Development of new renal scars: a collaborative study

Vesicoureteral reflux in infants with isolated antenatal hydronephrosis

Standardized evaluation of all newborns with antenatally recognized hydronephrosis (ANH) at The Hospital for Sick Children (HSC) has included voiding cystourethrography (VCUG). This paper reviews this protocol to determine: (1) the prevalence of vesicoureteral reflux (VUR) in isolated ANH and (2) the value of performing VCUG in cases of mild hydronephrosis, defined as renal pelvis dilatation <10 mm on postnatal ultrasonography (US). A retrospective chart review was performed on infants referred with ANH. The inclusion criterion was isolated ANH. Exclusion criteria were (1) presence of additional genitourinary abnormalities and (2) no VCUG. Pelviectasis was categorized according to the anteroposterior diameter of the renal pelvis. There were 111 infants with isolated ANH. All except 3 underwent VCUG. There were 68 children (63%) with normal postnatal US or mild pelviectasis (<10 mm). VUR was detected in 16 patients, of whom 10 had mild or absent pelvic dilatation. There was no correlation between the degree of pelviectasis on postnatal US and the presence or severity of VUR ( P=0.567 and P=0.802). VUR was detected in 15% of children with isolated ANH, many of whom had normal postnatal US or mild postnatal pelviectasis. VCUG is the only reliable test for detecting postnatal VUR.

New renal scars in children with severe VUR: a 10-year study of randomized treatment

The International Reflux Study in Children was set up to compare prospectively the outcome of medical or surgical management of children with grade III or IV vesicoureteral reflux and a history of symptomatic urinary tract infection. Development of new radiological scars was the main end point. Of the 306 children randomized, 302 (153 medical, 149 surgical) were available for radiological follow-up at 5 years. New scars had developed in 19 medically and 21 surgically treated children. Among 223 patients (113 medical, 110 surgical) who continued follow-up with urography at 10 years, only 2 further new scars developed. Overall, 47 new scars were acquired in 42 patients (20 medical, 22 surgical), 25 of them in children with unscarred kidneys at entry (13 medical, 12 surgical). New scars occurred mostly in children under 5 years of age and were observed more frequently in children with grade IV than grade III reflux. We conclude that with careful management, only a small proportion of children with severe reflux developed new scars and rarely after the first 5-year follow up period, and that there was no difference between children treated medically or surgically.

Incidence and severity of vesicoureteral reflux in children related to age, gender, race and diagnosis

PURPOSE

We determine if the incidence and grade of vesicoureteral reflux (VUR) differs in children based on age, race and gender, and if the incidence and severity of VUR are related to race in girls younger than 7 years presenting for evaluation after urinary tract infection (UTI).

MATERIALS AND METHODS

The records of all children who underwent a voiding cystourethrogram or radionuclide cystogram between 1993 and 2001 were retrospectively reviewed. Age, gender, race, clinical indication and highest grade of VUR were recorded for the first voiding cystourethrogram or radionuclide cystogram. Frequency tables and logistic regression were conducted to correlate demographics to incidence and severity of VUR.

RESULTS

A total of 15,504 patients were included in the analysis. Overall, black children were a third as likely as white children (p <0.0001) and females were twice as likely as males (p <0.0001) to have VUR. Compared to children 0 to 2 years old, the occurrence of reflux was 0.5 times as likely in those 3 to 6 years old (p <0.0001), 0.3 times as likely in those 7 to 11 years old (p <0.0001) and 0.15 times as likely in those 12 to 21 years old (p <0.0001). When analyzing children with UTI, results were similar. Of the patients with VUR 65% were younger than 7 years. The incidence of VUR in black girls younger than 7 years with a diagnosis of UTI was less than 10% compared to white girls, and no black girl had high grade reflux. In young children referred for UTI the incidence and severity of VUR in black patients were significantly lower than those of white girls.

CONCLUSIONS

This study validates previous observations regarding the low incidence of VUR in black children.

Vesicoureteric reflux and reflux nephropathy

Reflux nephropathy i.e. renal scarring associated with vesico-ureteric reflux (VUR) and urinary tract infection (UTI) was originally considered an acquired disease. The renal scarring seems to get worse with recurrent urine infections especially in the young. Therefore, in the past much effort was undertaken to correct the VUR surgically and minimize the number of recurrent urinary tract infections by antibiotic prophylaxis with the hope of reducing if not arresting the onset of complications that follow i.e. hypertension and renal failure. However, it is now becoming clear that reflux nephropathy encompass at least two major categories of disease; "acquired" renal scarring secondary to UTI and VUR predominantly affecting females and "congenital" scarring with dysplastic features associated with prenatal VUR but with no infection and predominantly affecting boys. The latter is much less common but is disproportionately represented in the group of patients with reflux nephropathy that go on to develop renal failure. Unfortunately, the susceptibility to renal scarring, the onset of hypertension and progression to renal failure seems to be significantly influenced by genetic factors and hence measures undertaken to prevent recurrence of UTI may not change the ultimate outcome although it will certainly improve the comfort of the individual. Therefore, the extensive investigation and management routines adopted today in these children may not be cost-effective in preventing end stage renal disease in VUR. The progression to renal failure, however, can be delayed but not halted with adequate control of high blood pressure and hence the need for life long follow-up.

Long-term followup of 158 young adults surgically treated for vesicoureteral reflux in childhood: the ongoing risk of urinary tract infections

PURPOSE

We recorded urinary tract infections in the long term after surgical reflux correction.

MATERIALS AND METHODS

A total of 158 of 189 patients (160 females and 29 males) who were followed in 1985, an average of 10.8 years after reflux surgery were contacted again in 1995. At that time median patient age was 26 years (range 15.7 to 38.8) and the average period of observation was 20.3 years (range 13.4 to 26).

