Update on dimercaptosuccinic acid renal scanning in children with urinary tract infection

The dimercaptosuccinic acid (DMSA) renal scan is a method for assessing kidney function. Indications for DMSA scanning in children with urinary tract infection (UTI), as well as timing, have changed. Pitfalls in interpreting DMSA scans include: (1) acute pyelonephritis (APN), (2) tubular dysfunction, (3) hypertension, (4) use of captopril in patients with renovascular hypertension and (5) duplex kidneys. Interpretation of DMSA scans in children with UTI vary according to timing and clinical setting. During the course of a febrile UTI a DMSA scan may reveal a normal kidney, APN or a non-functioning, small and/or ectopic kidney. In the absence of UTI (up to 6 months) in children with vesicoureteric reflux a DMSA scan may indicate a normal kidney, renal scarring (reflux nephropathy), occult duplex kidney and allows the progression of scarring and hypertrophy of normal areas of the kidney to be followed anatomically. The DMSA renal scan in now the most reliable test for the diagnosis of APN. The transient abnormalities due to APN can occur in normal or scarred kidneys. Lesions due to reflux nephropathy (defined as a defect in the renal outline or contraction of the whole kidney) are permanent. Intravenous urography reveals renal abnormalities later than the DMSA scan. If abnormalities are seen on a DMSA scan performed during the course of APN it is impossible to predict the outcome: they can progress to permanent scarring or heal completely. An abnormal DMSA scan during a febrile UTI allows the identification of children at risk of developing renal scars. These children should be carefully investigated, maintained on long-term quimioprophylaxis and followed.     

Comparison of ultrasound and dimercaptosuccinic acid scintigraphy changes in acute pyelonephritis

 The strategy for morphological investigations in children with acute pyelonephritis (APN) remains debatable. We studied 70 children (median age 2.0 years) admitted with a first episode of pyelonephritis using a high-resolution ultrasound technique (RUS) and compared the results with 99m technetium–dimercaptosuccinic acid (DMSA) renal scintigraphy. The DMSA scan was abnormal in 62 children (89%). However, using a high-frequency transducer we found abnormal sonogram changes in 61 children (87%), consisting of an increased kidney volume in 42, and/or a thickening of the wall of the renal pelvis in 42, and/or a focal hyper- or hypoechogenicity in 36, and/or a diffuse hyperechogenicity in 31 children. Micturating cystourethrography was performed in all children, revealing vesicoureteral reflux (VUR) in 22 (31%). Among those children with VUR, 4 had a normal DMSA scan, 2 an abnormal RUS, and 2 a normal DMSA scan and RUS. Our data suggest that B-mode RUS performed with a high-frequency transducer by a trained radiologist is nearly as sensitive as the DMSA scan in diagnosing renal involvement in children with unobstructed APN and in predicting VUR. Received: 9 January 1998 / Revised: 11 July 1998 / Accepted: 28 July 1998     

Vesicoureteric reflux in Kuwaiti children with first febrile urinary tract infection

The prevalence of vesicoureteric reflux (VUR) in children with urinary tract infection (UTI) varies among different racial groups. The purpose of this study was to determine the frequency of VUR and associated renal changes in a group of Arab Kuwaiti children with their first documented febrile UTI and to compare our findings with those reported from other racial groups. One hundred and seventy-four children (38 males and 136 females) fulfilled the study criteria and were divided into three age groups (<1 year, 1–5 years, and >5 years). Patients in each group had both micturating cystourethrography (MCUG) and 99m-Tc-dimercaptosuccinic acid (DMSA) renal scan after diagnosis. VUR was detected in 39 children (22%). Two-thirds of cases had mild reflux (grade I and II). Females (n=32) had more reflux than males (n=7) (24% vs. 18%). Sixty-three patients (36%) had abnormal (DMSA) renal scans (acute pyelonephritis [AP] or renal scars). Of these, 79% were children below 5 years. Abnormal DMSA scans were found in 4 of 38 males (11%) versus 59 of 136 females (43%). Abnormal scans in children with VUR were seen in 1 of 7 males (14%) versus 19 of 32 females (59%). In total, the combination of abnormal scan with VUR occurred in 1 of 38 males (3%) and in 19 of 136 females (14%), whereas abnormal scan without demonstrable VUR was seen in 3 of 38 males (8%) versus 40 of 136 females (29%). Our data showed that the frequency of VUR in Arab Kuwaiti children with febrile UTI is midway between Caucasian and other racial groups. In this study, males had a lower-risk profile than females, the latter having a higher rate of reflux as well as a higher rate of abnormal DMSA scans, irrespective of demonstrable VUR.     

