Long-term follow up to determine the prognostic value of imaging after urinary tract infections. Part 1: Reflux

Development of visual scoring system with Tc-99m DMSA renal scintigraphy to predict the risk of recurrence of symptomatic urinary tract infections in pediatric patients

OBJECTIVE

Vesicoureteral reflux (VUR) is a major risk factor for recurrent symptomatic urinary tract infection (UTI) in pediatric patients. In addition, dimercaptosuccinic acid renal scintigraphy (DMSA) is an important diagnostic modality of VUR. However, the value of DMSA for predicting recurrent pediatric UTI has not been studied. Therefore, we aimed to develop visual scoring system (VSS) with DMSA to predict the risk of recurrence of symptomatic urinary tract infection in pediatric patient under the age of 24 months.

METHODS

Pediatric UTI patients who visited our tertiary hospital emergency department and underwent DMSA for initial work-up from January 2006 to December 2014 were reviewed retrospectively. We developed a VSS with Tc-99m DMSA renal scintigraphy. We compared sensitivity and specificity between VSS with DMSA and other variables in predicting recurrent symptomatic UTI. Laboratory indices for systemic inflammation, abnormal finding on ultrasonography, VUR on voiding cystourethrogram (VCUG), and the VSS with DMSA were considered as variables. In addition, we used Kaplan-Meier estimator analyses and Cox proportional regression analyses to evaluate the predictive value of each variable for the recurrence of symptomatic UTI.

RESULTS

A total of 338 patients were enrolled. During the follow-up period, 42 patients (12.4%) had UTI recurrence. Visual scoring with DMSA resulted in 69.1% sensitivity and 79.4% specificity with an optimal cut-off value of score 2 (AUC = 0.790, p < 0.001). Significant predictive factors associated with recurrent symptomatic UTI were CRP ≥ 67.0 mg/L, VUR on VCUG and VSS with DMSA ≥ score 2. On multivariate analysis, the visual score with DMSA was the only independent prognostic factor for recurrent symptomatic UTI (p < 0.001; adjusted hazard ratio = 7.522; 95% CI = 2.799-20.224).

CONCLUSION

High scores in VSS with DMSA were associated with frequent recurrence and short recurrence periods in pediatric UTI patients. VSS with DMSA can stratify risk of recurrence in pediatric UTI patients.

The role of DMSA renal scintigraphy in the first episode of urinary tract infection in childhood

OBJECTIVE

The role of dimercaptosuccinic acid (DMSA) renal scintigraphy in the first episode of urinary tract infection (UTI) has been the subject of debate for many years. The aim of this study was to evaluate the relationship of voiding cystourethrography (VCUG), renal ultrasonography and DMSA renal scintigraphy and to detect renal parenchymal changes by performing DMSA renal scintigraphy at 6 months after the first episode of UTI.

METHODS

A prospective study was conducted in 67 hospitalized children (46 boys, 21 girls). Mean age of the patients was 0.97 ± 1.57 years (0.02-7.26 years). All children received VCUG, renal ultrasonography and DMSA renal scintigraphy. DMSA renal scintigraphy was performed at 1 and 6 months after UTI.

RESULTS

Of 67 children, 17 (25.4%), 23 (34.3%) and 20 (29.9%) had vesicoureteral reflux (VUR), abnormal renal ultrasonography and abnormal DMSA renal scintigraphy, respectively. Unilateral hydronephrosis had a significant correlation with VUR at p value 0.024. In renal units, abnormal renal ultrasonography and hydronephrosis had significant correlations with VUR at p values 0.039 and 0.021, respectively. In patients and renal units, hydronephrosis had no significant correlation with abnormal DMSA renal scintigraphy at 1 month after UTI. However, abnormal renal ultrasonography and VUR had significant correlations with abnormal DMSA renal scintigraphy at p values 0.022 and < 0.001 in patients and at p values 0.024 and < 0.001 in renal units, respectively. Both in patients and renal units, VUR (Grade I-III) had no significant correlation with abnormal DMSA renal scintigraphy. However, severe VUR (Grade IV-V) had significant correlations with abnormal DMSA renal scintigraphy at p values < 0.001 and < 0.001, respectively. Seventeen patients underwent DMSA renal scintigraphy at 6 months after UTI. In addition, 15 (88.2%) developed persistent renal scarring.

