US demonstration of pyelitis and ureteritis in children

Roles for urothelium in normal and aberrant urinary tract development

Congenital anomalies of the kidney and urinary tract (CAKUTs) represent the leading cause of chronic kidney disease and end-stage kidney disease in children. Increasing evidence points to critical roles for the urothelium in the developing urinary tract and in the genesis of CAKUTs. The involvement of the urothelium in patterning the urinary tract is supported by evidence that CAKUTs can arise as a result of abnormal urothelial development. Emerging evidence indicates that congenital urinary tract obstruction triggers urothelial remodelling that stabilizes the obstructed kidney and limits renal injury. Finally, the diagnostic potential of radiological findings and urinary biomarkers derived from the urothelium of patients with CAKUTs might aid their contribution to clinical care.

Uroepithelial thickening improves detection of vesicoureteral reflux in infants with prenatal hydronephrosis

INTRODUCTION

Postnatal evaluation of prenatal hydronephrosis (PNH) often includes a voiding cystourethrogram (VCUG) for VUR assessment. Despite limited supporting data, VCUG is currently recommended if postnatal renal and bladder ultrasound (RBUS) reveals moderate/severe hydronephrosis (HN) or hydroureter (HU). Recent studies have shown VUR is more accurately diagnosed by using certain sonographic findings as criteria for obtaining VCUG. Uroepithelial thickening (UET) of the renal pelvis is a finding associated with high-grade vesicoureteral reflux (HGVUR); however, the clinical significance of UET with PNH has not been studied.

OBJECTIVE

We sought to determine if the presence of UET implies increased risk for VUR, and to investigate whether UET can improve the test characteristics of RBUS for VUR.

STUDY DESIGN

We retrospectively analyzed postnatal RBUS and VCUG findings in infants ≤30 days undergoing evaluation for "prenatal hydronephrosis" over an 11-year period. We used logistic regression to identify factors associated with VUR. Test characteristics of RBUS for HGVUR were compared based on the presence of UET and two criteria sets to define abnormal RBUS. Criteria set 1 consisted of HN SFU grade 3-4 and/or HU; criteria set 2 was defined by the presence of two of following: UET, HU, duplication, and/or renal dysmorphia.

RESULTS

Of 135 patients, 39 (29%) had VUR, of whom 16 (41%) had HGVUR. UET was significantly associated with VUR (p < 0.001), and the sensitivity for HGVUR based on UET alone was 94%. On multivariable analysis, UET, HU, duplication, and renal dysmorphia remained significant independent predictors of HGVUR. Compared to criteria 1, using criteria 2 resulted in 43 fewer VCUGs, and significant improvement in sensitivity and specificity for HGVUR (Table).

DISCUSSION

Consistent with previous studies, HN alone on postnatal RBUS has little value in predicting the presence or severity of VUR. This study is the largest known series to evaluate UET in the setting of PNH, and our results demonstrate that UET, as well as HU, duplication and renal dysmorphia, are independent sonographic findings predicting HGVUR. Using our proposed criteria, the probability of HGVUR is fourfold more than the prevalence described in the literature, and importantly, when compared to the criteria recommended by the SFU and AUA, would have resulted in 53% fewer VCUGs while missing zero cases of HGVUR.

CONCLUSION

In infants with PNH, the sonographic findings of UET, HU, duplication and renal dysmorphia independently indicate greater risk of HGVUR, and the sensitivity and specificity of RBUS for HGVUR is markedly improved when at least two of the four are present.

Uroepithelial Thickening on Sonography Improves Detection of Vesicoureteral Reflux in Children with First Febrile Urinary Tract Infection

PURPOSE

The 2011 American Academy of Pediatrics clinical practice guideline for childhood febrile urinary tract infection recommends voiding cystourethrography if renal and bladder ultrasound reveals hydronephrosis, scarring or "other findings" that suggest high grade vesicoureteral reflux. We sought to determine if the finding of uroepithelial thickening indicates greater risk of high grade vesicoureteral reflux and whether uroepithelial thickening improves the screening value of renal and bladder ultrasound.