Power Doppler ultrasonography in the diagnosis of acute childhood pyelonephritis

In the absence of specific symptomatology in children, the early diagnosis of acute pyelonephritis (APN) is a challenge, particularly during infancy. In an attempt to differentiate APN from lower urinary tract infection (UTI), we evaluated the ability of power Doppler ultrasonography (PDU) to predict renal parenchymal involvement, as assessed by dimercaptosuccinic acid (^99m Tc-DMSA) scintigraphy. The study comprised 62 patients, 46 girls and 16 boys, aged 2 weeks to 5 years, admitted to the pediatric department with febrile UTI. All children were examined by PDU and DMSA scintigraphy within the first 3 days of admission. In the group of 31 patients with one or more DMSA scan abnormalities, the PDU showed a matching perfusion defect in 27 (87%). Of 26 children with normal DMSA scintigraphy, the PDU evaluation was also normal in 24. The sensitivity and specificity of PDU for the detection of affected kidneys were 87% and 92.3%, and the positive predictive value and negative predictive value were 93.1% and 85.7%, respectively. These data indicate the PDU has a high sensitivity and specificity for differentiating APN from lower UTI and may be a useful and practical tool for the diagnosis of APN in infants and children.     

Procalcitonin as a predictor of renal scarring in infants and young children

The aim of this study was to evaluate the usefulness of procalcitonin (PCT) as a marker of renal scars in infants and young children with a first episode of acute pyelonephritis. Children aged 7 days to 36 months admitted for first febrile urinary tract infection (UTI) to a pediatric emergency department were prospectively enrolled. The PCT concentration was determined at admission. Acute ^99mTc-dimercaptosuccinic acid (DMSA) scintigraphy was performed within 7 days of admission and repeated 12 months later when abnormal findings were obtained on the first scan. Of the 72 children enrolled in the study, 52 showed signs of acute pyelonephritis (APN) on the first DMSA scan. A follow-up scintigraphy at the 12-month follow-up performed on 41 patients revealed that 14 (34%) patients had developed renal scars; these patients also presented significantly higher PCT values than those without permanent renal lesions [2.3 (interquartile range 1–11.6) vs. 0.5 (0.2–1.4) ng/mL; p = 0.007]. A comparison of the PCT concentration in patients with febrile UTI without renal involvement, with APN without scar development and with APN with subsequent renal scarring revealed a significant increasing trend (p = 0.006, Kruskal–Wallis test). The area under the ROC curve for scar prediction was 0.74 (95% confidence interval 0.61–0.85), with an optimum statistical cut-off value of 1 ng/mL (sensitivity 78.6%; specificity 63.8%). Based on these results, we suggest that serum PCT concentration at admission is a useful predictive tool of renal scarring in infants and young children with acute pyelonephritis.     

Screening high-grade vesicoureteral reflux in young infants with a febrile urinary tract infection

Background

The lack of good evidence for improved outcomes in children and young infants with febrile urinary tract infection (UTI) after aggressive treatment for vesicoureteral reflux (VUR) has raised doubts regarding the need for routine voiding cystourethrography (VCUG), and the appropriate imaging evaluation in these children remains controversial.

Objectives

This prospective study aimed to determine whether abnormalities found on acute dimercaptosuccinic acid (DMSA) scan and ultrasound (US) can help indicate the necessity of voiding cystourethrography (VCUG) in young infants.

Methods

For 3.5?years, all infants younger than 3?months presenting with first febrile UTI were prospectively studied. All infants were hospitalized and investigated using US (<3?days after admission), DMSA scan (<5?days after admission), and VCUG (7–10?days after antibiotic treatment) after diagnosis. The association among findings of US, DMSA scan, and VCUG were evaluated.

