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 Previous studies have shown that renal scarring was almost always associated with vesicoureteric reflux (VUR).9 Later studies using the DMSA scan, however, have suggested that scarring may often occur in the absence of VUR,5 and it has been claimed that renal scarring may be independent of the presence or absence of VUR.10 We therefore need to reassess our knowledge in this field on the basis of studies in which acute pyelonephritis has been diagnosed and followed up with DMSA scans.The aim of this prospective clinical study was to determine the incidence of renal scarring after acute pyelonephritis and how this correlated with previously well known risk factors such as VUR, age, delay in starting treatment, and recurrent urinary tract infections. Patients and methodsSeventy six patients (152 kidneys), 18 boys and 58 girls, aged 0-15-9 (median 1 0) years, consecutively admitted to our hospital with the clinical diagnosis of acute pyelonephritis were studied with a DMSA scan within five days of admission and about two months later. Figure 1 gives the age and sex distributions of the children. Acute pyelonephritis was defined as fever :38 5°C, C reactive protein >20 mg/l, or erythrocyte sedimentation rate >20 mm/hour, and a positive urinary culture. The laboratory data during acute pyelonephritis in most of these children have been published previously.5 All the children were available for long term follow up and a DMSA scan was performed in 59 (78%) of them after two years. The remaining 17 (22%) children had a normal DMSA scan at two months and 11 (65%) of these also had a normal DMSA scan during infection. After the initial treatment, all children received prophylactic antibiotics until the second investigation at two months, and none had a breakthrough infection during that time.

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.

This study suggests a high UTI awareness in Sweden as indicated by a higher diagnostic rate and, despite stricter diagnostic criteria, a higher incidence of UTI in children <2 years of age than previously reported. It is suggested that a high UTI awareness may reduce chronic renal failure because of pyelonephritic renal scarring.

A total of 106 children with symptomatic urinary tract infection (73 girls and 33 boys, 0-15-9 years of age) were studied by means of a dimercaptosuccinic acid (DMSA) scan, renal ultrasound, and a desmopressin test during infection and at follow up approximately two months later. At follow up they were also investigated by means of intravenous urography (IVU) and micturition cystourethrography (MCU).During infection 23 children had a normal DMSA scan while 83 children had an abnormal one. The median C reactive protein and SD score for renal concentration capacity in the former group were 15 (range <10-178) mg/l and -1*0 SD score (range -2*4 to 1-8), respectively, and in the latter group 98 (range <10-320) mg/l and -3-1 SD score (range -5-7 to 1-1), respectively. In the former group there was no significant finding in any child on ultrasound or IVU and only one had significant vesicoureteric reflux (VUR) (grade 3).At follow up 51 children had a normal DMSA scan while 55 children showed persistent changes. The median SD score for renal concentration capacity in the former group was -0.9 SD score (range -3*2 to 1-4) and in the latter group -1-6 SD score (range -4-6 to 2-5). No significant changes were found in the former group on ultrasound or IVU and only two children had significant VUR (grade 3). In the latter group 20 children showed changes on ultrasound, 15 showed changes on IVU,