Tehran University Medical Journal

---

Background: Urinary tract infection is a common bacterial infection in children and may lead to irreversible renal damage. TC 99-m Dimercaptosuccinic acid renal scintigraphy is the most sensitive method for diagnosing acute pyelonephritis. We designed a study to evaluate the ability of DMSA scan and ultrasonography to detect renal paranchymal lesion.

Materials and Methods: 62 children 1 month to 12 years of age with the first episode of acute pyelonephritis were prospectively studied with DMSA scan and ultrasonography during acute phase of infection. A Voiding Cystourethrogram was performed in 60 children when urine culture became negative. Children with renal paranchymal changes were older at the time of acute pyelonephritis (P=0.04) but no difference was found between the groups with regard to levels of CRP, ESR (P>0.05).

Results: Changes on the DMSA scan were found in 106 (85.5 percent) kidneys of 62 children but ultrasonography showed renal changes in 19.4 percent (sensitivity=20 percent, specificity=83 percent) (Kappa=0.06). Vesicoureteric reflux was found in 14 children (23.3 percent) but 83 percent of the affected kidneys were drained by non-refluxing ureters.

Conclusion: It is concluded that DMSA scan is more sensitive than ultrasonography in detecting renal paranchymal changes in acute pyelonephritis and we found out that renal paranchymal changes after acute pyelonephritis is common, even in those without VUR.

---

Early diagnosis, treatment, investigation and follow up of children with urinary tract infection (UTI) are needed to minimize renal scarring. The aims of this study were 1) to evaluate the ability of DMSA scintigraphy, ultrasound and biological parameters in detecting renal parenchymal involvement in children with acute pyelonephritis (APN) 2) to assess the relation between renal parenchymal changes and creatinine clearance 3) to determine the incidence of renal scarring after APN.
Materials and Methods: We prospectively studied 54 children (median age 4.02± 3.41 range 1 month to 12 years) with first time symptomaticUTI. All patients had DMSA scan and ultrasonography within 5 days of admission. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), white blood cell (WBC), was measured at the time of infection, and voiding cystourethrography was performed in all children within 10 days. When scintigraphy showed renal parenchymal changes, repeat DMSA scan was done at least 3 months after initial infection.
Results: Changes on the DMSA scan were found in 93/108 (85.5 percent) renal units in 54 children during acute pyelonephritis. Among 42 children who had underwent repeat scintigraphy , renal scars were found in 9 of 16 (56.25 percent ) renal units in 8 infants under 1 year ,23 of 32 (71.87 percent) in 16 children aged 1-5 years, and 33 of 36(91 percent ) in 18 patients older than 5 years. Ultrasonography showed renal changes in 20 of 108 (18.5 percent) kidneys. Reflux was seen in 21 of 108 (19.44 percent ) renal units. The sensitivity of ESR, CRP, WBC, and ultrasonography was 78.5 percent , 64.5 percent , 69.9 percent , 18.5 percent respectively, and the specificity of them was 40 percent, 33.3 percent, 13.3 percent,
80 percent respectively. There was a positive correlation between renal parenchymal involvement and creatinine clearance level (p<0.001).
We found no difference between groups with or without scars with respect to levels of ESR, CRP, and WBC.
Conclusion: The present study suggest that DMSA scan may be a more reliable method of investigation than ultrasonography and biological parameters for identifying children at risk of permanent renal lesion. Additionally we found positive correlation between renal parenchymal change and creatinine clearance level. In order to detect persistent changes, it is suggested that DMSA scintigraphy should be performed at least three months after UTI.