99mTechnetium dimercaptosuccinic acid scintigraphy in the diagnosis of acute pyelonephritis in rats

SNMMI procedure standard/EANM practice guideline on pediatric [99mTc]Tc-DMSA renal cortical scintigraphy: an update

The Society of Nuclear Medicine and Molecular Imaging (SNMMI), founded in 1954, is an international scientific and professional organization with a purpose to promote the science, technology, and practical application of nuclear medicine. The European Association of Nuclear Medicine (EANM), founded in 1985, is a nonprofit professional medical association with a purpose to facilitate international communication among individuals in nuclear medicine pursuing clinical and academic excellence. Members of the SNMMI and EANM are physicians, technologists, and scientists who specialize in the research and practice of nuclear medicine. The SNMMI and EANM will periodically publish new guidelines for nuclear medicine practice to further advance the science of nuclear medicine and improve patient care. Existing standards/guidelines will be reviewed for revision or renewal, as appropriate. Each standard/guideline, representing a policy statement by the SNMMI/EANM, has undergone a thorough review, and represents an expert consensus. The SNMMI and EANM recognize that the safe and effective use of diagnostic nuclear medicine imaging requires specific training and skills, as described in each document. These standards/guidelines are educational resources designed to assist practitioners in providing appropriate nuclear medicine care for patients. They are consensus documents, and are not mandatory provisions or requirements of practice. They are not intended, nor should they be used, to establish a legal standard of care. For these reasons and those set forth below, the SNMMI and the EANM cautions against the use of these standards/guidelines in litigation procedures that call into question the clinical decisions of a practitioner. The ultimate judgment regarding the appropriateness and propriety of any specific procedure or course of action must be made by medical professionals, taking into account the unique context of each case. Thus, there is no implication that action differing from what is detailed in these standards/guidelines, on its own, is below the standard of care. On the contrary, a conscientious practitioner may responsibly adopt a course of action different from that set forth in the standards/guidelines when, based on the reasonable judgment of the practitioner, such course of action is warranted based on the condition of the patient, limitations of available resources, or advances in knowledge or technology subsequent to publication of the standards/guidelines. Practicing medicine involves not only the science, but also the art of dealing with the prevention, detection, diagnosis, and treatment of disease. The variety and complexity of human conditions make it impossible for general guidelines to consistently allow for an accurate diagnosis to be reached or a specific treatment response to be predicted. Therefore, it should be recognized that adhering to these standards/guidelines does not ensure a successful outcome. All that should be expected is that a practitioner follows a reasonable course of action based on their level of training, the current landscape of knowledge, the resources at their disposal, and the needs/context of the particular patient being treated. The purpose of this document is to provide nuclear medicine physicians, radiologists, and other clinicians with guidelines for the recommendation, performance and interpretation of 99mTc-dimercaptosuccinic acid renal cortical scintigraphy ([99mTc] Tc-DMSA scintigraphy) in pediatric patients. These recommendations represent the expert opinions of experienced leaders in this field, and these recommendations are not all supported by a high level of evidence. Further studies are required to have evidence-based recommendations for the application of [99mTc] Tc-DMSA renal cortical scintigraphy in pediatrics. This guideline summarizes the views of the SNMMI Renal Cortical Scintigraphy in Children Working Group and the EANM Pediatrics Committee. It reflects recommendations for which the SNMMI and EANM cannot be held responsible. The recommendations should be taken into context of good practice of nuclear medicine and do not substitute for national and international legal or regulatory provisions.

Accuracy of early DMSA scan for VUR in young children with febrile UTI

OBJECTIVE

To evaluate the accuracy of an acute (99m)Tc-dimercaptosuccinic acid (DMSA) scan in predicting dilating vesicoureteral reflux (VUR) among young children with a febrile urinary tract infection (UTI).

METHODS

The medical records of children (≤ 2 years of age), presenting with febrile UTI between January 2000 and December 2011, were retrospectively reviewed.

RESULTS

A total of 523 children were included in this study, of whom 397 children (75.9%) had abnormal DMSA results and 178 children (34.0%) were identified as VUR on micturating cystourethrography (MCU). Among all the patients, the number of children with dilating VUR was 151 (28.9%). The rate of abnormal results on DMSA for the dilating VUR group was significantly higher than the rates for the non-VUR and low-grade VUR groups (P < .01). In the <6 months age group and ≥ 6 months age group, the sensitivities of DMSA in predicting dilating VUR were 96.15% and 100.0%, respectively, the negative predictive values were 97.26% and 100.0%, respectively, and the negative likelihood ratios were 0.0911 and 0.0000, respectively.

