Usefulness of basic renal function tests in the management of hydronephrosis

Area of Science:

• Pediatric Nephrology
• Diagnostic Imaging
• Urology

Background:

• Hydronephrosis diagnosis in children often relies on invasive VCUG and DR.
• These procedures carry risks including radiation exposure and patient distress.
• Basic renal function tests (bRFTs) are not routinely incorporated into diagnostic algorithms.

Purpose of the Study:

• To evaluate the utility of bRFTs in potentially avoiding VCUG and/or DR in pediatric hydronephrosis patients.
• To determine if bRFTs can differentiate between obstructive and non-obstructive causes of hydronephrosis.
• To identify the most sensitive bRFT for detecting significant renal abnormalities.

Main Methods:

• Retrospective analysis of 38 pediatric hydronephrosis patients (PUS, VUR, NOH).
• Collected data included VCUG, DR, and three bRFTs: UOsm, Alb/Cr, and NAG/Cr.
• Compared bRFT results with diagnoses and need for surgery.

Main Results:

• Decreased UOsm was observed in 100% of VUR, 75% of PUS, and 16.7% of NOH patients.
• Increased Alb/Cr and NAG/Cr ratios were also noted, particularly in VUR patients.
• UOsm was significantly lower in patients requiring surgery compared to those who did not.

Conclusions:

• bRFTs, especially UOsm, show promise in guiding the need for VCUG and DR in pediatric hydronephrosis.
• Normal UOsm values could potentially allow avoidance of VCUG in approximately 43% of cases without missing high-grade VUR.
• UOsm is a sensitive marker, with no high-grade VUR patients exhibiting normal UOsm.