During assessment of the renal region, a dull percussion note at the costovertebral angle is most consistent with which interpretation?

• A. A normal finding
• B. Fluid overload
• C. Acute obstruction
• D. Severe infection

Answer: (A)

The main idea here is that percussion over the costovertebral angle is used to detect kidney tenderness, not to diagnose by the dullness of the sound alone. In a healthy person, the kidney region can feel dull to percussion because of the density of underlying tissues and the retroperitoneal position, but there should be no pain or tenderness when tapped. A dull note in this area by itself does not indicate fluid overload, acute obstruction, or severe infection. Those conditions typically present with additional signs—such as flank pain or tenderness (infections like pyelonephritis), symptoms of urinary obstruction, or systemic signs—and more than just the percussion sound. Therefore, a dull percussion note at the costovertebral angle, without tenderness or other symptoms, is most consistent with a normal finding.