RESULTS

In 82% of the patients febrile and in 18% afebrile symptomatic urinary tract infections had developed preoperatively. In the first 10-year period after operation 46% of patients continued to have symptomatic urinary tract infections compared with 52% in the second 10-year interval. In the 2 periods the incidence of febrile urinary tract infection was about 17%. In the whole postoperative observation period symptomatic urinary tract infections developed in 66% of all patients, including 74% of female patients. Symptomatic urinary tract infections were observed during 8 of 46 pregnancies (17%).

CONCLUSIONS

After successful surgical reflux correction susceptibility to urinary tract infection continues for a number of years in many girls and women. However, postoperatively urinary tract infections are primarily afebrile.

Long-term follow-up of reflux nephropathy in adults with vesicoureteral reflux--radiological and pathoanatomical analysis

PURPOSE

To study the long-term development of urographic renal morphology in adults with vesicoureteral reflux, to investigate the relationship between renal damage and reflux grade, and to analyse the association between the long-term urographic outcome and the occurrence of acute pyelonephritis and reflux during follow-up. The purpose was also to try to distinguish between acquired and developmental renal damage, based on analyses of renal histological specimens and urographic features, and to analyse associated congenital urogenital abnormalities and family history of reflux, reflux nephropathy, urological malformation or death from end-stage renal disease.

MATERIAL AND METHODS

Renal damage was identified in 100 (83 women) of 115 adults, selected because of documented reflux. Eighty-seven patients had two urographies done (median interval 14.3 years). The extent and progression of renal damage were assessed and features of developmental renal damage were determined. Histological renal specimens were available in 23 patients with renal damage.

RESULTS AND CONCLUSIONS

The extent of renal damage correlated positively with the severity of reflux. No renal damage developed during the follow-up in 45 previously undamaged kidneys and progression of renal damage was rare (4 of 120 previously damaged kidneys), despite persisting reflux in half of the cases and episodes of acute pyelonephritis during follow-up. Thus, repeated renal imaging is rarely justified in adults with reflux nephropathy. Histological examination showed "chronic pyelonephritis" in all 23 cases and co-existing renal dysplasia in 1 case. The detailed urographic analysis did not reveal support for developmental renal damage. High frequencies of associated congenital urogenital abnormalities and of a positive family history were found. Thus, congenital and/or hereditary factors cannot be discarded as background factors for the development of renal damage.

Renal scars masquerading as complex masses in a patient with vesicoureteral reflux nephropathy

Vesicoureteral reflux can lead to chronic pyelonephritis, renal scarring, and renal failure. We present a case of renal scarring masquerading as bilateral, complex renal masses. A 35-year old woman who was diagnosed with vesicoureteral reflux as a child presented for evaluation of recently developed hypertension and an abnormal renal ultrasound. Her serum creatinine level was 2.5 mg/dL and she had subnephrotic-range proteinuria. A renal sonogram showed small, echogenic kidneys and bilateral complex renal masses of 3.8 (right) and 4.4 (left) cm in greatest dimensions. CT scan of the kidneys revealed slightly contrast-enhancing masses with irregular walls. Renal angiogram showed decreased blood supply to the areas coinciding with the masses consistent with renal scarring. There was no increased vascularity. This case demonstrates that renal scarring may masquerade as renal masses. A step-wise, comprehensive approach is necessary to rule out potentially malignant lesions in these patients.

Medical versus surgical treatment in children with severe bilateral vesicoureteric reflux and bilateral nephropathy: a randomised trial

BACKGROUND

Nephropathy associated with vesicoureteric reflux (VUR) and urinary tract infection can result in end-stage renal failure, hypertension, or both. Whether long-term VUR contributes to these outcomes is unknown. We compared, in a randomised trial, medical with surgical management of children with bilateral severe VUR and bilateral nephropathy.

METHODS

We stratified by age and glomerular filtration rate (GFR) 25 boys and 27 girls aged 1-12 years and randomly assigned them to medical or surgical management. At enrolment and 4 years' follow-up we estimated GFR from the plasma clearance of 51Cr-labelled edetic acid (EDTA), and did intravenous urography. We also did a metastable 99mTc-labelled dimercaptosuccinic acid (DMSA) assay and contrast cystography. The change in GFR at 4 years, expressed as a percentage change between enrolment and 4 years, was available for 26 of 27 patients in the medical and 24 of 25 in the surgical group. We assessed GFR in 48 patients 10 years after enrolment.

FINDINGS

Mean GFR at enrolment was 72.4 mL/min per 1.73 m(2) (SD 24.1) in the medical and 71.7 mL/min per 1.73 m(2) (22.6) in the surgical group. The mean percentage change in GFR at 4 years was 2.4% (SE 4.5) versus 4.7% (5.0) in the medical and surgical groups, respectively. The difference in change in GFR at 4 years between the two groups was not significant (7.1%, 95% CI 6.4% to 20.6%).

INTERPRETATION

Our data do not lend support to the view that the outcome for renal function is improved by surgical correction of VUR in children with bilateral disease.

An audit of RCP guidelines on DMSA scanning after urinary tract infection

AIM

To assess the outcome of imaging investigations carried out in children with urinary tract infection (UTI), to compare the investigations with national guidelines, and to assess the impact on management.

METHODS

Retrospective review of inpatients and outpatients, aged 0-12 years, referred to the University Hospital of Wales Healthcare Trust between February 1997 and January 1998 with UTI. All children without bacterial evidence of UTI and children previously investigated for antenatal urological anomalies, major congenital anomalies, or UTI were excluded.

RESULTS

A total of 164 children (51 boys, 113 girls) were included. Thirteen of 56 infants (23%) and 82/108 older children (76%) were diagnosed at home over one year. The prevalence of dilatation on ultrasound was 8%, renal scarring on dimercaptosuccinic acid (DMSA) scan was 11%, and vesicoureteric reflux (VUR) was 34% when investigations were carried out following guidelines published by the Royal College of Physicians. In children aged 1-6 years, the prevalence of scarring was 1/54 (2%) in those treated at home and 6/18 (33%) in inpatients.

