Conservative management of paediatric renal abscess

ACR Appropriateness Criteria® Urinary Tract Infection-Child: 2023 Update

Urinary tract infection (UTI) is a frequent infection in childhood. The diagnosis is usually made by history and physical examination and confirmed by urine analysis. Cystitis is infection or inflammation confined to the bladder, whereas pyelonephritis is infection or inflammation of kidneys. Pyelonephritis can cause renal scarring, which is the most severe long-term sequela of UTI and can lead to accelerated nephrosclerosis, leading to hypertension and chronic renal failure. The role of imaging is to guide treatment by identifying patients who are at high risk to develop recurrent UTIs or renal scarring. This document provides initial imaging guidelines for children presenting with first febrile UTI with appropriate response to medical management, atypical or recurrent febrile UTI, and follow-up imaging for children with established vesicoureteral reflux. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Association between the imaging characteristics of renal abscess and vesicoureteral reflux

INTRODUCTION

Renal abscesses are rare in pediatric populations. We aimed to highlight the differences in the computed tomography (CT) imaging characteristics of renal abscesses in patients with and without vesicoureteral reflux (VUR).

MATERIALS AND METHODS

Thirteen children with renal abscesses were included and categorized into those with and without VUR. Blood and urine culture results were recorded as positive or negative. Imaging characteristics were recorded: with/without subcapsular fluid collection, with/without upper/lower pole involvement, and with single/multiple lesions in kidneys. Fisher's exact test was used for intergroup comparisons of the rate of positive pathogens and imaging characteristics.

RESULTS

Nine patients had VUR (45.9%). Blood and urine culture were positive in two (15.4%) and seven cases (53.8%), respectively. There was no significant difference in the rate of pathogen-positive blood and urine cultures (blood culture positive/negative status with VUR vs. that without VUR = 2/7 vs. 0/4, p > 0.999, urine culture positive/negative status with VUR vs. that without VUR = 4/5 vs. 3/1, p = 0.559). The two groups differed significantly regarding subcapsular fluid collection presence (with/without subcapsular fluid collection with VUR vs. that without VUR = 9/0 vs 1/3, p = 0.014). There was no significant difference in upper/lower pole involvement (with/without involving upper/lower pole with VUR vs. that without VUR = 8/1 vs 2/2, p = 0.203). Patients with VUR were non-significantly more likely to have multiple lesions compared to those without VUR.

CONCLUSIONS

VUR was associated with subcapsular fluid collection and possibly with multiple lesions, indicating the need for prompt detection of and specific treatment for VUR in cases with these findings.

Incidence of renal scarring on technetium-99 m dimercaptosuccinic acid renal scintigraphy after acute pyelonephritis, acute focal bacterial nephritis, and renal abscess

OBJECTIVE

To evaluate the association between the incidence of renal scarring on technetium-99 m dimercaptosuccinic acid (DMSA) renal scintigraphy and the severity of renal parenchymal infections, such as acute pyelonephritis (APN), acute focal bacterial nephritis (AFBN), and renal abscess, based on computed tomography (CT) diagnosis.

METHODS

Sixty-one children with renal parenchymal infections were included and classified into two groups: those with (renal scarring group) and without renal scarring (non-renal scarring group) on chronic-phase DMSA renal scintigraphy. The severity of renal parenchymal infection was classified into three grades using CT: APN, AFBN, and renal abscess as grades 1, 2, and 3, respectively. The severity of renal parenchymal infection, vesicoureteral reflux (VUR) grade, and intrarenal reflux occurrence during voiding cystourethrography (VCUG) were evaluated between the renal and non-renal scarring groups. Fisher's exact test and Mann-Whitney U test were used for statistical analysis.

RESULTS

Renal scars were detected in 28 (45.9%) of the 61 patients. We found that 2/9 (22.2%), 18/41 (43.9%), and 8/11 (72.7%) patients with APN (grade 1), AFBN (grade 2), and renal abscess (grade 3) had renal scarring, respectively. There was a significant difference in the grade of severity of renal parenchymal infection between the renal (median = 2 [interquartile range, 2-3]) and non-renal (median = 2 [interquartile range, 2-2]) scarring groups (p = 0.023). There was a significant difference in the grade of VUR between the renal (median = 3 [interquartile range, 0-4]) and non-renal (median = 0 [interquartile range, 0-2]) scarring groups (p = 0.004). No significant difference in intrarenal reflux occurrence was observed between the renal (present/absent: 3/25) and non-renal (present/absent: 0/29) scarring groups (p = 0.112).

CONCLUSION

Our results showed that pediatric patients with renal scarring on chronic-phase DMSA renal scintigraphy tended to have a more severe renal infection.

Role of ultrasound in the treatment of pediatric infectious diseases: case series and narrative review

BACKGROUND

Infectious diseases are common in pediatric patients. In these patients, ultrasound is a useful imaging modality that involves no irradiation or sedation and can be performed repeatedly at the patient's bedside. The purpose of this review was to show pediatric cases with infectious disease that used ultrasound to decide the methods of treatment.

