Usefulness of procalcitonin and C-reactive protein rapid tests for the management of children with urinary tract infection

BACKGROUND: Urinary tract infection (UTI) is a common problem in children. Because clinical findings and commonly used blood indices are nonspecific, the distinction between lower and upper urinary tract infection cannot be made easily in this population. However, this distinction is important because renal infection can induce parenchymal scarring. The objective of this study was to determine the accuracy of procalcitonin (PCT) compared with C-reactive protein (CRP) rapid tests to predict renal involvement in children with febrile UTI. METHODS: PCT and CRP were measured in the blood of children admitted to the emergency room with fever, signs and symptoms of urinary tract infection and/or a positive urine dipstick analysis. Renal parenchymal involvement was assessed by a 99mTc-labeled dimercaptosuccinic acid renal scan in the acute phase of infection in all children. Sensitivity, specificity and likelihood ratios were determined for both tests. RESULTS: Fifty-four children with a proven urinary tract infection were enrolled: 63% had renal involvement; and 37% had infection restricted to the lower urinary tract. No difference was found for age, sex and total white blood cell count between the groups. The calculated likelihood ratios of procalcitonin and C-reactive protein rapid tests were between 3.8 and 7 and 1.5 and 2.8, respectively. A positive PCT value predicted renal involvement in 87 to 92% of children with febrile UTI, compared with 44 to 83% using CRP values. CONCLUSIONS: A rapid determination of procalcitonin concentration could be useful for the management of children with febrile UTI in the emergency room.     

Usefulness of procalcitonin for the diagnosis of acute pyelonephritis in children]

BACKGROUND: Acute pyelonephritis can induce parenchymal scarring. The aim of this study was to evaluate the usefulness of procalcitonin (PCT) to predict renal involvement in febrile children with urinary tract infection (UTI). METHODS: In a prospective study serum PCT was measured and compared with others commonly used inflammatory markers in children admitted to the emergency unit with acute pyelonephritis. Renal parenchymal involvement was assessed by a (99 m)Tc-labeled dimercaptosuccinic acid (DMSA) renal scar performed in the first 3 days after the admission. RESULTS: Among 42 enrolled patients, 19 (45%) had acute renal involvement (Group A) ; 23 (55%) (Group B) had normal DMSA scan (n = 16), or old scarring (n = 4) or various anomalies related to uropathy (n = 3). In group A, the mean PCT level was significantly higher than in the group B (5.4 ng/ml, vs 0.4 ng /ml, p < 10(-5)). In these 2 groups, mean C reactive protein (CRP) levels were 99.1 mg/l and 44.6 mg/l respectively (p < 0.001). For a level of serum PCT > or = 0.5 ng/ml, the sensitivity and specificity to predict the renal involvement were 100% and 87% respectively; for a level> or= 20 mg/l CRP had a sensitivity of 94% but a specificity of 30%. CONCLUSION: Serum PCT levels were significantly increased in febrile children with UTI when acute renal parenchymal involvement was present. PCT seems a better marker than CRP for the prediction of patients at risk of renal lesions.     

Elevated serum procalcitonin values correlate with renal scarring in children with urinary tract infection

BACKGROUND: Urinary tract infection (UTI) in young children carries the risk of parenchymal damage and sequelae. The location of the infection within the urinary tract influences decisions regarding both therapeutics and follow-up. Because clinical features and laboratory markers of infection at an early age are not specific, it is difficult to make a distinction between lower UTI and acute pyelonephritis. Procalcitonin (PCT) has been studied as a marker of severe bacterial infection. The aim of this study was to test the usefulness of PCT concentration in serum to distinguish between uncomplicated UTI and severe acute pyelonephritis with renal scars. METHODS: PCT was measured by immunoluminometric assay in serum samples from children with microbiologically documented infection. Severe renal involvement was assessed by 99mTc-dimercaptosuccinic acid gammagraphy done 5 to 6 months after the episode to check for the presence of parenchymal scars. C-reactive protein (CRP) and leukocyte count were also measured. RESULTS: PCT at presentation showed a significant correlation (P < 0.001) with the presence of renal scars in children with UTI. Using a cutoff of 1 ng/ml for PCT and 20 mg/l for CRP, sensitivity and specificity in distinguishing between urinary tract infection with and without renal damage were 92.3 and 61.9%, respectively, for PCT and 92.3 and 34.4% for CRP. Positive and negative predictive values were 32 and 97.5%, respectively, for PCT and 23 and 95%, respectively, for CRP. CONCLUSIONS: A low PCT value at admission indicates a low risk of long term renal scarring. Increased PCT values at admission correlate with the presence of scars. PCT values have proved to be more specific than CRP and leukocyte count for identifying patients who might develop renal damage.     

