Which condition refers to distension of the renal pelvis typically due to upstream blockage?

• A. Polycystic kidney disease
• B. Nephroptosis
• C. Nephritis
• D. Nephrectasis

Answer: (D)

When urine cannot drain because of a blockage upstream, pressure backs up into the collecting system and causes dilation of the renal pelvis. This specific pelvic dilation is called nephrectasis. If the dilation extends to include the calyces as well, the term hydronephrosis is often used, but the key idea here is the pelvis itself distending due to obstruction.

The other conditions describe different processes: polycystic kidney disease involves cyst formation within the kidney tissue itself; nephroptosis is downward displacement of the kidney; nephritis is inflammation of kidney tissue. None of these describe distension of the renal pelvis from an upstream blockage, which is why nephrectasis is the best fit.