Determinación de función renal y cambios compensadores en niños con riñón único / Study of renal function and compensatory changes in children with single kidney

RESUMEN

Introducción. Se ha considerado siempre que la reducción de la masa renal durante la infancia, causa una serie de cambios funcionales que eventualmente pueden conducir a un daño irreversible en el riñón remanente con el paso de los años. Objetivos. La evidencia de estas lesiones en múltiples publicaciones nos movió a revisar a un grupo de 38 pacientes monorrenos en la edad infantil y a intentar determinar el riesgo de aparición de las mismas a través de parámetros como la función renal, la tensión arterial, la presencia de proteinuria y el volumen renal. Material y métodos. Se estudiaron 38 pacientes, 23 de ellos varones y 15 mujeres, de edades entre 1 y 13 años, que habían sufrido pérdida de masa renal por causas congénitas o adquiridas. Se separaron en dos grupos de enfermos Grupo I Ausencia congénita unilateral de riñón funcionante (25 casos). Grupo II Nefrectomizados por pérdida de un riñón(con función previa normal) después del segundo año de vida (13 casos). Se midió la somatometría, la tensión arterial (TA), el filtrado glomerular (FG), la proteinuria, el volumen renal (VR) y se consideró la presencia de anomalías contralaterales (AC). Resultados. El peso y la talla se encontró en percentiles normales. La TA se encontró elevada en 5 pacientes. La creatinina sérica sólo estaba elevada en 1 paciente con severa afectación del riñón remanente, el aclaramiento de creatinina (Ccr) resultó elevado de forma generalizada y se observó microalbuminuria en 2 pacientes. El volumen renal fue similar en ambos grupos. El estudio isotópico evidenció ectasia sin obstrucción en el 80% de todos los casos y el FG según el método de Inoue (corregido para niños) resultó en ambos grupos dentro de valores normales. Conclusiones. No encontramos diferencias significativas en la función renal entre los dos grupos de pacientes ni tampoco indicios de nefropatía por hiperfiltración. El Ccr evidenció una situación de hiperfiltrado en todos los casos. El filtrado glomerular calculado por estudio isotópico no confirmó estasituación. El volumen renal no se observó relacionado con la edad a la que se produjo la pérdida renal, y sí con el tiempo transcurrido postpérdida. La existencia de anomalías en el riñón contralateral influye en el grado de hipertrofia que desarrolla (AU)

ABSTRACT

Introduction. It has always been thought that a reduction of renal tissue in childhood sometimes causes some irreversible injury in the remnant kidney as the years go by. The aim of this paper is to look over the presence of these changes and identify the risk of nephropaty throughout several parameters. Material and methods. We reviewed 38 children, 23 males and 15 females, aged between 1 and 15 years, who had lost unilateral renal mass because of congenital or adquired diseases. We made two groups of patients on the basis of having born without any unilateral renal function –group I– or having lost unilateral renal function after the second year of life. We measured Somatometry, arterial pressure, glomerular filtration, microalbuminuria, renal volume and gammagraphic studies were also made. We also considered the presence of contralateral anomalies. Results. Body weight and height were within normal percentiles. Arterial pressure increased in 5 patients. Seric creatinine was normal, creatinine clearance (Ccr) was higher than normal in all patients of both groups, and urinary excretion of protein was normal. Renal volume of remnant kidney was similar in both groups, and no relation with renal function level was found, but it increased through the years. Isotopic studies showed ectatic drainage in all urinary systems. Contralateral anomalies were seen in 7 patients, and they consisted in hydronephrosis and vesico-ureteral reflux. Conclusions. Hypertension was not related to the cause of renal absence nor the pathology of remnant kidney. Ccr was higher than normal, showing an hyperfiltration status, not confirmed by the values of isotopic filtrate. Renal volume reached by the single kidney was affected by the time after the renal loss, and apparently has been slowed down in cases with contralateral anomalies Introduction. It has always been thought that a reduction of renal tissue in childhood sometimes causes some irreversible injury in the remnant kidney as the years go by. The aim of this paper is to look over the presence of these changes and identify the risk of nephropaty throughout several parameters. Material and methods. We reviewed 38 children, 23 males and 15 females, aged between 1 and 15 years, who had lost unilateral renal mass because of congenital or adquired diseases. We made two groups of patients on the basis of having born without any unilateral renal function –group I– or having lost unilateral renal function after the second year of life. We measured Somatometry, arterial pressure, glomerular filtration, microalbuminuria, renal volume and gammagraphic studies were also made. We also considered the presence of contralateral anomalies. Results. Body weight and height were within normal percentiles. Arterial pressure increased in 5 patients. Seric creatinine was normal, creatinine clearance (Ccr) was higher than normal in all patients of both groups, and urinary excretion of protein was normal. Renal volume of remnant kidney was similar in both groups, and no relation with renal function level was found, but it increased through the years. Isotopic studies showed ectatic drainage in all urinary systems. Contralateral anomalies were seen in 7 patients, and they consisted in hydronephrosis and vesico-ureteral reflux. Conclusions. Hypertension was not related to the cause of renal absence nor the pathology of remnant kidney. Ccr was higher than normal, showing an hyperfiltration status, not confirmed by the values of isotopic filtrate. Renal volume reached by the single kidney was affected by the time after the renal loss, and apparently has been slowed down in cases with contralateral anomalies (AU)