CONCLUSION

Abnormal renal ultrasonography and severe VUR identify renal parenchymal changes. DMSA renal scintigraphy in the first episode of UTI should be carried out in those patients. Abnormal DMSA renal scintigraphy at 1 month after UTI has a tendency to persist.

Childhood recurrent urinary tract infection in southern Thailand

INTRODUCTION

Recurrent urinary tract infection (UTI) is one of the major health problems in children because of its high rate of occurrence.

OBJECTIVE

Our aim of the study was to evaluate the prevalence and determine risk factors of recurrent UTI in Thai children.

PATIENTS AND METHODS

The medical records of children aged less than 15 years diagnosed with UTI at the Department of Pediatrics, Songklanagarind Hospital were reviewed.

RESULTS

A total of 307 children (144 boys, 163 girls) were followed up for at least 1 year. Fifty-six children, 31 (19.0%) boys and 25 (17.4%) girls, developed at least one recurrence totaling 153 recurrent UTI episodes. The recurrence rate was not statistically different between the sexes (p = 0.8). On multivariate analysis, genitourinary system (GU) anomalies, particularly vesicoureteral reflux (VUR), were the most significant risk factors. Children aged greater than 5 years had a slightly higher risk of recurrence, irrespective of gender. Comparison of organisms associated with recurrent UTI with those associated with first UTI showed that the prevalence of Escherichia coli decreased from 76.9% to 56.2% but was still the major causative agent. In contrast, the prevalence of Klebsiella pneumoniae and unusual or mixed organisms significantly increased from 7.8% to 15.0% and 6.2% to 16.3%, respectively.

CONCLUSION

One-fifth of children who had UTI developed recurrence and the rates were similar for males and females. Independent risk factors for recurrent UTI were found to be at age of >5 years and underlying disease of either GU anomaly or VUR.

Abnormal dimercaptosuccinic Acid scan may be related to persistence of vesicoureteral reflux in children with febrile urinary tract infection

PURPOSE

This study assessed whether (99m)technetium dimercaptosuccinic acid (DMSA) scintigraphy used for the assessment of renal sequelae after febrile urinary tract infection (UTI) has any prognostic value for outcome measurement of vesicoureteral reflux (VUR) by retrospectively evaluating the correlation between abnormal DMSA scintigraphy results and persistence of VUR in children with febrile UTI.

MATERIALS AND METHODS

The medical records of 142 children (57 boys, 85 girls) admitted with febrile UTI from January 2004 to December 2006 and who were followed up for more than 1 year were retrospectively reviewed. At the initial and follow-up visits, renal ultrasound and DMSA scans were performed within 7 days from the diagnosis and voiding cystourethrography (VCUG) was performed within 1 month in all case and follow-up evaluations.

RESULTS

The children's mean age was 4.8±3.6 years (range, 0.3 to 14 years). The mean follow-up was 28.2±4.8 months. At the initial examination, VUR was more often associated with an abnormal DMSA scan result (83.3%) than with a normal DMSA scan result (16.7%, p=0.02). The frequency of VUR with an abnormal DMSA scan during acute UTI was significantly higher than the frequency of VUR with a normal DMSA scan (38.8% vs, 25.8%, respectively, p=0.004). Also, high-grade VUR was associated with an abnormal DMSA scan result (32.5%) more often than with a normal DMSA scan result (0%, p=0.01). Children with an abnormal DMSA scan had a lower resolution rate of VUR (17.5%) than did children with a normal DMSA scan (75.0%) at the follow-up VCUG (p=0.02).

CONCLUSIONS

An abnormal result on a DMSA scan during febrile UTI is associated with high-grade and persistent VUR. DMSA scans performed during febrile UTI are useful in reflux resolution in childhood.

Prediction of vesicoureteral reflux in children with first urinary tract infection by dimercaptosuccinic Acid and ultrasonography

OBJECTIVE

Urinary tract infection (UTI) is one of the most common causes of febrile pediatric diseases. Also, vesicoureteral reflux (VUR) is a significant risk factor for UTI. Voiding cystourethrography (VCUG) is the method of choice for evaluation of VUR. This study was done to predict VUR by DMSA scan (technetium 99 m-labeled dimercaptosuccinic acid) and ultrasonography (US).

