Urological and nephrological findings of renal ectopia

Urological characteristics of renal ectopia have been addressed previously but little is known about the functional consequences. We sought to study renal function, blood pressure, proteinuria and urological abnormalities in children with renal ectopia. As a secondary objective, we compared these parameters between simple and crossed ectopia.

For this retrospective, single center, observational study we reviewed case documents and radiological records. We also analyzed longitudinal data on blood pressure, proteinuria and kidney function.

Renal ectopia was diagnosed in 41 cases, of which 26 (63%) were simple renal ectopia, ie unilateral pelvic kidney. In 32% of patients the diagnosis was made during prenatal screening. Median patient age was 0.24 years at diagnosis and 7.7 years at the most recent control visit. Associated urological abnormalities were found in 66% of patients. Voiding cystourethrography was performed in all patients, with vesicoureteral reflux shown in 13. In 8 of 10 cases with unilateral reflux the condition manifested in the orthotopic kidney. The relative function of the ectopic kidney on dimercapto-succinic acid scan was 38%, and in 22% of patients glomerular filtration rate was less than 90 ml per minute per 1.73 m(2). Albuminuria and proteinuria were absent in most cases. Longitudinal analysis of blood pressure, glomerular filtration rate and albuminuria revealed a stable course for all parameters. No substantial difference was observed between simple and crossed renal ectopia.

Our data suggest no adverse effects on blood pressure or kidney function in children with renal ectopia. However, periodic followup seems warranted, at least until young adulthood.