Renal parenchymal damage on DMSA-scintigraphy in pelviureteric obstruction

During a 1.5 year period 21 children were investigated with 99-m-technetium dimercaptosuccinic acid (DMSA) before operation for hydronephrosis due to pelviureteric obstruction. The age at investigation was 0.2-11.5 years. Fourty-two kidneys were examined. Hydronephrosis existed on the right side in 8 cases, left side in 9 and bilateral in 4 cases. Seventeen kidneys had no obstruction. The scintigraphy was interpreted as normal in 19 kidneys. Decreased isotope uptake was found in 23 kidneys and localized to the upper pole area in 19 kidneys, middle-lateral part in 7, lower pole area in 15 and the middle-medial part in 12 kidneys. There were no predominance for any part of the kidney to be affected by parenchymal damage. In 8 children investigated before the age of 1 year, 4 of 10 hydronephrotic kidneys revealed normal DMSA scintigram. DMSA scintigraphy delineates functioning renal parenchyma. DMSA scintigraphy delineates functioning renal parenchyma. It can be recommended as a routine method for evaluation of the renal parenchyma before surgery and for follow up studies in all ages of childhood.     

The etiology of renal scars in infants with pyelonephritis and vesicoureteral reflux

We aimed to investigate, by means of dimercaptosuccinic acid (DMSA) scan, the relations between vesicoureteral reflux (VUR) and its degree, pyelonephritis during infancy, and renal parenchymal findings. Seventy-four infants with pyelonephritis, 44 girls and 30 boys (mean age at their first pyelonephritic episode 4.12 months, median 3 months), were enrolled in the study. Voiding cystourethrography (VCU) and ultrasonography (US) were performed within 6 weeks following the infection. DMSA was performed at least 4 months after the urinary tract infection (UTI). The renal parenchymal pathology was defined as focal or multifocal defects or as a split renal uptake of less than 45%. DMSA scintigraphy revealed that 19% (14/74) of the children had renal damage. Renal parenchymal findings were observed only when VUR was present, and its grade was above 3/5. No abnormality was found in 51 renal units without reflux, 9 with VUR grade 1/5, and 54 with grade 2/5. Renal pathology was observed in 9/24 renal units with VUR grade 3, 3/8 with grade 4, and 2/2 with grade 5. No correlation was found between renal parenchymal defects and clinical presentation of the pyelonephritis, type of the microorganism, presence of bacteremia, or the number of recurrent infections. In adequately treated infants, renal damage is probably due to a reflux-associated, preexisting, congenital renal parenchymal pathology and not to the inflammatory process. We suggest that DMSA scintigraphy should not be performed routinely in every infant with UTI and should be reserved primarily for children with VUR grade 3 and above. Received: 17 February 1999 / Revised: 30 June 1999 / Accepted: 7 July 1999     

Post-pyelonephritic renal scars are not associated with vesicoureteral reflux in children

PURPOSE: Children with pyelonephritis are at risk for renal damage. We assess the value of clinical signs and urological abnormalities in predicting renal scars in children following pyelonephritis. MATERIALS AND METHODS: A total of 64 hospitalized children (29 females and 35 males, median age 2.9 years) underwent ultrasonography and technetium labeled dimercapto-succinic acid (DMSA) scintigraphy imaging within 1 week following the diagnosis of the first pyelonephritis. Voiding cystourethrography was performed 8 weeks after the diagnosis. Followup DMSA scintigraphy was performed in 58 patients after 2 years of followup. RESULTS: Urological abnormalities observed were vesicoureteral reflux (VUR, grade 2 or higher) in 11 patients (19%), nonrefluxing and nonobstructed megaureter in 2 (4%) and pyeloureteral obstruction in 1 (2%). The first DMSA scintigraphy showed parenchymal defects in 48% of patients. VUR did not increase the risk of renal defects. At 2 years after the infection 12 of the 58 patients (21%) had renal scars. Nine of these patients did not have VUR. However, 2 patients with high grade VUR and repeat infections demonstrated deterioration of kidney function during followup. The patients with renal scars were older than those without scars (3.1 vs 0.8 years, p = 0.0291) at the time of infection. CONCLUSIONS: Renal scars after first pyelonephritis are in most cases not associated with abnormalities of the urinary tract, but are caused by the infection itself. However, structural abnormalities may predispose to recurrent infections. Following pyelonephritis new renal scars may develop in all age groups in both sexes.     

