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Objectives: To compare characteristics and outcomes of vesicoureteral reflux (VUR) detected solely on isotopic cystography (IC) ("occult" VUR) with voiding cystourethrography (VCUG)-detected VUR., Materials and Methods: Between 2015 and 2020, we retrospectively enrolled all male children first undergoing VCUG and, if negative, IC in the same session. Kidney injury (KI) was defined by abnormal estimated glomerular filtration rate and/or blood pressure and/or proteinuria., Results: We enrolled 421 males with a median age of 3 months and a follow-up of 5.3 years. None exhibited KI initially, but 10% of those with VUR developed KI during follow-up. Two hundred and twenty-two patients (52.7%) did not show VUR, 152 (36.1%) had VCUG-diagnosed VUR, and 47 (11.2%) had occult VUR. Therefore, 47/199 patients (23.6%) with VUR had occult VUR. Among these, 34/47 (72.3%) had dilated VUR, and 22/47 (46.8%) exhibited split renal function < 45% and/or scar (scintigraphic damage). Compared to patients with occult VUR, those with VCUG-diagnosed VUR showed a similar prevalence of febrile urinary tract infection (fUTI) before and after VUR diagnostics and KI at the last follow-up but a higher prevalence of dilated VUR, of scintigraphic damage, and underwent surgery more frequently. At multiple logistic regression analysis, patients with VCUG-diagnosed VUR presented an increased risk of fUTI either before or after VUR diagnosis and of KI, while patients with occult VUR presented an increased risk of fUTI before (and among patients with dilated VUR also after) VUR diagnosis and of KI., Conclusion: Occult VUR affects 23.6% of male children with VUR with a non-negligible risk of VUR-associated KI and fUTI. IC could select, among males with recurrent fUTIs and negative VCUG, those requiring surgery for a possible dilated occult VUR., Clinical Relevance Statement: Vesicoureteral reflux may be overlooked in 25% of boys during VCUG, yet they are at risk of fUTIs and KI. In case of recurrent infections post-negative cystourethrography, IC could detect occult reflux, guiding surgical intervention., (© 2024. The Author(s).)

Objectives: To identify the diagnostic performance of clinical and radiological signs (on voiding cystourethrography [VCUG]) to detect posterior urethral valves (PUV) in the post-neonatal period., Materials and Methods: One hundred eighteen males (median age = 0.8 years, range = 1 month-14 years, 48 toilet-trained) undergoing VCUG in a 2-year period were prospectively enrolled. Direct (dilated posterior urethra) and indirect (hypertrophied bladder neck, musculus interuretericus hypertrophy, and trabeculated appearance of the bladder wall) PUV signs on VCUG were assessed. Uroflowmetry was defined pathological by patterns suggesting infravesical obstruction., Results: Twenty-two patients with direct, 28 with indirect PUV signs on VCUG, and one with normal VCUG but persisting micturition symptoms with pathological uroflowmetry underwent urethrocystoscopy and in 43/51 a PUV diagnosis was made (n = 22, 51.2%, with direct PUV signs). In 8/28 patients with indirect signs, PUV were not confirmed. Among non-toilet-trained patients, none of the clinical signs/symptoms was associated with PUV while among toilet-trained patients only pathological uroflowmetry (odds ratio, OR = 4.0 [95% confidence interval:1.2-13.2; p = 0.02]) and pathological uroflowmetry with history of urinary tract infection (OR = infinity) were significantly associated with PUV. Significant associations with PUV of direct and indirect signs on VCUG were found both in toilet-trained and non-toilet trained patients. Direct PUV sign had 100% specificity and sensitivity while indirect PUV signs showed sensitivity = 58.1% and specificity = 89.3%. The absence of any radiological sign had a negative predictive value = 98.5%., Conclusion: Only half of patients with endoscopy-confirmed PUV presents with direct sign of PUV on VCUG. Accounting for indirect PUV signs on VCUG and pathological uroflowmetry (in toilet-trained children) could improve the PUV detection rate., Clinical Relevance Statement: Indirect radiological PUV signs should be valorized when interpreting VCUG to improve the PUV detection rate. The absence of any radiological PUV (direct and indirect) sign on VCUG excludes PUV with a very high negative predictive value., Key Points: • Worldwide agreement is that a non-dilated urethra on voiding cystourethrography excludes obstruction. • Half of patients with posterior urethral valves have non-dilated urethra on voiding cystourethrography. • Accounting for indirect signs of posterior urethral valves on voiding cystourethrography improves the diagnostic performance., (© 2023. The Author(s).)

