On renal ultrasound, which finding is classic for chronic kidney disease?

• A. Large kidneys
• B. Small kidneys
• C. Hydronephrosis
• D. Cystic kidneys with calcifications

Answer: (B)

Chronic kidney disease causes progressive loss of nephron mass with scarring and shrinkage of the renal parenchyma. On ultrasound this appears as small, atrophic kidneys with increased echogenicity from fibrotic tissue and thinning of the cortex. The reduced size is a classic indicator of long-standing parenchymal damage.

In contrast, enlarged kidneys are more typical of polycystic kidney disease or certain acute conditions; hydronephrosis shows dilation of the collecting system rather than atrophy; cystic kidneys with calcifications describe other cystic or calcific processes. So the hallmark ultrasound finding in chronic kidney disease is small kidneys.