Renal damage in vesico-ureteric reflux

OBJECTIVE: To detect the different extent of renal parenchymal involvement in primary vesico-ureteric reflux (VUR), and to evaluate the relationship between VUR grade, patient age and different patterns of parenchymal damage. PATIENTS AND METHODS: This blinded retrospective study included 197 consecutive children (mean age 4.26 years, range 1 month to 13 years) with primary VUR detected by voiding cysto-urethrography (VCUG), 99mTc-dimercaptosuccinic acid (DMSA; 120 MBq/1.73 m2) renal scintigraphy, with scanning for 3 h after intravenous injection. An abnormal DMSA scan was classified into three subtypes: cortical defects as a single scar (SS), multiple cortical scarring (MS) and diffuse reduced uptake with small renal size. Renal absolute uptake (AU), and split-kidney relative uptake were evaluated in refluxing and nonrefluxing renal units, and correlated with parenchymal damage and patient age. Student's t-test and the chi-square test were used for the statistical analysis. RESULTS: In all, 282 refluxing and 112 nonrefluxing units were assessed. Renal damage was detected in 188 of 282 units with VUR (67%) and in 18 of 112 (16%) contralateral nonrefluxing kidneys. The mean AU was 18.7% in kidneys with VUR and 29% in nonrefluxing units (P < 0.001). The mean (SD) AU decreased from lower to higher grades of VUR, i.e. grade 0 VUR (group A), 28.97 (9.71); grade 1-3 (group B), 21.28 (8.33); grade 4-5 (group C), 14.78 (8.02). The differences were statistically significant (A vs B, B vs C, both P < 0.001). Renal damage was differently distributed in the three groups: 69 of 109 kidneys (63%) in group C (MS prevalent), 39 of 173 (22.5%) in group B (SS prevalent) and 17 of 112 (15.2%) in group A. There was no significant difference in the distribution of renal damage subtypes in patients aged < or > 2 years (SS 19.6% vs 17.9%, MS 29.6% vs 30.1%, small size 48.2% vs 46.3%). The VUR was severe (group C) in 65% of patients aged < 2 years and in 46% aged > 2 years (chi-square, P = 0.016). CONCLUSIONS: VUR is commonly associated with renal damage. Age (< or > 2 years) did not significantly influence the kidney lesion subtype. Reduced parenchymal function (AU) progressively decreased with the severity of VUR. Focal MS, reduced size and relative uptake were significantly more common in severe VUR, leading to multifocal lesions and hypo-dysplasia. Renal scarring was present in up to 15% of contralateral nonrefluxing kidneys. Severe VUR behaved differently from lesser VUR in the renal scan parenchymal uptake.     

Primary vesicoureteral reflux mediated renal scarring after urinary tract infection in Thai children

AIM: To evaluate the association between primary vesicoureteral reflux (VUR) and renal scarring in children using 99 m Technetium-labelled dimercaptosuccinic acid (DMSA). METHODS: Children attending at Songklanagarind Hospital from 1987 to 2002 were evaluated. RESULTS: Ages at diagnosis of VUR in 46 boys and 52 girls were 1.1+/-1.6 and 2.9+/-2.5 years, median 0.6 and 2.3 years, respectively (P<0.001). DMSA scans were performed at 4.1+/-3.6 years. Renal parenchymal damage was detected in 34 kidneys (22%) of 154 demonstrated refluxing ureters, and one kidney (2%) of 42 non-refluxing ureters (P=0.002). Of 79 refluxing ureters in boys and 75 refluxing ureters in girls, there were 25 and nine renal scars, respectively (32% and 12%, P=0.003). Renal scars in VUR grades I-V were 11%, 7%, 12%, 44% and 64%, respectively (P<0.001). Multivariate analysis revealed that high grade VUR (P<0.001), age of diagnosis of VUR greater than 5 years (P=0.001), and male gender (P=0.002) were the most significant risk factors for renal scarring. CONCLUSION: High-grade VUR, age of diagnosis of VUR greater than 5 years and male gender were the most significant risk factors for renal scarring.     

