Obstructive diseases of the urinary tract in children: lessons from the last 15 years

Efficacy of contrast-enhanced percutaneous nephrosonography to evaluate urinary tract patency in children

A novel method known as contrast-enhanced percutaneous nephrosonography (cePNS), using an ultrasound contrast agent administered through the nephrostomy catheter, has been used to evaluate the urinary tract patency in children. Nine cePNS examinations were performed in seven children to evaluate the urinary tract patency prior to further management. The cePNS results were compared with the clinical evaluation of patent urinary tract cases or with surgery results. Both, the technical success rate and accuracy of cePNS examinations were 100%. CePNS is a radiation-free method and can be performed as a continuation of an ultrasound examination.

Pediatric congenital hydronephrosis (ureteropelvic junction obstruction): Medical management guide

The prevalence of asymptomatic hydronephrosis, now detected by ultrasonography, has increased. However, definitive management guidelines for the management of congenital hydronephrosis have not been established. The Japanese Society of Pediatric Urology created a "medical management guide" based on new findings for physicians practicing pediatric urology. We developed a medical management guide focused on congenital hydronephrosis caused by ureteropelvic junction obstruction. This medical management guide consists of the definition, pathophysiology, epidemiology, diagnosis, classification, treatment using a clinical management algorithm of hydronephrosis and the long-term course of the disease. The aim of hydronephrosis management is to determine whether surgery should be carried out to avoid renal dysfunction, as there is a possibility for improvement without intervention. Ultrasonography is essential to make treatment decisions. Management is determined by a comprehensive assessment, including the degree of hydronephrosis, anterior-posterior diameter of the renal pelvis and, if necessary, a nuclear medicine evaluation of the status of urine drainage and renal function.

Renal Expression and Urinary Excretion of Na-K-2Cl Cotransporter in Obstructive Nephropathy

Renal damage due to urinary tract obstruction accounts for up to 30% of acute kidney injury in paediatrics and adults. Bilateral ureteral obstruction (BUO) is associated with polyuria and reduced urinary concentrating capacity. We investigated the renal handling of water and electrolytes together with the renal expression and the urinary excretion of the Na-K-Cl cotransporter (NKCC2) after 1 (BUO-1), 2 (BUO-2), and 7 (BUO-7) days of release of BUO. Immunoblotting and immunohistochemical studies showed that NKCC2 expression was upregulated in apical membranes both from BUO-2 and from BUO-7 rats. The apical membrane expression, where NKCC2 is functional, may be sufficient to normalize water, potassium, sodium, and osmolytes tubular handling. NKCC2 abundance in homogenates and mRNA levels of NKCC2 was significantly decreased in almost all groups suggesting a decrease in the synthesis of the transporter. Urinary excretion of NKCC2 was increased in BUO-7 groups. These data suggest that the upregulation in the expression of NKCC2 in apical membranes during the postobstructive phase of BUO could contribute to improving the excretion of sodium and consequently also the excretion of potassium, osmolytes, and water. Moreover, the increase in urinary excretion of NKCC2 in BUO-7 group could be a potential additional biomarker of renal function recovery.

Proximal ureteral atresia, a rare congenital anomaly-incidental finding: a case report

Ureteral atresia is a rare disease usually associated with a non-functioning dysplastic kidney. The condition may be unilateral or bilateral; focal, short or long and may involve any part of the ureter. Association with other urinary anomalies is rare. We report the case of a 10-month-old boy with prenatal diagnosis of multicystic right kidney. This suspicion was confirmed after birth by ultrasound and static scintigraphy; a right vesicoureteral reflux (VUR) was recorded at cystography. The boy presented a regular renal function but was hospitalized twice for suspected pyelonephritis between the 8th and the 10th month of life and were recorded occasional mild changes in blood pressure. Antibiotic prophylaxis was administered until surgery. When he was 10-month underwent retroperitoneoscopy to perform a nephroureterectomy finding a complete atresia of the upper third of the ureter with the blind end at the level of the uretero-pelvic-junction. The programmed surgery was performed. By a revision of literature, only few cases of imperforate distal ureter have been described. This condition is associated with a kidney dysplasia. The atresia of the ureter with no signs of infection in the dysplastic kidney may be unknown up to adulthood or throughout one's life. Prognosis usually depends on the severity of the obstruction.

Hypothesis on etiopathogenesis, congenital or acquired, of an imperforate distal ureter: a case report

INTRODUCTION

Ureteral atresia is a rare disease usually associated with a non-functioning kidney. Its association with other urinary anomalies is rare.