Results

From 220 infants, there were abnormal results in 136 (61.8%) US and in 111 (50.5%) DMSA scans. By US, ten infants (4.5%) with abscess or structural abnormalities other than VUR were diagnosed. High-grade (III–V) VUR was present in 39 patients (17.7%). The sensitivities for high-grade VUR of renal US alone (76.9%) or DMSA scan alone (82.1%) were not as good as that of the “OR rule” strategy, which had 92.3% sensitivity and 94.3% negative predictive value.

Conclusions

To screen high-grade VUR in young infants with febrile UTI, US and acute DMSA scan could be performed first. VCUG is only indicated when abnormalities are apparent on either US or DMSA scan or both.     

99mTechnetium-dimercaptosuccinic acid scan in the diagnosis of acute pyelonephritis in children: relation to clinical and radiological findings

Seventy-two children, 59 girls and 13 boys, 0.1–15.9 (median 1.1) years of age, with acute pyelonephritis (APN) were investigated with the aid of a dimercaptosuccinic acid (DMSA) scan, renal ultrasonography (US) and a desmopressin test within 5 days of admission. Sixty-two children were reinvestigated approximately 2 months later when intravenous urography (IVU) and micturition cysto-urethrography were also performed. During infection, 92% of the children showed changes in the DMSA scan with 69% by US, and the two investigations agreed in 58% of the kidneys. At follow-up, 68% showed changes in the DMSA scan, 47% by US and 48% by IVU. The DMSA scan and IVU agreed in 60% of the kidneys. Twenty-nine percent of the children had vesico-ureteric reflux (VUR). The presence of grade>-3 VUR was associated with greater defects on the DMSA scan during infection, and at follow-up with a higher frequency of persistent changes compared with no VUR (P<0.02 and 0.01, respectively). During infection the size of the defect on the DMSA scan correlated with renal vooume and C-reactive protein and inversely with the glomerular filtration rate, and at follow-up it correlated inversely with the renal concentration capacity. The DMSA scan is a sensitive method for diagnosing and localizing APN in children, and findings on DMSA scan show a weak but significant correlation with routine clinical and radiological parameters. It is suggested that persistent renal damage after APN in children without VUR may be more common than previously assumed.     

The efficacy of ultrasound and dimercaptosuccinic acid scan in predicting vesicoureteral reflux in children below the age of 2 years with their first febrile urinary tract infection

We evaluated the efficacy of dimercaptosuccinic acid (DMSA) scan and ultrasound (US) in comparison with voiding cystourethrography (VCUG) in predicting vesicoureteral reflux (VUR) in children below the age of 2 years. Medical records and radiologic studies of children (<2 years) suffering their first febrile urinary tract infection (UTI) between January 2001 and May 2007 were retrospectively reviewed. We evaluated the sensitivity, specificity, and positive and negative predictive values of US and DMSA scans in diagnosing VUR. Among 220 children with their first febrile UTI, VUR was detected in 67 (30.4%). The detection rate of VUR by US was 41.7% and 86% in the low (I, II) and high grade (III~IV) groups, respectively. Detection rate of VUR by DMSA scan was 37.5% and 88.4% in the low and high grade groups, respectively. Combining US and DMSA scan, we found that the detection rate of high grade VUR was 95.3% and that of low grade was 62.5%. During follow up, most of the low grade VURs with normal DMSA and US scans resolved or were downgraded. Most high grade VURs could be detected by US and DMSA scan, but the prediction rate was not as high in low grade VURs. However, we can anticipate spontaneous improvement without complications in patients with either low or high grade reflux and negative findings on US and DMSA scan.     

