Question 1

Q: Which of the following is NOT a chest X-ray feature suggestive of Ventricular Septal Defect (VSD) in a child?

Large aortic knob. **Explanation:** Ventricular Septal Defect (VSD) is a left-to-right shunt characterized by increased pulmonary blood flow and volume overload of the left heart chambers. **1. Why "Large aortic knob" is the correct answer:** In VSD, blood shunts from the left ventricle directly into the right ventricle and then into the pulmonary circulation. Because the shunt occurs **distal** to the aorta, the aorta does not carry the excess volume. In fact, in large shunts, the systemic output may decrease, leading to a **small or inconspicuous aortic knob**. A large aortic knob is typically seen in Patent Ductus Arteriosus (PDA), where the aorta must carry the extra volume before it shunts into the pulmonary artery. **2. Analysis of incorrect options:** * **Increased splaying of the carina:** Large VSDs lead to left atrial enlargement (due to increased venous return from the lungs). An enlarged left atrium pushes the left main bronchus upward, widening the subcarinal angle. * **Cardiomegaly:** This occurs due to volume overload and subsequent hypertrophy/dilation of the left atrium and left ventricle (and eventually the right ventricle if pulmonary hypertension develops). * **Pulmonary plethora:** Increased pulmonary blood flow (left-to-right shunt) manifests on X-ray as prominent vascular markings extending to the outer third of the lung fields. **Clinical Pearls for NEET-PG:** * **VSD** is the most common congenital heart disease. * **Shunt Rule:** VSD and PDA cause **Left** atrial/ventricular enlargement; ASD causes **Right** atrial/ventricular enlargement. * **Small Aorta:** Common in VSD and ASD. * **Large Aorta:** Characteristic of PDA and Tetralogy of Fallot (compensatory). * **Eisenmenger Syndrome:** Look for "pruning" of peripheral vessels (central pulmonary artery dilation with peripheral tapering).

Question

Which of the following is NOT a chest X-ray feature suggestive of Ventricular Septal Defect (VSD) in a child?

Accepted Answer

Large aortic knob

Answer

Increased splaying of the carina

Answer

Cardiomegaly

Answer

Pulmonary plethora

Cardiology — MCQs

Cardiology — MCQs

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