CONCLUSION

For children ≤ 2 years of age with a febrile UTI, an acute DMSA scan is valuable in the exclusion of dilating VUR. The likelihood of the presence of dilating VUR on MCU is rather low when the result of DMSA is negative. DMSA should be conducted to assess the need for an MCU.

Is Imaging Time Between two Tc 99m DMSA Scans Sufficient for Reporting as Renal Parenchymal Scarring? Healed Parenchymal Renal Defect After 6 Years

We aimed to report a healed renal parenchymal defect after 6 years in a 9-year-old girl who was being followed for recurrent urinary tract infection (UTI). The first UTI was at the age of two. She was being followed with ultrasonography, urine analysis and urine culture since the first UTI. Technetium-99m dimercaptosuccinic acid (DMSA) scintigraphy was repeated four times up to the present day. She had a renal parenchymal defect reported as parenchymal scarring, which healed 6 years after the first DMSA scintigraphy.

Conflict of interest:None declared.

Hyponatremia may reflect severe inflammation in children with febrile urinary tract infection

BACKGROUND

Hyponatremia is the most common electrolyte abnormality in clinical practice, but little is known about the association between febrile urinary tract infection (UTI) and hyponatremia or its significance to clinical outcomes.

METHODS

Data from 140 children with febrile UTI between 2000 and 2010 were retrospectively analyzed. Laboratory examinations [white blood cell (WBC) count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and serum sodium concentration], renal ultrasonography, (99m)Technetium-dimercaptosuccinic acid (DMSA) scintigraphy, and voiding cystourethrogram were performed. Culture growing >50,000 colonies of one single bacterial species on a urine sample obtained by catheter or >100,000 colonies on two clean-catch samples was required to establish diagnosis of UTI.

RESULTS

In children with renal cortical defects diagnosed after DMSA scintigraphy (group 1), duration of fever was significantly longer (P = 0.038) and WBC (P = 0.047) and CRP (P < 0.0001) levels significantly higher than in those without renal cortical defects (group 2). However, serum sodium levels were significantly lower in group 1 than group 2 (135.9 ± 2.4 vs 137.4 ± 2.7 mEq/L, P = 0.007). Hyponatremia (serum sodium ≤ 135 mEq/L) was also more frequent in group 1 than in group 2 (74.1 % vs 45.3 %, P = 0.012). Serum sodium concentration was negatively correlated with WBC count (r = -0.156, P = 0.011) and CRP levels (r = -0.160, P= 0.028).

CONCLUSIONS

Our study indicates that hyponatremia may be a substantial inflammatory marker and is significantly and independently associated with the degree of inflammation in children with febrile UTI.

Discordant findings on dimercaptosuccinic acid scintigraphy in children with multi-detector row computed tomography-proven acute pyelonephritis

PURPOSE

The diagnosis of acute pyelonephritis (APN) is often difficult, as its clinical and biological manifestations are non-specific in children. If not treated quickly and adequately, however, APN may cause irreversible renal damage, possibly leading to hypertension and chronic renal failure. We were suspecting the diagnostic value of (99m)Tc-dimercaptosuccinic acid (DMSA) scan by experiences and so compared the results of DMSA scan to those of multi-detector row computed tomography (MDCT).

METHODS

We retrospectively selected and analyzed 81 patients who were diagnosed as APN by MDCT during evaluation of their acute abdomen in emergency room and then received DMSA scan also for the diagnostic work-up of APN after admission. We evaluated the results of imaging studies and compared the diagnostic value of each method by age groups, <2 years (n=45) and ≥2 years (n=36).

RESULTS

Among total 81 patients with MDCT-proven APN. DMSA scan was diagnostic only in 55 children (68%), while the remaining 26 children (32%) showed false negative normal findings. These 26 patients were predominantly male with average age of 21 months and most of them, 19 (73.1%) were <2 years of age.