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.     

Primary vesicoureteric reflux as a predictor of renal damage in children hospitalized with urinary tract infection: a systematic review and meta-analysis

Renal parenchymal disease after urinary tract infection (UTI) has been associated with the development of hypertension and renal functional impairment. A systematic literature review and meta-analysis was performed to determine how effectively the finding of primary vesicoureteric reflux (VUR) on micturating cystography (MCU) in children hospitalized with UTI predicted renal parenchymal disease on (99m)Technetium-dimercaptosuccinic acid ((99m)Tc-DMSA) scintigraphy. Medline, Embase, and PubMed were use to find reports with original data for children hospitalized with bacteriologically-proven UTI who had undergone both MCU and (99m)Tc-DMSA scintigraphy, and which also reported both positive and negative results of these tests. A meta-analysis of likelihood ratios positive and negative for MCU was then performed, including tests for heterogeneity. Twelve valid studies were found, seven with data for 537 children, with a positive (99m)Tc-DMSA scan prevalence of 59% overall, and seven studies with data for 1062 kidneys, with a positive (99m)Tc-DMSA scan prevalence of 36%. The likelihood ratio positive for MCU was 1.96 (95% CI, 1.51 to 2.54) for children, and 2.34 (1.53 to 3.57) for kidneys. The likelihood ratio negative was 0.71 (0.58 to 0.85) for children and 0.72 (0.61 to 0.86) for kidneys. There was evidence of heterogeneity. The meta-analysis showed that a positive MCU increases the risk of renal damage in hospitalized UTI patients by about 20%, whereas a negative MCU increases the chance of no renal involvement by just 8%. VUR is hence a weak predictor of renal damage in pediatric patients hospitalized with UTI. Physicians should be aware of the limitations of using MCU-detected primary VUR as an effective screening test for renal damage in this population. Furthermore, the pathogenesis of renal damage in such patients is probably complex because it is often detected without demonstrable VUR.     

Scintigraphic screening for renal damage in siblings of children with symptomatic primary vesico-ureteric reflux

OBJECTIVE: To define prospectively the incidence of renal parenchymal lesions in the siblings of patients treated at one institution for primary vesico-ureteric reflux (VUR). PATIENTS AND METHODS: From January 1997 to October 1998, a prospective study including renal scintigraphy (using dimercaptosuccinic acid, DMSA) and a radionuclide cystogram was proposed systematically to the asymptomatic siblings of children treated for primary VUR. The radionuclide cystograms were interpreted as showing the presence or absence of VUR and the DMSA scan as symmetrical or asymmetrical differential function, with or with no renal defect. RESULTS: Fifty-five families gave informed consent, of whom 46 completed the study (eight refused secondarily and one was omitted by exclusion criteria), representing 46 symptomatic patients and 65 siblings. There were 17 siblings with VUR (26%) including two of 13 infants and 15 of 52 children aged > 18 months. One radionuclide cystogram failed. Of the 17 refluxing siblings, four had a history of symptomatic urinary tract infection; 62 of the 65 siblings had a DMSA scan, of which 56 were normal and six (10%) showed abnormalities (five asymmetrical differential function and one parenchymal defect). Only one of these six patients had VUR at the time of the evaluation and only one had a small kidney detected by ultrasonography on one side (and no VUR). There were no adverse effects associated with screening. CONCLUSION: This study confirms a significant overall incidence of VUR (26%) in the asymptomatic siblings of patients treated for primary VUR. From the results of the DMSA scan (only one sibling had a parenchymal defect), the systematic screening of asymptomatic siblings does not appear to be beneficial.     

