A 22-month-old boy is evaluated in the emergency department in the late evening for a loud… — USMLE Step 2 CK

A 22-month-old boy is evaluated in the emergency department in the late evening for a loud, barking cough and noisy breathing. The symptoms began abruptly a few hours ago. He has had clear rhinorrhea, nasal congestion, and a low-grade fever for the past 48 hours. The patient is fully vaccinated according to the standard schedule. His temperature is $37.8^\circ\text{C}$ ( $100.0^\circ\text{F}$ ), heart rate is $138/\text{min}$ , respiratory rate is $42/\text{min}$ , and oxygen saturation is $95\%$ on room air. Physical examination reveals an anxious child with a hoarse voice. Inspiratory stridor is clearly audible both when the child is crying and when he is sitting calmly in his father's arms. Mild suprasternal and intercostal retractions are noted. Lung fields are clear to auscultation bilaterally without wheezing. Which of the following is the most appropriate next step in the management of this patient?

Administration of nebulized epinephrine and oral dexamethasoneAnswer
B
Administration of inhaled albuterol and nebulized hypertonic saline
C
Prescription of oral amoxicillin and home humidification
D
Lateral neck radiography to evaluate the upper airway
E
Intramuscular ceftriaxone and preparation for airway management

Answer

Administration of nebulized epinephrine and oral dexamethasone

This patient's clinical presentation is classic for croup (viral laryngotracheitis), characterized by a prodrome of rhinorrhea and low-grade fever that progresses to a barking, 'seal-like' cough, hoarseness, and inspiratory stridor. The severity of croup is determined primarily by the work of breathing and the timing of stridor. Because this child has stridor while resting calmly in his father's arms, he meets the criteria for moderate-to-severe croup. The standard of care for this severity level is the immediate administration of nebulized epinephrine alongside systemic corticosteroids (oral, intramuscular, or intravenous dexamethasone). Nebulized epinephrine stimulates alpha-adrenergic receptors in the airway mucosa, causing rapid vasoconstriction and a quick decrease in subglottic edema. Since the effect of epinephrine is transient and can lead to rebound edema, the patient must be observed for several hours, and corticosteroids are given to provide sustained anti-inflammatory action.

Step-by-Step Solution

Identify the clinical diagnosis based on the patient's presentation.

The patient has a viral prodrome followed by a barking cough, hoarseness, and inspiratory stridor, which is the classic presentation of croup (laryngotracheitis).

Recognizing the pattern of symptoms localizes the pathology to subglottic airway edema caused by a viral infection (most commonly parainfluenza virus).

Assess the severity of the respiratory distress.

The presence of inspiratory stridor while the patient is resting calmly, combined with chest wall retractions, classifies this as moderate-to-severe croup.

Severity dictates management. Mild croup (stridor only with agitation) requires only dexamethasone, while moderate-to-severe croup requires additional immediate intervention.

Determine the appropriate pharmacological intervention for moderate-to-severe croup.

The patient requires both systemic corticosteroids (dexamethasone) and nebulized epinephrine.

Nebulized epinephrine acts rapidly via vasoconstriction to decrease airway edema and improve airflow temporarily, while dexamethasone provides longer-lasting anti-inflammatory effects.

Key Concept

Patients with moderate-to-severe croup (indicated by stridor at rest) require treatment with both corticosteroids (e.g., dexamethasone) to reduce inflammation and nebulized epinephrine for rapid, temporary reduction of subglottic edema.

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