CONCLUSION

The low yield of positive results and lack of evidence of impact on management indicate that DMSA scanning, with all the implications of isotope exposure, intravenous injection, staff time, psychological trauma, and expense, could be omitted in children over 1 year with first simple UTI not sufficiently ill to be admitted to hospital. The low rate of detection of UTI in primary care in infants may represent under diagnosis.

Empiric use of cefepime in the treatment of serious urinary tract infections in children

BACKGROUND

Urinary tract infections (UTIs) are common in childhood. They represent a significant proportion (10%) of hospital-acquired infections in children. Bacteria causing UTIs in children vary, depending on the setting (community-acquired vs. nosocomial), underlying anatomic anomalies and concurrent medical conditions.

OBJECTIVE

To review published and unpublished clinical studies that have used cefepime for the treatment of UTIs in children.

METHODS AND RESULTS

In two recent multicenter, randomized trials, cefepime (50 mg/kg/dose every 8 h and every 12 h) was compared with ceftazidime (50 mg/kg/dose every 8 h) for the treatment of serious urinary tract infections including pyelonephritis in children less than 12 years of age. In these studies a favorable clinical and microbiologic response was observed in >95% of cefepime-treated and ceftazidime-treated children assessed at the end of treatment.

CONCLUSIONS

These results indicate that cefepime represents an important therapeutic option for the treatment of serious UTIs in children.

A bioassay evaluation of the urinary antibacterial efficacy of low dose prophylactic antibiotics in children with vesicoureteral reflux

PURPOSE

We evaluated by means of a bioassay the efficacy of 4 different antibiotics administered in a prophylactic dose to children with vesicoureteral reflux.

MATERIALS AND METHODS

A total of 159 urine samples from 53 children taking prophylactic antibiotics with proved vesicoureteral reflux were tested. The children were divided into 4 groups according to the antibiotic given, which included nalidixic acid, cephalexin, cotrimoxazole and cefixime. Urine samples were collected in the morning, at noon and in the evening, and each sample was bioassayed for growth inhibition of a standard Escherichia coli. The urine volume used was specifically determined for each antibiotic, and growth inhibition by this specific volume was equivalent to that produced by standard diffusion disks. In addition, the specific gravity, which reflected urinary concentration of each sample, was measured.

RESULTS

Mean patient age plus or minus standard deviation of the 4 groups was 53 +/- 41 for nalidixic acid, 23 +/- 34 for cephalexin, 55 +/- 35 for cotrimoxazole and 47 +/- 35 months for cefixime, respectively. In children less than 2 years old specific gravity was higher in the morning (1.021 +/- 0.0006 versus 1.0008 +/- 0.0004 at 8 a.m. and 2 p. m., respectively, p <0.05). In contrast, in children older than 4 years the specific gravity was higher in the afternoon and evening hours (1.019 +/- 0.003 versus 1.007 +/- 0.003 at 2 p.m. and 8 a.m., respectively, p <0.05). The percentage of patients who demonstrated growth inhibition in all 3 samples of the test day was 7%, 6%, 69% and 44% for nalidixic acid, cephalexin, cotrimoxazole and cefixime, respectively (p <0.001 for cotrimoxazole and cefixime versus nalidixic acid and cephalexin. Divided into morning, noon and evening, the percentage of samples that demonstrated growth inhibition was 85.7%, 21.4% and 7.1% for nalidixic acid, 37.5%, 12. 5% and 6.3% for cephalexin, 100%, 92.3% and 76.9% for cotrimoxazole and 100%, 77.7% and 55.5% for cefixime, respectively. A direct correlation was found between specific gravity and growth inhibition (r = 0.55, p <0.001).

CONCLUSIONS

Urine concentration during the day is dependent on age with older children having more concentrated urine in the latter part of the day. Growth inhibition is enhanced by concentrated urine. Compared to nalidixic acid and cephalexin, cotrimoxazole and cefixime produce a sustained bactericidal effect for about 60% of a 24-hour day due to the longer half-life.

Sibling vesicoureteral reflux in multiple gestation births

BACKGROUND

Vesicoureteral reflux (VUR) is the most commonly inherited disease of the genitourinary tract. Although the majority of evidence supports a genetic cause, the tendency for this condition to spontaneously improve over time has made it difficult to determine the actual mode of transmission. We report the incidence of VUR in siblings of multiple gestation births and for the first time compare the relative incidence of reflux between identical and fraternal twins.

METHODS

A database consisting of all radionuclide cystograms and voiding cystourethrograms performed between the years 1986 and 1996 was searched for multiple gestation births. The medical records of each patient were evaluated for age at presentation, zygosity, reflux grade, and time to resolution. Children with secondary causes of VUR (eg, posterior urethral valves) were excluded. Triplets were treated as 2 pairs of twins for statistical analysis.

RESULTS

Forty-six pairs met the inclusion criteria (31 dizygotic and 15 monozygotic). Overall, 23 (50%) of 46 siblings of index cases had demonstrable VUR. Comparison of VUR prevalence between identical and nonidentical twins was revealing with 80% (12/15) of identical twins and 35% (11/31) of fraternal twins having VUR. When only the youngest individuals in each group were considered, 100% (7/7) of the monozygotics and 50% (5/10) of the dizygotics demonstrated this trait.

CONCLUSIONS

High concordance for VUR in identical twin siblings supports a genetic basis for the transmission of this disease. Results obtained from fraternal twin siblings provides convincing evidence that this trait is transmitted in an autosomal dominant fashion.

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

OBJECTIVES

To determine when pyelonephritic renal scarring was detected in children with urinary tract infection (UTI) and characterize those with primary and acquired scarring, respectively.

