Shortly after delivery via scheduled cesarean section, an infant develops progressively wo… — USMLE Step 2 CK

Shortly after delivery via scheduled cesarean section, an infant develops progressively worsening tachypnea and expiratory grunting. The infant was born at $39$ weeks of gestation to a $34$ -year-old mother whose pregnancy was complicated by poorly controlled gestational diabetes mellitus. Birth weight is $4.6\text{ kg}$ ( $10\text{ lb } 2\text{ oz}$ ). Vital signs include a temperature of $36.8^\circ\text{C}$ ( $98.2^\circ\text{F}$ ), heart rate of $155\text{/min}$ , and respiratory rate of $78\text{/min}$ . Pulse oximetry shows $87\%$ on room air. Physical examination reveals marked intercostal retractions and decreased air entry bilaterally. Skin examination shows a diffuse rash consisting of $2\text{-mm}$ pale pustules on an erythematous base across the chest and abdomen. A chest radiograph demonstrates decreased lung volumes, diffuse fine reticulogranular opacities, and prominent air bronchograms. Which of the following is the most appropriate next step in the management of this patient?

Initiate continuous positive airway pressureCevap
B
Administer intravenous acyclovir and place in contact isolation
C
Administer intravenous vancomycin and cefepime
D
Perform immediate endotracheal intubation for prophylactic surfactant administration
E
Provide supplemental oxygen via nasal cannula and observe for spontaneous resolution

Cevap

The most appropriate next step is to initiate continuous positive airway pressure to manage the infant's Respiratory Distress Syndrome.

The correct approach involves recognizing that this infant has Respiratory Distress Syndrome (RDS), despite being born at term. Infants of diabetic mothers are at exceptionally high risk for RDS because fetal hyperinsulinemia inhibits the maturation of surfactant-producing type II pneumocytes. The chest radiograph findings of reticulogranular opacities and air bronchograms are classic for RDS. The appropriate initial management for a spontaneously breathing neonate with RDS is continuous positive airway pressure (CPAP). CPAP provides positive end-expiratory pressure, which splints the alveoli open, increases functional residual capacity, and improves oxygenation.

Adım Adım Çözüm

Evaluate the patient's demographic risk factors.

The infant is term (

39

weeks) but macrosomic due to poorly controlled maternal gestational diabetes.

Maternal hyperglycemia induces fetal hyperinsulinemia, which antagonizes the endogenous cortisol surge necessary for surfactant production, placing even term infants at risk for Respiratory Distress Syndrome (RDS).

Interpret the radiographic findings in the context of the physical exam.

The chest radiograph shows fine reticulogranular opacities and air bronchograms.

These findings are pathognomonic for RDS, differentiating it from Transient Tachypnea of the Newborn (TTN), which typically presents with perihilar streaking and fluid in the fissures.

Identify the nature of the dermatological findings.

The diffuse rash with

2\text{-mm}

pale pustules on an erythematous base is diagnosed as Erythema Toxicum Neonatorum (ETN).

ETN is a common, benign, self-limiting condition in healthy newborns that requires no diagnostic workup or pharmacological treatment.

Select the appropriate initial management for the respiratory failure.

Continuous positive airway pressure (CPAP) is selected.

For a spontaneously breathing neonate with RDS, early CPAP is the standard initial therapy to splint alveoli open, establish functional residual capacity, and improve oxygenation without resorting to premature invasive intubation.

Anahtar Kavram

Maternal diabetes increases the risk of Respiratory Distress Syndrome (RDS) in term infants due to fetal hyperinsulinemia delaying lung maturation. The initial management of RDS in a spontaneously breathing infant is early continuous positive airway pressure (CPAP).

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Cevap

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