CONCLUSION

DMSA scan has obvious limitation compared to MDCT in depicting acute inflammatory lesions of kidney in children with APN, especially in early childhood less than 2 years of age. MDCT showed hidden lesions of APN, those were undetectable through DMSA scan in children.

The effects of methylene blue on renal scarring due to pyelonephritis in rats

The aim of this study was to evaluate the efficiency of methylene blue (MB) in preventing renal scar formation after the induction of pyelonephritis (PNP) in a rat model with delayed antimicrobial therapy. An inoculum of the K-12 strain of Escherichia coli was injected into both kidneys. Control groups received isotonic saline instead of bacterial solution. Four equal groups were then formed: the PNP group was untreated and the PNP ciprofloxacin (CIP) treated group was treated only with CIP intraperitoneally (i.p.) starting on the third day following bacterial inoculation. In the PNP (MB)-treated group, MB was given i.p., and in the PNP MB + CIP-treated group, MB + CIP were administered i.p.. In the sixth week following bacterial inoculation, all rats were sacrificed, and both kidneys of the rats in all groups were examined biochemically and histopathologically for renal scarring. Renal scar was significant in the groups treated with MB alone or MB + CIP combination compared with untreated or antibiotic only groups. Delayed treatment with antibiotics had no effect on scarring. These results suggest that the addition of MB to the delayed antibiotic therapy might be beneficial in preventing PNP-induced oxidative renal tissue damage.

Risk factors in the development of early technetium-99m dimercaptosuccinic acid renal scintigraphy lesions during first urinary tract infection in children

AIM

To establish the variables that correlate with uptake defects in dimercaptosuccinic acid (DMSA) scintigraphy performed in the acute phase of a first episode of urinary tract infection (UTI).

METHODS

A prospective observational study was conducted in a cohort of 158 consecutive children with a first episode of symptomatic UTI. The therapeutic delay time (TDT) was recorded. DMSA scintigraphy was performed in all children and voiding cystourethrography in 150 of them.

RESULTS

85% of the patients were younger than 2 y. Mean TDT was 33.5 h. The aetiological agent was Escherichia coli in 140 children. DMSA scintigraphy was normal in 81. Vesicoureteric reflux was detected in 33. After a multivariate logistic regression analysis the following variables were retained in the final model: TDT > or = 48 h, growth of bacteria other than E. coli, percentage of polymorphonuclear cells > or = 60% and C-reactive protein > or = 30 mg l(-1).

CONCLUSION

TDT > or = 48 h, bacteria other than E. coli, percentage of polymorphonuclear cells > or = 60% and CRP > or = 30 mg l(-1) influence the findings detected in the DMSA scintigraphy performed in the acute phase of a first episode of UTI.

Renal growth in children with severe vesicoureteral reflux: 10-year prospective study of medical and surgical treatment: the International Reflux Study in Children (European branch)

PURPOSE

To determine whether medical or surgical treatment better promotes renal growth in children with severe vesicoureteric reflux (VUR) and to examine factors influencing renal growth.

MATERIALS AND METHODS

Three hundred two children younger than 11 years with urinary tract infection and grade III or IV VUR were randomly assigned to surgical (n = 149) or medical (n = 153) treatment and were followed up at serial intravenous urography for up to 5 years; 223, for up to 10 years (surgical, n = 110; medical, n = 113). Renal size was measured planimetrically on serial intravenous urograms and was related to the virtual height of L1 through L3 by expressing it as an SD score.

RESULTS

There was no significant difference in mean renal growth between patients treated surgically or those treated medically after 5- or 10-year follow-up. Bilateral renal size of 80 surgical and 75 medical patients remained within 1 SD score. In patients entering the study at 2 years of age or younger and in those with grade IV VUR, bilateral VUR, or renal scars, there was a trend toward improved renal growth in those treated medically, but this finding was not statistically significant. When renal scarring or thin parenchyma was unilateral, the affected kidney grew less well, irrespective of treatment. Bilateral renal scarring was usually asymmetrical, with a corresponding effect on renal growth.

CONCLUSION

There was no significant difference in renal growth during 10 years between surgical and medical treatment in patients with severe reflux.