STUDY DESIGN

A population-based cohort of 1221 children (989 girls and 232 boys) with first recognized symptomatic UTI, aged 0 to 15 years, were diagnosed and followed up prospectively at a single children's hospital; 652 had febrile UTI. Seven hundred fifty-three were evaluated by urography. Renal scarring was classified as primary or acquired, the latter without signs of scarring at the first investigation. To evaluate the frequency of recurrent UTI in those with acquired scarring, a comparison with group-matched children without scarring was performed.

RESULTS

A total of 74 children without obstruction had renal scarring (acquired in 40). Primary scarring was found in 18 of 21 (86%) of the boys and 16 of 53 (30%) of the girls (P <.001). The majority of boys with scarring had dilated reflux (67%) in contrast to girls (23%). Recurrent UTI was rare in boys, whereas girls with acquired scarring had significantly more febrile recurrences than girls without scarring.

CONCLUSIONS

Most boys had primary, probably congenital, reflux-associated renal damage, whereas most girls had acquired scarring related to recurrences of febrile UTI.

Management of pyelonephritis and upper urinary tract infections

The most frequent cause of upper urinary tract infection remains E. coli. Other organisms are found in complicated infections associated with diabetes mellitus, instrumentation, stone, and immunosuppression. The pathogenesis of acute pyelonephritis is reviewed herein, with an emphasis on the virulence factors responsible for its initiation, including urothelial adhesion by P-fimbriae of E. coli and other common factors including hemolysin and aerobactin. Renal damage does not always ensue following such infection. It is seen when toxic oxygen radicals are released during the ischemic episode and the respiratory burst of phagocytosis is marked and prolonged. These events occur when effective antibacterial treatment is delayed when the diagnosis is not made early or when socioeconomic factors prevent treatment. The scarring of chronic pyelonephritis leads to the loss of renal tissue and function and may progress to end-stage renal disease. With effective antibacterial therapy, the immune response by both T and B lymphocytes leads to antibodies that assist in bacterial eradication. Therapy must be both rapid and effective. In many instances, antibacterial agents may be used as outpatient therapy. If the Gram stain shows only gram-negative organisms and if the infection is community acquired, oral outpatient therapy with trimethoprim/sulfamethoxazole or a fluoroquinolone may suffice if the patient has no nausea. When the patient is septic, hospitalization and treatment with parenteral antibiotics are needed. Both ceftriaxone and gentamycin are cost-effective parenteral therapy because only once-daily dosing is needed. If gram-positive organisms are found, an enterococcus should be suspected, and a beta-lactam penicillin such as piperacillin or a third-generation cephalosporin such as ceftriaxone is indicated. If penicillin allergy exists, vancomycin should be used. If the patient does not improve rapidly, diagnostic studies including ultrasound and CT will assist in the diagnosis of obstruction, abscess, or emphysematous pyelonephritis. Most of these complications are now rapidly treated percutaneously, with surgical therapy following as needed. Complicated infections, such as those occurring in patients with anatomic abnormalities, stone, or immunosuppression, are often caused by organisms other than E. coli, and long-term antibacterial therapy often leads to fungal infections such as candidiasis. A recrudescence of tuberculosis is occurring, often with resistance to antituberculous drugs. The increased incidence has been associated with the immunosuppression of AIDS but is also occurring in intravenous drug users, perhaps because of poor nutrition but also owing to noncompliance with treatment. The symptoms of renal tuberculosis are usually limited to fever, frequency, urgency, and dysuria. Hematuria with sterile pyuria is the usual laboratory finding. The young urologist should remember this renal disease in the differential diagnosis of hematuria, because medical therapy can provide a cure.

Antibacterial prophylaxis in children with urinary tract infection

The aim, in conservative management of vesico-ureteric reflux by antimicrobial prophylaxis, is to prevent recurrent febrile urinary tract infections and consequent renal scarring. However, the effects of this prophylactic strategy are difficult to evaluate, since the required studies comparing children on prophylaxis with controls (without prophylaxis but under careful supervision) are lacking. Furthermore, the optimal length of prophylaxis needs to be defined. Since risk of renal scarring is believed to occur more frequently in young people, and since recurrent urinary infections mainly affect girls, the age and sex of subjects are important in the design of a prophylactic regimen. Nitrofurantoin and trimethoprim are the most common agents used for long-term, low-dose antibacterial prophylaxis. Break-through infections still result from non-compliance and from development of bacterial resistance, the latter mainly arising with trimethoprim. Few studies of prophylactic drugs are available that adequately define patient materials and include a random allocation to the different agents. Further studies of the effects of alternative prophylactic agents are called for, preferably combined with fresh insight into the ecological impact on the bowel and periurethral floras.

Evaluation and management of pediatric urinary tract infections

Urinary tract infections (UTIs) are relatively common in children. We describe the evaluation and management of children with UTIs, as well as the risks and consequences related to the UTI. This article describes a rational approach to the evaluation and management of childhood UTIs with the relation to the natural history and risk factors.

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.

The value of Ga-67 renal SPECT in diagnosing and monitoring complete and incomplete treatment in children with acute pyelonephritis

PURPOSE

This study evaluated the utility of Ga-67 renal SPECT for diagnosing acute pyelonephritis (APN) in children and monitoring them.

METHODS

Seventy-one children (ages 1 week to 12 years) who were thought clinically to have APN were included in the study. The disease was considered present if the patients had all of the following: fever (38.5 degrees C), pyuria (leukocyte counts/per high-power field > or = 10), and a positive result of a urinary culture or blood culture. Tc-99m DMSA, Ga-67 renal SPECT, and voiding cystourethrography were performed, with informed consent from the patients' parents, within 3 days after hospitalization. Three months after treatment, Tc-99m DMSA and Ga-67 renal SPECT were repeated in those patients who had abnormal results of the initial Ga-67 renal SPECT.

