Pelvi‐Ureteric Junction Obstruction in a Solitary Functioning Kidney in Children: An Unfavourable Combination

Aim Solitary functioning kidney (SFK) is linked to chronic kidney disease (CKD) in children, particularly when associated with congenital anomalies of the kidney and urinary tract (CAKUT). Pelvi‐ureteric junction obstruction (PUJO) is the most frequent obstructive uropathy in SFK. This study aimed to evaluate long‐term kidney function in children operated on for PUJO in an SFK. Methods Among a retrospective cohort study of children with an SFK, a subgroup analysis was performed: primary SFK with operated PUJO ( n = 35); primary SFK without CAKUT ( n = 108); primary SFK with CAKUT other than PUJO ( n = 24). Markers of CKD and measured glomerular filtration rate were assessed during follow‐up. Results Surgery was indicated because of neonatal acute kidney injury (AKI) ( n = 21), worsening renal pelvis dilation ( n = 10). The median age at surgery was 15 months (1.2–30 months). At a median age of 13 years at last follow‐up, the proportion of CKD was higher in primary SFK with PUJO compared to primary SFK without CAKUT (43% vs. 12%, p = 0.0008). In SFK/PUJO, neonatal AKI was predictive of subsequent CKD (OR 4.8, p = 0.04). Conclusion PUJO in an SFK is associated with a high rate of CKD during childhood, particularly when neonatal AKI is present.