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[Intrarenal reflux in children with vesicoureteral reflux]
1Department of Urology, Hokkaido University School of Medicine.
Insights
Intrarenal reflux (IRR) in children with vesicoureteral reflux (VUR) is uncommon, often linked to febrile urinary infections and various VUR causes. While IRR can lead to renal scarring, its presence doesn't always correlate with scar location or extent.
Area of Science:
- Pediatric Urology
- Nephrology
- Radiology
Background:
- Vesicoureteral reflux (VUR) is a common condition in children, often associated with urinary tract infections.
- Intrarenal reflux (IRR) is a less common variant of VUR, where urine flows back into the renal parenchyma.
- Understanding IRR is crucial for diagnosing and managing potential renal damage in pediatric patients.
Purpose of the Study:
- To investigate the incidence, characteristics, and clinical implications of intrarenal reflux (IRR) in children with vesicoureteral reflux (VUR).
- To evaluate the association between IRR, VUR severity, and renal scarring.
- To analyze the role of urinary infections in the development of renal damage in the presence of IRR.
Main Methods:
- Retrospective review of voiding cystourethrography (VCU) findings in 407 children with VUR.
- Identification of cases with intrarenal reflux (IRR).
- Assessment of renal scarring using excretory urography (IVP) and/or 99mTc-DMSA renoscintigraphy.
Main Results:
- Seven cases (8 ureters) of IRR were identified among 407 children with VUR (1.7% incidence).
- All identified children were male with febrile urinary infection before one year of age.
- IRR was associated with moderate to massive VUR and various underlying causes, including urethral anomalies and neurogenic bladder.
- Renal scarring was observed in evaluable kidneys, with polar scars being most common; however, IRR did not always correlate with corresponding renal scars.
- New scar formation was noted in some cases, suggesting ongoing renal damage.
Conclusions:
- Intrarenal reflux (IRR) is an infrequent finding in children with VUR, predominantly seen in males with early-onset febrile urinary infections.
- The presence and location of IRR may not directly predict the presence or pattern of renal scarring.
- Urinary infection appears to play a significant role in renal scar formation, even in the context of IRR.
Abstract:
Voiding cystourethrography (VCU) of 407 children with vesicoureteral reflux (VUR) at our hospital during 1969-1990 was reviewed and 7 cases (8 ureters) of intrarenal reflux (IRR) were found. All the children were male and had had an episode of febrile urinary infection under one year of age. One child had a left flank mass, which was later proven a urinoma. VUR was moderate (grade III) in 3 and massive (grade IV and V) in 5. VUR was estimated as primary in one child and as secondary in 6 (anterior urethral ring 2, posterior urethral valve 2, neurogenic bladder 2). IRR was localized to the upper area in 3, to the lower area in 2, and to the whole kidney in 3. Sixty percent of those with IRR in the polar areas was associated with moderate VUR, whereas all of those in the whole kidney was with massive one. Renal scarring was assessed by excretory urography (IVP) and/or 99mTc-DMSA renoscintigraphy. Seven kidneys were evaluable; polar scars in 5, dwarf with polar scar in 1 and dwarf with poor function (suspected hypodysplasia) in 1. In 4 kidneys new scar formation was observed. It was noted, however, that IRR did not necessarily accompany renal scars of the corresponding areas and IRR to the whole kidney did not always lead to multiple scars in the whole kidney. The nature and problems of IRR, renal scars and 99mTc-DMSA renoscintigraphy were discussed. It was suggested that urinary infection played a greater part in renal scar formation.