RESULTS

In the diagnostic study, Ga-67 renal SPECT was superior to DMSA renal SPECT in detecting lesions (97% vs. 79%). Three children had false-negative results with Ga-67 renal SPECT. Seventeen kidneys were negative with Tc-99m DMSA but positive with Ga-67 renal SPECT. No patients had any Ga-67 uptake on post-therapy imaging. However, 32 of 107 kidneys (30%) had permanent renal scars. In these 107 kidneys, 78 (73%) were associated with high-grade vesicoureteral reflux (VUR; VUR grade > or = 3) and 29 (27%) with low-grade or no VUR.

CONCLUSIONS

High-grade VUR tends to be associated more with APN than has been reported by others, probably because of an underestimation of APN by ultrasonography or DMSA. Ga-67 renal SPECT is sensitive and useful not only in diagnosis but also for monitoring and follow-up of children with clinical suspicion of APN, especially in those with equivocal results after DMSA renal SPECT studies.

Vesico-ureteral reflux in pediatric kidney transplants: clinical relevance to graft and patient outcome

From June 1985 to December 1998, 173 pediatric renal transplants were carried out in 170 patients at our center. From this pool, 73 patients (34 males and 39 females) with a follow-up of 48 months were examined. In all patients, ureteroneocystostomy was performed according to the Lich-Grégoire procedure. All patients were treated with cyclosporin A (CsA)-based immunosuppression, including prednisone and sometimes azathioprine (AZA). Six months after transplantation, voiding cystography (VCU) was performed in all patients and reflux was classified from Grade I to Grade IV. The patients were divided into two groups: those with reflux (Group A: 25 patients) and those without (Group B: 48 patients). Grade I reflux was found in four patients, Grade II in seven patients, Grade III in seven patients, and Grade IV in seven patients. All the patients with severe reflux (Grade IV) underwent a corrective surgical procedure. Both groups were examined for immunologic and non-immunologic risk factors and no significant differences were found. Analysis of patient and graft survival rates revealed no statistical differences (NS) between Groups A and B. Mean serum creatinine (mg/dL) was 1.06 +/- 0.28 and 1.12 +/- 0.41 at 4 yr in Groups A and B, respectively (NS). Mean calculated creatinine clearance (cCrC; ml/min) was 76.74 +/- 15.92 and 77.96 +/- 15.66 in Groups A and B, respectively (NS). The analysis was further extended by considering the grade of reflux (I to IV). Again, no significant differences in the above parameters emerged between the reflux sub-groups; only in the Grade IV sub-group was a slight decrease in cCrC detected, although this difference was not statistically significant when compared with the other sub-groups. In conclusion, vesico-ureteral reflux (VUR) does not seem to negatively affect graft function. However, as all severe reflux patients (Grade IV) were surgically corrected, no conclusions can be drawn with regard to the influence of Grade IV reflux on long-term graft function.

Oral versus initial intravenous therapy for urinary tract infections in young febrile children

BACKGROUND

The standard recommendation for treatment of young, febrile children with urinary tract infection has been hospitalization for intravenous antimicrobials. The availability of potent, oral, third-generation cephalosporins as well as interest in cost containment and avoidance of nosocomial risks prompted evaluation of the safety and efficacy of outpatient therapy.

METHODS

In a multicenter, randomized clinical trial, we evaluated the efficacy of oral versus initial intravenous therapy in 306 children 1 to 24 months old with fever and urinary tract infection, in terms of short-term clinical outcomes (sterilization of the urine and defervescence) and long-term morbidity (incidence of reinfection and incidence and extent of renal scarring documented at 6 months by 99mTc-dimercaptosuccinic acid renal scans). Children received either oral cefixime for 14 days (double dose on day 1) or initial intravenous cefotaxime for 3 days followed by oral cefixime for 11 days.

RESULTS

Treatment groups were comparable regarding demographic, clinical, and laboratory characteristics. Bacteremia was present in 3.4% of children treated orally and 5.3% of children treated intravenously. Of the short-term outcomes, 1) repeat urine cultures were sterile within 24 hours in all children, and 2) mean time to defervescence was 25 and 24 hours for children treated orally and intravenously, respectively. Of the long-term outcomes, 1) symptomatic reinfections occurred in 4.6% of children treated orally and 7.2% of children treated intravenously, 2) renal scarring at 6 months was noted in 9.8% children treated orally versus 7.2% of children treated intravenously, and 3) mean extent of scarring was approximately 8% in both treatment groups. Mean costs were at least twofold higher for children treated intravenously ($3577 vs $1473) compared with those treated orally.

CONCLUSIONS

Oral cefixime can be recommended as a safe and effective treatment for children with fever and urinary tract infection. Use of cefixime will result in substantial reductions of health care expenditures.

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.

Identification of new renal scarring in repeated episodes of acute pyelonephritis using Tc-99m DMSA renal SPECT

PURPOSE

This prospective study compared the value of Tc-99m DMSA renal planar scintigraphy with SPECT to detect new renal involvement in patients with repeated episodes of acute pyelonephritis (APN).

MATERIALS AND METHODS

Children with suspected APN were transferred to our department for DMSA renal scans. Seventy-two children (ages 1 week to 15 years) had DMSA planar and SPECT imaging performed twice because of clinical or laboratory suspicion of repeated APN. In addition, radiographic voiding cystourethrography was also performed in all cases. The presence of vesicoureteral reflux (VUR) was graded on a scale of 0 to 5.

RESULTS

New lesions were observed with SPECT in 56 kidneys and with planar scintigraphy in 38 kidneys. No patients had a negative result of Tc-99m DMSA renal SPECT who also had a positive Tc-99m DMSA planar result. The degree of VUR as related to APN was diagnosed better with SPECT than with planar scintigraphy (46 compared with 30 and 10 compared with 8, respectively). There is a significant difference (P < 0.05) between the diagnostic ability of these two methods to identify the increased tendency of repeated APN to occur with high-grade VUR compared with low-grade or no VUR.

CONCLUSIONS

High-grade VUR is more commonly associated with renal injury than is low-grade or no VUR. If only Tc-99m DMSA renal planar scintigraphy is performed, renal scarring may be underestimated. Our results suggest that Tc-99m DMSA renal SPECT, rather than planar scintigraphy, should be used routinely in children with a clinical suspicion of APN, especially for those with scarred kidneys and high-grade VUR.

