infant supine or in a position of comfort, avoiding upright posture which can precipitate empty ventricle syndrome. Provide high-flow oxygen and prepare for potential bag-valve-mask ventilation or advanced airway placement if respiratory effort deteriorates.

Ongoing Monitoring and Support

After epinephrine administration, continuously monitor airway patency, oxygen saturation, heart rate, and blood pressure. A second dose of epinephrine may be required after 5-15 minutes if symptoms persist. Anticipate the need for adjunctive therapies such as nebulized racemic epinephrine for stridor, intravenous fluids for hypotension, and antihistamines or corticosteroids as secondary agents. Transfer to an emergency care setting for extended observation is mandatory, as biphasic reactions can occur.

## 핵심 개념

- **Inspiratory Stridor** — A high-pitched, harsh sound heard during inhalation, indicating partial obstruction of the upper airway at the larynx or trachea level.
- **Anaphylaxis** — A severe, life-threatening systemic hypersensitivity reaction involving IgE-mediated mast cell degranulation and release of vasoactive mediators like histamine.
- **Angioedema** — Rapid swelling of the dermis, subcutaneous tissue, mucosa, and submucosal tissues, often caused by fluid shifting into interstitial tissues due to vasoactive mediators.
- **ABC Priority** — A triage and assessment framework prioritizing Airway, Breathing, and Circulation to identify and manage immediate life threats.

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