Evaluation of renal scarring in children with primary VUR by 99mTc-DMSA renoscintigraphy

Renal scarring in 271 kidneys of 172 children with primary vesicoureteral reflux (VUR) was evaluated by 99mTc-DMSA renoscintigraphy. 58% of refluxing kidneys were with renal scar by the initial DMSA renoscintigraphy. Only 52% of these kidneys showed good correlation between the findings on IVP and DMSA renoscintigram. Of the 144 refluxing kidneys with normal IVP, 41% had renal scarring on DMSA renoscintigram. DMSA renoscintigram revealed widespread renal scarring in 28% of kidneys with only calyceal clubbing and in 60% of those with segmental cortical thinning on IVP. It is realized that IVP was an in-sensitive method to evaluate renal scarring of refluxing kidneys and such kidneys with segmental renal scar on IVP accompanies more widespread scar on DMSA renoscintigram. These cases were allocated to 2 age groups, younger than 3 years and older than 4 years. In the former group less than 10% of kidneys with low grade VUR and about 40% with high grade UVR had widespread renal scarring. On the contrary, in the latter group severe renal scar was recognized in more than 20% of kidneys with low grade VUR and in about 60% with high grade UVR.     

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     

Asymptomatic vesicoureteral reflux detected by neonatal ultrasonographic screening

Renal ultrasonography was performed in 2,384 healthy and asymptomatic neonates. The definition and grading of hydronephrosis was according to the system of the Society for Fetal Urology. Voiding cystourethrography was performed in the cases with moderate to severe hydronephrosis or persistent mild hydronephrosis. In cases with vesicoureteral reflux (VUR), a dimercaptosuccinic acid (DMSA) renal scan was arranged immediately to evaluate the renal parenchyma. VUR was diagnosed in 30 infants with a prevalence of 1.26%; 7 had bilateral VUR. The male/female ratio was 4:1 and the right/left ratio was 1.85:1. Comparing with the abnormal ultrasonographic findings, VUR appeared ipsilaterally in 23 ureters and contralaterally in 14 ureters. Using ultrasonography for diagnosing VUR, the sensitivity, specificity, positive predictive value, and negative predictive value were 62.2%, 36.1%, 11.0%, and 88.2%, respectively. DMSA renal scan was perfomed in 31 refluxing kidneys, and congenital renal scarring was found in 9 (29.0%) kidneys. Six neonates underwent reimplantation surgery. We conclude that although ultrasonography is not a reliable tool for diagnosing VUR, it can detect many cases of VUR during the newborn stage using our screening program, which thus makes early treatment from the neonatal period possible. Whether our screening program can improve the outcome of VUR will require further follow-up. Received January 10, 1997; received in revised form September 2, 1997; accepted September 3, 1997     

Utility of SPECT DMSA renal scanning in the evaluation of children with primary vesicoureteral reflux

OBJECTIVES: DMSA renal scanning is more sensitive than ultrasound in detecting renal parenchymal scars. We proposed to determine the utility of single-photon emission computed tomography (SPECT) dimercaptosuccinic acid (DMSA) renal scanning in children with primary vesicoureteral reflux (VUR). METHODS: During a 24-month period, we evaluated the charts of 368 patients who had undergone SPECT DMSA renal scanning for primary VUR. Patients were divided into three age groups: (a) less than 1 year, (b) between 1 and 5 years, and (c) older than 6 years. Renal scars were deemed severe or focal. The data were analyzed to evaluate the utility of SPECT DMSA scanning in children with primary VUR and to determine the indications for performing SPECT DMSA. We also evaluated the sensitivity of recent renal ultrasound technology in detecting focal and diffuse scars. RESULTS: One hundred twenty-eight patients were younger than 1 year at presentation. These included 24 cases that were detected prenatally. One hundred eighty-five were between the ages of 1 and 5 years, and 55 were 6 years or older. Reflux nephropathy at presentation was found in 99 (26.9%) of 368 patients. DMSA scanning changed the treatment in only 13 patients (3.5%). When scarring was diffuse, ultrasound examination correlated 100% with DMSA scanning; when focal scarring was present, the correlation was poor. CONCLUSIONS: Our results suggest that DMSA scans should be tailored to children who have ultrasound abnormalities, high-grade reflux, or recurrent breakthrough urinary tract infections. These guidelines will result in a substantial cost savings and a significant decrease in radiation exposure.     

