Consecutive renal biopsies were performed on native kidneys in 109 children and adolescents, aged 0.1-19.8 (mean 9.9) years (119 biopsies). Bleeding diatheses were excluded or treated pre-operatively with intravenous desmopressin acetate. Biopsies were performed by a radiologist under ultrasound imaging, using an automated spring-loaded device allowing selection of the length of the needle movement and score size. Diagnostically adequate tissue was retrieved in 118 of 119 (99.2%) biopsy procedures; 24-h post-biopsy ultrasonography disclosed a small haematoma of the biopsied kidney in 26% of the cases. No correlation was seen between the occurrence of haematoma and (treated) prolonged bleeding time or a decrease in the haemoglobin level. No major complications occurred. Newly developed macroscopic haematuria was reported by 7% and micturition pain by 7% of patients. Painful body movements were reported by 37%. We conclude that the use of ultrasound imaging and an automated gunshot technique is a safe and efficient method for performing renal biopsies in paediatric patients.

Objective A major aim of the treatment of urinary tract infections in children is to prevent renal scars. We have studied the renal scar incidence in a defined population in order to assess the quality of the medical handling of these infections. Design Retrospective, population‐based study. Records of children with renal scars were identified by means of hospital and health district register. Sample All children under 16 years of age (average number 55 971) residing in a Stockholm county health district in 1990–95. Results The incidence of children with renal scars was 9.3 per 100 000 child–years, with a possible range from 7.5 to 11. The medical handling was close to optimal; e.g. the median time between the debut of symptoms and treatment with antibiotics was 48 hours. Conclusion The incidence of renal scars was as high as in previous studies from the 1960s and 1990s, in spite of improved quality of medical care. The incidence of renal scars in children did not seemed to be related to the quality of medical care as per this regime. This finding calls into question the assumption that further improvement of medical care of urinary tract infections might prevent permanent renal damage. Estimation of renal scar incidence, used as a method for outcome quality assessment, is not recommended until the aetiology of renal scars in children is better understood.