Imaging of renal scarring

Children with urinary tract infection should be investigated and followed up, as those with pyelonephritis may develop renal scarring. In this review, after discussing the advantages and disadvantages of various imaging modalities for diagnosis of renal scarring, it is concluded that DMSA scintigraphy and urography can both be used to detect significant renal scarring. With DMSA scintigraphy, small renal lesions (functional uptake defects) not seen at urography will also be detected. The long-term clinical significance of these lesions is, as yet, unknown. A normal DMSA scintigraphy after infection indicates low risk for clinically significant damage. In order to allow acute, reversible lesions to first disappear, a follow-up DMSA examination should not be performed until at least 6 mo after the acute infection. Ultrasonography in isolation cannot be recommended for the diagnosis of renal scarring.

Vesico-ureteric reflux and other risk factors for renal damage: identification of high- and low-risk children

This article reviews the literature with respect to various risk factors for permanent renal damage in children with urinary tract infection. Vesico-ureteric reflux is an important risk factor, but renal damage can occur in the absence of reflux. Renal damage does not always occur in the presence of gross reflux. Renal scars always develop at the same site as a previous infection in the kidney. Recurrent pyelonephritis and delay in therapy increase the likelihood of renal damage, although it is not known how long a delay is dangerous to the human kidney. Recent studies using 99mtechnetium-dimercaptosuccinic acid (DMSA) scintigraphy have not confirmed the findings of previous studies showing that children below 1 y of age are more vulnerable to renal damage. It is more likely that all children run the risk of renal scarring in cases of acute pyelonephritis. The role of bladder pressure is still not entirely understood. Therefore more studies are needed in order to determine the relationship between high voiding pressures in some, otherwise healthy, children with urinary tract infection and renal scarring. The importance of bacterial virulence in the development of renal scarring is unclear. DMSA scintigraphy and voiding cystourethrography are the most reliable tools for identifying children at risk of renal scarring. As a single method DMSA scintigraphy appears to be better than voiding cystourethrography.

Consensus on renal cortical scintigraphy in children with urinary tract infection. Scientific Committee of Radionuclides in Nephrourology

A questionnaire related to cortical scintigraphy in children with urinary tract infection was submitted to 30 experts. A wide consensus was reached on several issues related to planar images: 99mTc dimercapto succinic acid (DMSA) appears as the most appropriate tracer for renal imaging; dynamic tracers are considered to be inferior, in particular 99mTc diethylenetriaminepentaacetate, which is not recommended. The general opinion is that DMSA scintigraphy is not feasible with a minimal dose below 15 MBq, whereas the maximum dose should not be higher than 110 MBq. The dose schedule generally is based on body surface area, and sedation is only exceptionally given to children. Images are obtained 2 to 3 hours after injection, preferably with high resolution collimators; pinhole images are used by only half of the experts. Posterior and posterior oblique views are used by most of the experts, and the posterior view is acquired in supine positions. At least 200.000 kcounts or 5 minute acquisition is required for nonzoomed images. As a quality control, experts check the presence of blurred or double outlines on the DMSA images. Color images are not used and experts report on film or directly on the computer screen. As far as normal DMSA images are concerned, most experts agree on several normal variants. Hydronephrosis is not a contraindication for DMSA scintigraphy but constitutes a pitfall. Differential renal function generally is measured, but no consensus is reached whether or not background should be subtracted. Most of the experts consider 45% as the lowest normal value. A consensus is reached on some scintigraphic aspects that are likely to improve and on some others that probably represent persistent sequelae. There is a wide consensus for the systematic use of DMSA scintigraphy for detection of renal sequelae, whereas only 58% of the experts are systematically performing this examination during the acute phase of infection.

Early 99mTc dimercaptosuccinic acid (DMSA) scintigraphy in symptomatic first-time urinary tract infection

During a 2 year period, 175 children below 6 years of age (median 0.4 year) with non-obstructive symptomatic urinary tract infection were studied by 99mTc dimercaptosuccinic acid (DMSA) scintigraphy. DMSA scintigraphy was performed at a median of 10 days after the start of treatment and was abnormal in 73 children (42%), equivocal in 29 (16%) and normal in 73 (42%). Reflux was seen in 27% of all children and in 38% of the renal units that were abnormal at DMSA scintigraphy. A decreasing frequency of abnormalities at DMSA scintigraphy was seen within the first 14 days after the start of treatment. C-reactive protein and grade of reflux correlated significantly with abnormal DMSA studies. To demonstrate renal involvement in acute urinary tract infection, DMSA scintigraphy should be performed within days after the start of treatment. It is noteworthy that reflux was seen in less than half of renal units with abnormal DMSA scintigraphy.