The office management of recurrent urinary tract infection and vesicoureteral reflux in children

Recurrent urinary tract infections (UTIs) and vesicoureteral reflux are common diagnosis' in infants and children who are referred to a urologist. Recurrent UTIs in these patients can be challenging, especially when radiographic evaluation reveals no structural abnormality. Prophylaxis and correction of voiding and bowel dysfunction are important treatment strategies. Febrile UTIs are commonly associated with reflux and should be treated aggressively to avoid renal scarring and its sequelae. Based on a comprehensive survey of the literature, long-term treatment strategies for children with reflux are now available.

The DMSA scan in paediatric urinary tract infection

The objective of the present paper was to review the use of the dimercaptosuccinic acid (DMSA) scan in urinary tract infection at British Columbia's Children's Hospital to determine the frequency of cortical defects and the association between vesico-ureteric reflux and the presence of cortical defects in children with urinary tract infection. A total of 129 consecutive children with a urinary tract infection referred for a DMSA scan in a 2-year period (January 1992-January 1994) were retrospectively studied. The results were analysed in terms of kidneys, and the incidence of cortical defects was determined. Eighty-eight patients (68%) had a radiographic micturating cysto-urethrogram within 6 months of the DMSA scan, and in this group the relationship of defects with vesico-ureteric reflux was determined. Overall, 81/258 (31%) of kidneys had a cortical defect on a DMSA scan. Of those who had a micturating cysto-urethrogram, 53/176 (30%) kidneys had vesico-ureteric reflux, and of those that had reflux, 21/53 (40%) had a cortical defect on a DMSA scan. In the group of children without reflux, 38/123 (31%) had a cortical defect. Renal cortical scan defects are common findings in paediatric urinary infection, and frequently occur in the absence of vesico-ureteric reflux. These defects represent either established scars or acute pyelonephritis that can proceed to scarring. The micturating cysto-urethrogram alone is insufficient as a screening modality to identify those kidneys at risk of renal scarring.

Progressive renal shrinkage after simple pyelonephritis

Nonobstructive, nonrefluxing pyelonephritis (or "simple" pyelonephritis) is not commonly associated with progressive renal scarring and global shrinkage. Although children are believed to be particularly susceptible to renal parenchymal scarring after simple pyelonephritis, progressive and global renal shrinkage remains an elusive clinical entity. We present such a case with close radiologic documentation.

Urinary tract infections in children. Epidemiology, evaluation, and management

Accurate documentation of UTIs in children is essential for proper evaluation and management. Urine cultures with multiple organisms or colony counts less than 50,000 to 100,000 CFU/ml should be considered suspect and require confirmation, particularly with clean-catch specimens. Children with well-documented UTIs should be evaluated based on their age and presenting symptoms. Infants and young children require imaging, usually with a cystogram and sonogram of the kidneys and bladder. Older girls with febrile UTIs and boys at any age should also be considered for urinary tract imaging. Renal cortical scintigraphy with 99mTc-DMSA has emerged as the imaging study of choice for acute pyelonephritis and renal scarring in children with UTIs. Treatment of UTIs in children ideally commences with culture-specific antimicrobial therapy, although treatment may be started in sick children before culture results are available. Short-course treatment (3-5 days) is sufficient for children with acute uncomplicated lower UTIs. Children with acute pyelonephritis require 10 to 14 days of antibiotics, which can be administered on an outpatient basis in older infants and children who are not toxic, as long as good compliance is expected. Patients with first-time UTIs who require imaging should be maintained on low-dose antibiotic prophylaxis until their workup is completed. Treatment of ABU does not seem necessary if the urinary tract is otherwise normal. Long-term antibiotic prophylaxis is indicated for children with frequent symptomatic recurrences of UTI and for those with known VUR. Diagnosis and treatment of underlying voiding dysfunction and constipation is an essential component of the successful management of UTIs in children.

Transient pyelonephritic changes on 99mTechnetium-dimercaptosuccinic acid scan for at least five months after infection

A prospective study was performed on 185 children with symptomatic urinary tract infection (UTI), 130F and 55M, having a median age of 0.9 y (range 0.1-9.8) at the time of UTI. The aim of the study was to find out how the 99mTechnetium-dimercaptosuccinic acid (DMSA) scan should be used to investigate UTI, and to follow the development of renal changes during pyelonephritis into subsequent permanent renal damage. All children were investigated with a DMSA scan within 5 days after admission and after 3.9-53.3 (median 9.2) weeks, and 159 were studied again after approximately 2 y (range 1.5-3.9 y). They all underwent micturition cystourethrography at the time of the second study. At the time of infection, the DMSA scan was abnormal in 85% of the children, in 58% at the first follow-up and in 36% at the second follow-up. An abnormal DMSA scan performed within 20 weeks from infection became normal in 38% of cases on the third study, while only 1/10 abnormal DMSA scans performed more than 20 weeks after infection became normal after 1.5-3.9 y. Persistent renal changes were more common in children > 4 y of age than in children < or = 1 y of age. Two months after the presenting infection, it was unusual to see a normal DMSA scan in a child with a VUR gr. > or = 3. The study suggests that DMSA changes after an index UTI may be transient for a longer period of time than has been previously considered. Therefore, in order to detect persistent changes, a DMSA scan should be performed more than 5 months after UTI.

