A physician evaluates a 24-day-old neonate in the emergency department who presents with p… — USMLE Step 2 CK

A physician evaluates a $24$ -day-old neonate in the emergency department who presents with progressive respiratory distress and a truncal eruption. The parents note that the symptoms began two days ago with nasal congestion and reduced breast milk intake, following close contact with a sick preschool-aged sibling. The neonate was delivered at term without complications. Current vital signs include a temperature of $37.9^\circ\text{C}$ ( $100.2^\circ\text{F}$ ), pulse of $158/\text{min}$ , respirations of $66/\text{min}$ , and oxygen saturation of $93\%$ on room air. Cardiopulmonary auscultation reveals prolonged expiration, diffuse polyphonic wheezing, and bilateral fine crackles, accompanied by visible subcostal retractions. Dermatologic evaluation shows scattered erythematous macules on the anterior chest and back; several macules have small, central, yellow-white pustules. A rapid microscopic evaluation of the pustular fluid reveals a dense infiltration of eosinophils. Which of the following is the most appropriate clinical intervention?

Admit the patient, provide nasopharyngeal suctioning, and administer intravenous hydration as neededAnswer
B
Administer a nebulized beta-2 agonist and a dose of oral dexamethasone, then observe for clinical improvement
C
Perform a lumbar puncture, obtain blood cultures, and immediately initiate intravenous acyclovir and ampicillin
D
Prescribe a 7-day course of oral amoxicillin-clavulanate and discharge home with close outpatient follow-up
E
Provide supportive respiratory care and administer the live-attenuated intranasal influenza vaccine prior to discharge

Answer

The most appropriate intervention is to admit the patient to the hospital for supportive care, including nasopharyngeal suctioning and appropriate hydration.

The correct approach involves admission for supportive care. The neonate's respiratory distress (tachypnea, retractions, wheezing, low-normal oxygen saturation) following a sick contact is classic for viral bronchiolitis. According to pediatric guidelines, the mainstay of treatment for bronchiolitis is entirely supportive, including hydration, oxygenation, and nasopharyngeal suctioning. Furthermore, the patient's truncal rash with central pustules containing eosinophils is pathognomonic for erythema toxicum neonatorum (ETN), a benign, self-limiting condition requiring zero intervention. Because the patient is strictly afebrile (temperature

< 38.0^\circ\text{C}

100.4^\circ\text{F}

) with a clear viral etiology, a full neonatal sepsis workup is avoided.

Step-by-Step Solution

Evaluate the patient's respiratory status and vital signs.

The neonate exhibits tachypnea (

66/\text{min}

), retractions, wheezing, and borderline hypoxia (

93\%

) after a sick contact.

These findings are classic for acute viral bronchiolitis, which necessitates inpatient admission for supportive care in a neonate.

Analyze the dermatologic findings and microscopic fluid evaluation.

The rash consists of erythematous macules with central pustules containing numerous eosinophils.

Eosinophils in a central pustule confirm the diagnosis of Erythema Toxicum Neonatorum (ETN), a benign, self-limiting rash that requires no intervention.

Synthesize findings to determine the need for a neonatal sepsis workup.

The temperature is

37.9^\circ\text{C}

(

100.2^\circ\text{F}

), which does not meet the strict fever threshold (

38.0^\circ\text{C}

) for a full neonatal sepsis protocol, and the rash is benign.

Because there is a clear viral etiology for the distress, no true fever, and the rash is confirmed as ETN rather than HSV or bacterial infection, invasive diagnostic tests and empiric antibiotics/antivirals are contraindicated.

Key Concept

Management of acute viral bronchiolitis and differentiation of benign neonatal rashes (Erythema Toxicum Neonatorum) from life-threatening neonatal infections.

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