This study was conducted to retrospectively investigate the indications for renal biopsy in native kidneys and to analyze pathological findings in the last 35 years in a single tertiary pediatric hospital in Southern Italy.
All patients who underwent renal biopsy at our hospital from 1979 to 2013 were included in the present study. Renal biopsies of transplanted kidneys were excluded. All the renal biopsies were performed under ultrasonographic assistance. All renal tissue specimens were studied under light and immunofluorescent microscopy, while electron microscopy was performed only for specific clinic indications.
The study group included 200 patients (46% female) who underwent 210 percutaneous native kidney biopsies. Median age was 10.3 years (range 0.6-24 years). The most frequent indications for renal biopsy were nephrotic syndrome (44.8%), proteinuria (26.7%), asymptomatic hematuria (17.1%) and acute kidney injury (10.5%). Gross hematuria appeared after biopsy in less than 5% of the patients, but none of them needed blood transfusion. Adequate renal tissue sample was obtained in 95.2% of the renal biopsies. Primary glomerulonephritis (GN) was the most common finding (70.0%), followed by secondary GN (13.5%), tubulointerstitial diseases (4.0%) and hereditary nephropathy (2.5%), while in 10.0% of case a normal renal tissue was found. According to histopathological diagnosis, the most common causes of primary GN was IgA nephropathy (IgAN) (19.5%), followed by minimal change disease (MCD) (17.5%) and focal segmental glomerulosclerosis (FSGS) (12.5%). Noteworthy, before 1996 IgAN was the most common GN, while after 1997 the diagnosis of MCD and FSGS raised probably due to more aggressive policy in performing renal biopsy in nephrotic syndromes.
The epidemiology of glomerular disease in our single-center cohort is similar to that showed in other national and international reports. Moreover our study shows that percutaneous ultrasound-guided renal biopsy is a safe, reliable and effective technique in children.