CASE PRESENTATION

In this study we discuss the possibility of congenital or acquired etiology of a right imperforate distal ureter. Here we report the case of 11-month-old white boy with a right ureteropelvic junction obstruction. He underwent a right pyeloplasty when he was 11-months old, and 3 weeks after surgery a cystoscopy was performed. Two months after the first operation, he underwent a right ureteral meatoplasty and a new pyeloplasty.

CONCLUSIONS

To the best of our knowledge, few cases of imperforate distal ureter have been described in the literature. The suspicion of a non-patent terminal ureter, occurring during upper urinary tract surgery, must be intraoperatively clarified to preserve the renal function and to avoid more complex surgical approaches.

Drainage-related ultrasonography (DRUS): a novel technique for discriminating obstructive and nonobstructive hydroureters in children

BACKGROUND

Despite advances in urologic imaging, the paucity of an optimal technique that accurately clarifies obstructive and nonobstructive hydroureter exists.

OBJECTIVE

This study was conducted to introduce a novel and modified ultrasonographic technique, known as drainage-related ultrasonography (DRUS), discriminating obstructive and nonobstructive, nonrefluxing hydroureter.

MATERIALS AND METHODS

A total of 358 children (mean age, 3.7 years) with 418 nonrefluxing hydroureter were included. These children were composed of two groups of obstructive nonrefluxing (141 children with 157 dilated ureters) and nonobstructive, nonrefluxing (217 children with 261 hydroureter). The definite diagnosis regarding the subtype of hydroureter was derived from appropriate investigation. The maximum diameter of the dilated ureter, which was observed on ultrasonography, was recorded before and after 3 h of catheterization, as D1 and D2, respectively. To assess the D ratio, a formula was developed, that is, [(|D1 - D2|)/D1] × 100. Values were recorded and cutoff points were set to discriminate between subtypes.

RESULTS

Obstructive versus nonobstructive subtypes of nonrefluxing hydroureter were clarified with 78.5 % sensitivity and 83.4 % specificity, by setting a cutoff point of 22 % for the D ratio. Regardless of the cutoff point assigned to the reduction in D (D2 compared with D1), DRUS revealed 93.9 % sensitivity, 80.6 % specificity, 63.2 % positive predictive value, and 97.4 % negative predictive value in discriminating upper from lower obstruction.

CONCLUSION

DRUS affords favorable results in terms of differentiating between obstructive and nonobstructive, nonrefluxing hydroureter, as well as between upper and lower obstruction in obstructive cases. It has the potential to become an efficient imaging modality in the diagnostic algorithm of hydroureter.

Acute kidney injury due to bilateral ureteral obstruction in children

Bilateral ureteral obstruction in children is a rare condition arising from several medical or surgical pictures. It needs to be promptly suspected in order to attempt a quick renal function recovery. In this paper we concentrated on uncommon causes of obstruction, with the aim of giving a summary of such multiple, rare and heterogeneous conditions joint together by the common denominator of sudden bilateral ureteral obstruction, difficult to be suspected at times. Conversely, typical and well-known diseases have been just run over. We considered pediatric cases of ureteral obstruction presenting as bilateral, along with some cases which truly appeared as single-sided, because of their potential bilateral presentation. We performed a review of the literature by a search on PubMed, CrossRef Metadata Search, internet and reference lists of single articles updated to May 2014, with no time limits in the past. Given that we deal with rare conditions, we decided to include also papers in non-English languages, published with an English abstract. For the sake of clearness, we divided our research results into 8 categories: (1) urolithiasis; (2) congenital urinary tract malformations; (3) immuno-rheumatologic causes of ureteral obstruction; (4) ureteral localization of infections; (5) other systemic infective causes of ureteral obstructions; (6) neoplastic intrinsic ureteral obstructions; (7) extrinsic ureteral obstructions; and (8) iatrogenic trigonal obstruction or inflammation. Of course, different pathogenic mechanisms underlay those clinical pictures, partly well-known and partly not completely understood.

A case of complete renal duplex with h-shaped ureter

We present a case of complete renal duplex with H-shaped double ureter opening into the bladder with 2 separate orifices. It is an extremely rare variety of renal duplex which was reported only once in the literature. Fifty-four-year-old male presented to our department with right renal pain. Noncontrast CT revealed stone midthird right ureter with duplex right kidney. Retrograde ureteropyelography and ureteroscopy revealed this rare anomaly.

Magnetic resonance urography in duplex kidney with ectopic ureteral insertion

This is a report on the use of magnetic resonance urography (MRU) in a 6-year-old girl who presented with urinary incontinence. She had a left duplex kidney with poorly functioning upper moiety and ectopic insertion of the dilated upper pole ureter. MRU has been shown to be superior to conventional imaging techniques in delineating poorly functioning moieties of duplex kidneys and ectopic ureters.