Rosh Pediatrics Practice Exam

What is the most likely cause of a continuous murmur in a 7-year-old boy that resolves when lying supine?

1. AAortic stenosis

2. BCervical venous hum

3. CInnocent Still murmur

4. DPatent ductus arteriosus

The correct answer is: BCervical venous hum

A continuous murmur that resolves when the patient lies supine is most commonly associated with a cervical venous hum. This type of murmur results from the blood flow in the jugular veins, which can create a continuous sound. It is particularly common in children due to the anatomical positioning and development of their vascular structures. The murmur is often more pronounced when the child is sitting or standing, as gravity influences venous return. When lying supine, the pressure and flow dynamics change, leading to a reduction in the murmur's intensity or complete resolution. In contrast, other options do not present with this specific behavior. Aortic stenosis typically causes a systolic ejection murmur that does not vary with position. An innocent Still murmur is usually a systolic murmur that can be influenced by factors like positioning but does not present continuously. Patent ductus arteriosus causes a continuous murmur that typically does not resolve with changes in position and is generally associated with a distinct clinical presentation related to heart failure or increased pulmonary flow.