METHODS

In a prospective study, all children with first time acute pyelonephritis were selected and evaluated by DMSA scan and US. Then VCUG was done with negative urine culture. All children with final diagnosis of obstructive congenital anomaly were excluded. The sensitivity, specifity, positive predictive values, negative predictive values, Confidence Interval of DMSA scan and US were calculated for prediction or exclusion of VUR.

FINDINGS

Among 100 children with UTI diagnosis, VUR was detected in 39 children and 63 (31.5%) kidneys. DMSA scan was abnormal in 103 (51.5%) units, 45 units had VUR (PPV=44%), 79 units with normal DMSA scan had no VUR (NPV=81%). Of kidney units that were abnormal by DMSA or US, 51 units had VUR. PPV and NPV were 44% and 56%, respectively.

CONCLUSION

DMSA scan alone or with US cannot predict VUR (especially low grade VUR). But according to NPV, it seems that absence of VUR can be predicted. So, more studies are needed to determine the usefulness of DMSA scan and US instead of VCUG for detection of VUR.

Endoscopic treatment of vesicoureteric reflux with Deflux: a Canadian experience

INTRODUCTION

Vesicoureteric reflux is a common problem encountered in urological practice. Traditionally, if medical management with low-dose antibiotic prophylaxis failed, the only alternative was ureteroneocystostomy. Recently, promising results with subureteric injection of dextranomer/hyaluronic acid copolymer (Deflux) have renewed interest in the endoscopic treatment of vesicoureteric reflux (VUR).

OBJECTIVE

We reviewed the outcome of the subtrigonal injection (STING) procedure with Deflux at a single pediatric hospital and included the rate of VUR resolution and complications.

METHODS

An Institutional Review Board approved the retrospective review of all cases of STING performed with Deflux at the Children's Hospital of Eastern Ontario, from April 2003 to October 2005. We used voiding cystourethrogram (VCUG) or radionuclide cystogram (RNC) for diagnosis of VUR. The most common indications for surgery were breakthrough infection, progression of renal scars and parental preference. A subureteral or intra-ureteral injection, at the 6 o'clock position, delivered the material to support the ureter and correct VUR.

RESULTS

We reviewed the cases of 64 patients, 47 girls (73%) and 17 boys (27%), with a mean age of 6 years (range 1-17 yr) and a mean follow-up of 8 months (range 2-23 mo). A total of 26 patients (41%) had bilateral VUR and 38 (59%) had unilateral VUR (90 renal units were treated). Overall cure rate was 79.7% (51/64) per child and 74% (67/90) per renal unit. Among the 64 patients treated, 62.5% (40/64) were cured with a single injection, and a second and third injection raised the cure rate to 78% (50/64) and 79.7% (51/64), respectively. Contralateral low-grade de novo VUR was present in 7.9% (3/38) of the 38 unilateral cases. Postoperatively, de novo hydronephrosis developed in 3.3% (3/90) of the ureters, in 2 patients.

CONCLUSIONS

The endoscopic treatment of VUR with Deflux is a feasible outpatient procedure, requires minimal operating room time and is associated with low morbidity. In our study, it demonstrated a cure rate of 80% of patients and 74% of renal units. Dysfunctional voiding and neurogenic bladder (NB) do not seem to adversely affect results. STING should be considered for failed open reimplants, because it is much less morbid than redo reimplants. Further experience with the material and increased use of intraureteral injection may improve our cure rates.

[Modern imaging technology for childhood urinary tract infection]

Imaging in childhood urinary tract infection (UTI) is still a matter of debate. There are established guidelines, however new knowledge and the changed medical environment have enhanced this ongoing discussion. These new insights have impacted therapy and consequently the imaging algorithm. Modern imaging methods -- particularly MRI and modern ultrasound (US) -- are less invasive with a lower radiation burden. Additionally, it has been shown that VUR is a poor predictor for renal scarring out, which affects long-term results. Furthermore, the majority of UT malformations is depicted by prenatal US. The most crucial aspect of improving long-term outcome appears to be the early and reliable depiction of UTI and effective treatment to prevent renal scarring. This review tries to present this new knowledge and to discuss the potential of modern imaging. Recent changes in imaging algorithms are highlighted and an outcome-oriented algorithm that addresses these recent developments is proposed, without lightly abandoning established standards. It consists of an orienting US and -- for depiction of renal involvement -- amplitude coded color Doppler sonography or renal static scintigraphy (considered the gold standard, particularly for evaluating scars); in future MRI may play a role. Based on this concept, only patients with renal damage as well as patients with complex urinary tract malformations or intractable recurrent UTI may have to undergo VCUG.

