Abstract
Under supervision of authors there were 226 patients with complicated nephrolithiasis from age of 1 year till 15 years. The risk factors of nephrolithiasis are diseases of mothers, related marriages and the various pathologies burdening the basic disease were revealed which seen at 87% of sick children. Anomalies of development of urinary tract are revealed in 35,8% of cases. The results of excretory urography has shown dysfunctions of kidneys in 61,5% of cases. Among complications the first one is calculous pyelonephritis (81,7%), then calculous hydronephrosis was observed at every second child (49,7%). In 86,1% of cases at children of early age nephrolithiasis was observed with pathologies of somatic and urological character. Intraoperative incisional biopsy has allowed to define the criteria of combined kidney defeats hydro- and pyelonephritic processes, and also various dysplastic changes of parenchyma of kidneys.