Pyelonephritis provokes growth retardation and apoptosis in infant rat renal cortex

Childhood pyelonephritis is a common cause of renal cortical scarring and hypoplastic kidneys. To understand the mechanisms underlying the cortical lesions, urinary tract infection was induced in three-week-old rats by an intravesical infusion of E. coli, type 06 K13 HL a rat nephropathogenic strain. Four days after infection, histopathological examination showed marked infiltration of leukocytes in the medullary tissue adjoining the calyces and pelvis. In the cortex, signs of inflammation were found only in the cortical zone adjacent to the pelvis. No cells indicative of inflammation were observed in other parts of the cortex. Immunohistochemistry for endogenous proliferating cell nuclear antigen (PCNA) demonstrated a marked decrease in immunoreactivity in proximal tubular (PT) cells. The mitotic response of PT cells, assessed by 3H-thymidine autoradiography, showed a highly significant decrease during the first four days after induction of the infection. Four days after infection, a transient increase in apoptotic cells was observed in cortical cells outside the inflammatory areas. No increase in apoptotic cells was detected in the cortex 10 days after infection. Only a few apoptotic cells were detected in the control kidneys. In conclusion, the data indicate that inhibition of cell proliferation and enhancement of apoptosis may contribute to the renal parenchymal loss after childhood pyelonephritis.

How general practitioners manage children with urinary tract infection: an audit in the former Northern Region

BACKGROUND

Urinary tract infections (UTIs) in childhood are common and may be difficult to diagnose because of non-specific symptoms and technical problems with urine collection. Active management is important because UTIs may cause permanent renal scarring in young children.

AIM

To determine how general practitioners (GPs) manage children with suspected UTIs.

METHOD

A postal questionnaire to 494 GPs in the former Northern Region (a random selection of 26.2%) asking how they manage children with suspected UTI and their perception of their training needs.

RESULTS

A total of 333 (67.4%) GPs replied. On weekdays, up to 22.9% of GPs treated children who had symptoms suggestive of UTI without collecting a diagnostic urine sample, and up to 64.8% did so at weekends. Urine collection was satisfactory in 73.2% of boys and girls aged under one year, but in only 50.4% of older boys and 48.0% of older girls, caused in part by the use of unreliably 'cleaned' potties in the older group. On weekdays, up to 87.2% of GPs culture the urine, but up to 4.8% use dipsticks as the sole diagnostic test; at weekends, only up to 58.6% culture urines, and up to 19.1% rely on dipsticks alone. Up to 11.0% of GPs examine urine under a microscope for bacteria to test for UTI on weekdays and at weekends. Up to 23.8% of GPs who collect urines on weekdays wait for a positive culture result before starting antibiotics. At weekends, only 3.9% of GPs build in this delay to treatment, mainly because far fewer take urine samples at all. GPs refer younger children for diagnostic imaging more readily than older ones, and boys more readily than girls at all ages. Although virtually all GPs refer all children under five years, some still do so only after recurrent infections. Over half the GPs wanted more training in managing UTI in children.

CONCLUSION

There is a wide variation in clinical practice by GPs. Some always appropriately collect and test urine samples, treat without delay and refer for imaging after one proven UTI. Some never collect urines, treat blindly and refer only young infants with recurrent UTIs. Many vary their standards of practice from weekdays to weekends. The provision for GPs of clear, local, practical guidelines, drawn up between paediatricians and GPs and backed up with study days, might produce a consistent improvement in standards.

Are younger children at highest risk of renal sequelae after pyelonephritis?

BACKGROUND

The general belief about the relation between risk of renal sequelae after pyelonephritis and age is that infants are at highest risk and children older than 5 years at lower risk. This assumption has led to differences in treatment based on age. The aim of this prospective study was to investigate the occurrence of renal lesions in children aged 0-16 years.

METHODS

Between May, 1994, and January, 1996, all children aged 0-16 years who were admitted to our department with a diagnosis of probable pyelonephritis and a positive urine culture were included in this prospective study. All patients received antibiotics for 7-21 days. During the acute phase of urinary-tract infection, scintigraphy with technetium-99m-dimercaptosuccinic acid (DMSA) and ultrasonography were done. Voiding cystourethrography was undertaken at least 6 weeks after the end of antibiotic treatment. When scintigraphy showed renal parenchymal lesions, repeat scintigraphy was done after at least 2 months to assess the progression of renal lesions. For the analysis, children were grouped by age according to presumed risk of renal sequelae after pyelonephritis: high risk (< 1 year), moderate risk (1-5 years), low risk (> 5 years).

FINDINGS

201 patients were enrolled in the study (119 < 1 year, 47 aged 1-5 years, 35 > 5 years). During the acute phase of urinary-tract infection, renal lesions were found in 66 (55%) infants under 1 year, in 37 (79%) children aged 1-5 years, and in 24 (69%) children older than 5 years. Of these 127 children, 108 underwent repeat scintigraphy after an average of 3 months (50 < 1 year, 36 aged 1-5 years, 22 > 5 years). Overall, renal scars were found on repeat scintigraphy in 20 (40%) infants under 1 year, in 31 (86%) children aged 1-5 years, and in 14 (64%) children older than 5 years. 38 (36%) of these 65 patients had vesicoureteric reflux. Among 88 children who had a first documented urinary-tract infection and underwent repeat scintigraphy, renal scars were found in 20 (43%) under 1 year, in 26 (84%) aged 1-5 years, and in eight (80%) older than 5 years.

INTERPRETATION

This study did not confirm the conventional view that the risk of renal scars after pyelonephritis diminishes with age. We believe that all children, irrespective of age, will benefit from any measure that prevents the development of renal sequelae.

Renal damage one year after first urinary tract infection: role of dimercaptosuccinic acid scintigraphy

OBJECTIVE

The aim of this study was to determine whether age, C-reactive protein (CRP), body temperature, or results of voiding cystourethrography at diagnosis of first-time symptomatic urinary tract infection could predict the risk of renal damage as evaluated by dimercaptosuccinic acid (DMSA) scintigraphy performed 1 year after the infection.

DESIGN

The study included 157 children (median age, 0.4 year, range, 5 days to 5.8 years) with first-time symptomatic urinary tract infection. In children 1 year of age or older, a body temperature of 38.5 degrees C or higher was necessary for inclusion. CRP and body temperature were measured at the time of infection, and voiding cystourethrography was performed shortly thereafter. DMSA scintigraphy was performed 1 year later in all children.

