Correlation of 99mTc-DMSA scan with radiological and laboratory examinations in childhood acute pyelonephritis: a time-series study.

BACKGROUND

Urinary tract infections are one of the most common diseases in children. They may lead to hypertension and renal failure later in life. Renal scintigraphy with technetium-99m dimercaptosuccinic acid (99mTc-DMSA) is one method used to diagnose acute pyelonephritis (APN) and renal parenchymal scars. The aim of the present study was to determine the ideal time to perform a follow-up 99mTc-DMSA scan to detect renal scars and also to evaluate the factors predicting the development of permanent renal damage after APN.

METHODS

Sixty-four children with a first episode of APN underwent a 99mTc-DMSA scan. If there were abnormal findings on this scan, another scan was performed 6 and 12 months later.

RESULTS

The baseline 99mTc-DMSA scan showed cortical changes in 35 patients (54.7 %). One the 6- and 12-month follow-up scans, 25 patients (39.06 %) and 21 patients (32.8 %), respectively, had cortical lesions. In multiple logistic regressions with the final 99mTc-DMSA scan results as the dependent variable, only the age range of the patients (β = 1.062; 95 % CI 1.014-1.113; p = 0.01) showed an independent and significant association. Gender, therapeutic delay time, ultrasonography, and voiding cystourethrogram results, as well as laboratory test results including the erythrocyte sedimentation rate, C-reactive protein level, white blood cell counts, and type of bacteria in the urine, did not show such an association (p > 0.05).

CONCLUSION

There is not a significant difference between the results of 6- and 12-month 99mTc-DMSA follow-up scans. A follow-up 99mTc-DMSA scan should be performed 12 months after the acute scan to yield a more accurate diagnosis of permanent renal damage. If present, long-term follow-up of patients is necessary.