Screening for vesicoureteral reflux and renal scars in siblings of children with known reflux

The incidence of vesicoureteral reflux (VUR) in the general population is less than 1%, but it is high in families with reflux. The reported prevalence of VUR among siblings of index patients with reflux has ranged from 4.7% to 51%. Reflux carries an increased risk of pyelonephritis and long-term renal impairment. The purpose of this study was to identify the age-related incidence and severity of reflux, and the frequency of associated renal parenchymal damage in siblings of children with reflux in order to assess the use of screening at different ages. Between October 1994 and February 2003, 40 siblings of 34 index patients were screened with direct voiding cystography. 99( m ) technetium (Tc)-dimercaptosuccinic acid (DMSA) nuclear renal scans were performed in siblings with VUR to detect renal scarring. The cystograms were interpreted as showing the presence or absence of VUR and the DMSA scan as symmetrical or asymmetrical differential function, with or without renal scarring. Of 40 siblings, 17 had VUR, representing an incidence of 42.5%. The mean age at study entry of the 15 boys and 25 girls was 63 months (range 6 months to 12 years). The majority of siblings with abnormal DMSA scans were asymptomatic. Reflux was unilateral in 12 siblings and bilateral in 5. Of the 17 refluxing siblings (22 refluxing ureters), 7 (41.17%) had a history of symptomatic urinary tract infection (UTI). The frequency of VUR was nearly equal in siblings over 6 years and those younger than 6 years. Of the 17 siblings with VUR, 16 had DMSA scintigraphy. Of these, 5 were normal and 11 (68.75%) showed abnormalities (7 asymmetrical differential function and 4 parenchymal defect), which was bilateral in 7 and unilateral in 4. In conclusion, this study confirms a significant overall incidence of VUR and renal parenchymal damage in the siblings of patients with known reflux. The prevalence of reflux in older siblings is similar to that in younger siblings. Our review suggests that all siblings over 6 years should undergo a screening cystogram, even in the absence of urinary tract infection. DMSA scintigraphy of asymptomatic siblings appears to be beneficial in preventing renal injury.

Prevalence of vesicoureteral reflux in neonatal urinary tract infection

Vesicoureteral reflux (VUR) after a first episode of urinary tract infection (UTI) is apparently diagnosed much more frequently (25%-40%) in children than in neonates. The aims of the study were to determine the actual rate of VUR in neonates with UTI and to define the clinical clues to its diagnosis. The study sample included term infants with a diagnosis of UTI during their first month of life who were seen in this hospital between January 1997 and May 1999. All infants underwent complete diagnostic work-up (renal ultrasound and voiding cystourethrography [VCUG]). The medical files were reviewed for patient sex, age at UTI diagnosis, laboratory findings (including causative pathogen), and ultrasonographic findings. These parameters were correlated with the finding of VUR on VCUG. Sixty-four neonates (55 males, 9 females) with UTI were included in this study. UTI was 6 times more common in males than females, although the incidence of VUR was equal between the sexes (about 20%). The presence of VUR was associated with a significantly younger age at presentation of UTI (11.4+/-4 vs 16.9+/-6.6 days, p<0.01). VUR was diagnosed at a fourfold higher rate in neonates with Klebsiella-induced UTI compared to those with E. Coli-UTI. In 80% of those with significantly abnormal ultrasonographic findings VUR was found on VCUG. Jaundice was noted at UTI diagnosis 3 times more often in infants with VUR, and elevated creatinine level, 2.5 times more often.