MATERIALS AND METHODS

We retrospectively analyzed renal and bladder ultrasound and voiding cystourethrogram findings in children 2 to 24 months old with first febrile urinary tract infection during an 11-year period. Patients with uroepithelial thickening were compared to an age and gender matched sample without uroepithelial thickening. Logistic regression was used to identify factors associated with high grade vesicoureteral reflux. Test characteristics of renal and bladder ultrasound for high grade reflux were compared based on different criteria to define an abnormal renal and bladder ultrasound.

RESULTS

Of 226 patients 143 (63%) had vesicoureteral reflux, of whom 37 (26%) had high grade reflux. On multivariable analysis uroepithelial thickening was a significant independent predictor of high grade vesicoureteral reflux (OR 5.41, 95% CI 1.74-16.79, p = 0.004). When hydronephrosis and hydroureter were considered the only abnormal renal and bladder ultrasound findings warranting voiding cystourethrography, sensitivity of renal and bladder ultrasound for high grade reflux was 84%, and 6 children with high grade and 82 with low grade reflux would have been missed. When uroepithelial thickening was also considered an abnormal finding, the sensitivity increased to 97%, and only 1 child with high grade and 57 with low grade reflux would have been missed.

CONCLUSIONS

Uroepithelial thickening is associated with an increased risk of high grade vesicoureteral reflux and is an abnormal finding warranting voiding cystourethrography. Sensitivity of renal and bladder ultrasound as a screening test for high grade vesicoureteral reflux is markedly improved when uroepithelial thickening is considered.

Sonographic finding of persistent renal pelvic wall thickening in children

OBJECTIVE

Renal pelvic wall thickening (RPWT) is a sonographic finding, which is associated with urinary tract infection (UTI) and other genitourinary tract abnormalities. We aimed to determine the prevalence of RPWT and whether persistent RPWT related to vesicoureteral reflux (VUR).

MATERIALS AND METHODS

We retrospectively reviewed sonographic findings of RPWT in children and adolescents referred for renal ultrasound study from January 2010 to December 2011. A total of 502 patients showing RPWT were included, 372 of whom received follow-up sonograms. Among them, 86 children underwent both follow-up sonograms and voiding cystourethrography studies. The association between persistent RPWT and VUR was analyzed.

RESULTS

A total of 602 sonograms with RPWT were identified, accounting for a prevalence of 11.4%. Follow-up sonograms, revealing that these patients had recovered from RPWT, was found in 93.7% (459/490) of renal units and in 92.7% (345/372) of the patients. Children with persistent RPWT had a strong association with VUR occurrence (p = 0.018) and high VUR grading (p = 0.006) compared to those without persistent RPWT.

CONCLUSION

RPWT is a common finding in children and adolescents. Persistent RPWT is associated with VUR, especially with high grade VUR. Complementary uroradiological studies should be performed for children and adolescents with persistent RPWT.

[Imaging in the management of urinary tract infections]

This review analyzes the role of imaging in the diagnosis, follow-up and management of urinary tract infections. Uncomplicated infection of the urinary tract is frequent and usually resolves rapidly with treatment; in such cases imaging is unnecessary except to exclude dilatation or the existence of an obstacle. Progression towards complex infection often occurs in patients with predisposing factors. Imaging helps in evaluating the extent of the disease; it has a role in the selection of therapy and interventional procedures.

Renal pelvic wall thickening in childhood urinary tract infections--evidence of acute pyelitis or vesicoureteral reflux?

OBJECTIVE

The aim of this study was to determine whether renal pelvic wall thickening in active childhood urinary tract infections (UTIs), as demonstrated using ultrasound, is caused by acute pyelitis or by vesicoureteral reflux (VUR)-related chronic changes.

MATERIAL AND METHODS

A total of 41 children with at least unilateral renal pelvic wall thickening as demonstrated using ultrasound during the acute stage of UTI, and confirmed using voiding cystourethrography (VCUG), were analyzed. All cases underwent ultrasound studies at 6 months follow-up.