Urine interleukin-1beta in children with acute pyelonephritis and renal scarring

AIM: Acute pyelonephritis is a common infectious disease in children and can result in permanent renal damage. Interleukin (IL)-1beta is an important inflammatory mediator that appears early during bacterial infection. This prospective study examined urine IL-1beta levels in children with acute pyelonephritis documented by (99m)Tc-dimercaptosuccinic acid (DMSA) scan, and also evaluated whether this cytokine correlated with renal scarring. METHODS: A total of 75 children aged 1-121 months with a diagnosis of first-time febrile urinary tract infection (UTI) were studied. The following inflammatory markers were assessed: fever, white blood cell (WBC), neutrophil, C-reactive protein (CRP) and urine IL-1beta. Urine samples were collected for IL-1beta measurement by enzyme-linked immunosorbent assay before and after antibiotic treatment of the infection. Follow-up DMSA scan was performed at 6-12 months after the acute pyelonephritis to detect renal scarring. Twenty children with other febrile illnesses served as non-renal febrile controls. RESULTS: The 75 children were divided into acute pyelonephritis (n = 41) and lower UTI (n = 34) groups according to the findings of DMSA scans. Fever, WBC count, neutrophil count and CRP were significantly higher in the children with acute pyelonephritis than in those with lower UTI (all P < 0.001). The initial urine IL-1beta levels of children with acute pyelonephritis were significantly higher when compared with lower UTI and non-renal febrile controls (P < 0.001). Urine IL-1beta in children with acute pyelonephritis was positively correlated with fever, CRP, WBC, neutrophil and leucocyturia. Renal scarring was found in 12 (29.3%) of the 41 children with acute pyelonephritis. The mean age was significantly lower in the children with renal scarring compared with those without (P < 0.05). CONCLUSION: These results have shown that urine IL-1beta level may serve as a useful marker for the early detection of acute pyelonephritis in febrile children. Young children are at a risk of the development of renal scarring following acute pyelonephritis.     

Diagnostic significance of clinical and laboratory findings to localize site of urinary infection

The aim of this study was to define in children younger than 2 years of age the diagnostic significance of clinical and laboratory findings to localize site of febrile urinary tract infection. We reviewed the records of 185 children younger than 2 years of age admitted to hospital with febrile urinary tract infection. Patients were divided into having either acute pyelonephritis or acute cystitis according to the presence or absence of acute lesions on dimercaptosuccinic acid (DMSA) renal scintigraphy. Clinical and laboratory [white blood cell count (WBC), urinalysis, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP)] findings were compared between the two groups using Student’s t test, chi-square test, and multivariate analysis. Patients with pyelonephritis had statistically significant higher age, WBC, ESR, and CRP than those with cystitis. Although the sensitivity of the tests was 80–100%, their specificity was <28%. On multivariate analysis, 33% of patients with cystitis were diagnosed as having pyelonephritis, whereas 22% of those with pyelonephritis were considered to have cystitis. Given the low specificity of clinical findings and available laboratory tests to define the site of urine infection in this age group, we recommend DMSA renal scintigram as the test of choice to make the diagnosis of acute pyelonephritis in these patients.     

The value of direct radionuclide cystography in the detection of vesicoureteral reflux in children with normal voiding cystourethrography

Background

Vesicoureteral reflux (VUR) is one of the most important risk factors for urinary tract infection (UTI). Diagnosis and treatment of VUR is important to prevent irreversible complications, such as renal scarring and chronic renal failure. This study was conducted to assess the value of direct radionuclide cystography (DRNC) in the detection of VUR in children with UTI and a normal voiding cystourethrography (VCUG).

Methods

DRNC was performed in 35 children with a normal VCUG after an episode of febrile UTI who had hydronephrosis or hydroureter, abnormal acute dimercaptosuccinic acid (DMSA) scan results and/or febrile UTI recurrence. This study was conducted in the nephrology department of Mofid Children’s Hospital, Tehran (Iran).

Results

The results were statistically analyzed. Among the 70 ureters studied, 33 (49.1 %) were observed to have VUR. Of these, 17 (51.5 %) had mild, 14 (42.4 %) moderate, and 2 (6.1 %) severe reflux. A significant relationship was observed between DRNC results and DMSA renal scan findings (P?<?0.05).

Conclusions

Based on our results, we suggest that DRNC may reveal VUR despite a normal VCUG in children with hydronephrosis, abnormal acute DMSA, and/or recurrent febrile UTI.

