Kidney length and scarring in children with urinary tract infection: importance of ultrasound scans

Sonographic temporary nephromegaly in children during their first febrile urinary tract infection is a significant prognostic factor for recurrent infection

There are currently no available data on the relationship between sonographic temporary nephromegaly in children during their first febrile urinary tract infection (fUTI) and recurrent fUTI. For this analysis, a multicenter retrospective cohort study of 343 children who underwent renal ultrasound during their first fUTI was conducted between 2013 and 2020. Sonographic temporary nephromegaly was defined as increased renal length during the initial fUTI, followed by normal renal length after antibiotic treatment. Compared with children without sonographic temporary nephromegaly (n = 307), the duration of fever and intravenous antibiotics was significantly longer, and C-reactive protein, creatinine, and the proportion of children who had recurrent fUTI were significantly higher, in those with sonographic temporary nephromegaly (n = 36). In an additional analysis of 100 patients who received voiding cystourethrography, a logistic regression model confirmed that the odds of vesicoureteral reflux (VUR) were significantly higher in children with temporary nephromegaly or those who experienced fUTI recurrence. In nine out of 16 children with VUR who had temporary nephromegaly, the reason for receiving voiding cystourethrography was recurrent fUTI. Our results suggest that sonographic temporary nephromegaly during an initial fUTI is predictive for recurrence and VUR, and that in children with temporary nephromegaly, VUR may be detectable before fUTI recurrence.

The Intrarenal Reflux Diagnosed by Contrast-Enhanced Voiding Urosonography (ceVUS): A Reason for the Reclassification of Vesicoureteral Reflux and New Therapeutic Approach?

Vesicoureteral reflux (VUR) is defined as the urine backflow from the urinary bladder to the pyelo-caliceal system. In contrast, intrarenal reflux (IRR) is the backflow of urine from the renal calyces into the tubulointerstitial space. VURs, particularly those associated with IRR can result in reflux nephropathy when accompanied by urinary tract infection (UTI). The prevalence of IRR in patients with diagnosed VUR is 1-11% when using voiding cystourethrography (VCUG), while 11.9-61% when applying the contrast-enhanced voiding urosonography (ceVUS). The presence of IRR diagnosed by VCUG often correlates with parenchymal scars, when diagnosed by a 99mTc dimercaptosuccinic acid scan (DMSA scan), mostly in kidneys with high-grade VURs, and when diagnosed by ceVUS, it correlates with the wide spectrum of parenchymal changes on DMSA scan. The study performed by both ceVUS and DMSA scans showed IRRs associated with non-dilated VURs in 21% of all detected VURs. A significant difference regarding the existence of parenchymal damage was disclosed between the IRR-associated and IRR-non-associated VURs. A higher portion of parenchymal changes existed in the IRR-associated VURs, regardless of the VUR grade. That means that kidneys with IRR-associated VURs represent the high-risk group of VURs, which must be considered in the future classification of VURs. When using ceVUS, 62% of places where IRR was found were still unaffected by parenchymal changes. That was the basis for our recommendation of preventive use of long-term antibiotic prophylaxis until the IRR disappearance, regardless of the VUR grade. We propose a new classification of VURs using the ceVUS method, in which each VUR grade is subdivided based on the presence of an IRR.

Evaluation of quality of renal tract ultrasound scans and reports performed in children with first urinary tract infection

PURPOSE

To determine the quality of renal tract ultrasound (US) imaging records performed in children for evaluation of urinary tract infection (UTI) by multiple professionals with different levels of experience in a dedicated academic children's hospital.

METHODS

Retrospective analysis of US images and reports for children ≤ 13-years with first presentation of a UTI. 9 Operators (6 consultant radiologists and 3 sonographers) were anonymised and the adequacy of their US images and reports were evaluated for the following categories; Image acquisition, Image labelling, Metric labelling, and Final reporting. The frequency of the reporting quality of the elements assessed was compared between radiologists and sonographers using Chi-square or fisher exact test.

RESULTS

Renal tract US studies for 100 children (20 males, 80 females) with first UTI episode were assessed. Mean age was 4.5 ± 3.4 years. 54% of the studies were performed by sonographers and 46% by radiologists. Kidneys and pre-micturition bladder scans were acquired in more than 96% of exams by both sonographers and radiologists. Kidney image and metric labelling was adequate in almost all exams (98-100%) with the exception of plane labelling which was not routinely done by US operators (less than 3%). Sonographers performed consistently better than radiologists in post-micturition bladder scanning, pre- and post-micturition bladder labelling and renal length reporting (p<0.05). Least to be recorded by US operators (both radiologists and sonographers) were doppler scan acquisitions (less than 3%), bladder wall thickness labelling (less than 3%), and renal calculi reporting (less than 1%).

CONCLUSION

The inconsistency of the reporting quality between the different elements assessed highlights the difference in US training and experience received by sonographers and radiologists. A pro-forma structured reporting template may ensure US operators provide consistent, thorough and good quality ultrasound images and reports.

Is antibiotic prophylaxis in children with vesicoureteral reflux effective in preventing pyelonephritis and renal scars? A randomized, controlled trial

OBJECTIVES

There has been intense discussion on the effectiveness of continuous antibiotic prophylaxis for children with vesicoureteral reflux, and randomized, controlled trials are still needed to determine the effectiveness of long-term antibiotics for the prevention of acute pyelonephritis. In this multicenter, open-label, randomized, controlled trial, we tested the effectiveness of antibiotic prophylaxis in preventing recurrence of pyelonephritis and avoiding new scars in a sample of children who were younger than 30 months and vesicoureteral reflux.

METHODS

One hundred patients with vesicoureteral reflux (grade II, III, or IV) diagnosed with cystourethrography after a first episode of acute pyelonephritis were randomly assigned to receive antibiotic prophylaxis with sulfamethoxazole/trimethoprim or not for 2 years. The main outcome of the study was the recurrence of pyelonephritis during a follow-up period of 4 years. During follow-up, the patients were evaluated through repeated cystourethrographies, renal ultrasounds, and dimercaptosuccinic acid scans.

RESULTS

The baseline characteristics in the 2 study groups were similar. There were no differences in the risk for having at least 1 pyelonephritis episode between the intervention and control groups. At the end of follow-up, the presence of renal scars was the same in children with and without antibiotic prophylaxis.

CONCLUSIONS

Continuous antibiotic prophylaxis was ineffective in reducing the rate of pyelonephritis recurrence and the incidence of renal damage in children who were younger than 30 months and had vesicoureteral reflux grades II through IV.