Procalcitonin is a marker of severity of renal lesions in pyelonephritis

OBJECTIVE: In an attempt to differentiate acute pyelonephritis from lower urinary tract infection (UTI), we measured serum procalcitonin levels, a recently described marker of infection. We compared it with other commonly used inflammatory markers and evaluated its ability to predict renal involvement as assessed by dimercaptosuccinic acid (DMSA) scintigraphy. METHODS: Serum C-reactive protein, leukocyte counts, and procalcitonin levels were measured in 80 children, 1 month to 16 years of age, admitted for suspected pyelonephritis. Renal involvement was assessed by 99mTe-DMSA scintigraphy in the first 5 days after admission. The examination was repeated at least 3 months later if the first result was abnormal. RESULTS: In lower UTI, the mean procalcitonin (PCT) was 0.38 micrograms/L +/- 0.19 compared with 5.37 micrograms/L +/- 1.9 in pyelonephritis. In these two groups, respectively, leukocyte counts were 10939/mm3 +/- 834 and 17429/mm3 +/- 994, and C-reactive protein (CRP) levels were 30.3 mg/L +/- 7.6 and 120.8 mg/L +/- 8.9. When inflammatory markers were correlated to the severity of the renal lesion as ranked by DMSA scintigraphy, we found a highly significant correlation with plasma levels of PCT, but borderline significance with CRP and none with leukocyte counts. Patients without vesicoureteral reflux had a mean PCT of 5.16 micrograms/L +/- 2.33, which was not significantly different from that in patients with reflux who had a mean PCT of 5.76 micrograms/L +/- 3.49. For the prediction of renal lesions at admission, CRP had a sensitivity of 100% and a specificity of 26.1%. The sensitivity and specificity of PCT were 70.3% and 82.6%, respectively. CONCLUSION: We conclude that serum PCT levels were increased significantly in children with febrile UTI when renal parenchymal involvement (assessed by DMSA scintigraphy) was present and allowed for prediction of patients at risk of severe renal lesions.     

降钙素原对儿童急性肾盂肾炎的诊断价值

目的：探讨降钙素原（PCT）对儿童急性肾盂肾炎（APN）的诊断价值。方法：回顾性分析2011年9月至2012年2月诊断为初发的尿路感染（UTI）且年龄<3岁患儿的病例资料,以核素肾静态扫描（99mTc-DMSA）结果作为诊断APN的金标准,比较上尿路感染（APN）及下尿路感染（非APN）患儿血清PCT、CRP的水平,并绘制二者诊断APN的受试者工作特征曲线（ROC曲线）,判断其诊断性能。结果：共65例UTI患儿纳入研究,其中APN 39例,下尿路感染者26例,前者的血清PCT、CRP水平显著高于后者（分别 3.08 ng/mL vs 0.37 ng/mL;6.25 mg/L vs 3.01 mg/L;均P<0.01）。血清PCT诊断APN的敏感性为84.6%,特异性为88.5%,曲线下面积为0.873（95%可信区间为0.781~0.965）,最佳阈值为1.03 ng/mL;血清CRP诊断APN的敏感性为71.8%,特异性为69.2%,曲线下面积为0.735（95%可信区间为0.612~0.858）,最佳阈值为3.91 mg/L。结论：PCT对儿童APN的诊断具有较高的敏感性及特异性,有助于临床对APN的早期识别。     