RESULTS

Using ultrasound, 50 halves of the pelvis showed renal pelvic wall thickening. In 27 (54%), ipsilateral VUR could be demonstrated using VCUG. The sensitivity, specificity and positive predictive value of renal pelvic wall thickening for predicting ipsilateral VUR were 79.4%, 52.1% and 54%, respectively. Only 2 (7%) cases presented with wall thickening at 6 months follow-up. Most of the thickening recovered after clinical improvement, although VUR became persistent in half the cases.

CONCLUSIONS

Renal pelvic wall thickening is an abnormal finding in the acute stage of childhood UTI and predominantly indicates acute pyelitis rather than VUR-related chronic changes. Renal pelvic wall thickening is not sufficiently predictive of VUR in acute UTI, although it does provide evidence of upper UTI.

Pediatric abdominal applications of color Doppler ultrasonography

Color Doppler ultrasonography (US) is a valuable imaging method because of the important information it provides with respect to organ perfusion, vessel patency, and tumor characterization. In addition, it is a noninvasive technique that does not use ionizing radiation. This review summarizes current applications of color Doppler US in the diagnosis of diseases or abnormalities of the liver and biliary tree, the urinary and gastrointestinal tracts, and the inguinal region.

[Initial imaging in pediatric urinary tract infection]

First step imaging investigations in urinary tract infections in children rely upon conventional sonography, and, when available. Power Doppler sonography. Enhanced computerised tomography (CT) and dimercaptosuccinic acid (DMSA) scintigraphy are complementary investigations in difficult cases. Contrast cystourethrogram has always to be performed. Intravenous pyelography is no longer used as a first step imaging technique.

Can careful ultrasound examination of the urinary tract exclude vesicoureteric reflux in the neonate?

The aim of the study was to determine whether a urinary tract appearing normal when assessed by meticulous ultrasound (US) examination may coexist with vesicoureteric reflux (VUR) and whether a normal US scan can be used to exclude VUR, thereby avoiding unnecessary voiding cystourethrography (VCUG). The US features of 35 neonates with known VUR were reviewed. Criteria studied included pelvic dilatation above 7 mm on a transverse scan, calyceal or ureteral dilatation, pelvic or ureteral wall thickening, absence of the corticomedullary differentiation (CMD) and signs of renal dysplasia (small kidney, thinned or hyperechoic cortex and cortical cysts); all signs that have been shown to result from or to be associated with VUR. 57 refluxing renal units (RRU) were found among the 35 patients. VUR was bilateral in 22. Among the 57 RRU, at least one US anomaly that would have prompted VCUG was present in 50 (87.7%). Pelvic dilatation above 7 mm was present in 29 RRU (50.9%) only. Calyceal dilatation was present in 24 RRU, the dilatation involving the calyces but not the renal pelvis in seven. Ureteral dilatation was observed in 15 RRU. Pelvic or ureteral wall thickening was present in seven RRU. CMD was absent in 32 RRU (56.1%). US signs of dysplasia were found in 19 RRU. No US anomaly was found in seven RRU (12.3%) in six patients. A careful and meticulous US examination of the neonatal urinary tract allows the detection of over 87% of RRU by showing at least one sonographic abnormality. It is concluded that a normal appearing urinary tract on US does not usually coexist with VUR and that in such cases VCUG is not necessary.

Pelvocalyceal thickening in HIV-associated nephropathy

BACKGROUND

Previously reported causes of renal pelvocalyceal thickening (PCT) include infection, acute tubular necrosis and obstruction. This study was performed to evaluate the significance of PCT noted sonographically in patients with hyperechoic native kidneys.

METHODS

We evaluated sonograms of 178 consecutive patients with hyperechoic native (excluding small and hydronephrotic) kidneys for the presence of PCT, and reviewed medical charts of patients with this finding. We also reviewed sonograms of two control groups: 20 consecutive patients with nephrosis unrelated to human immunodeficiency virus (HIV) infection who underwent renal biopsy, and 30 consecutive patients with severe hypoalbuminemia unrelated to kidney disease.

