Xanthogranulomatous pyelonephritis in childhood

Background-Xanthogranulomatous pyelonephritis is a severe, atypical form of chronic renal parenchymal infection accounting for 6/1000 surgically prove d cases of chronic pyelonephritis. Its manifestations mimic those of neopla stic and other inflammatory renal parenchymal diseases and, consequently, i t is often misdiagnosed preoperatively. Aim-To examine the relation between clinical history and the results of ren al investigations performed in children with xanthogranulomatous pyelonephr itis. Method-A retrospective review of 31 cases presenting with the histopatholog ical diagnosis of xanthogranulomatous pyelonephritis between 1963 and 1999. Results-The mean follow up was 8.2 years. The male:female ratio was 1:1.1. The left kidney was affected in 26 of the 31 patients. The positive finding s on examination and investigation at presentation were: fever, 16 children ; pyuria, 26 children; positive urine culture, 16 children. A haemoglobin o f < 100 g/l was measured in 27 of 31 patients and 15 of 18 patients tested had a raised erythrocyte sedimentation rate of > 20 mm in the first hour. T wenty six children had renal calculi, with a large reduction in the functio n of the affected kidney on isotope scintigraphy in 27 of the 29 patients t ested. Hypertrophy of the contralateral kidney, shown on imaging, was prese nt in 17 of 31 patients. Conclusions-Increasing awareness of this condition should lead to the diagn osis being suspected preoperatively.