Fluctuating fetal or neonatal renal pelvis: marker of high-grade vesicoureteral reflux

Fetal renal pelvic dilatation is a predictor of vesicoureteral reflux (VUR), but has low specificity. The aim of this study was to determine the clinical significance of fluctuating size of the renal pelvis on sonography, particularly in relationship to VUR. We prospectively recorded fetal renal pelvic diameter >/=4 mm in 1,092 fetuses (692 boys), from May 1989 to December 1995, with a minimum follow-up of 7 years. Fluctuation, defined as size of renal pelvis changing by more than 4 mm during the course of obstetric (23), postnatal (128), and both pre- and postnatal (7) renal sonograms, was recorded prospectively in 159 (117 boys). Of the 1,092, 849 (593 boys) had a voiding cystourethrogram at a mean age of 7 weeks (range 3-20 weeks). Of the 31 (16 girls) with high-grade VUR, fluctuation was observed in 20 (9 girls). Fluctuation was strongly associated with high-grade VUR (odds ratio 11.1, P=0.0000003) and with renal damage (sensitivity 61%, positive predictive value 31%). Primary high-grade VUR was persistent, seen equally in boys and girls, and required surgery in the majority. Fluctuation was associated with renal duplication anomalies ( P=0.00009) and megaureter ( P<0.00000001). Fluctuation of the renal pelvis on sonography is a marker for persistent high-grade VUR and renal damage in girls and boys.

DMSA study performed during febrile urinary tract infection: a predictor of patient outcome?

Technetium-99m dimercaptosuccinic acid (DMSA) study has been advocated as a method for the assessment of renal sequelae after acute febrile urinary tract infection (UTI). However, it is not known whether DMSA scintigraphy performed during acute UTI has any prognostic value for outcome assessment. The objective of this study was to evaluate the usefulness of DMSA scintigraphy performed during UTI as a predictor of patient outcome, to identify children at risk of events [vesico-ureteral reflux (VUR) or recurrent UTI] that may lead to the development of progressive renal damage. One hundred and fifty-two children (including 78 girls) with a mean age of 20 months (range 1 month to 12 years) with first febrile UTI were evaluated by DMSA scintigraphy during acute UTI. After acute UTI, children were explored by voiding cysto-urethrography. Children who presented an abnormal DMSA study, or a normal DMSA study but VUR or recurrent UTI, underwent a DMSA control study 6 months after UTI. Children with VUR were followed up by direct radionuclide cystography. DMSA scintigraphy performed during acute UTI was normal in 112 children (74%). In 95 of these children, follow-up DMSA scintigraphy was not performed owing to a good clinical outcome. In the remaining 17 children, follow-up scintigraphy was normal. Forty children (26%) presented abnormal DMSA study during acute UTI. Twenty-five of them presented a normal follow-up DMSA, and 15 presented cortical lesions. Children with abnormal DMSA had a higher frequency of VUR than children with normal DMSA (48% vs 12%). It is concluded that children with normal DMSA during acute UTI have a low risk of renal damage. Children with normal follow-up DMSA and low-grade VUR have more frequent spontaneous resolution of VUR.

Follow-up of acute pyelonephritis in children by Tc-99m DMSA scintigraphy: quantitative and qualitative assessment

PURPOSE

The author's goal was to create a system to identify children at risk for development of progressive renal damage.

METHODS

Thirty-four children were examined with Tc-99m DMSA scintigraphy in the acute stage of an initial episode of pyelonephritis, after 6 months, and again after 1 year. The scintigraphic findings were correlated with clinical and laboratory data.

RESULTS

All children had parenchymal defects in the acute stage: 93% of the kidneys and 85% bilaterally. After 6 months, the defects had diminished or disappeared in 66% of the kidneys. New defects appeared in 22%. At 1 year, no further improvement was seen in the kidneys, with an improved or unchanged pattern at 6 months. New defects appeared in 34%. Mean kidney activity uptake expressed as the percentage of administered dose (KU/AD), was low in the acute stage, increased at 6 months, with no further significant increase at 1 year. Eighty-three percent of children with urine cultures growing > or = 104 bacteria/ml at follow-up had decreased KU/AD values, whereas all children with urine cultures growing < 104 bacteria/ml had increased KU/AD values.

CONCLUSIONS

Quantitative assessment increases the sensitivity of Tc-99m DMSA scintigraphy. Follow-up with this method makes it possible to identify the children with decreasing renal tubular function who may be at risk for progressive renal damage. Moderate bacteruria of 104 bacteria/ml urine is associated with deterioration of renal tubular function.