Dimercapto-succinic acid scintigraphy instead of voiding cystourethrography for infants with urinary tract infection

PURPOSE: We study the ability of dimercapto-succinic acid (DMSA) scintigraphy to predict the presence of dilating vesicoureteral reflux (VUR) in infants with urinary tract infection (UTI) to simplify the evaluation protocol. MATERIALS AND METHODS: A retrospective analysis of the records of 303 children younger than 2 years with initial UTI investigated with DMSA scintigraphy and voiding cystourethrography (VCU) within 3 months after UTI was performed. RESULTS: In 156 of the 303 children (51%) DMSA scintigraphy showed renal lesions. VUR was found in 80 patients (26%) and VUR grade significantly correlated with the presence of renal lesions. A normal DMSA scintigraphy and dilating VUR (grade III) occurred in 7 infants. At followup after 1 to 2 years, 6 of these 7 patients had normal DMSA scans and 1 had a scarred duplex kidney. VUR resolved spontaneously in 5 and improved spontaneously to grade 1 in 2 patients. None of the 7 children had recurrent UTI. CONCLUSIONS: DMSA scintigraphy in infants with UTI may replace VCU as a first line investigation. A strategy to perform VCU in only patients with renal lesions is proposed. In this study 147 of 303 VCUs would have been unnecessary as only 1 child with a damaged kidney was missed.     

The Efficacy of Tc99m Dimercaptosuccinic Acid (Tc-DMSA) Scintigraphy and Ultrasonography in Detecting Renal Scars in Children with Primary Vesicoureteral Reflux (VUR)

Introduction: Pyelonephritis-induced renal scarring in children is a major predisposing factor for proteinuria, hypertension, and ultimate renal failure. The aim of this study was to investigate and compare the efficacy of Tc99m dimercaptosuccinic acid (Tc-DMSA) renal scintigraphy and renal ultrasonography (USG) in detecting renal scars in children with primary vesicoureteral reflux (VUR). Materials and methods: Tc-DMSA scan and USG studies were done in 62 children who were admitted to our clinic between 1997 and 2003 because of documented urinary tract infection (UTI) and diagnosed with primary VUR. Renal scarring detection rates of Tc-DMSA scan and USG were compared according to reflux grades. Results: In the whole group, renal scars were detected by Tc-DMSA scan and USG in 55% and 38% of refluxing units, respectively. Detection rates of Tc-DMSA and USG according to reflux grades were as follows: 47% and 29 % in low-grade VUR (grades 1 and 2), 46 % and 25% in mid-grade VUR (grade 3), 76% and 65% in high-grade VUR (grades 4 and 5), respectively. Conclusion: USG was found to be an inappropriate study in the detection of renal parenchymal scars, irrespective of the reflux grade. In this study, Tc-DMSA scan detected scars in 35% of kidneys reported to be normal on USG.     

sup 99m TECHNETIUM-DIMERCAPTO-SUCCINIC ACID RENAL SCAN IN THE EVALUATION OF POTENTIAL LONG-TERM RENAL PARENCHYMAL DAMAGE ASSOCIATED WITH EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY IN CHILDREN

Purpose

Extracorporeal shock wave lithotripsy (ESWL ^†) has been reported as efficient and safe in children. Because of reports of renal parenchymal damage in adults, this study was designed to assess the effects of ESWL in pediatric kidneys evaluated before and after treatment with^99m technetium dimercapto-succinic acid (DMSA) renal scan.

