Usefulness of basic renal function tests in the management of hydronephrosis. / Utilidad de las pruebas básicas de función renal en el manejo de la hidronefrosis.

OBJECTIVE: Nowadays, the algorithms for the study of hydronephrosis in children include voiding cystourethrogram (VCUG) and diuretic renogram (DR) in all patients. Both are invasive, distressing, and associated with radiation risk. However, basic renal function tests (bRFTs) are not included. This study was designed to determine whether bRFTs may help avoid VCUG and/or DR in some children. METHODS: Retrospective review of hydronephrosis (≥20 mm renal pelvis) patient records over one year (n = 38) (pyeloureteral stenosis (PUS) n = 12; high-grade vesicoureteral reflux (VUR) n = 8; non-obstructive hydronephrosis (NOH) n = 18. Data from the three protocolized bRFTs (maximum urine osmolality after DDAVP (UOsm), albumin/creatinine ratio (Alb/Cr), and NAG/creatinine ratio (NAG/Cr), together with VCUG and DR, were analyzed. RESULTS: 38 hydronephrosis patients (pyeloureteral stenosis (PUS) n = 12; high grade vesicoureteral reflux (VUR) n = 8; non-obstructive hydronephrosis (NOH) n = 18. UOsm was decreased in 100% of VUR patients, 75% of PUS patients, and 16.7% of NOH patients. Alb/Cr ratio was increased in 62.5% of VUR patients, 8.3% of PUS patients, and 11.1% of NOH patients. NAG/Cr ratio was increased in 42.8% of VUR patients, 25% of PUS patients, and 6.7% of NOH patients. UOsm was decreased in most patients who required surgery (100% of VUR patients and 74% of PUS patients), but only in 11.1% of patients who did not (NOH group). CONCLUSIONS: These results suggest that bRFTs may be useful in delaying or avoiding VCUG in some hydronephrosis cases. UOsm is the most sensitive test. No child with (high grade) VUR had a normal UOsm. VCUG could have been avoided in 43% of our patients -with a normal UOsm- without missing any high grade VUR.

OBJETIVO: Actualmente, los algoritmos para estudiar hidronefrosis en niños, incluyen realizar cistografía miccional (CUMS) y renograma diurético (RD) a todos. Ambos son invasivos, molestos, y con riesgo de radiación. Contrariamente, las pruebas básicas de función renal (PFRb), no están incluidas. Este estudio se realizó para saber si las PFRb, pueden ayudarnos a evitar alguna CUMS y/o RD. METODOS: Análisis retrospectivo de todas las historias de niños con hidronefrosis (pelvis renal ≥20 mm) atendidos durante un año (n=38), [estenosis pieloureteral (EPU) n = 12; reflujo vesicoureteral (RVU) de alto grado n = 8; hidronefrosis no obstructiva (HNO) n = 18]. Analizamos las tres PFRb protocolizadas [osmolalidad urinaria máxima tras DDAVP (UOsm), albúmina/creatinina (Alb/Cr) y NAG/creatinina (NAG/Cr)], junto con CUMS y RD. RESULTADOS: UOsm estaba disminuida en 100% RVU, 75% EPU, 16,7% HNO. Alb/Cr estaba aumentado en 62,5% RVU, 8,3% EPU, 11,1% HNO. NAG/Cr estaba aumentado en 42,8% RVU, 25% EPU, 6,7% HNO. En relación a la necesidad de cirugía, UOsm estaba disminuida en la mayoría de pacientes intervenidos (100% con RVU y 74% con EPU), mientras solo en el 11% de pacientes sin cirugía (HNO). CONCLUSION: Estos resultados sugieren que las PFRb pueden ser útiles para retrasar o evitar CUMS en algunos niños con hidronefrosis. La UOsm es la PFRb más sensible. Ningún niño con RVU (de alto grado) mostró una UOsm normal. Se podrían haber evitado CUMS en el 43% de nuestros pacientes, con UOsm normal, sin haber perdido ningún diagnóstico de VUR (de alto grado).

[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.

[Are simple renal cysts another manifestation of prelithiasis in infancy?]. / ¿Los quistes renales simples son otra forma de manifestación de prelitiasis en la infancia?

