[Determination of renal function at the end of the follow-up period in children with vesicoureteral reflux]. / Determinación de la función renal al final del periodo de seguimiento en niños diagnosticados de reflujo vesicoureteral.

OBJECTIVES: Vesicoureteral reflux (VUR) has been associated, since the old times, with chronic renal failure (CRF). Nevertheless, some functional parameters may be altered before glomerular filtration rate deteriorates, such as maximum urinary osmolality (Uosm) and urinary excretion of microalbumin. METHODS: We retrospectively studied the records of 77 children (37 males and 14 females; 48% and 52% respectively) with the diagnosis of VUR that were cured at the time of the study and were two years old or older (6.28 +/- 3.75; range: 2-16 years). In addition to Uosm and urinary excretion of microalbumin, the grade of VUR, creatinine levels, GFR, and morphological anomalies detected in 99Tc dimercaptosuccinate gammagrams (DMSA) were collected. RESULTS: Only four patients had moderate CREF. No differences in Uosm values were observed according to VUR grade. All children with grade I and II VUR had a normal renal concentration test. A long-term concentration defect was observed in 15 children, six with grade III, 8 with grade IV and 1 with grade V. Only 2 patients with normal DMSA had reduced Uosm. Uosm had a direct correlation with GFR (r = 0.6; p < 0.001). Regarding urinary excretion of microalbumin, elevated values were found in 11 children, one with grade II, four with grade III, and six with grade IV. Only four patients with normal DMSA showed microalbumin values over the normal range. A negative correlation between osmolality levels and microalbumin/creatinine quotient was observed (r = - 0.37; p < 0.001). In comparison with patients with normal DMSA, patients with bilateral scars showed significantly lower values of Uosm and GFR. CONCLUSIONS: At the end of the follow-up period we observed a defect on concentration capacity in 19.5% and increase of microalbuminuria in 14.3% of the children with the diagnosis of VUR. The frequency of CRF in our series is very low (5.1%). The observed renal tubular function deterioration is more in relation with the loss of renal parenchyma than the initial grade of VUR.

Determinación de la función renal al final del periodo de seguimiento en niños diagnosticados de reflujo vesicoureteral / Determination of renal function at the end of the follow-up period in children with vesicoureteral reflux

Objetivo: El reflujo vesicoureteral (RVU) se ha asociado, desde antiguo, a insuficiencia renal crónica (IRC). No obstante, antes de alterarse el filtrado glomerular, pueden afectarse algunos parámetros funcionales como la osmolalidad urinaria máxima (Uosm) y la eliminación urinaria de microalbúmina. Métodos: Se han estudiado retrospectivamente las historias clínicas de 77 niños (37 varones y 40 mujeres; 48% y 52%, respectivamente) diagnosticados de RVU y que en el momento del estudio estaban curados y tenían dos o más años de edad (6.28±3.75: rango: 2-16 años). Además de la Uosm y la eliminación urinaria de microalbúmina, se recogieron el grado de RVU, los niveles de creatinina y GFR y las anomalías morfológicas detectadas en las gammagrafías realizadas con ácido Tc-99 dimercaptosuccínico (DMSA). Resultados: Sólo cuatro pacientes tenían IRC moderada. No se observaron diferencias en los valores de Uosm según los grados de RVU. Todos los niños con RVU de grado I y II tuvieron una prueba de concentración renal normal. Se observó defecto de concentración a largo plazo en 15 niños, seis con grado III, ocho con grado IV y uno con grado V. Sólo dos pacientes con DMSA normal tuvieron la Uosm reducida. La Uosm se correlacionó directamente con el GFR (r = 0.6; p< 0.001). Con respecto a la eliminación urinaria de microalbúmina, se comprobaron valores elevados en 11 niños, uno con grado II, cuatro con grado III y seis con grado IV. Únicamente, cuatro pacientes con DMSA normal mostraron valores de microalbúminuria por encima de lo normal. Se observó una correlación negativa entre los niveles de osmolalidad y el cociente microalbúmina/creatinina (r = -0.37; p< 0.001). Los pacientes con cicatrices bilaterales mostraron con respecto a aquellos con DMSA normal, valores significativamente reducidos de Uosm y de GFR. Conclusiones: Al final del periodo de seguimiento, hemos comprobado defecto de la capacidad de concentración en el 19.5% y aumento de la microalbuminuria en el 14.3% de los niños que habían sido diagnosticados de RVU. La frecuencia de IRC en nuestra serie es muy reducida (5,1%). El deterioro observado de la función renal se relaciona con la pérdida de parénquima renal más que con el grado inicial de RVU (AU)

Objectives: Vesicoureteral reflux (VUR) has been associated, since the old times, with chronic renal failure (CRF). Nevertheless, some functional parameters may be altered before glomerular filtration rate deteriorates, such as maximum urinary osmolality (Uosm) and urinary excretion of microalbumin. Methods: We retrospectively studied the records of 77 children (37 males and 14 females; 48% and 52% respectively) with the diagnosis of VUR that were cured at the time of the study and were two years old or older (6.28 ± 3.75; range: 2-16 years). In addition to Uosm and urinary excretion of microalbumin, the grade of VUR, creatinine levels, GFR, and morphological anomalies detected in 99Tc dimercaptosuccinate gammagrams (DMSA) were collected. Results: Only four patients had moderate CRF. No differences in Uosm values were observed according to VUR grade. All children with grade I and II VUR had a normal renal concentration test. A long-term concentration defect was observed in 15 children, six with grade III, 8 with grade IV, and 1 with grade V. Only 2 patients with normal DMSA had reduced Uosm. Uosm had a direct correlation with GFR (r = 0.6; p < 0.001). Regarding urinary excretion of microalbumin, elevated values were found in 11 children, one with grade II, four with grade III, and six with grade IV. Only four patients with normal DMSA showed microalbumin values over the normal range. A negative correlation between osmolality levels and microalbumin/creatinine quotient was observed (r = - 0.37; p < 0.001). In comparison with patients with normal DMSA, patients with bilateral scars showed significantly lower values of Uosm and GFR. Conclusions: At the end of the follow-up period we observed a defect on concentration capacity in 19.5% and increase of microalbuminuria in 14.3% of the children with the diagnosis of VUR. The frequency of CRF in our series is very low (5.1%). The observed renal tubular function deterioration is more in relation with the loss of renal parenchyma than the initial grade of VUR (AU)