[Prenatal diagnosis of malformative uropathies: multicentric retrospective study and a proposed feto-neonatal diagnostic protocol]. / Diagnosi prenatale delle uropatie malformative: studio retrospettivo multicentrico e proposta di protocollo diagnostico feto-neonatale.

We have wanted to appraise the diagnostic reliability of fetal ultrasonography (FU) and its correlation with postnatal ultrasonography (PU). For two years we have studied 20.506 children born in 12 Pediatric Division of Veneto, all provided with FU. Between the 23rd and the 40th week of gestation the FU has individualized 177 fetuses with pelvic dilatation. The PU, performed in the 2nd and 7th day of life and then repeated to 1 month of life, has confirmed the prenatal diagnosis in 150 of the 247 renal unities, we have observed the 39% of false positive and the 8% of false negative. The sensibility has been 94%, specificity of 46%. The definitive diagnosis was: mild pelvic ectasia in 45%, ureteropelvic junction stenosis in 26%, vescicoureteric reflux in 15%, duplication of the renal collecting system and primary megaureter in 3%, multicystic kidneys and urethral valves in 5%. 20 children have been submitted to surgical corrective intervention. From the correlation performed between the entity of pelvic dilatation to the FU and to the PU we think it advisable to submit all the fetuses that show a caliceal dilation of > 5 mm to two ultrasounds, the first one between the 2nd-5th day of life and the second one at 30 days of life. In the newborn with caliceal dilatation of > 10 mm a micturating cystogram must be performed and subsequently in case of vescico ureteric reflux a DMSA scan is advisable, while in absence of reflux a DTPA scan or MAG3 scan is necessary. The renal pelvis with a diameter between 5-10 mm will perform ultrasound controls only each three months, unless there are partial or total reductions of the renal parenchymal, dilatation of the calices and/or the ureters.

Use of calcium excretion values to distinguish two forms of primary renal tubular hypokalemic alkalosis: Bartter and Gitelman syndromes.

Clinical or biochemical findings were reevaluated in 34 pediatric patients with primary renal tubular hypokalemic metabolic alkalosis. The patients were subdivided into two groups. Bartter syndrome (primary renal tubular hypokalemic metabolic alkalosis with normocalciuria or hypercalciuria) was diagnosed in 18 patients with molar urinary calcium/creatinine ratios greater than 0.20, and Gitelman syndrome (primary renal tubular hypokalemic metabolic alkalosis with magnesium deficiency and hypocalciuria) was diagnosed in 16 patients with molar urinary calcium/creatinine ratios less than or equal to 0.20 and plasma magnesium levels less than 0.75 mmol/L. Some clinically important differences between the groups were observed. Patients with Bartter syndrome were often born after pregnancies complicated by polyhydramnios (8/18) or premature delivery (7/18) and had short stature (11/18) or polyuria, polydipsia, and a tendency to dehydration (16/18) during infancy (12/18) or before school age (18/18). Patients with Gitelman syndrome had tetanic episodes (12/16) or short stature (3/16) at school age (14/16). We conclude that the Bartter and Gitelman syndromes represent two distinct variants of primary renal tubular hypokalemic metabolic alkalosis and are easily distinguished on the basis of urinary calcium levels.

The prognostic significance of acute neonatal renal failure.

We evaluated 38 newborns with acute renal failure (plasma creatinine (Pcr) concentration greater than = 1.5 mg/dl), measured between the 2nd and 5th days. We used renal ultrasound to exclude the possibility of congenital renal anomalies, obstructive pathology or vascular disorders. We calculated the glomerular filtration rate (GFR) using Schwartz' formula and the maximal concentrating capacity using intranasal administration of desamino-cis-1-D-arginine-8-vasopressin (DDAVP test). Two newborns were treated with peritoneal dialysis and died during the first month of life. Thirty-six had a follow-up blood sample drawn: 24 preterm babies between 1 and 12 months, and 12 full-term babies between 1 and 36 months of life. From this sampling 4 babies (11.1%) showed defective maximal concentrating ability. Our data reveal the persistence of altered concentrating ability in newborns affected by renal failure and shows that this problem needs a longitudinal study and further diagnostic investigations.