DATA SOURCES

Literature review was performed using Pubmed as the medical database source. No year-of-publication restriction was placed. The mesh terms used were: "ultrasound", "sonography", "infectious disease", "treatment", "antibiotics", "surgical intervention", "pediatric", "children", "deep neck abscess", "pyothorax", "empyema", "pneumonia", "urinary tract infection", "intra-abdominal abscess", "soft tissue infection", "septic arthritis", "osteomyelitis", and "surgical site infection".

RESULTS

We presented pediatric case series with infectious diseases, including deep neck abscess, pyothorax and empyema, pneumonia, urinary tract infection, intra-abdominal abscess, soft tissue infection, septic arthritis and osteomyelitis, and surgical-site infection. Ultrasound was useful for evaluating the extent and location of inflammation and abscess and for decision-making concerning surgical intervention.

CONCLUSION

Knowledge of these sonographic findings is important for sonographers during examinations and for physicians when determining the treatment plan and period of antibiotic therapy for infected lesions.

Renal abscesses in children: an 11-year retrospective study and review of the literature

BACKGROUND

There is limited literature on renal abscesses in children and therefore no consensus on management. The objectives of this study were to describe renal abscesses in a contemporary paediatric Australian population and present a 20 year review of the literature.

METHODS

An 11 year retrospective comparative study was conducted of paediatric patients with renal abscesses. A literature review of all eight original articles on paediatric renal abscesses from January 2001 to December 2021 was performed.

RESULTS

Fourteen children with a mean age of 11 years were diagnosed with a renal abscess on ultrasound and/or computed tomography. The most common presenting symptoms were fever (n = 13, 93%) and flank or abdominal pain (n = 12, 86%). The most common causative organisms were Staphylococcus aureus (n = 7, 50%) and Escherichia coli (n = 4, 29%). All renal abscesses less than 3 cm were managed with antibiotics alone. Five out of nine abscesses 3-5 cm were managed with percutaenous drainage (56%). Two multi-loculated abscesses greater than 5 cm required open drainage in theatre (100%).

CONCLUSIONS

The most common causative organism in the North Queensland population was S. aureus, with a higher incidence of MRSA. This should be taken into consideration when prescribing empirical antibiotics. Most renal abscesses in children that are less than 3 cm in size can be managed with antibiotic therapy only. The evidence for management of larger abscesses is less clear, but where clinically appropriate conservative management with antibiotic therapy should be considered in the first instance, with percutaneous drainage in cases of antibiotic failure.

Renal abscess in children: Is size an important determinant in deciding treatment options?

Background:

Renal abscess (RA) is rarely seen in the paediatric age group. The proposed management protocols are mainly derived from the adult series which may not be appropriate in children.

Objective:

In this retrospective analysis of cases with renal and perinephric abscesses, the objective is to correlate the clinical presentation, radiological findings and treatment options and also to propose a paediatric-specific practical management algorithm.

Study design:

This is a retrospective study of cases with renal and perinephric abscesses admitted between March 2012 and February 2020. The patients were reviewed for demographics, presentation, predisposing factors, laboratory investigations, imaging, management and outcome.

Results:

Analysis of 12 paediatric patients (13 renal units) with RA (median age 4 years) was done. Organisms were isolated in 8 of 12 (66.6%) patients with Gram-negative organisms being the commonest. On admission, all patients were started on empirical broad-spectrum antibiotics. Except for two patients who were critically ill with frank sepsis and had a tender renal lump, the rest of them were initially offered conservative management with intravenous antibiotics, and the response was reviewed after 48–72 hours. Of five units with abscess size of ⩽3 cm, two units (40%) responded to conservative management, while three units (60%) required intervention, and of eight units of size >3 cm, three units (37.5%) responded to conservative management and five units (62.5%) required intervention. None of the abscesses with perinephric collection (30.7%) responded to antibiotics and required intervention.

Conclusion:

A protocol based on the size of RA as recommended in most of the adult series may not be appropriate in the paediatric age group because of the differences in clinical presentation, predisposing factors and immune response. The clinical condition on presentation, response to antibiotic therapy and the presence of perinephric collection should be considered as an important determinant in deciding the need for intervention.

Level of evidence:

4

Salmonella Renal Abscess in an Immunocompetent Child: Case Report and Literature Review

We describe a case of a 10-year-old immunocompetent girl with a left renal abscess due to Group C Salmonella (Salmonella serovar Oranienburg). Percutaneous drainage of the abscess was done. She also received 2 weeks of intravenous ceftriaxone, followed by 4 weeks of oral co-trimoxazole with resolution seen on ultrasound. A review of pediatric Salmonella renal abscesses is also presented.

Renal abscess with bacteremia caused by extended-spectrum β-lactamase-producing Escherichia coli: a case report

Background

Renal abscess in children is a rare and severe form of infectious kidney disease that is responsible for several serious complications. In this report, we describe a previously healthy 5-year-old girl with a renal abscess caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli), which led to bacteremia and renal scarring.

