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Difficulty: MediumPediatric Cardiovascular Disorders

A 14-week-old female infant is evaluated in the pediatric emergency department for increased work of breathing and diaphoresis during feeding. Over the past three weeks, her mother has noticed that she tires easily during nursing and fails to complete feeds. Her weight is below the 5th percentile, having previously tracked at the 50th percentile at birth. Vital signs demonstrate a temperature of 36.9°C (98.4°F), heart rate of 172/min, respiratory rate of 68/min, and oxygen saturation of 94% on room air. Physical examination reveals subcostal retractions and diffuse expiratory wheezes accompanied by basilar crackles bilaterally. Cardiac auscultation demonstrates a hyperdynamic precordium and a grade 4/6 harsh holosystolic murmur over the left lower sternal border with a palpable thrill. Palpation of the abdomen reveals hepatomegaly 3.5 cm below the right costal margin. Which of the following is the most appropriate next step in the management of this patient?

  1. Intravenous furosemide administrationAnswer
  2. B
    Inhaled short-acting beta-agonist therapy
  3. C
    Empiric intravenous broad-spectrum antibiotics
  4. D
    Systemic glucocorticoids and inhaled ipratropium
  5. E
    Referral for a comprehensive neurodevelopmental evaluation

Answer

Intravenous furosemide administration
The correct intervention is intravenous furosemide administration. This infant is presenting with classic signs of congestive heart failure (CHF) secondary to a large ventricular septal defect (VSD). As pulmonary vascular resistance naturally drops over the first few weeks of life, a large VSD allows significant left-to-right shunting of blood. This causes pulmonary overcirculation (leading to tachypnea, wheezing, and crackles) and decreases systemic cardiac output, which triggers sympathetic activation (tachycardia and diaphoresis during exertion, such as feeding). The increased metabolic demand of breathing coupled with poor feeding efficiency results in failure to thrive. Furosemide is a loop diuretic that decreases intravascular volume and reduces pulmonary congestion, serving as the essential first step in stabilizing an infant with acute CHF before potential surgical correction.

Step-by-Step Solution

1
Analyze the physical examination findings, specifically the cardiac auscultation.
The patient has a grade 4/6 harsh holosystolic murmur with a thrill at the left lower sternal border.
This murmur is the classic hallmark of a ventricular septal defect (VSD).
2
Evaluate the respiratory and systemic symptoms in the context of the cardiac anomaly.
The infant exhibits tachypnea, retractions, wheezing, basilar crackles, diaphoresis with feeding, failure to thrive, and hepatomegaly.
These findings collectively indicate acute decompensated congestive heart failure, caused by a significant left-to-right shunt resulting in pulmonary overcirculation and systemic hypoperfusion.
3
Determine the most appropriate immediate medical intervention.
Select a diuretic, such as intravenous furosemide.
Diuretics are the first-line acute pharmacological treatment for heart failure in infants with large left-to-right shunts; they reduce preload and alleviate the pulmonary edema (crackles, wheezing, and respiratory distress).

Key Concept

Large ventricular septal defects (VSDs) typically present with congestive heart failure at 1 to 2 months of age as pulmonary vascular resistance falls. Initial management focuses on diuresis (e.g., furosemide) to relieve pulmonary congestion.
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Topics

Pediatric Cardiovascular Disorders

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