Radiological evaluation of the urinary tract in children with urinary infection

Objective: This article in to study the association of structural abnormalities of the urinary tract in children with urinary tract infection (UTI) using ultrasound examination.Methods : 262 children with culture proven urinary tract infection were studied. Antibiotics were given as per sensitivity pattern. All children had an ultrasound of the abdomen done within 3 weeks. A micturating cystourethrogram (MCU) was done in those with abnormalities of the lower urinary tract detected on ultrasound, as well as in those who had recurrence of infection, after a normal ultrasound. IVU and renal isotope scans were done in selected cases.Result : All children were followed up until one year after the study period. Fifty-four patients had an underlying urinary tract anomaly; 42 were picked up by ultrasound and 12 by MCU. 22.9% of males and 15.9% of females had anomaly of the urinary tract. Children less than 2 years had the highest incidence of anomalies.Conclusion : Pelviureteric junction obstruction with hydronephrosis, vesicoureteric reflux and non-refluxing megaureter are the major anomalies picked up. 20% of children with urinary tract infections have an underlying structural abnormality of the urinary tract, three-fourth of which are picked up on ultrasound. An ultrasound abdomen is recommended in all children after the first UTI. In addition, an MCU is also indicated in all boys below 2 years with UTI, since one-third of anomalies will be missed if only ultrasound is done.     

Imaging the urinary tract in children with urinary tract infection

Aim: To evaluate whether ultrasonography (US) alone is sufficient in imaging the urinary tract in 1185 children with urinary tract infection (UTI). Methods: The reports on US and voiding cystourethrography (VCUG) were reviewed. Results: Initial US was normal in 861/1185 patients (73%). VCUG revealed abnormal findings in 285/861 (33%), of which grade III–V vesicoureteral reflux (VUR) comprised 97 cases (11%). During follow‐up, VUR had resolved in 88/97 (91%) patients: in 50/57 (88%) patients without active treatment for VUR, in 27/29 (93%) with endoscopic and in 11/11 (100%) with open surgery for VUR. During follow‐up, 11/97 patients (11%) had developed new renal scarring detectable in US, but no renal impairment occurred. Except for VUR, VCUG showed nonobstructive urethral valves in two infant boys with normal initial US. Thus, in 861 children with normal initial US, 40 patients with grade III–V VUR and two patients with significant nonreflux pathology may have benefited from surgical treatment, giving the total number of possibly missed pathological finding in 42/861 (4.9%) cases if VCUG had not been performed. Conclusion: We suggest that children with UTI could be examined using US alone and to use VCUG only after additional indications.     

Urinary tract infection: is there a need for routine renal ultrasonography?

AIMS: To assess the yield of routine renal ultrasound (RUS) in the management of young children hospitalised with first uncomplicated febrile urinary tract infection (UTI). METHODS: All children aged 0-5 years who had been hospitalised over a two year period with first uncomplicated febrile UTI in a medium size institutional regional medical centre were included. Children with known urinary abnormalities and/or who had been treated with antibacterial agents within seven days before admission were excluded. All included children underwent renal ultrasonography during hospitalisation and voiding cystouretrography (VCUG) within 2-6 months. The yield of RUS was measured by its ability to detect renal abnormalities, its sensitivity, specificity, and positive and negative predictive values for detecting vesicoureteral reflux (VUR), and by its impact on UTI management. RESULTS: Of 255 children that were included in the study, 33 children had mild to moderate renal pelvis dilatation on RUS suggesting VUR, of whom only nine had VUR on VCUG. On the other hand, in 36 children with VUR on VCUG the RUS was normal. The sensitivity, specificity, positive predictive value, and negative predictive value of abnormal RUS for detecting VUR were 17.7%, 87.6%, 23.5%, and 83.2% respectively. In none of the patients with abnormal RUS was a change in the management at or following hospitalisation needed. CONCLUSION: Results show that the yield of RUS to the management of children with first uncomplicated UTI is questionable.     