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.

The intravenous urogram in the detection and evaluation of renal damage following urinary tract infection

Intravenous urography (IVU) still provides the most comprehensive structural assessment of the urinary tract. In particular, the radiological renal appearances approximate closely to the morphology of the renal scarring of reflux nephropathy or chronic atrophic pyelonephritis. It also provides reproducible renal measurements for follow-up assessment of renal growth and scarring. It is now less often used for first-line investigation of the acute urinary tract infection (UTI) because the swelling accompanying acute renal involvement is less easily recognised than the areas of defective function demonstrated on 99mtechnetium-dimercaptosuccinic acid (DMSA) studies. Also IVU contributes a higher radiation dose when calculated for full IVU (dependent on the number of films exposed) and there is a slight risk of side effects from injected contrast media, reduced by using non-ionic compounds. Because of its value in confirming such a serious diagnosis as renal scarring, suspected on ultrasonography or DMSA scintigraphy, modification of the technique of IVU with adequate preparation and the use of a reduced number of films, or single films localised to the renal areas, should be considered. Expertise in the interpretation of IVU must also be maintained because of the ancillary information regarding bowel and bladder function, the spine and evidence of stones, pertinent to the management of children with UTI and renal scarring. IVU and DMSA study remain complementary investigations.

Pitfalls in the investigation of children with urinary tract infection

The histories and imaging results are presented in 10 children in whom errors had been made in the interpretation of early investigations. Ultrasonography may not detect either vesicoureteric reflux (VUR) or renal scars or inflammation. The reduced nephrogram or renal swelling following a first attack of acute pyelonephritis may not be recognised without renal measurement on an intravenous urogram. Renal scarring may be diagnosed incorrectly on the basis of functional defects of isotope uptake on a technetium 99m-dimercaptosuccinic acid study. In the absence of VUR, the micturating cystogram will not visualise the kidneys.

Tc-99m dimercaptosuccinic acid(DMSA) renal scintigraphy in patients with acute pyelonephritis

OBJECTIVES

Recently, several authors reported that Tc-99m DMSA renal scan frequently showed cortical defects of the involved kidneys even in the patients with acute pyelonephritis who did not show abnormal findings in the ultrasonography and intravenous pyelography (IVP).

METHODS

In order to evaluate the utilities of Tc-99m DMSA renal scan and the clinical meaning of cortical defects in the Tc-99m DMSA renal scan of the patients with acute pyelonephritis, ninety two patients with acute pyelonephritis, from March 1991 to February 1994 in Chungnam National University Hospital(CNUH), were included in this study. Patients were subdivided as Group A:Patients showing normal Tc-99m DMSA renal scan (n = 42) and Group B:Patients with definite cortical defects on the Tc-99m DMSA renal scan (n = 50). We compared clinical characteristics such as age and sex, recurrency, duration of fever, bacterial culture study, incidence of renal insufficiency and the results of renal ultrasonography and intravenous pyelography between the two groups.

RESULTS

Fifty four percents of 92 patients with acute pyelonephritis showed a significantly longer febrile period after admission, higher positive rates on the urine and blood culture studies and higher incidence of renal insufficiency than those of the Group A patients. Sixty nine percents of Group B patients showed normal results in ultrasonography or IVP study.

CONCLUSIONS

Tc-99m DMSA renal scan was a more sensitive imaging test than ultrasonography in kidneys and IVP to detect pyelonephritis lesions and may be useful to predict the patient group with a severe disease course. These patients may need more careful management and further studies to evaluate the possibility of complications.

Radiologic evaluation of urinary tract infection

This prospective study was designed to investigate the most relevant radiological approach for the evaluation of urinary tract infections (UTI) in childhood. In the first 48 hours following the diagnosis of UTI, all patients underwent 99mTc dimercaptosuccinic acid (DMSA) scanning, ultrasonography (US) and intravenous urography (IVU). For the imaging of renal parenchymal infection the sensitivity of IVU and US as compared to DMSA scanning were found to be 9.09% and 25%, respectively. It was concluded that 99mTc DMSA, where available, should be the first step for the accurate diagnosis and follow-up of patients with UTI.