Benefits and risks of anemia correction with recombinant human erythropoietin in children maintained by hemodialysis.

Ten children with renal failure (age range 2 years 6 months to 18 years 9 months; median 11 years 10 months), maintained by long-term hemodialysis, had successful correction of their anemia after intravenous administration of recombinant human erythropoietin in a dosage escalating every 2 weeks (75 to 150 to 300 to 450 IU/kg/wk). Mean hemoglobin concentration increased from 6.4 +/- 0.9 to 11.5 +/- 1.0 gm/dl. Blood cell counts used to evaluate the correction of anemia were done after dialysis; this was especially important for children less compliant with water restriction. The higher hemoglobin concentration resulted in improvement of the quality of life, a greater tolerance for physical effort (exercise tolerance doubled and the ventilatory anaerobic threshold increased significantly), correction of some subclinical central nervous system abnormalities detected by evoked potentials testing, and reduction of bleeding time. Few side effects were noted; severe hypertension developed in one patient when postdialysis hematocrit was only 28%, and there were two episodes of hypertransaminasemia with no other evidence of liver dysfunction. We conclude that in children with renal failure the use of recombinant human erythropoietin to correct anemia is safe and strongly advisable, because of the resolution of many of the symptoms correlated with anemia.

Plasma infusion for hemolytic-uremic syndrome in children: results of a multicenter controlled trial.

The results of a controlled trial to ascertain the usefulness of plasma infusion for the treatment of hemolytic-uremic syndrome (HUS) are reported. Criteria for admission were (1) observation within 8 days from first symptoms, (2) dialysis treatment required, and (3) no special treatments and no more than 25 ml blood/kg previously received. Children were subdivided according to age (less than or more than 3 years) and then randomly assigned to treatment with plasma or symptomatic therapy. Thirty-two children ranging in age from 4 months to 6 years entered this study; 17 received plasma (P+ group) and 15 only symptomatic therapy (P- group). The mean follow-up period was 16 months in both groups. Surgical renal biopsy was performed 29 to 49 days after onset in 11 P+ and 11 P- children, and 33 histologic findings were semiquantitatively evaluated. No death occurred in either group. No differences were found in blood pressure, proteinuria, or hematuria at the end of the follow-up period; in no case were severe arteriolar lesions found. There were no significant differences for the scores of the individual histologic measurements; on electron microscopy, no vascular changes were observed in seven children of the P+ group, whereas in five of seven of the P- group, thickening of the lamina rara interna and arteriolar damage were present. The ability of plasma to stimulate prostacyclin (PGI2) production, measured as its stable derivative 6-keto-PGF1 alpha, was within the normal range for all patients. In our patients with predominant glomerular involvement who were treated in a very early phase of HUS, infusions of plasma did not significantly influence the short- and medium-term clinical outcome and were not effective in severe HUS when given later in the course of the disease. A longer follow-up is needed to ascertain whether the presence of endothelial damage, demonstrated by electron microscopy in children who were not given plasma, is of clinical relevance.

Further definition of lipid-lipoprotein abnormalities in children with various degrees of chronic renal insufficiency.