The presence of vesicoureteric reflux does not identify a population at risk for renal scarring following a first urinary tract infection

Background: Childhood urinary tract infection (UTI) with or without vesicoureteric reflux (VUR) may predispose to renal scarring. There is no clear consensus in the literature regarding imaging following UTI in infancy. Aims: To define the role of cystography following a first UTI in children aged under 1 year, when urinary tract ultrasonography (US) is normal. Methods: Retrospective data collection of 108 children (216 renal units) aged under 1 year at the time of a bacteriologically proven UTI. All had a normal US and underwent both catheter cystogram and DMSA test. Sensitivity, specificity, likelihood ratios positive and negative, and diagnostic odds ratio were calculated for VUR on cystography versus scarring on DMSA. Results: VUR was shown in 25 (11.6%) renal units. Scarring on DMSA was seen in 8 (3.7 %) kidneys. Only 16% of kidneys with VUR had associated scarring; 50% of scarred kidneys were not associated with VUR. The likelihood ratio positive was 4.95 (95% CI 2.22 to 11.05) and the likelihood ratio negative was 0.56 (95% CI 0.28 to 1.11). The diagnostic odds ratio was 8.9, suggesting that cystography provided little additional information. Conclusion: Since only 16% of children with VUR had an abnormal kidney, the presence of VUR does not identify a susceptible population with an abnormal kidney on DMSA. In the context of a normal ultrasound examination, cystography contributes little to the management of children under the age of 1 year with a UTI. In this context, a normal DMSA study reinforces the redundancy of cystography.     

The presence of vesicoureteric reflux does not identify a population at risk for renal scarring following a first urinary tract infection.

BACKGROUND: Childhood urinary tract infection (UTI) with or without vesicoureteric reflux (VUR) may predispose to renal scarring. There is no clear consensus in the literature regarding imaging following UTI in infancy. AIMS: To define the role of cystography following a first UTI in children aged under 1 year, when urinary tract ultrasonography (US) is normal. METHODS: Retrospective data collection of 108 children (216 renal units) aged under 1 year at the time of a bacteriologically proven UTI. All had a normal US and underwent both catheter cystogram and DMSA test. Sensitivity, specificity, likelihood ratios positive and negative, and diagnostic odds ratio were calculated for VUR on cystography versus scarring on DMSA. RESULTS: VUR was shown in 25 (11.6%) renal units. Scarring on DMSA was seen in 8 (3.7 %) kidneys. Only 16% of kidneys with VUR had associated scarring; 50% of scarred kidneys were not associated with VUR. The likelihood ratio positive was 4.95 (95% CI 2.22 to 11.05) and the likelihood ratio negative was 0.56 (95% CI 0.28 to 1.11). The diagnostic odds ratio was 8.9, suggesting that cystography provided little additional information. CONCLUSION: Since only 16% of children with VUR had an abnormal kidney, the presence of VUR does not identify a susceptible population with an abnormal kidney on DMSA. In the context of a normal ultrasound examination, cystography contributes little to the management of children under the age of 1 year with a UTI. In this context, a normal DMSA study reinforces the redundancy of cystography.     

Prevalence of urinary tract infection in childhood: a meta-analysis

BACKGROUND: Knowledge of baseline risk of urinary tract infection can help clinicians make informed diagnostic and therapeutic decisions. We conducted a meta-analysis to determine the pooled prevalence of urinary tract infection (UTI) in children by age, gender, race, and circumcision status. METHODS: MEDLINE and EMBASE databases were searched for articles about pediatric urinary tract infection. Search terms included urinary tract infection, cystitis, pyelonephritis, prevalence and incidence. We included articles in our review if they contained data on the prevalence of UTI in children 0-19 years of age presenting with symptoms of UTI. Of the 51 articles with data on UTI prevalence, 18 met all inclusion criteria. Two evaluators independently reviewed, rated, and abstracted data from each article. RESULTS: Among infants presenting with fever, the overall prevalence (and 95% confidence interval) of UTI was 7.0% (CI: 5.5-8.4). The pooled prevalence rates of febrile UTIs in females aged 0-3 months, 3-6 months, 6-12 months, and >12 months was 7.5%, 5.7%, 8.3%, and 2.1% respectively. Among febrile male infants less than 3 months of age, 2.4% (CI: 1.4-3.5) of circumcised males and 20.1% (CI: 16.8-23.4) of uncircumcised males had a UTI. For the 4 studies that reported UTI prevalence by race, UTI rates were higher among white infants 8.0% (CI: 5.1-11.0) than among black infants 4.7% (CI: 2.1-7.3). Among older children (<19 years) with urinary symptoms, the pooled prevalence of UTI (both febrile and afebrile) was 7.8% (CI: 6.6-8.9). CONCLUSIONS: Prevalence rates of UTI varied by age, gender, race, and circumcision status. Uncircumcised male infants less than 3 months of age and females less than 12 months of age had the highest baseline prevalence of UTI. Prevalence estimates can help clinicians make informed decisions regarding diagnostic testing in children presenting with signs and symptoms of urinary tract infection.     

