Association between urinary tract infection, renal damage and birth size.

UNLABELLED: The aim of this study was to investigate whether birth size is associated with permanent renal damage in children with urinary tract infection (UTI). A cohort of 1221 children under 16 y of age was diagnosed with their first symptomatic UTI between 1970 and 1979. Of these, 74 had urographic renal scarring in childhood and 57 were re-examined as adults. The birth files of 48 of these patients (35F, 13M) were available, and birthweight and birthlength in relation to gestational age were analysed and compared with a Swedish reference population. Children who had renal damage without vesicoureteric reflux were significantly smaller at birth (median weight, -0.76 SDS) compared with both children who had renal damage and reflux (median weight, -0.01 SDS) and the reference population. CONCLUSION: The demonstration of low birthweight among children with UTI and renal damage but no reflux suggests that low birthweight may be a risk factor for the development of renal damage.

Ambulatory blood pressure 16-26 years after the first urinary tract infection in childhood.

OBJECTIVE: To evaluate blood pressure in a population-based cohort with urographic renal scarring after childhood urinary tract infection. DESIGN: Follow-up investigation 16-26 years after the first recognized urinary tract infection. SETTING: University out-patient clinic for children with urinary infections serving the local area. PATIENTS: From the original cohort of 1221 consecutive children with first urinary tract infection diagnosed during 1970-1979, 57 of 68 with non-obstructive renal scarring participated as well as 51 matched subjects without scarring. MAIN OUTCOME MEASURE: 24 h ambulatory blood pressure. RESULTS: Acceptable blood pressure monitorings were obtained from 53 individuals with and 47 without scarring. There were no significant differences between the two groups even when only patients with the most extensive scarring (individual kidney clearance < 30 ml/min per 1.73 m2) or patients with bilateral scarring were compared with the non-scarring group. Mean systolic or diastolic blood pressure above +2 SD were found in 5/53 (9%) and 3/47 (6%) in the scarring and non-scarring group, respectively. Plasma renin activity, angiotensin II and aldosterone concentrations were not significantly different, but atrial natriuretic protein was significantly higher in the scarring group (P = 0.004). CONCLUSION: This study demonstrates a low risk of hypertension two decades after childhood urinary tract infection. It should be stressed that the patients with renal scarring were under close supervision throughout childhood. Those with scarring had higher concentrations of atrial natriuretic protein which might indicate a counter-regulation mechanism.

Renal function 16 to 26 years after the first urinary tract infection in childhood.

OBJECTIVE: To evaluate renal function in a population-based cohort with urographic renal scarring after childhood urinary tract infection (UTI). DESIGN: Follow-up investigation 16 to 26 years after the first recognized UTI. SETTING: Outpatient university clinic for children with UTI serving the local area. PATIENTS: From the original cohort of 1221 consecutive children with first UTI diagnosed during 1970 to 1979, 57 (41 females and 16 males; mean age, 24.5 years) of 68 with nonobstructive renal scarring participated as well as 51 (38 females and 13 males; mean age, 24.9 years) matched subjects without scarring. MAIN OUTCOME MEASURE: Glomerular filtration rate (GFR) measured by chromium 51-EDTA clearance, expressed as milliliters per minute per 1.73 square meters. RESULTS: Median GFR was 99 in both those with and without renal scarring. In patients with unilateral scarring, the total GFR remained unchanged over the years whereas the individual GFR of the scarred kidneys declined significantly from 46 to 39. In 7 patients with bilateral scarring, the GFR declined from 94 to 84 (P = .14); compared with those with unilateral scarring, the GFR was significantly lower at follow-up (P = .007). Median urinary albumin-creatinine ratio was 1.2 and 0.6 mg/mmol in those with scarring and those without, respectively (P = .30). CONCLUSIONS: The GFR 2 decades after the first recognized UTI in childhood was well preserved. However, a significant reduction of individual renal GFR in the unilaterally scarred kidneys indicates that further follow-up is required. Although there were few patients with bilateral scarring, a more serious prognosis can be expected among them.

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.

Disappearance of vesicoureteral reflux in children.

OBJECTIVE: To describe the disappearance of reflux in children with vesicoureteral reflux, in whom there are presently no population-based long-term studies. DESIGN: An unselected cohort of children with reflux detected after their first known symptomatic urinary tract infection was followed up prospectively for up to 15 years. SETTING: A single children's hospital in a distinct geographical area at which most children with symptomatic urinary tract infection were treated. PATIENTS: Two hundred thirty children--173 girls and 57 boys--with unilateral (n=130) and bilateral (n=100) reflux. Dilated reflux (grades III-V) was found in 54 patients (23.5%). The frequency of reflux was 34% in girls and 31% in boys who were examined after urinary tract infection. MAIN OUTCOME MEASURE: Disappearance of reflux. RESULTS: The probability of spontaneous disappearance of reflux was estimated using Kaplan-Meier survival curves based on 164 children who underwent multiple voiding cystourethrographies. There was a marked tendency for disappearance of reflux, with 73% of children with dilated reflux having no or only grade I reflux after 10 years. Shorter persistence of reflux was found in children with undilated reflux at the initial investigation and in boys compared with girls. However, age at first investigation was not related to the rate of disappearance, and there was no difference between children with bilateral compared with unilateral reflux. CONCLUSIONS: This study of an unselected group of children with urinary tract infection shows a favorable long-term outcome concerning disappearance of reflux. In children with dilated reflux, this tendency was more pronounced than previously reported.