Direct comparison of radiology and nuclear medicine cystograms in young infants with vesico-ureteric reflux

OBJECTIVE

To determine the sensitivity of the direct radionuclide cystogram (DRC) in detecting vesico-ureteric reflux compared with the micturating cysto-urethrogram (MCU) in the same initial setting, in infants younger than one year.

PATIENTS AND METHODS

The results from the dual cystograms of 62 refluxing infants < 1 year old (mean 0.58) were compared. Results from same-day renal scintigraphy with dimercaptosuccinic acid (DMSA) in 60 of the 62 infants were also compared with the reflux grades.

RESULTS

Reflux was detected in 105 units, 96 detected on the DRC and 47 on the MCU, representing a sensitivity of 91% and 45%, respectively. The DRC missed half of grade 1, 20% of grade 2 and 6% of grade 3 reflux. Reflux at low bladder filling rates (DRC) represented 40% of all reflux units, and a half (52%) of scarred renal units detected by DMSA scintigraphy.

CONCLUSIONS

In young infants the MCU may fail to detect significant reflux and the DRC may fail to detect the lesser grades. The combination of both cystograms in the initial investigation of reflux provides more comprehensive information.

Risk assessment of renal cortical scarring with urinary tract infection by clinical features and ultrasonography

AIMS

To address some of the issues in the ongoing debate over the optimal diagnostic imaging following childhood urinary tract infection (UTI), by determining the risk of missing renal cortical scarring which would be detected on a technetium-99m dimercaptosuccinic acid (DMSA) gold standard if ultrasound alone were used, factoring for clinical features (upper or lower tract), UTI recurrence, and age group (infants, preschool, or school age).

METHODS

Details of UTI clinical features and recurrence were recorded for 990 children with a proven UTI, and their DMSA and ultrasound results were compared for each kidney.

RESULTS

The risks of missing DMSA scarring varied between 0.4% (school age children with solitary lower tract UTI) and 11.1% (infants with recurrent upper tract UTI).

CONCLUSIONS

UTI clinical features are important in assessing the need for DMSA imaging. Current UK imaging guidelines are endorsed, although preschool children with solitary lower tract UTI remain a controversial group and more attention needs to focused on children with recurrent UTI.

Diagnosis of vesico-ureteric reflux

The demonstration and grading of reflux is crucial in examination and follow-up of any child with upper urinary tract infection. A variety of factors can influence the occurrence of reflux, e.g. race, genetics, state of maturation of the ureterovesical valve, diuresis, infection and bladder dysfunction, including obstruction and neurogenic disorders. Even when reflux is investigated under strictly standardized conditions, two consecutive bladder fillings frequently show different grades of reflux. Voiding cystourethrography is, to date, the only method with a generally accepted, well-defined grading of reflux. It also allows detection of intrarenal reflux and anatomical and functional information about the bladder and urethra that is unobtainable by other methods. It is therefore usually considered the method of choice. Radionuclide cystography and, possibly, contrast enhanced ultrasonography can be complementary to voiding cystourethrography, but mainly for postoperative follow-up and screening of siblings.

Vesico-ureteric reflux: occurrence and long-term risks

The prevalence of vesico-ureteric reflux in the general population is unknown, but it is increased in risk groups, such as children with symptomatic urinary tract infection, schoolgirls with asymptomatic bacteriuria, first-degree relatives of patients with reflux and children with prenatal dilatation of their upper urinary tract. Children and adults with pyelonephritic renal scarring are at risk of serious long-term complications, e.g. hypertension and renal failure. Modern paediatric care, with early detection and treatment of urinary tract infections and reflux during childhood and adolescence, may improve long-term prognosis. In the adult patient with established pyelonephritic renal scarring, careful control of hypertension may retard the rate of progression, and angiotensin converting enzyme inhibitors may have renal protective properties.

The use of urinary dipstix in children with high-risk renal tracts

Urinary tract infection (UTI) is one of the most common acute illnesses found in infants and children and up to 5% of girls and 1% of boys will experience one or more episodes. Bables and children with abnormal renal tracts are at risk of developing scarred kidneys as a result of recurrent UTI, leading to an increased risk of hypertension and end-stage renal failure in later life. It seems logical, therefore, to place high priority on the early detection, prompt treatment and adequate follow up of children with high-risk renal tracts. This article describes the use of home urine testing for the early detection of UTI in children with high-risk renal tracts.