Functional parameters and 99mtechnetium-dimercaptosuccinic acid scan in acute pyelonephritis

The diagnostic value of 99mtechnetium-dimercaptosuccinic acid (DMSA) scintigraphy, ultrasonography and renal functional parameters [urine N-acetyl-beta-D-glucosaminidase (NAG)/creatinine and urine albumin/creatinine quotients] in acute pyelonephritis (APN) were studied in 39 children (28 girls, 11 boys, median age 9 months, range 2 weeks to 9.4 years, 28 patients < 1 year, 11 patients > 1 year) with first-time urinary tract infection. Ultrasonography of the urinary tract was performed on admission and together with DMSA scintigraphy (< 10 days from admission). Urine NAG/creatinine and urine albumin/creatinine quotients were measured daily and after 6-8 weeks. Ultrasonography revealed abnormalities in 12 of 39 (31%) patients [11/32 patients (34%) with positive DMSA scintigraphy], while DMSA uptake defects were present in 32 of 39 (82%) patients [21/28 < 1 year (75%), 11/11 > 1 year (100%), P = 0.08]. Urine NAG/creatinine and urine albumin/creatinine quotients were significantly higher in children < 1 year with APN, as well as in non-renal fever controls, than in older children. However, in both age groups the urine NAG/creatinine and urine albumin/creatinine quotients were significantly higher in APN than in non-renal fever. The urine NAG and albumin excretion decreased rapidly after the initiation of antimicrobial therapy and had normalized at 6-8 weeks. The size and grade of the DMSA uptake defect (DMSA score) did not correlate with duration of disease at admission, maximum C-reactive protein or maximum fever. The urine NAG/creatinine quotient in the children < 1 year showed, however, a significant correlation with the DMSA score (r = 0.58, P < 0.05), while no correlation was found in the older children. We conclude that DMSA scintigraphy is a sensitive method to confirm the clinical diagnosis of APN, although a substantial number of infants appear to have normal scans. Early determination of the urine NAG/creatinine and albumin/ creatinine quotients may further improve the diagnostics in the infant.

Retrospective study of children with renal scarring associated with reflux and urinary infection

OBJECTIVE

To review the histories of children with bilateral renal scarring and severe vesicoureteric reflux to determine whether an improvement in early management might reduce the risk of scarring.

DESIGN

Retrospective study of medical records and discussion with parents.

SETTING

Outpatient departments of two teaching hospitals.

PATIENTS

52 children aged 1-12 years participating in a randomised comparison of medical and surgical management. All had a history of symptomatic urinary tract infection. Two thirds presented with fever and two with hypertension or renal failure. In only one out of 32 children examined by antenatal ultrasonography was an abnormality suspected.

RESULTS

There was delay in diagnosis or appropriate imaging or effective treatment of urinary infection in 50 of the 52 children. In 41 there was delay in diagnosis; there was delay in treating a confirmed infection in 45; no antibacterial prophylaxis was prescribed before imaging in 28; and investigation of the urinary tract was delayed in 33. The severity of scarring was significantly related to delay in diagnosis (chi 2 for trend 7.43, P = 0.01). Four children of mothers known to have reflux nephropathy were not investigated until they developed urinary tract infection.

CONCLUSIONS

Efforts to reduce the incidence and severity of renal scarring should be directed towards rapid diagnosis and effective early management of urinary tract infection in infancy and childhood. Siblings and offspring of known patients with severe reflux nephropathy should be investigated for reflux.

Renal scarring after acute pyelonephritis

Seventy six children, 18 boys and 58 girls, aged 0-15.9 (median 1.0) years, with acute pyelonephritis were prospectively studied with a technetium-99m dimercaptosuccinic acid (DMSA) scan during infection and two months later. Fifty nine of these children were also studied two years after the infection. Seventeen children with a normal DMSA scan during infection or at two months after infection, or both, were not investigated by a DMSA scan at two years after acute pyelonephritis. A micturition cystourethrogram was performed in all the children after two months. Changes on the DMSA scan were found in 65 (86%) children during acute pyelonephritis, in 45 (59%) children at two months, and in 28 (37%) children at two years after infection. Vesicoureteric reflux (VUR) was found in 19 (25%) children at two months. Renal scarring was significantly correlated with the presence of gross VUR and recurrent pyelonephritis, but 62% of the scarred kidneys were drained by non-refluxing ureters. Children with scars were older at the time of acute pyelonephritis than those without scars but no difference was found between the groups with regard to duration of illness, levels of C reactive protein and maximum white cell count, glomerular filtration rate, nor renal concentration capacity at the time of infection. It is concluded that renal scarring after acute pyelonephritis in children is more common than has been previously thought. Although children with gross VUR and recurrent pyelonephritis are at the greatest risk, renal scarring is more often seen without these risk factors.

