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Difficulty: EasyPediatric Cardiovascular Disorders

A couple brings their 12-week-old infant son to the pediatric clinic because they noticed he breathes rapidly and sweats profusely whenever he nurses. The mother reports that feedings take nearly an hour, yet he often falls asleep exhausted before finishing. He has had no fever, cough, or nasal congestion. Review of his growth chart shows his weight has declined from the 30th percentile at birth to below the 5th percentile today. Vital signs show a temperature of 37.0°C (98.6°F), pulse of 168/min, and respiratory rate of 65/min. Pulse oximetry is 97% on room air. Physical examination reveals a thin infant with mild subcostal retractions and diffuse expiratory wheezes bilaterally. Cardiac auscultation demonstrates a hyperdynamic precordium and a prominent, harsh, grade 3/6 holosystolic murmur best heard at the left lower sternal border. The liver edge is palpable 4 cm below the right costal margin. Which of the following is the most appropriate initial pharmacological management for this patient?

  1. Administer furosemideAnswer
  2. B
    Administer nebulized albuterol
  3. C
    Prescribe oral azithromycin
  4. D
    Provide reassurance and routine follow-up
  5. E
    Administer oral dexamethasone

Answer

Administer furosemide
The correct answer is administering furosemide. This infant's presentation is classic for congestive heart failure (CHF) secondary to a congenital left-to-right shunt, most likely a Ventricular Septal Defect (VSD) given the prominent, harsh holosystolic murmur at the left lower sternal border. As normal neonatal pulmonary vascular resistance drops over the first few weeks of life, the left-to-right shunt increases, leading to pulmonary overcirculation. This manifests as tachypnea, wheezing (often termed 'cardiac asthma' due to pulmonary edema), diaphoresis during exertion (such as feeding), and failure to thrive. Systemic venous congestion leads to hepatomegaly. The initial pharmacological management for pediatric CHF involves loop diuretics (e.g., furosemide) to reduce intravascular volume, alleviate pulmonary congestion, and improve the work of breathing, allowing the infant to feed and gain weight prior to eventual surgical repair.

Step-by-Step Solution

1
Analyze the patient's history and physical examination findings.
The infant presents with failure to thrive, diaphoresis with feeds, tachypnea, hepatomegaly, and a harsh holosystolic murmur at the left lower sternal border.
Identifying the constellation of symptoms is crucial for differentiating primary pulmonary disease from cardiac disease.
2
Synthesize the findings to establish the most likely underlying diagnosis.
The clinical picture is highly characteristic of congestive heart failure secondary to a large left-to-right cardiac shunt, most commonly a Ventricular Septal Defect (VSD).
A VSD typically presents at 1-2 months of age as pulmonary vascular resistance falls, allowing significant left-to-right shunting, pulmonary overcirculation, and subsequent heart failure.
3
Determine the appropriate initial pharmacological therapy for the established diagnosis.
Diuretics, specifically loop diuretics like furosemide, are the first-line medical therapy to alleviate symptoms of pulmonary congestion.
Reducing intravascular volume decreases pulmonary edema (which is causing the wheezing and tachypnea) and improves the infant's ability to feed and grow prior to definitive surgical repair.

Key Concept

Pediatric patients with large left-to-right shunts (like Ventricular Septal Defects) commonly present with congestive heart failure (failure to thrive, diaphoresis with feeds, hepatomegaly, and pulmonary edema manifesting as wheezing); initial medical management includes diuretics such as furosemide.
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Topics

Pediatric Cardiovascular Disorders

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