RESULTS

PCT was observed in 20 study patients with hyperechoic kidneys. HIV-associated nephropathy (HIVAN) was diagnosed in 15 patients (14 with bilateral PCT) in whom previously reported causes of this appearance were excluded. PCT was not observed in control patients.

CONCLUSION

Renal PCT can occur in patients with HIVAN in the absence of HIV-related complications. PCT in HIVAN does not merely reflect nonspecific nephrosis or hypoalbuminemia. HIVAN should be considered if PCT is noted sonographically in hyperechoic kidneys, even in patients not clinically suspected of harboring HIV infection.

Ultrasonography of ureteric abnormalities induced by Schistosoma haematobium infection before and after praziquantel treatment

OBJECTIVE

To describe the ultrasonographic appearance of ureteric lesions due to Schistosoma haematobium infection and to report prevalence rates of such lesions in endemic communities in Mali before and after praziquantel treatment.

SUBJECTS AND METHODS

The total population (n = 961) of three S. haematobium-endemic villages in Mali was examined ultrasonographically to detect urinary tract morbidity. Urine was tested for S. haematobium ova and for haematuria. An identical follow-up study was performed 1 year after mass treatment with praziquantel.

RESULTS

Prevalence rates of S. haematobium infection in the three villages were 53%, 72% and 73%. Ultrasonography revealed dilatation of the ureters in 143 subjects (15%). In 20 of these, mainly children and adolescents, thickening and irregularities of the ureteric wall with distal ureter obstruction were directly visualized on ultrasonography. Within the bladder of two others, an intraluminal structure of ureterocele-like appearance was seen. None of these alterations has been previously described as an ultrasonographic feature of schistosomal uropathy. Active S. haematobium infection and microhaematuria were found in 21 and 20 of these 22 subjects respectively. Significant renal obstruction was present in 10 of them. One year after treatment, an entirely normal urinary tract was found in 85% of 104 re-examined individuals who had had ureter dilatation. Ureteric wall thickening or ureterocele-like lesions had disappeared in 95% of subjects.

CONCLUSIONS

The role of ultrasound in the evaluation of schistosomal uropathy is confirmed. Ureteric wall abnormalities causing strictures and ureterocele-like lesions of the ostium must be regarded as further ultrasonographic features of this condition. The study documents the excellent reversibility of ureteric abnormalities after antischistosomal treatment in children and adolescents, thus emphasizing the need for early and efficient medical treatment of the infection.

The value of ultrasound in the child with an acute urinary tract infection

OBJECTIVE

To assess the value of an ultrasound examination in children with a proven urinary tract infection.

PATIENTS AND METHODS

The results of renal ultrasound and 99mTc-dimercapto-succinic acid (DMSA) studies were compared in 112 children with a first documented symptomatic Escherichia coli urinary tract infection.

RESULTS

Ultrasound was particularly effective in detecting the presence of obstruction, renal swelling and parenchymal change consistent with acute pyelonephritis. However, ultrasound failed to detect half of the kidneys with photon deficient areas on 99mTc DMSA scan and was unreliable in detecting the presence of scarring.

CONCLUSION

An ultrasound examination alone should not be relied on in the child with an acute urinary tract infection.

Sonographically demonstrated thickening of the renal pelvis in children

Thickening of the wall of the renal pelvis has been attributed to infection, to rejection in allografts and to non-specific causes by different authors. We reviewed the clinical data, imaging studies and pathology of 35 patients with sonographically demonstrable thickening in 41 renal pelves of native kidneys. Our findings are that less than 50% of the patients had infection. The others had a wide variety of apparent causes for the thickening which include obstruction, surgery, edema induced by chemicals and other processes. Vesicoureteral reflux was demonstrated in 50% of the patients studied by cystography. We concluded that renal pelvic thickening is a non-specific finding.