Age-related radiological imaging in children with acute pyelonephritis

Accurate diagnosis of acute pyelonephritis (APN) using clinical and laboratory parameters is often difficult in children. The aims of this retrospective study were twofold. Firstly, to correlate the clinical and laboratory manifestations of APN with the results of the dimercaptosuccinic acid (DMSA) renal scan in different age groups. Secondly, to compare the DMSA renal scan, renal ultrasonography (RUS), and voiding cystourethrography (VCUG) in patients with clinical APN. The DMSA renal scan was utilized as the gold standard for renal involvement. We determined the sensitivity of these tests in febrile urinary tract infections (UTI) in three age groups: group I less than 2 years; group II 2-8 years; group III older than 8 years. During the period January 1992 through December 1998, 222 children presented with a febrile UTI. All patients had a DMSA renal scan, 208 had contrast VCUG, and 163 had RUS. The clinical and laboratory manifestation of pyelonephritis correlated better with a positive DMSA renal scan in the older children than in the younger children; 85% of the DMSA renal scans were positive in group III; 69% in group II; 48% in group I (P<0.001). Vesicoureteral reflux detected by contrast VCUG was more prevalent in the younger age groups. Although high grades of reflux (grade IV-V) correlated better with a positive DMSA renal scan, it did not reach a level of statistical significance (P>0.05). RUS did not correlate with a positive DMSA renal scan in any age group.