     

Evaluation of acute pyelonephritis with DMSA scans in children presenting after the age of 5 years

It is generally believed that infants are more susceptible to development of renal scarring after pyelonephritis than children over 5 years old. This view has led to differences in investigations and treatment according to age. The aim of this prospective study was to assess the occurrence of renal parenchymal lesion in children over 5 years admitted with a first-time symptomatic urinary tract infection (UTI). Between October 2000 and April 2002, 52 children aged over 5 years who were admitted to our department with probable acute pyelonephritis (APN) and a positive urine culture were included in this study. All children received antibiotics for 14 days. During the acute phase of infection, scintigraphy with technetium-99 ^m -labeled dimercaptosuccinic acid (DMSA) and ultrasonography (US) were done. Voiding cystourethrography (VCUG) was performed in all children early in the course of the illness, generally within 5–7 days of hospitalization. When scintigraphy showed renal parenchymal changes, repeat scintigraphy was done after at least 3 months to assess the progression of renal abnormalities. Of the 52 children with a first-time documented pyelonephritis, cortical scintigraphy showed renal lesion in 41 children (78.8%). US was normal in all children with normal renal scintigraphy, while it detected renal abnormalities in 16 of the 41 (39 %) with abnormal scintigraphy ( p <0.0001). Topographic analysis of the 165 focal lesions showed that 42.4% were localized to the upper poles, 17.5% to the middle third, and 40% to the lower poles of the kidneys. Repeat scintigraphy showed persistent lesions corresponding to those on the initial scan in nine (28.2%) of the 32 children. Renal lesions had partly regressed in 23 (71.8%) of the patients who underwent repeat scintigraphy. Vesicoureteral reflux was observed in 13.4% of kidneys and renal parenchymal abnormalities were identified in 71.4% and 72.2% of renal units, respectively, with and without reflux ( p >0.05). In conclusion, our data did not confirm the conventional opinion that the risk of renal scarring after pyelonephritis is low in children over the age of 5 years. Our findings suggest that renal scintigraphy may be a more appropriate method of investigation than VCUG for evaluation of the children over 5 years with acute pyelonephritis. Additionally, the frequency of scintigraphic changes is high, and a strategy based exclusively on ultrasound findings would miss about 61% of the abnormal renal units. We recommend that all children, irrespective of age, will benefit from further investigations that might prevent or limit the development of scarring process and renal complications.     

Resistive index in febrile urinary tract infections: predictive value of renal outcome

In the absence of specific symptomatology in children, the early diagnosis of acute pyelonephritis is a challenge, particularly during infancy. In an attempt to differentiate acute pyelonephritis from lower urinary tract infection (UTI), we measured intrarenal resistive index (RI). We evaluated its ability to predict renal involvement as assessed by dimercaptosuccinic acid (DMSA) scintigraphy. In total 157 patients admitted to the pediatric department of the ili Etfal Hospital with clinical signs of febrile UTI were included in the study. The children were divided into groups according to their age at the time of ultrasonography (US). RI was measured from the renal arteries with Doppler US in the first 72 h in all 157 children. Renal involvement was assessed by ^99mTc-DMSA scintigraphy in the first 7 days after admission. The examination was repeated at least 6 months later if the first result was abnormal. All available patients with an abnormal scintigraphy underwent voiding cystourethrography 4–6 weeks after the acute infection. All patients with vesicoureteral reflux and scarred kidneys were excluded from the study. DMSA scintigraphy demonstrated abnormal changes in 114 of 157 children and was normal in the remaining 43 children. Of these 114 children, 104 underwent repeat scintigraphy, of whom 77 showed partially or totally reversible lesion(s). Of these 77 children, 17 children (22%) with vesicoureteral reflux were excluded. Thus, we compared the 43 children with lower UTI with the 60 children with definite acute pyelonephritis at admission. Kidneys with changes of acute pyelonephritis had a mean RI of 0.744±0.06 in infants, 0.745±0.03 in preschool children, and 0.733±0.09 in patients of school age with upper UTI. However, the mean RI was 0.703±0.06 in infants, 0.696±0.1 in preschool children, and 0.671±0.09 in school-aged patients with lower UTI. The mean RI values were significantly higher in patients with upper UTI (P<0.001). There was a highly significant correlation between RI values and the severity of the renal lesion as ranked by DMSA scintigraphy (P<0.001). When the cut-off RI value was 0.715, there was an 80% sensitivity and a 89% specificity for diagnosing upper UTI. Refluxing kidneys and scarred kidneys also had higher RI values. In conclusion, RI values were increased significantly in children with febrile UTI when renal parenchymal involvement (assessed by DMSA scintigraphy) was present. Our results also support the view that the children with high RI values are at a high risk of reflux, scarring, or both, which was frequently observed in febrile UTI. This might allow identification of patients at risk for severe renal lesions that require more aggressive therapy, investigation, and follow-up than those with lower UTI.An erratum to this article can be found at     

