A 6-week-old boy is evaluated in the pediatric clinic due to difficulty with feeding. His mother reports that he requires frequent pauses while nursing and becomes remarkably sweaty and breathless during his feeds. His weight has dropped from the 50th percentile at birth to the 5th percentile currently. Vital signs demonstrate a heart rate of 158/min and a respiratory rate of 68/min. Physical examination reveals a loud, harsh holosystolic murmur heard best at the left lower sternal border, accompanied by a palpable thrill. Lung auscultation reveals bilateral basilar crackles and diffuse wheezing. Which of the following is the most appropriate next step in the management of this patient?
- Transthoracic echocardiographyAnswer
- BTrial of nebulized albuterol
- CReassurance and return for the two-month well-child visit
- DPrescription for a course of oral amoxicillin
- EMeasurement of serum thyroid-stimulating hormone
Answer
Transthoracic echocardiography
The correct answer is transthoracic echocardiography. This infant presents with textbook signs of congestive heart failure secondary to a large Ventricular Septal Defect (VSD). A VSD commonly presents at 4 to 6 weeks of age as pulmonary vascular resistance falls, allowing significant left-to-right shunting. This results in pulmonary overcirculation (manifesting as tachypnea, crackles, and wheezing) and high metabolic demand (manifesting as diaphoresis during feeding and failure to thrive). The harsh holosystolic murmur at the left lower sternal border is the hallmark physical finding. Transthoracic echocardiography is the definitive diagnostic test to visualize the defect, quantify the shunting, and plan appropriate therapy.
Step-by-Step Solution
Key Concept
Diagnosis of Ventricular Septal Defect (VSD) presenting as congestive heart failure in infancy.