Materials and Methods

A total of 15 children, 9 months to 15 years old (mean age 6.5 years), underwent ESWL treatment for urolithiasis. Evaluation imaging included plain abdominal radiography, excretory urogram and/or renal sonography. DMSA renal scan was performed 24 hours before ESWL and at least 6 months after treatment.

Results

ESWL was performed in 1 session for 8 patients, 2 sessions for 6 and 3 sessions for 1, delivering a range of 600 to 3,000 shock waves per session. Treatment was successful in achieving stone-free status in 87% of the cases. Long-term followup (1 to 5 years) showed no blood pressure changes. On DMSA renal scan no acquired parenchymal scar was identified at least 6 months after ESWL treatment.

Conclusions

The efficacy of ESWL in treating pediatric urolithiasis is confirmed. Renal parenchymal trauma associated with ESWL does not appear to cause long-term lesions identifiable by DMSA renal scan.     

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.     

Evaluation of renal function in children with primary VUR up to two years old

The function of 99 refluxing kidneys of 61 children up to two years old at the time of diagnosis was evaluated by 99mTc-DMSA renoscintigraphy, urinary beta 2-microglobulin (beta 2-MG), alpha 1-microglobulin (alpha 1-MG) and N-acetyl-beta-D-glucosamidase (NAG). High grade reflex (grade IV, V) was found in 45% of the cases. 76%, 51% and 92% of the cases showed abnormally high value of urinary beta 2-MG, alpha 1-MG and NAG, respectively. These results indicate that they have already had tubular dysfunction at the time of diagnosis. DMSA renoscintigraphy of 82 refluxing kidneys of 49 children was performed. Of these, 48% had renal scar and 28% had serious renal dysfunction [DMSA uptake rate less than 18%]. 10-20% of low grade VUR had less than 18% DMSA uptake rate. Two patterns were noticed in the group in which urinary beta 2-MG ranged 0.33-1.0. One was characterized by good bilateral renal function with slight tubular damage and the other serious renal dysfunction with fixed tubular damage. No remarkable recovery of the renal function was noticed after antireflux operation in the second pattern cases. In many cases, in which urinary beta 2-MG was more than 1.0, improvement of DMSA uptake rate was noticed after antireflux operation.     

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.     

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.     

Early renal parenchymal histological changes in an experimental model of vesico-ureteral reflux and the role of apoptosis

OBJECTIVES: To observe early renal parenchymal cellular changes in an experimental model of vesico-ureteral reflux (VUR) and to show whether the apoptotic pathway plays a role in these cellular changes. MATERIAL AND METHODS: Fourteen New Zealand breed rabbits were used and were divided into two equal groups (control and experimental groups). Urine samples were obtained in a sterile manner and cultured. In the study group, reflux was created in the right kidneys surgically. Renal scintigraphy and voiding cystourethrography (VCUG) were performed in both groups on Day 17. The kidneys were examined in terms of histology, apoptotic activity and caspase activity. RESULTS: No growth was observed in urine cultures in either group. VUR was manifested in only two rabbits in the experimental group on VCUG. On renal scintigraphy, no renal scarring was observed in either of the groups and renal uptake values were in the normal range. There was a greater increase in collagen in the right kidneys in the experimental group than in the control group and apoptotic activity was significantly increased in the study group: 0% in the control group, 10.8%+/-0.7% in the experimental group (p<0.001). Caspase-6 activity was strongly positive and caspase-8 and -9 activities were moderately positive in the right kidneys of the experimental group. Caspase-6 activity was moderately positive, and caspase-8 and -9 activities were weakly positive in the contralateral kidneys of the experimental group. Caspase activities in the control group were negative (p<0.001). CONCLUSIONS: In this experimental model of VUR, apoptotic activity was initiated via the caspase-8 and -9 pathway and collagen tissue increased in the renal parenchyma where reflux occurred. The balance of apoptotic activity may play a key role in the occurrence of reflux nephropathy.