A 3-month-old infant with Down syndrome presents with poor feeding, failure to thrive, and recurrent chest infections. On examination, there is a harsh pansystolic murmur at the lower left sternal border, and a soft mid-diastolic murmur at the apex. Echocardiography reveals a complete atrioventricular septal defect (AVSD). What is the MOST important reason for early surgical repair before 6 months?
- A Risk of Eisenmenger syndrome developing rapidly due to high pulmonary blood flow ✓
- B High risk of infective endocarditis in the first year
- C Risk of paradoxical embolism through the AV defect
- D Progressive left ventricular outflow tract obstruction
Correct answer: A. Risk of Eisenmenger syndrome developing rapidly due to high pulmonary blood flow
Explanation
Complete AVSD has a large left-to-right shunt that leads to high pulmonary blood flow and pressure. Children with Down syndrome develop pulmonary vascular disease (Eisenmenger syndrome) earlier and more rapidly than chromosomally normal children with AVSD. If uncorrected, irreversible pulmonary hypertension develops by 12–18 months, making surgery impossible. Early repair before 3–6 months prevents this. The additional mitral regurgitation from the common AV valve contributes to congestive heart failure.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.