Acute childhood pyelonephritis: predictive value of positive sonographic findings in regard to later parenchymal scarring

RATIONALE AND OBJECTIVES

The authors evaluated the importance of positive sonographic findings in acute childhood pyelonephritis.

MATERIALS AND METHODS

A total of 290 children (91 boys, 199 girls, aged 4 days to 15 years [median, 394 days]) with clinically suspected acute pyelonephritis underwent initial renal gray-scale ultrasound (US) and dimercaptosuccinate scintigraphic examination within 3 days of onset. A total of 173 patients underwent color or energy US examination. One hundred fifteen children with normal scintigraphic or pathologic findings (other than acute pyelonephritis) were excluded from further study; 170 patients with abnormal scintigraphic findings underwent follow-up scintigraphic scanning 60-90 days later.

RESULTS

When pathologic structures other than acute pyelonephritis were not considered, the diagnostic value of gray-scale US was poor, with a sensitivity of 45.5%, a specificity of 86.6%, a positive predictive value of 88.8%, and a negative predictive value of only 40.6%. In regard to future renal scarring, gray-scale US had a positive predictive value of 67.7%, a negative predictive value of 40%, and a likelihood ratio of 1.16. Abnormal Doppler findings helped predict future scarring with a positive predictive value of 85.7%, a negative predictive value of 37.2%, a very low sensitivity of 26.9%, a high specificity of 90.6%, and a likelihood ratio of 2.87.

CONCLUSION

Positive US Doppler findings in children with clinically suspected acute pyelonephritis indicate the need for immediate treatment. A positive initial gray-scale US examination does not predict future renal scarring, but a positive Doppler examination indicates a high probability of scarring. Negative gray-scale or Doppler US does not exclude a diagnosis of acute pyelonephritis and it cannot predict an absence of future scarring.

Distress and radiological investigations of the urinary tract in children

The distress associated with radiological investigations may be related to the information and style of parental explanation given to the child and the parents own coping style. In a questionnaire survey we assessed distress in relation to investigations of the urinary tract using the Groningen Distress Rating Scale and the Utrecht Coping List. We found the micturating cystourethrogram (MCUG) to be significantly more distressing than radionuclide investigations. MCUG distress was adversely correlated with passive and palliative parental coping styles. Results suggested that cognitive coping styles modelled by the parents ameliorated distress on dimercaptosuccinic acid scintigraphy.

CONCLUSION

The high level of MCUG associated distress and presence of traumatised children in the MCUG sample, along with the potential for parental contribution to distress reduction, suggests that both children and parents would benefit from more active preparation programmes prior to MCUG testing.

Long-term follow up to determine the prognostic value of imaging after urinary tract infections. Part 2: Scarring

Long term follow up of children with urinary tract infections, in whom imaging investigations were performed at presentation, has been used to identify features that distinguish those at greatest risk of progressive renal damage. No single investigation at presentation was able to predict subsequent deterioration but, by employing a combination of imaging investigations, it was possible to separate groups with high or low probability of progressive damage. In the low risk group the incidence of progressive damage was 0.2% (95% confidence interval (CI) 0 to 1.3%). The combination of both scarring and reflux at presentation, or one only of these but accompanied by subsequent documented urinary tract infection, was associated with a 17-fold (95% CI 2.5 to 118) increase in the relative risk of progressive renal damage compared with children without these features. The recommended combination of investigations at presentation for girls of any age and boys over 1 year is ultrasound and dimercaptosuccinic acid (DMSA) scintigraphy in all, to detect both scarring and significant structural abnormalities, renography in children with dilatation of any part of the urinary tract on ultrasound, to distinguish dilatation from obstruction, and an isotope voiding study in all who have acquired bladder control. This gives the best separation between those at high and those at low risk of progressive damage with least radiation dose and lowest rate of instrumentation. Micturating cystourethrography (MCU) should be restricted to girls who have not acquired bladder control, unless there is reason to suspect a significant structural abnormality such as urethral valves. A single non-febrile urinary tract infection that responds promptly to treatment is not a justification for performing MCU in boys under 1 year or in children of any age with bladder control. No case can be made for any abbreviated schedule of investigation. These risk factors should be taken into account when designing follow up protocols.