RESULTS

After 1 year, 59 (38%) of the 157 children had renal damage as evaluated by DMSA scintigraphy, and of these, 28 (47%) had reflux. There was a positive correlation between renal damage and CRP, body temperature, and reflux. Children with high levels of CRP, high fever, and dilating reflux had a risk of renal damage up to 10 times higher than children with normal or slightly elevated CRP levels, no or mild fever, and no reflux.

CONCLUSION

CRP concentration and body temperature at the index infection, in combination with the results of voiding cystourethrography, are useful in classifying children at high and low risk of scintigraphic renal damage 1 year after urinary tract infection.

Urinary beta 2-microglobulin as a marker for vesicoureteral reflux

To determine whether urinary beta 2-microglobulin (beta 2 M) excretion would be elevated in patients with severity of vesicoureteral reflux, urinary beta 2 M/creatinine (Cr) ratios were measured on random urine samples in 56 children with various grades of reflux. Results were compared with ratios of 39 nonrefluxing patients matched for age and gender. Patients with evidence of renal insufficiency or urinary tract infection were excluded. Bladder urine was obtained at the time of the vesicoureterogram. Reflux was graded using the International Reflux Classification System. The mean urinary beta 2 M/Cr ratio was higher in the refluxing group (1.82 +/- 0.6 micrograms/mg Cr) than in the nonrefluxing control group (0.54 +/- 0.09 microgram/mg Cr. P < 0.01). When the mean urinary beta 2 M/Cr ratios were compared for each grade of reflux with the nonrefluxing control group, patients with grade IV and V reflux had significantly higher urinary beta 2 M/Cr values than the nonrefluxing patients (2.83 +/- 0.71 micrograms/mg Cr and 4.61 +/- 0.65 micrograms/mg Cr, P < 0.001, respectively). No patient with grade I, II, or III reflux had a urinary beta 2 M/Cr ratio above 0.92 microgram/mg Cr. Statistical analysis revealed no significant differences among the mean beta 2 M/Cr ratio for grade I (0.53 +/- 0.08), II (0.51 +/- 0.09), or III (0.59 +/- 0.17) refluxers or the nonrefluxing controls. Therefore, urinary beta 2 M/Cr ratios are increased in children with a high grade of reflux. Such values may be useful in the early detection of tubular damage in patients with vesicoureteral reflux.

Routine diagnostic imaging for childhood urinary tract infections: a systematic overview

OBJECTIVE

To assess the quality of the evidence on which current recommendations for routine diagnostic imaging for childhood urinary tract infection are based.

METHODS

A systematic overview of the literature using the MEDLINE database (1966 to October 1994), article bibliographies, and a manual search of current publications using Current Contents, was undertaken. Preset criteria were used to categorize study sample and design, and interrater reliability was assessed with a random sample.

RESULTS

A total of 434 publications were evaluated, and 63 studies met the criteria for inclusion. There was 100% interrater agreement on inclusion eligibility and design classification. No controlled trials or analytic studies evaluating routine diagnostic imaging were found. All 63 studies were descriptive, and only 10 were prospective. None of the studies provided evidence of the impact of routine imaging on the development of renal scars and clinical outcomes in children with their first urinary tract infection.

CONCLUSION

Methodologically sound, prospective studies are needed to assess whether children with their first urinary tract infection who have routine diagnostic imaging are better off than children who have imaging for specific indications. We conclude that the current recommendations are not based on firm evidence.

Urinary tract infections. Old and new concepts

The recommendations for evaluation and management of pediatric patients with UTIs are summarized in Table 5. These recommendations were designed to minimize the risk of kidney damage in children with UTIs based on current perceptions of the pathogenesis of renal injury. The children at greatest risk for kidney damage are the infants and young children with febrile UTIs in whom effective treatment is delayed, those with gross VUR, and those with anatomic or neurogenic urinary tract obstruction. These recommendations likely will be modified as more is learned about the pathogenesis of renal injury associated with UTIs, as new therapeutic approaches are developed, and as imaging technology improves.

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

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

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

In 3646 children with at least one confirmed urinary tract infection the prevalence of vesicoureteric reflux at presentation was correlated with progressive renal damage during follow up of not less than two and up to 16 years. Reflux was not demonstrated either at presentation or at any subsequent time in almost one half of the children who suffered progressive renal damage and was not a risk factor for progressive renal damage in boys under 1 year. It was an important risk factor in boys over 1 year and in girls of any age. The risk of progressive renal damage in children in whom micturating cystourethrography (MCU) did not reveal vesicoureteric reflux was substantially greater than in those who indirect isotope voiding study (IVS) did not show reflux. The risk of deterioration for those in whom reflux was demonstrated was similar for both techniques. This discrepancy indicates an appreciably higher false negative rate for the MCU than the IVS. Dilatation of the renal pelvis detected by ultrasound was associated with a significantly increased risk of progressive damage only when associated with reflux, but most children with progressive damage did not have a dilated collecting system at presentation.

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.

Diagnostic imaging in children with urinary tract infection: the role of intravenous urography

Ninety children referred to hospital with urinary tract infection (UTI) were investigated by iv urography (IVU), ultrasonography (US) and 99mTc dimercaptosuccinic acid scan (DMSA). Fifty-eight children also underwent micturating cystourethrography (MCUG). In 36 (40%) of the children, at least one result was abnormal. Abnormal findings were found in 29 children with IVU, in 10 with US and in 16 with DMSA. Six of the 58 children had vesicoureteric reflux (VUR) in 8 kidneys. In 16 children, IVU was the only examination with an abnormal result, and in 10 of these the findings were considered important for treatment or prognosis. IVU is an important supplement to US and DMSA in investigation programs for children with UTI. IVU should be performed in cases of renal scars, dilatations or in children with recurrent infections.