[Should a cystography be performed on all breastfeeding infants with mild to moderate dilatation of the urinary tract? Renal function tests can help to answer this question]. / ¿Debe realizarse una cistografía a todos los lactantes con dilatación leve y moderada de las vías urinarias? Las pruebas de función renal pueden ayudar a responder a esta pregunta.

INTRODUCTION: Pyelectasis can be defined as mild to moderate dilatation of the urinary tract and is diagnosed by means of an ultrasound scan (0.5-2cm transverse diameter in the initial ultrasound performed after birth). There is some disagreement about whether cystography should be indicated as standard practice. The aim of this study was to establish if renal function tests are useful in determining which cases of mild to moderate dilatation of the urinary tract do not require an initial cystography. PATIENTS AND METHODS: The study was conducted on 79 infants (57 males, 22 females) with pyelectasis. Seventy-three were diagnosed in utero and 6 after birth. All infants underwent at least one cystography and one desmopressin urine concentration test before one year of age. RESULTS: Compared to infants without vesicoureteral reflux (VUR) (n=68), infants with VUR (n=11; two with Grade I, three with Grade II, five with Grade III, two with Grade IV) showed a significantly lower (P=.006) maximum urine osmolality and a significantly higher microalbumin/creatinine ratio (P<.001) and NAG/creatinine ratio (P=.003). The negative predictive value of the first two tests was 93%. Sensitivity of the maximum urine osmolality to detect VUR was 72.7% (specificity 63.2%). Sensitivity of the microalbumin/creatinine ratio to detect VUR was 62.5% (specificity 75%). The positive probability ratio (PR) was 1.29 for the NAG/creatinine ratio, 2.03 for the maximum urine osmolality and 2.5 for the microalbumin/creatinine ratio. The negative PR was 0.95 for the NAG/creatinine ratio, 0.43 for the maximum urine osmolality and 0.5 for the microalbumin/creatinine ratio. CONCLUSIONS: Pyelectasis is a benign condition. Only 2 patients required pharmacological intervention (prophylactic treatment for VUR Grade IV patients). Initially at least, cystography should not be indicated in cases of microalbuminuria and/or normal urine concentrations.

[Study of the renal acidification capacity in children diagnosed of idiopathic hypercalciuria]. / Estudio de la capacidad de acidificación renal en niños diagnosticados de hipercalciuria idiopática.

OBJECTIVE: To study the capacity of renal acidification in a group of children diagnosed of idiopathic hypercalciuria. PATIENT AND METHODS: 36 children were studied, to those that were determined the pCO2 (UpCO2) maximum urinary with two different stimuli, acetazolamide and sodium bicarbonate (NaHCO3). At 33 of them, was performed an acidification test with frusemide stimulus. We studied a control group of 13 healthy children so much for the first one as the second tests and other 14 healthy children for the acidification test with frusemide. RESULTS: In the tests performed with NaHCO3 and acetazolamide stimulus, they were not proven differences in the values of UpCO2 neither in the urinary concentration of HCO3- (UHCO3-) than control children. Nevertheless, the UpCO2 and the concentration of UHCO3- in the patients were significantly lower with acetazolamide with regard to the NaHCO3 stimulus. In the acidification test with frusemide, significantly lower values of titratable acid and ammonium were obtained than control children. CONCLUSIONS: In children with idiopathic hypercalciuria, the capacity of secretion of H+ is normal, what is evidenced, especially, when studying the maximum UpCO2 after stimulus with NaHCO3. When diuretics are used as stimuli, exists more negative results that can be due to a certain partial resistance to the action of the same ones or to that are less potent to induce the secretion of H+.

Estudio de la capacidad de acidificación renal en niños diagnosticados de hipercalciuria idiopática / Study of renal acidification capacity in children diagnosed of idiopathic hypercalciuria

Objetivo: Estudiar la capacidad de acidificación renal en un grupo de niños diagnosticados de hipercalciuria idiopática. Pacientes y Métodos: Se estudiaron 36 niños, a los que se les determinó la pCO2 (UpCO2) urinaria máxima con dos estímulos diferentes, acetazolamida y bicarbonato sódico (CO3HNa). A 33 de ellos, se les realizó una prueba de acidificación con estímulo de furosemida. Se estudiaron 13 controles tanto para la primera como la segunda pruebas y otros 14 para la prueba de acidificación con furosemida. Resultados: En la pruebas realizadas tanto con CO3HNa como con acetazolamida, no se comprobaron diferencias en los valores de UpCO2 ni en la concentración urinaria de CO3H- (UCO3H-) con respecto al grupo control. No obstante, la UpCO2 y la concentración de UCO3H- en los pacientes fueron significativamente inferiores con acetazolamida con respecto al estímulo de CO3HNa. En la prueba de acidificación con furosemida, se alcanzaron valores significativamente inferiores de acidez titulable y de amonio en relación al grupo control. Conclusiones: En niños diagnosticados de hipercalciuria idiopática, la capacidad de secreción de H+ es normal lo que se evidencia, especialmente, al estudiar la UpCO2 máxima con estímulo de CO3HNa. Cuando se utilizan diuréticos como estímulos, existen más resultados negativos, que pueden deberse a una cierta resistencia parcial a la acción de los mismos o a que son menos potentes para inducir la secreción de H+

Objective: To study the capacity of renal acidification in a group of children diagnosed of idiopathic hypercalciuria. Patient and Methods: 36 children were studied, to those that were determined the pCO2 (UpCO2) maximum urinary with two different stimuli, acetazolamide and sodium bicarbonate (NaHCO3). At 33 of them, was performed an acidification test with frusemide stimulus. We studied a control group of 13 healthy children so much for the first one as the second tests and other 14 healthy children for the acidification test with frusemide. Results: In the tests performed with NaHCO3 and acetazolamide stimulus, they were not proven differences in the values of UpCO2 neither in the urinary concentration of HCO3 - (UHCO3 -) than control children. Nevertheless, the UpCO2 and the concentration of UHCO3 - in the patients were significantly lower with acetazolamide with regard to the NaHCO3 stimulus. In the acidification test with frusemide, significantly lower values of titratable acid and ammonium were obtained than control children. Conclusions: In children with idiopathic hypercalciuria, the capacity of secretion of H+ is normal, what is evidenced, especially, when studying the maximum UpCO2 after stimulus with NaHCO3. When diuretics are used as stimuli, exists more negative results that can be due to a certain partial resistance to the action of the same ones or to that are less potent to induce the secretion of H+

Tratornos del metabolismo óseo en las enfermedades renales de la infancia / Bone metabolism disorders in renal diseases in childhood

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