Purpose: This multicentric international retrospective study aimed to report the outcome of robot-assisted extravesical ureteral reimplantation (REVUR) in patients with unilateral vesico-ureteral reflux (VUR)., Methods: The medical records of 55 patients (35 girls, 20 boys) underwent REVUR in four international centers of pediatric robotic surgery for primary unilateral VUR were retrospectively reviewed. Patients' average age was 4.9 years. The preoperative grade of reflux was III in 12.7%, IV in 47.3% and V in 40%. Twenty-six patients (47.3%) presented a loss of renal function preoperatively and 10 (18.1%) had a duplex system., Results: Average robot docking time was 16.2 min (range 5-30). Average total operative time was 92.2 min (range 50-170). No conversions or intra-operative complications were recorded. All patients had a bladder Foley catheter for 24 h post-operatively. Average hospital stay was 2 days (range 1-3). Average follow-up length was 28 months (range 9-60). We recorded three (5.4%) postoperative complications: 1 small urinoma resolved spontaneously (II Clavien) and 2 persistent reflux, only one requiring redo-surgery using endoscopic injection (IIIb Clavien)., Conclusion: REVUR is a safe and effective technique for treatment of primary unilateral VUR. The procedure is easy and fast to perform thanks to the 6° of freedom of robotic arms. The learning curve is short and it is useful to begin the robotics experience with a surgeon expert in robotic surgery as proctor on the 2nd robot console. The high cost and the diameter of instruments remain the main challenges of robotics applications in pediatric urology.

Purpose: To compare the outcome of laparoscopic and retroperitoneoscopic approach for partial nephrectomy in infants and children with duplex kidneys., Methods: Data of 102 patients underwent partial nephrectomy in a 5-year period using MIS procedures were analyzed. Fifty-two children underwent laparoscopic partial nephrectomy (LPN), and 50 children underwent retroperitoneoscopic partial nephrectomy (RPN). Median age at surgery was 4.2 years. Statistical analysis was performed using χ (2) test and Student's t test., Results: The overall complications rate was significantly higher after RPN (15/50, 30 %) than after LPN (10/52, 19 %) [χ (2) = 0.05]. In LPN group, complications [4 urinomas, 2 symptomatic refluxing distal ureteral stumps (RDUS) and 4 urinary leakages] were conservatively managed. In RPN group, complications (6 urinomas, 8 RDUS, 1 opening of remaining calyxes) required a re-operation in 2 patients. In both groups no conversion to open surgery was reported. Operative time (LPN:166.2 min vs RPN: 255 min; p < 0.001) and hospitalization (LPN: 3.5 days vs RPN: 4.1 days; p < 0.001) were significantly shorter in LPN group. No postoperative loss of renal function was reported in both groups., Conclusions: Our results demonstrate that RPN remains a technically demanding procedure with a significantly higher complications and re-operation rate compared to LPN. In addition, length of surgery and hospitalization were significantly shorter after LPN compared to RPN. LPN seems to be a faster, safer and technically easier procedure to perform in children compared to RPN due to a larger operative space and the possibility to perform a complete ureterectomy in refluxing systems.

Although pediatricians are frequently confronted with patients presenting urolithiasis symptoms without obvious stones, the syndrome of occult urolithiasis may be still viewed with some skepticism. We have compared the clinical and metabolic features of 197 children with obvious calculi, 189 with microcalculi (diameter ≤ 3 mm based on renal sonography), and 114 with symptoms of urolithiasis and normal renal sonography findings. Only microcalculi and normal sonography subjects with a urinary abnormality potentially leading to urolithiasis were included in the study. Age at presentation increased significantly (p = 0.0001) in the groups in the order normal sonography to microcalculi to calculi groups. There was no significant difference among the three groups in terms of family history of urolithiasis, gender distribution, and degree of hypercalciuria, hyperuricosuria, hyperoxaluria, or hypocitraturia. The average frequency of pain attacks of patients with recurrent abdominal pain (RAP) ranged from 3.6 to 4.6 days of pain per month among the three groups, which is four to ninefold lower than that reported for children with functional or organic gastrointestinal RAP. The consistency of many clinical and urinary metabolic characteristics indicates a common underlying disorder in overt and occult urolithiasis. The increase of age at presentation from the normal sonography to microcalculi and calculi groups may reflect progressive crystal accretion leading ultimately to overt stone formation.

Hypokalemia is a recognized cause of rhabdomyolysis but very few reports document its association with inborn renal tubular disorders. We report our experience with hypokalemic rhabdomyolysis in 5 pediatric patients affected by inborn renal tubular disorders and the results of a careful review of the literature disclosing 9 further cases for a total of 14 patients (8 male and 6 female subjects, aged between 1.6 and 46, median 16 years). The inborn renal tubular disorders underlying rhabdomyolysis were classic distal renal tubular acidosis (n = 7), Gitelman syndrome (n = 5), classic Bartter syndrome (n = 1), and antenatal Bartter syndrome (n = 1). In 8 patients rhabdomyolysis followed an acute intestinal disease, an upper respiratory illness or the discontinuation of regular medication. Five patients experienced two or more episodes of rhabdomyolysis. In 10 patients the underlying renal tubular disorder was recognized concurrently with the episode of rhabdomyolysis or some weeks later. In conclusion some congenital renal tubular disorders predispose to hypokalemic rhabdomyolysis. Prevention of discontinuation of regular medication and electrolyte repair in the context of acute intercurrent illnesses might avoid the development of hypokalemic rhabdomyolysis.

