Differential Diagnosis
The patient's symptoms and diagnostic results suggest a cardiac issue. Here's a breakdown of the differential diagnosis:
Single most likely diagnosis
- A. Anomalous pulmonary venous return: The increase in oxygen saturation from the inferior vena cava to the right atrium suggests that oxygenated blood is entering the right heart, which is consistent with anomalous pulmonary venous return. This condition occurs when the pulmonary veins connect to the right atrium or one of its tributaries instead of the left atrium.
Other Likely diagnoses
- E. Ventricular septal defect: Although the data does not directly support this diagnosis, a ventricular septal defect could lead to increased flow through the pulmonary artery, potentially causing exertional dyspnea. However, the lack of a significant step-up in oxygen saturation between the right ventricle and the pulmonary artery makes this less likely.
- C. Primary pulmonary arterial hypertension: This condition could cause exertional dyspnea and prominence of the right heart border on chest x-ray. However, it would not typically cause an increase in oxygen saturation between the inferior vena cava and the right atrium.
Do Not Miss
- D. Tetralogy of Fallot: Although the patient's age and lack of cyanosis make this diagnosis less likely, tetralogy of Fallot can present with exertional dyspnea. It is essential to consider this diagnosis due to its potential severity and the need for prompt treatment.
- B. Hypoplastic left heart syndrome: This condition is typically diagnosed in infancy, but it's crucial to consider it in the differential diagnosis due to its high mortality rate if left untreated.
Rare diagnoses
- Other rare cardiac anomalies, such as cor triatriatum or pulmonary arteriovenous malformation, could potentially cause similar symptoms. However, these conditions are less likely and would require additional diagnostic testing to confirm.