Reflux filling the pelvicalyceal system with moderate dilatation of ureter is
**Core Concept**
Reflux of urine into the pelvicalyceal system can occur due to various reasons, including vesicoureteral reflux (VUR) or ureteropelvic junction obstruction (UPJO). This phenomenon can lead to moderate dilatation of the ureter as the urine flows back from the bladder into the upper urinary tract.
**Why the Correct Answer is Right**
The correct answer is associated with a condition where the urine flows back from the bladder into the upper urinary tract, causing dilatation of the ureter. This is a characteristic feature of vesicoureteral reflux (VUR), where the abnormal anatomy of the ureterovesical junction (UVJ) allows urine to flow back from the bladder into the ureter. The moderate dilatation of the ureter is a result of the increased pressure and volume of urine flowing back into the upper urinary tract.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not directly related to the reflux filling the pelvicalyceal system. It might refer to a different condition such as ureteral obstruction or ureteral stone causing dilatation of the ureter.
**Option B:** This option is incorrect as it does not describe the condition of reflux filling the pelvicalyceal system. It might refer to a condition such as pyelonephritis or renal abscess.
**Option C:** This option is incorrect as it does not describe the condition of reflux filling the pelvicalyceal system. It might refer to a condition such as renal artery stenosis or renal vein thrombosis.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that vesicoureteral reflux (VUR) is a common cause of upper urinary tract dilation in children, and it can increase the risk of recurrent urinary tract infections (UTIs) and renal scarring.
**Correct Answer: C. Hydro-ureteronephrosis**