Xanthogranulomatous pyelonephritis in childhood

Background-Xanthogranulomatous pyelonephritis is a severe, atypical form of chronic renal parenchymal infection accounting for 6/1000 surgically proved cases of chronic pyelonephritis. Its manifestations mimic those of neoplastic and other inflammatory renal parenchymal diseases and, consequently, it is often misdiagnosed preoperatively. Aim-To examine the relation between clinical history and the results of renal investigations performed in children with xanthogranulomatous pyelonephritis. Method-A retrospective review of 31 cases presenting with the histopathological 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 findings on examination and investigation at presentation were: fever, 16 children; pyuria, 26 children; positive urine culture, 16 children. A haemoglobin of < 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. Twenty six children had renal calculi, with a large reduction in the function of the affected kidney on isotope scintigraphy in 27 of the 29 patients tested. Hypertrophy of the contralateral kidney, shown on imaging, was present in 17 of 31 patients. Conclusions-Increasing awareness of this condition should lead to the diagnosis being suspected preoperatively.