A 2-week-old girl is found to have a harsh murmur along the left sternal border. The parents report that the baby gets “bluish” when she cries or drinks from her bottle. Echocardiogram reveals a congenital heart defect associated with pulmonary stenosis, ventricular septal defect, dextroposition of the aorta, and right ventricular hypertrophy. What is the appropriate diagnosis?

**Core Concept**
The question is testing the student's knowledge of a congenital heart defect characterized by a unique combination of pulmonary stenosis, ventricular septal defect, dextroposition of the aorta, and right ventricular hypertrophy. This defect is a classic example of a cyanotic congenital heart disease.

**Why the Correct Answer is Right**
The correct diagnosis is Tetralogy of Fallot (TOF). TOF is a congenital heart defect that occurs due to the abnormal development of the heart during fetal development. The four classic features of TOF are:
- Ventricular septal defect (VSD): a hole in the wall between the two ventricles.
- Pulmonary stenosis: narrowing of the pulmonary valve, which obstructs blood flow from the right ventricle to the pulmonary artery.
- Dextroposition of the aorta: the aorta is positioned to the right of the pulmonary artery, rather than its normal position to the left.
- Right ventricular hypertrophy: thickening of the muscle wall of the right ventricle due to increased pressure and workload.

The symptoms described, such as cyanosis (bluish discoloration of the skin) when the baby cries or drinks, are due to the decreased oxygenation of the blood. The harsh murmur along the left sternal border is likely due to the turbulent blood flow across the VSD.

**Why Each Wrong Option is Incorrect**
**Option A:** Tricuspid Atresia - This condition is characterized by the absence of the tricuspid valve, which is not present in TOF.

**Option B:** Transposition of the Great Arteries - This condition involves the aorta and pulmonary artery being reversed, which is not the case in TOF.

**Option C:** Ebstein's Anomaly - This condition involves the abnormal development of the tricuspid valve and right ventricle, which is not characteristic of TOF.

**Clinical Pearl / High-Yield Fact**
TOF is a cyanotic congenital heart disease that is often associated with clubbing of the fingers and toes, and a characteristic "boot-shaped" heart on chest X-ray.

**Correct Answer:** C. Tetralogy of Fallot.

✓ Correct Answer: D. Tetralogy of Fallot