Simple renal cysts are uncommon lesions in paediatric patients. In the absence of hypokalaemia or an increase in the production of NH+, the cause of simple renal cysts is unknown. Hepler, in 1930, suggested that they may be caused by a tubular obstruction. We prospectively studied the presence of hypercalciuria or hypocitraturia as well as the family history of urolithiasis in a group of children diagnosed sonographically with simple renal cysts. The average age of the 22 patients (12M, 10F) was 6.04 +/- 2.9 years at the time of diagnosis. The ultrasound examination had been requested due to urinary tract infection, abdominal pain, haematuria or other disorders. The cysts were slightly more frequent on the left side (54.5%). All were located in the upper kidney pole. 14 patients were found to have hypercalciuria and/or hypocitraturia (hypercalciuria n = 11, 50%). Thirteen families had history of renal stones. The metabolic abnormalities associated with calculi in children and/or family history of stones were present in 19 families (86.3%). Our hypothesis is that both entities, renal cysts, and genetic predisposition to kidney stones, are related.

[Celebrating fifty years of percutaneous renal biopsies in Spain]. / En el cincuentenario de las primeras biopsias renales percutáneas realizadas en España.

The first renal biopsies, made as much in adults as in children, were surgical. They were made to patients who were under renal decapsulation with the intention to reduce the kidney pressure, especially in cases of nephrotic syndrome. In 1944, Nils Alwall initiated the accomplishment of percutaneous kidney biopsies by means of a needle and aspiration at the University of Lund (Sweden), although his experience was published in 1952. The first article that had by subject the practice of a percutaneous renal biopsy was written in 1950 by a Cuban doctor, Antonino Pérez Ara, and published in a local journal with little diffusion. The first work that appeared in a Spanish journal (1953) about the practice of the percutaneus renal biopsies was not signed by any Spanish group but by members of the Hospital "Calixto García" of the University of The Havana, Cuba. The first article published in Spain regarding to this subject, saw the light in 1958, now 50 years ago, in the Revista Clínica Española. The two first signers were Alfonso de la Peña Pineda and Vicente Gilsanz García, professors of the Medicine Faculty of Madrid. Later, the practice of the percutaneous renal biopsy became general in other Spanish hospitals.

[Multicystic kidney disease in a segment of horseshoe kidney: an uncommon combination of malformations]. / Displasia renal multiquística en un segmento de un riñón ''en herradura'': una asociación de malformaciones poco usual.

Multicystic dysplasia is the most common type of renal cystic disease, and it is one of the most common causes of an abdominal mass in infants. The contralateral system is also frequently abnormal. The most commonly associated anomalies are contralateral ureteropelvic junction obstruction and contralateral vesicoureteral reflux. In a few cases, multicystic dysplasia involves a horseshoe kidney or one pole of a duplex kidney. We present a female patient diagnosed with this condition at 9 years old, when she was being studied due to recurrent abdominal pain. The renal function was normal.

[Study of renal morphology and function in children with nocturnal enuresis. Relationship with sensitivity or resistance to desmopressin]. / Estudio de la morfología y la función renal en niños diagnosticados de enuresis nocturna. Su relación con la sensibilidad o la resistencia a la desmopresina.

BACKGROUND: In the last few years, there have been reports that children with nocturnal enuresis frequently have hypercalciuria. Likewise, children with desmopressin-resistant enuresis have recently been reported to have a higher renal concentration capacity than patients with desmopressin-sensitive enuresis. OBJECTIVES: To study renal function and urinary calcium excretion and to register familial history of enuresis and urolithiasis in a group of children with enuresis, whether responders or nonresponders to desmopressin, followed-up in our hospital. MATERIAL AND METHODS: A cohort of 60 patients (42 boys and 18 girls) who were referred to the hospital because of nocturnal enuresis. RESULTS: Hypercalciuria was detected in 26 children (43.3 %) and hypocitraturia in eight (13.3 %). The frequency of hypercalciuria was higher in desmopressin-resistant patients than in desmopressin-sensitive patients, but this difference was not statistically significant. Sonographic renal morphological anomalies were detected in 11 children (18.3 %). No differences in renal handling of water were detected when the patients were distributed according to the grade of sensitivity to desmopressin. CONCLUSIONS: In our cohort we found a high frequency of hypercalciuria in children with nocturnal enuresis. No differences were observed in maximal urinary osmolality among desmopressin-resistant and desmopressin-sensitive children.