Kidney imaging in management of delayed febrile urinary tract infection

We report a cross-sectional study performed to evaluate the imaging findings of 40 children, aged one month to five years (16.65 ± 14.97 months), who presented with protracted fever of more than 48 hours due to urinary tract infection (UTI). About 85% of the patients had positive Tc99-Dimercaptosuccinic acid (DMSA) scan and 58% had vesicoureteral reflux (VUR). Kidney sonography aided in the diagnosis and treatment in 10% of the patients. Age, sex, presence or laterality of VUR did not contribute to defective DMSA scan (pyelonephritis) (P > 0.05). Delayed diagnosis and treatment of febrile UTI is associated with a high incidence of positive findings of DMSA scan irrespective of age, sex or presence/absence of VUR. In mild VUR, the DMSA scan may be normal while in patients with moderate and severe VUR the DMSA scan is almost always abnormal. Thus, our study shows that a normal DMSA scan can help in ruling out moderate to severe forms of VUR and that cystography remains an excellent and standard tool for the diagnosis of VUR.     

Acute pyelonephritis and sequelae of renal scar in pediatric first febrile urinary tract infection

To investigate the incidence of acute pyelonephritis (APN) and renal scarring in children with febrile urinary tract infection (UTI), 191 of 216 (88%) children with their first episode of UTI received (99m)Tc-dimercaptosuccinic acid renal single-photon emission computed tomography. They were investigated within 7 days of admission and were followed for 6 months. One hundred and six patients (49.1%) underwent a voiding cystourethrogram. The incidence of vesicoureteric reflux (VUR) in group I (相似文献   

Urinary tract infection in the newborn: clinical and radio imaging studies

The objective of this study was to assess clinical characteristics and results of radio imaging studies and compare community-acquired urinary tract infection (UTI) with nosocomial UTI in 301 neonates with UTI consecutively admitted to 28 neonatal units in Spain over 3 years (community-acquired UTI, n = 250; nosocomial UTI, n = 51). UTI was diagnosed in the presence of symptoms of infection together with any colony growth for a single pathogen from urine obtained by suprapubic aspiration, or >or=10(4) CFU/ml for a single pathogen from urine obtained by urethral catheterization. Abnormal renal ultrasound was present in 37.1% of cases (34% in community-acquired UTI and 54.5% in nosocomial UTI, P < 0.01). The voiding cystourethrography (VCUG) showed vesicoureteral reflux (VUR) in 27% of cases (23.8% in community-acquired UTI and 48.6% in nosocomial UTI, P < 0.01). In patients with abnormal renal ultrasound and VUR, renal scan with dimercaptosuccinic acid (DMSA) performed early after UTI revealed cortical defects in 69.5% of cases. However, in patients with abnormal renal ultrasound and normal VCUG, DMSA also revealed cortical defects in 39% of cases. The absence of VUR in neonates with UTI and abnormal renal ultrasound does not exclude the presence of cortical defects suggestive of pyelonephritis.     

The IL-6 −174G/C polymorphism and renal scarring in children with first acute pyelonephritis

Urinary tract infections (UTI) are common in infants and children and may result in serious complications, such as renal scarring, hypertension, and renal failure. Identification of the new markers in relation to acute pyelonephritis (APN) and its treatment is essential for designing interventions that would minimize tissue damage. This prospective study investigated the first UTI infection in 71 children (age range: 1–24 months) in respect to interleukin-6 (IL-6) ?174G/C polymorphism and renal scarring. The patients were divided into an APN group and a lower UTI group according to dimercaptosuccinic acid (DMSA). The IL-6 ?174G/C genotypes were determined by tetra-primer ARMSPCR. Serum IL-6 was significantly higher in the APN group than in the group with lower UTI (p?<?0.05). In both groups, the ?174G/C genotype and allele frequencies did not differ significantly from the control group. The highest white blood cell (WBC) count was observed in the CC genotype (p?<?0.05). A non-significant trend toward higher serum IL-6 was observed in children with CC genotype. On follow-up DMSA imaging performed 6 months later, renal scarring was detected in 36.9% of APN children. We did not find the significant association of IL-6 ?174G/C polymorphism with APN and/or postinfectious renal scarring. These results indicate that serum IL-6 concentrations were significantly higher in children with APN than in patients with lower UTI.     