Urine interleukin-6 and interleukin-8 in children with acute pyelonephritis, in relation to DMSA scintigraphy in the acute phase and at 1-year follow-up

The relationship between urine interleukin-6 (IL-6) and interleukin-8 (IL-8)/creatinine quotients and 99mTc-dimercaptosuccinic acid (DMSA) scintigraphy, performed within 10 days of acute first-time pyelonephritis and after 1 year, was studied in 41 children. The urine IL-6 and IL-8/creatinine quotients were also related to the urine N-acetyl-beta-D-glucosaminidase (NAG) and albumin/creatinine quotients. Presence of DMSA uptake defects, reflecting local inflammation, in children in the acute phase of pyelonephritis, were associated with elevated urine IL-6/creatinine quotients (median 27 pg/mumol); in children without DMSA changes there was no increase in quotients (median non-detectable) (P < 0.05). Persistent DMSA changes at the 1-year follow-up, probably reflecting renal scarring, were only seen in children with increased urine IL-6/creatinine quotients in the acute phase (P < 0.01). No correlation was found between urine IL-8 and DMSA uptake defects. Vesicoureteral reflux (VUR) at 6-8 weeks did not correlate with the urine cytokine levels in the acute phase. The urine excretion of NAG and albumin, reflecting renal dysfunction, was associated with values of both urine IL-6 and IL-8/creatinine quotients, but not with DMSA defects or VUR. Thus, the initial urine IL-6/creatinine quotients might be used as an indicator of risk for persistent renal damage in acute pyelonephritis.

Typical technetium dimercaptosuccinic acid distribution patterns in acute pyelonephritis

Technetium dimercaptosuccinic acid renal scintiscans in 37 children with clinical diagnosis of acute pyelonephritis were reviewed. In 18 children, follow-up scintigraphy was obtained after an interval ranging from 5 to 8 months. Uptake abnormalities were found in 89% of the children (74% of the kidneys). We were able to identify four typical pathological uptake patterns: (i) pole defect(s), usually wedge shaped (60%); (ii) lateral wedge shaped defect (4%); (ii) scattered multiple defects (21%); and (iv) swollen kidney without areas of diminished uptake (15%). Remaining pathology at follow-up was found in 52% of the kidneys. Vesicoureteric reflux was present in 33% of the children with scintigraphic signs of pyelonephritis. Frequencies of parenchymal changes in the acute phase and at follow-up were not significantly correlated to the presence of reflux.

Primary vesicoureteral reflux in infants with a dilated fetal urinary tract

Vesicoureteral reflux (VUR) was recognized neonatally by voiding cystography in 25 of 117 infants with a dilated fetal urinary tract. There was a male preponderance (76%) and a high percentage (40%) of associated urinary malformations. Thirty-nine refluxing units were studied. All grades of VUR were detected but gross dilating VUR dominated (59%). Spontaneous resolution was excellent in lower grades of VUR but was poor in gross VUR. Surgery was successfully performed in 13 renal units of nine patients with gross reflux, additional ipsilateral malformations, or pyelonephritis during antibiotic prophylaxis. Segmental renal scars developed in four kidneys after urinary infections, and a diffuse parenchymal lesion was noted in nine kidneys even at birth. One boy with duplication had a non-functioning refluxing system. Our results in a small number of infants show differences to children with VUR detected after urinary infections and seem to support the existence of a congenital reflux nephropathy.