Is a routine voiding cystourethrogram necessary in children after the first febrile urinary tract infection?

Aim: The aim of this study was to estimate the value of identifying vesicoureteral reflux (VUR) on a voiding cystourethrogram (VCUG) and the benefit of VUR management according to imaging strategies at the first febrile urinary tract infection (UTI). Methods: Children aged 1–144 months (n = 618) with the first febrile UTI admitted at our hospital from 2000 to 2009 were enrolled. In all patients, renal sonogram (US), ^99mTc‐dimercaptosuccinic acid (DMSA) renal scanning and VCUG were performed. Retrospective analyses per patient and per renal unit were performed. Results: Abnormal US or DMSA scans had a sensitivity of 100% and a negative predictive value (NPV) of 100% to detect high‐grade reflux. In hydronephrotic kidneys, DMSA scanning had a sensitivity of 88.2% and a NPV of 97.1% to detect high‐grade reflux. Conclusion: Routine VCUG is not required after the first febrile UTI in patients with normal US or normal DMSA scan. Even if the US reveals hydronephrosis, routine VCUG is not necessary if the DMSA findings are normal. It is recommended that children who did not receive both a DMSA scan and VCUG after the first febrile UTI should be followed up over the long term.     

Ultrasonography as predictor of permanent renal damage in infants with urinary tract infection

Aim:  To evaluate the ability of ultrasound (US) in infants (<1 year) with acute urinary tract infection (UTI), to identify those with permanent renal damage (PRD) at scintigraphy 1 year later.
Methods:  US, dimercaptosuccinic acid scintigraphy and voiding cystourethrography were performed in 191 infants.
Results:  US was abnormal in 46 infants (24%). PRD was found in 46 infants (24%); 19 of these had abnormal US (sensitivity 41%). In 145 infants without PRD, 27 had abnormal US (specificity 81%). Dilating reflux or verified obstruction occurred in 21 (11%) infants, of whom 18 (86%) had PRD while 28 of 170 (16%) without such diagnoses had PRD. Of 16 infants with dilating reflux, 9 (sensitivity 56%) had abnormal US and 14 (88%) PRD. Dilatation at US was seen in 27 children; 7 of these had dilating reflux and 5 verified obstruction.
Conclusion:  US performed in association with acute UTI had limited ability to identify children with PRD at ^99mTc-dimercaptosuccinic acid (DMSA) 1 year later, although abnormal renal size was a strong indicator of renal damage. The ability of US to identify children with dilating reflux was also limited. However, once detected at US, dilatation of the urinary tract was associated with dilating reflux or obstruction in half of the cases. Our study confirms that dilating reflux and obstruction are strong indicators of PRD but only half of those who developed PRD had such diagnoses.     

Renal scintigraphy using technetium dimercaptosuccinic acid in the diagnosis of pyelonephritis in children: study of 17 cases

OBJECTIVE: To determine whether the presence of abnormal results in DMSA renal scintigraphy indicates pyelonephritis. METHODS: We performed the washout test in 17 children with urinary tract infection, as a criterion standard, to locate the infection site. All the children underwent DMSA renal scintigraphy in the acute phase of the disease. The results were analyzed by the chi-square test or Fisher test. RESULTS: DMSA renal scintigraphy revealed changes in all five cases of pyelonephritis, suggesting acute kidney involvement. On the other hand, only one child with cystitis (total = 12 cases) had abnormal results in renal scintigraphy. Sensitivity and specificity were 100% and 92%, respectively. CONCLUSION: DMSA renal scintigraphy is a sensitive method for the diagnosis of pyelonephritis in children.     