Vesicoureteral reflux (VUR) is the most common disease of the urinary tract in children. In order to identify gene(s) involved in this complex disorder, we performed a genome-wide search in a selected sample of 31 patients with primary VUR from eight families originating from southern Italy. Sixteen additional families with 41 patients were included in a second stage. Nonparametric, affected-only linkage analysis identified four genomic areas on chromosomes 1, 3, and 4 (p < 0.05); the best result corresponded to the D3S3681-D3S1569 interval on chromosome 3 (nonparametric linkage score, NPL = 2.75, p = 0.008). This region was then saturated with 26 additional markers, tested in the complete group of 72 patients from 24 families (NPL = 2.01, p = 0.01). We identified a genomic area on 3q22.2-23, where 26 patients from six multiplex families shared overlapping haplotypes. However, we did not find evidence for a common ancestral haplotype. The region on chromosome 1 was delimited to 1p36.2-34.3 (D1S228-D1S255, max. NPL = 1.70, p = 0.03), after additional fine typing. Furthermore, on chromosome 22q11.22-12.3, patients from a single family showed excess allele sharing (NPL = 3.35, p = 0.015). Only the chromosome 3q region has been previously reported in the single genome-wide screening available for primary VUR. Our results suggest the presence of several novel loci for primary VUR, giving further evidence for the genetic heterogeneity of this disorder.

Little is known about the prescription pattern of antihypertensive drugs for children with impaired kidney function. We have therefore documented the use of antihypertensive drugs in this patient group by evaluating the Italian pediatric population-based registry of patients with chronic kidney disease on conservative treatment (ItalKid) from 1995 to 2003. In 1995, prescriptions written for antihypertensive drugs for use by children were approximately equally divided among drugs blocking the renin-angiotensin system and calcium channel blockers (38 vs. 43% of all prescriptions), followed by beta-blockers and diuretics (15 and 4%, respectively). During subsequent years the proportion of prescriptions for drugs blocking the renin-angiotensin system increased (2003: 61%; p<0.001) and that of calcium channel blockers decreased (2003: 18%, p<0.001). In 1995, blockers of the renin-angiotensin system were prescribed, either as monotherapy or in combination, in 53% of the patients, but the relative frequency of the patients prescribed these drugs increased up to 83% in 2003 (p<0.0005). In conclusion, physicians caring for Italian children with impaired kidney function are increasingly prescribing drugs blocking the renin-angiotensin system.

The finding of scintigraphic renal defects in children with febrile urinary tract infection (UTI) even in the absence of vesicoureteric reflux (VUR) has led to the conclusion that VUR is a weak predictor of renal defects in these patients. We used isotopic cystography (IC) for diagnosis of VUR in children with febrile UTI. Dimercaptosuccinic acid renal scintigraphy was performed 6 months after cure of the last UTI. Renal defects were defined by the finding of focal defects of radionuclide uptake and/or by a split renal function <43%. The study included 206 children with primary VUR and 77 without VUR. Among the subjects with and without VUR, respectively, renal defects were found in 40 and 6% (p=0.0001), focal uptake defects in 33 and 5% (p=0.0001) and split renal function <43% in 26 and 5% (p=0.0001). Permanent renal defects in children with febrile UTI are closely associated with VUR. The possibility that a child will have permanent renal defects can reasonably be ruled out on the basis of the absence of VUR by IC.

Growth retardation and osteopenia have been reported in some children with idiopathic hypercalciuria (IHC), particularly in those with nephrocalcinosis. The duration of hypercalciuria might be a risk factor for osteopenia. A retrospective longitudinal analysis of statural growth and a cross-sectional evaluation of bone mineral density (BMD) was carried out in 26 IHC children followed for 4-13 years. None of the patients had nephrocalcinosis. Growth, including pubertal growth spurt, was normal in all subjects. BMD Z score less than -1 was recorded in 3 subjects with hyperuricosuria. BMD Z score averaged -0.68+/-0.99 in the 9 subjects with associated hyperuricosuria and 0.21+/-0.64 in the 17 with occasional or no hyperuricosuria ( P=0.018). Our analysis shows that children with long-lasting IHC without nephrocalcinosis have normal growth, but those with associated hyperuricosuria may be at risk for osteopenia.