The importance of 99mTc DMSA scanning in the localization of childhood urinary tract infections

The use of 99mTechnetium dimercaptosuccinic acid (99mTc DMSA) scanning for the early diagnosis of upper urinary tract infections has been preferred for a few years. In this research we investigated the use of 99mTc DMSA scanning in the localization of renal parenchymal involvement in urinary tract infection. Twenty-four children presenting with first acute urinary tract infection were studied. Investigations included physical examination, white blood cell count (WBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), antibody-coated bacteria (ACB) and early 99mTc DMSA scanning. 99mTc DMSA scanning was taken as the gold standard method in determining renal parenchymal inflammation. According to the 99mTc DMSA scanning the sensitivity of clinical findings was 57.14%, WBC 23.80%, ESR 33.33%, CRP 14.28% and ACB 71.42% in the localization of urinary tract infection. We propose early 99mTc DMSA scanning performed around the time of infection as a good technique for localization of the level of infection in the urinary tract.

Commentary: management of children with severe vesicoureteral reflux

The main findings of the IRSC after 5 years of observation are summarized. Of the 434 children entered 128 were from centers in America and 306 from Europe. They were randomly allocated and stratified to a medical or surgical regimen. Of the children 50% had scarred kidneys at entry evenly distributed between the groups. After 5 years of observation there was no difference in outcome between the 2 treatment groups in terms of renal size and growth, the development of new radiological renal scars or areas of parenchymal thinning, or of progression of established scarring. In Europe infection recurred in equal numbers of children but pyelonephritic symptoms were more common in the medical group. Nevertheless, new scars developed in 19 of 155 children treated medically and 20 of 151 children treated surgically, including 5 and 7, respectively, with previously normal kidneys. Factors influencing the choice of treatment include patient age, availability of expert surgical care and experienced medical supervision, parental choice and compliance. Followup studies indicate that renal scarring rather than persistence of reflux determines the prognosis and, therefore, emphasis should be placed on the prevention of scarring.

Involvement of the renal parenchyma in acute urinary tract infection: the contribution of 99mTc dimercaptosuccinic acid scan

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.

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 greater than or equal to 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 less than 0.02 and 0.01, respectively). During infection the size of the defect on the DMSA scan correlated with renal volume 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.

Normokalaemic pseudohypoaldosteronism is present in children with acute pyelonephritis

The present study demonstrates that renal tubular unresponsiveness to aldosterone, without associated hyperkalaemia, is present in children with acute pyelonephritis. We studied 32 children with a diagnosis of acute pyelonephritis established by high fever, flank pain/tenderness, increased blood levels of C-reactive protein and significant Escherichia coli growth in the urine culture. Renal tubular function tests and determinations of plasma renin activity and aldosterone concentration were performed at diagnosis (study 1), after three days of iv gentamycin (study 2) and after 21 days of antibiotic therapy (study 3). Findings were compared to those present in 32 normal children of similar age. Despite normal plasma potassium concentration, fractional potassium excretion and transtubular potassium concentration gradient were significantly decreased in studies 1 and 2, becoming normal in study 3. Decreased renal potassium excretion coexisted with increased values for plasma renin activity and aldosterone concentration. In study 3 these hormones remained elevated only in patients with scarred kidneys. The functional alteration present in acute pyelonephritis may be directly caused by the interstitial inflammation or be mediated by some E. coli endotoxin.

Renal growth in infancy and childhood--experimental studies of regulatory mechanisms

During the peri- and early postnatal period, nephrogenesis is completed and kidney growth is accomplished both by cellular proliferation and enlargement. The number of nephrons in a given species is predetermined, whereas cellular growth can be influenced by environmental factors in an age-dependent manner. Unilateral nephrectomy or a high-protein diet stimulates renal growth more in the young than in the adult. Conversely, pyelonephritis inhibits renal growth in infancy but not in adulthood. The relative importance of hyperplasia and hypertrophy for renal growth also changes with renal maturation. The mechanisms behind these developmental changes in regulation of renal growth are largely unknown, but age-dependent changes in the expression of several proto-oncogene products have been demonstrated. These include growth factor receptors as well as components of the intracellular system that transfers the signal from an activated growth factor receptor to the cell nucleus. Studies on rat proximal tubule cells in primary culture might be of great value in expanding our knowledge of growth regulation in the developing kidney. Such studies have already shown that under identical environmental conditions the basal proliferative rate is age dependent, that the proliferative response to growth stimulation changes postnatally, and that this is associated with changes of both the response of the Na+/H(+)-exchanger and the expression of the c-fos proto-oncogene.