Power Doppler sonographic evaluation of acute childhood pyelonephritis

Urinary tract infection is common in children. The available gold standard methods for diagnosis, Tc-99m dimercaptosuccinic acid (DMSA) scan and computed tomography (CT) are invasive and expensive. This study was performed to assess the role of power Doppler ultrasound (PDU) for diagnosis of acute pyelonephritis (APN) compared with Tc-99m DMSA scan. A prospective study was conducted in 34 children with the mean age of 2.8±2.7 years who were hospitalized with the first episode of febrile urinary tract infection. All children were examined in the first 3 days of admission by PDU and Tc-99m DMSA scan. Patients with congenital structural anomaly were excluded. Each kidney was divided into three zones. The comparison between PDU and DMSA scan was performed on the basis of patients and renal units. According to the patient’s number, sensitivity, specificity, positive and negative predictive values, and accuracy of PDU were 89%, 53%, 70%, 80%, and 74%, respectively, but based on the renal units, changed to 66%, 81%, 46%, 91%, and 79%, respectively. Although PDU has the potential for identifying APN in children, it is still soon to replace DMSA scan.     

Acute renal damage in infants after first urinary tract infection

Urinary tract infection (UTI) is one of the most common causes of unexplained fever in neonates. The aim of this study was to determine the incidence of urinary tract anomalies and acute renal damage in neonates who presented with first urinary tract infection in the first 8 weeks of life. We reviewed the records of 95 infants, who were hospitalised with UTI during a 6-year period (1994-1999). Patients with antenatally diagnosed hydronephrosis and incomplete radiological investigations were excluded from the study. Of the remaining 57 patients, 42 were boys and 15 girls. The mean age at diagnosis was 32 days (range 5-60 days). All patients underwent renal ultrasonography (US), voiding cystourethrogram (VCUG) and (99m)Tc-dimercaptosuccinic acid (DMSA) scan. Urinary tract abnormalities were detected in 20 (35%) patients. Vesicoureteral reflux (VUR) was found in 19 (33%) neonates, 7 girls and 12 boys. Acute cortical defects on DMSA scan were present in 19 kidneys of patients with VUR and in 25 of those without reflux. Only one-third of neonates after first symptomatic UTI had VUR. We recommend that US, VCUG, and DMSA scan should be routinely performed after the first UTI in infants younger than 8 weeks.     

Acute pyelonephritis and renal scarring in Kuwaiti children: a follow-up study using 99mTc DMSA renal scintigraphy

The aim of this study was to determine the prevalence of renal scarring in a group of Kuwaiti Arab children with their first documented acute pyelonephritis (APN). Eighty-two Kuwaiti Arab children (10 males and 72 females) who had abnormal ^99mTc DMSA renal scan findings of acute pyelonephritis were prospectively studied with the same imaging modality 6 months after treatment to identify those who developed renal scarring. A micturition cystourethrogram (MCUG) was performed for all of the children 1 month after diagnosis. Children were divided into 3 age groups (<2 years, 2–5 years and above 5 years). The follow-up DMSA renal scans 6 months after diagnosis revealed normalization of renal changes in 56% (46 patients), much improvement with residual renal abnormality in 6% (5 patients), and persistent parenchymal defects in 38% (31 patients). Vesicoureteric reflux (VUR) was found in 32% of children (26/82) and the majority were between grade I and III. Thirteen of those with VUR (50%) developed renal scars on follow-up. Fifty-three percent of the scarred kidneys (19/36) were drained by non-refluxing ureters. In this study, children older than 2 years had less VUR yet were more susceptible to APN and to the development of renal scars. Girls were more prone to developing APN and renal scarring than boys. This work shows that APN is a serious cause for renal scarring in our patients, particularly if associated with other risk factors such as recurrent infections and the female sex.