A newborn baby is readmitted to the hospital with hypoxia and upon testing is found to have pulmonary stenosis, dextraposition of the aoa, interventricular septal defect, and hyperophy of the right ventricle. Which of the following is best described by these symptoms?
**Core Concept**
Pulmonary stenosis, dextraposition of the aorta, interventricular septal defect, and hypertrophy of the right ventricle are characteristic features of a congenital heart defect known as Tetralogy of Fallot (TOF). TOF is a cyanotic heart defect that involves four anatomical abnormalities: ventricular septal defect, pulmonary stenosis, right ventricular hypertrophy, and an overriding aorta.
**Why the Correct Answer is Right**
The combination of these four features is pathognomonic for Tetralogy of Fallot. The interventricular septal defect allows blood to flow from the left to the right ventricle, while the pulmonary stenosis restricts blood flow from the right ventricle to the lungs. As a result, the right ventricle becomes hypertrophied due to the increased resistance to blood flow. The aorta is dextraposed, or displaced to the right, due to the increased pressure in the right ventricle. This leads to cyanosis and hypoxia in the newborn.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not correct as it does not describe the characteristic features of Tetralogy of Fallot. The combination of symptoms described in the question is unique to TOF.
**Option B:** This option is not correct as it describes a different congenital heart defect, such as Transposition of the Great Arteries (TGA). While TGA also involves cyanosis and hypoxia, the characteristic features of TGA are different from those described in the question.
**Option C:** This option is not correct as it describes a different congenital heart defect, such as Ventricular Septal Defect (VSD). While VSD involves a defect in the interventricular septum, it does not typically involve pulmonary stenosis or an overriding aorta.
**Option D:** This option is not correct as it describes a different congenital heart defect, such as Truncus Arteriosus. While Truncus Arteriosus involves a single blood vessel arising from the heart, it does not typically involve pulmonary stenosis or an overriding aorta.
**Clinical Pearl / High-Yield Fact**
Tetralogy of Fallot is a classic example of a cyanotic heart defect that requires prompt medical attention. The symptoms described in the question, such as hypoxia and cyanosis, are characteristic of TOF and should prompt a search for the characteristic features of the defect.
**Correct Answer:** C. Tetralogy of Fallot.