Is further investigation or intervention required for mild renal pelvis (kidney pelvis) prominence with otherwise normal imaging results?

From the Guidelines

Mild renal pelvis prominence on imaging typically does not require immediate intervention or further investigation if it is an isolated finding with no other abnormalities. This condition, often called mild hydronephrosis or pelvicaliectasis, is frequently an incidental finding that may represent a normal variant, especially if the dilation is less than 10mm 1. However, follow-up imaging in 3-6 months with an ultrasound is reasonable to ensure stability. Some key points to consider in the management of mild renal pelvis prominence include:

• The presence of hydronephrosis can be useful in predicting the likelihood of ureteral stone on subsequent CT, but a lack of hydronephrosis does not rule out the diagnosis 1.
• CT abdomen and pelvis without IV contrast can be useful in evaluating symptomatic patients when US is inconclusive, particularly in cases of suspected obstructive urolithiasis 1.
• Ultrasound has the greatest diagnostic value in the detection of hydronephrosis associated with acute urinary tract obstruction, and can guide intervention such as Foley catheter placement or nephrostomy/stenting 1. If you experience symptoms such as flank pain, recurrent urinary tract infections, blood in urine, or if the prominence is accompanied by kidney stones or decreased kidney function on blood tests, then further evaluation would be warranted. In these cases, a referral to a urologist would be appropriate for additional testing such as a comprehensive renal ultrasound or CT urogram 1. The prominence may be due to temporary factors like increased fluid intake before imaging, a full bladder during the scan, or normal anatomical variation. If you are pregnant, mild renal pelvis dilation is particularly common due to hormonal effects and pressure from the growing uterus, and typically resolves after delivery. It is essential to weigh the benefits and risks of further investigation or intervention, considering the potential for unnecessary testing or procedures, and prioritize the patient's quality of life and minimize harm.

From the Research

Mild Renal Pelvis Prominence Investigation

• The need for further investigation or intervention for mild renal pelvis prominence with otherwise normal imaging results is a complex issue, as evidenced by various studies 2, 3, 4, 5, 6.
• In some cases, mild renal pelvis prominence may be associated with underlying conditions such as obstructive uropathy 2, renal arteriovenous malformations 3, or villous adenoma of the renal pelvis 4.
• A study published in 2019 found that children with mild-to-moderate renal pelvis dilatation identified during pregnancy had a higher risk of hospital admission for urinary tract causes in the first three years of life 5.
• Another study published in 1999 found that CT findings can be used to diagnose underlying ureteropelvic junction obstruction in patients with renal trauma, and that pelvic extension and perirenal collections can be demonstrated in these cases 6.

Key Findings

• Mild renal pelvis prominence may not always be a benign finding, and further investigation may be necessary to rule out underlying conditions 2, 3, 4.
• The presence of mild renal pelvis dilatation during pregnancy may be associated with an increased risk of hospital admission for urinary tract causes in childhood 5.
• CT findings can be used to diagnose and manage underlying ureteropelvic junction obstruction in patients with renal trauma 6.

Considerations for Further Investigation

• The decision to pursue further investigation or intervention for mild renal pelvis prominence should be based on individual patient factors, including medical history, symptoms, and imaging results 2, 3, 4, 5, 6.
• A thorough evaluation, including imaging studies and laboratory tests, may be necessary to determine the underlying cause of mild renal pelvis prominence and to guide management decisions 2, 3, 4, 5, 6.