An approach to the paediatric renal biopsy

Although the principles the pathologist uses to assess renal biopsies are similar when reporting adult and paediatric biopsies, the interpretation of the findings may differ owing to relative differences in the frequencies of particular diagnoses in childhood versus adulthood, as well as age-related changes in normal histological appearances. In addition, there are a range of conditions that are either unique to or much more frequent in childhood compared with adult practice, for example congenital nephrotic syndrome subtypes, whereas other conditions, such as hypertensive renal disease or diabetic nephropathy, remain a significant component of adult renal pathology practise but are almost never encountered in childhood. The renal biopsy plays a central role in the management of many paediatric conditions presenting to the nephrologist, and percutaneous ultrasound-guided renal biopsy in children appears safe, with a low frequency (<1%) of serious complications. The most common indication for renal biopsy in childhood is nephrotic syndrome, either in the first year of life, in which the differential diagnoses are usually relatively specific to this age group, or in later childhood, when the major differential diagnoses are minimal-change nephropathy (minimal-change disease) and focal segmental glomerulosclerosis. Other entities that may be encountered commonly in paediatric renal biopsy practise include congenital disorders of the glomerular capillary basement membrane, such as Alport nephropathy, and a range of cystic diseases of the kidney. This review will provide an overview of these issues, focusing predominantly on those issues and entities specific to paediatric practise.