Involvement of the renal parenchyma in acute urinary tract infection: The contribution of99mTc dimercaptosuccinic acid scan

Summary We performed^99mTc dimercaptosuccinic acid (DMSA) scan and ultrasonography in 146 children during the acute phase of a proven urinary tract infection (UTI). In 99 a micturating cysto-urethrography and in 83 an intravenous urography was also done. The occurrence of fever and increased WBC count, CRP and ESR were also studied. It appeared from this retrospective study that 47% of the kidneys had a cortical or patchy pattern of decreased uptake of^99mTc DMSA, as compared to 23% with abnormal findings on US. Vesico-ureteral reflux was present in 38% of the kidneys with parenchymal involvement on^99mTc DMSA scan. Although fever, leucocytosis and elevated CRP and ESR were significantly correlated with abnormal^99mTc DMSA scan, they were also observed in children without renal parenchymal involvement. Our results suggest that^99mTc DMSA scan is a sensitive method for the detection of parenchymal involvement during acute UTI. The exact nature of these lesions and their relation with scars need, however, to be defined.     

Primary and acquired renal scarring in boys and girls with urinary tract infection

OBJECTIVES: To determine when pyelonephritic renal scarring was detected in children with urinary tract infection (UTI) and characterize those with primary and acquired scarring, respectively. STUDY DESIGN: A population-based cohort of 1221 children (989 girls and 232 boys) with first recognized symptomatic UTI, aged 0 to 15 years, were diagnosed and followed up prospectively at a single children's hospital; 652 had febrile UTI. Seven hundred fifty-three were evaluated by urography. Renal scarring was classified as primary or acquired, the latter without signs of scarring at the first investigation. To evaluate the frequency of recurrent UTI in those with acquired scarring, a comparison with group-matched children without scarring was performed. RESULTS: A total of 74 children without obstruction had renal scarring (acquired in 40). Primary scarring was found in 18 of 21 (86%) of the boys and 16 of 53 (30%) of the girls (P <.001). The majority of boys with scarring had dilated reflux (67%) in contrast to girls (23%). Recurrent UTI was rare in boys, whereas girls with acquired scarring had significantly more febrile recurrences than girls without scarring. CONCLUSIONS: Most boys had primary, probably congenital, reflux-associated renal damage, whereas most girls had acquired scarring related to recurrences of febrile UTI.     

Ultrasonography in urinary tract infection in infancy

In a prospective study 77 infants (35 boys) with a mean age of 5.23 months were studied to determine the value of sonography for detection of renal parenchymal involvement in urinary tract infection (UTI). Sonography was performed during UTI and about one month later. UTI was classified as upper and lower UTI according to the clinical and laboratory findings; radiological investigations (voiding cystoureterography = MCU) were performed in all infants. 40 infants were classified to have upper UTI. There was a high sensitivity (80%) and specificity (97%) for detection of renal involvement by sonography. Incidence for vesicoureteral reflux (VUR) was significantly higher in infants with repeated pathological findings on sonography. In contrast, no VUR was detected on MCU in all 12 infants with normal findings in both sonographic examinations. Yet, sonography without catheterization could not detect VUR in all infants with radiologically confirmed reflux. Our results show, that sonography is of definite value in infants with UTI, but cannot replace radiological work up.     

儿童泌尿系统感染诊治进展

泌尿系统感染(UTI)是儿科最常见的细菌感染性疾病之一,约30%的婴幼儿在初次感染6~12个月反复发作。而在有泌尿系统发育畸形的儿童中,约30%的患儿以UTI为首发表现,故UTI可能是潜在肾脏结构异常的前哨事件。婴幼儿UTI常并膀胱输尿管反流等先天性尿路畸形,对于反复感染的高危患儿,易出现肾脏损害及肾瘢痕,进而导致终末期肾病。因此,早期识别、及时治疗和合理管理对改善预后十分重要。现总结近年来国内外相关文献,以期为儿童UTI的诊治提供临床参考。