We characterized the lipid-lipoprotein abnormalities encountered in a series of 45 nonnephrotic uremic children with various degrees of chronic renal insufficiency. A mild hypertriglyceridemia associated with decreased serum high-density lipoprotein cholesterol levels was confirmed. The correlation between high-density lipoprotein cholesterol and creatinine clearance showed a power behavior with a marked decrease in high-density lipoprotein cholesterol below a creatinine clearance value of 40 ml/min/1.73 m2. A number of uremic children accumulate an abnormal population of very low-density lipoprotein particles in their plasma. On agarose gel electrophoresis these particles migrate as a slow moving pre-beta band and are clearly distinguished from the regular fast moving pre-beta very low-density lipoprotein band. This electrophoretic phenomenon has been called double pre-beta lipoproteinemia. The prevalence of double pre-beta lipoproteinemia increased significantly with the degree of impairment of renal function, reaching highest figures in patients on hemodialysis. Accordingly, the very low-density lipoprotein cholesterol/triglyceride ratio also was significantly increased. The double pre-beta lipoproteinemia phenomenon was not detected in any of the control, nonuremic subjects. The clinical importance of double pre-beta lipoproteinemia in uremic plasma is related to its possible atherogenic role.

[Medullary sponge kidney. Description of a pediatric case]. / Il rene a spugna midollare. Descrizione di un caso pediatrico.

The case of a 11 year old boy with medullary sponge Kidney and nephrolithiasis discovered because of abdominal pain is described. Functional tubular impairment (concentrating defect, distal tubular acidosis) was present. No hypercalciuria nor hyperparathyroidism was detected. The diagnosis of medullary sponge Kidney was confirmed histopathologically. The pediatric cases described in the literature are characterized by a higher incidence of concentrating defect and acidosis, while the adults subjects often show hypercalciuria and or hyperparathyroidism. The careful study of tubular functions in the pediatric cases appears to be very useful to understand which are primary tubular disturbances and which are only secondary.

Upper urinary tract obstruction in children caused by Candida fungus balls.

2 children with upper urinary tract obstruction from Candida fungus balls are reported. A presumptive diagnosis, made on the basis of clinical and radiological findings, was confirmed by microscopic examination of urinary sediment. Medical treatment was successful in both patients. Since Candida infections can occur in patients with altered host resistance, this should alert clinicians to the possibility of fungal involvement when radiolucent filling defects are found in the renal pelvis. Such a presumptive diagnosis can then lead to a correct approach with conservation of renal function.

Juvenile renal stone disease: a study of urinary promoting and inhibiting factors.

Urinary excretion of the most widely studied renal stone promoting (calcium, oxalate, uric acid and phosphate) and inhibiting (citrate, magnesium, pyrophosphate and glycosaminoglycans) factors, as well as the Tamm-Horsfall mucoprotein, was evaluated in 14 children with idiopathic calcium nephrolithiasis, 6 children with renal stone disease secondary to excretory malformations and 19 normal controls. No statistically significant differences in urinary excretion of promoting and inhibiting factors were found in children with idiopathic calcium nephrolithiasis but the relationship between promoting and inhibiting factors was changed as shown by an abnormal ratio of oxalate/citrate X glycosaminoglycans. This finding suggests that there is an imbalance between promoting and inhibiting factors in children with idiopathic calcium nephrolithiasis, and it is not detected by assay of each single substance.

Cystinuria in children.

7 children, 20 months to 11 years old, with cystinuria and renal calculi were studied. Surgical treatment and alpha-mercaptopropionylglycine (MPG) gave satisfactory results in 5 children. The causes of the recurrences in the other 2 children are discussed. MPG therapy is effective but can cause a nephrotic syndrome at a dose of more than 50 mg/kg/day. A cystinuria of less than 200 mg/day cannot always be considered safe in children. The alkalinization and dilution of urine remain extremely important in the treatment of cystinuria.

Nephrotic syndrome during treatment with alpha-mercaptopropionylglycine.

We report 2 cases of cystinuria in which a nephrotic syndrome developed during treatment with alpha-mercaptopropionylglycine. This syndrome resolved after withdrawal of the drug and it did not recur when the alpha-mercaptopropionylglycine was given again in lower doses. The hypothesis is made that the nephrotic syndrome was dose-related. The alpha-mercaptopropionylglycine must be used in doses less than 50 mg./kg per day with regular monitoring of 24-hour urinary protein in cystinuric children.