Case presentation

The patient presented to our department with high fever, headache, vomiting for 2 days and high inflammatory response. We diagnosed her with a urinary tract infection and initiated treatment with ampicillin and cefotaxime. Gram-negative bacilli bacteremia was noted on day 3. On day 4, her fever persisted, and a computed tomography (CT) scan revealed a renal abscess in the left kidney. After identifying the bacteria as ESBL-producing E. coli from the blood culture, we switched to the antibiotic meropenem and continued treatment for 3 weeks. The renal abscess was not drained. Although the renal abscess was successfully treated and it disappeared, a low-density area remained in same lesion on subsequent CT scans and a dimercaptosuccinic acid renal scan performed 4 months after onset revealed renal scarring.

Conclusion

Given the increasing prevalence of ESBL-producing microorganisms, clinicians should be aware of the possibility of renal abscesses caused by community-acquired ESBL-producing organisms even in previously healthy children. Once a renal abscess is suspected, early diagnosis and management are important for reducing the risk of life-threating complications and renal scarring.

ACR Appropriateness Criteria® Urinary Tract Infection-Child

Urinary tract infection (UTI) is common in young children and may cause pyelonephritis and renal scarring. Long-term complications from renal scarring are low. The role of imaging is to evaluate for underlying urologic abnormalities and guide treatment. In neonates there is increased risk for underlying urologic abnormalities. Evaluation for vesicoureteral reflux (VUR) may be appropriate especially in boys because of higher prevalence of VUR and to exclude posterior urethral valve. In children older than 2 months with first episode of uncomplicated UTI, there is no clear benefit of prophylactic antibiotic. Ultrasound is the only study that is usually appropriate. After the age of 6 years, UTIs are infrequent. There is no need for routine imaging as VUR is less common. In children with recurrent or complicated UTI, in addition to ultrasound, imaging of VUR is usually appropriate. Renal cortical scintigraphy may be appropriate in children with VUR, as renal scarring may support surgical intervention. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Abscesos renales en pediatría: reporte de caso

Los abscesos renales y perirrenales hacen parte de un grupo de infecciones poco frecuentes en pediatría que comprometen el parénquima renal y el espacio perinefrítico. Estas entidades no tienen una clínica específica y, por lo tanto, se deben sospechar en todos los pacientes con infección urinaria que no respondan a la terapia antimicrobiana adecuada. De su apropiado diagnóstico dependerá la evolución y el pronóstico del paciente. Si bien el drenaje percutáneo mediante radiología intervencionista es un procedimiento descrito para el tratamiento de esta patología en los adultos, este puede hacer parte del manejo en pediatría. En este artículo, se presenta el caso clínico de un niño de tres años con diagnóstico de absceso renal y su manejo en un centro pediátrico de Bogotá, junto a una revisión actualizada de esta patología.

Pediatric renal abscesses: A contemporary series

INTRODUCTION

Pediatric renal abscesses are an uncommon diagnosis, with a paucity of data comparing treatment modalities. Patient presentation ranges from persistent dull flank/abdominal pain with or without fevers, to those who are overtly ill, presenting with hemodynamic instability and bacteremia. Management for pediatric renal abscesses is typically based on results extrapolated from small series in adult cohorts, with conservative measures recommended when the lesion is <3 cm.

OBJECTIVE

This study evaluated the presentation, management and outcomes of a contemporary cohort of pediatric patients with renal abscesses.

STUDY DESIGN

A total of 16 consecutive pediatric patients with radiologically diagnosed intra-renal or peri-nephric abscesses from 1990 to 2012 were identified. Patients were identified by querying institutional records via ICD-9 and CPT codes referencing renal abscess. Charts were retrospectively reviewed to evaluate multiple clinical variables, including: presenting symptoms, size of abscess, management strategy and clinical outcomes. Clinical resolution was confirmed via repeat ultrasound or computed tomography.

RESULTS

The median age at presentation was 13 years (range 1 month-18 years) and 13/16 patients (81%) were female. Abscess formation was secondary to: urinary tract infection in 13 (81%); hematogenous seeding from a skin infection in one (6%); and an unknown etiology in two (12%) patients. The most common organism identified on urine culture was Escherichia coli (10, 77%). Hematogenous seeding was confirmed in only one case, with Staphylococcus aureus growing on culture from both a cutaneous lesion and percutaneous drainage of the renal lesion. Overall, abscesses were a median of 2.2 cm (IQR 2, 3.7), with 13 (81%) successfully managed with conservative therapy, including intravenous antibiotics, with resolution on repeat imaging at a median of 21 days (range 6-55). For patients presenting with abscesses ≤3 cm, conservative measures were employed in 10/11 cases, with 100% success rate. Three patients had larger abscesses (3.8, 4, and 10 cm), which resolved after treatment with percutaneous drainage. A voiding cystourethrogram was performed in 10 patients, with two (20%) detecting an abnormality (low-grade vesicoureteral reflux, which required no further intervention).

CONCLUSIONS

Pediatric renal abscesses were most commonly small and secondary to an E. coli UTI. Most small (≤3 cm) renal abscesses resolved with conservative management. Percutaneous drainage should be considered for lesions >3 cm and in patients who remain persistently febrile, despite culture-specific antibiotics, are immunocompromised or critically ill.