The glomerular changes in children with reflux nephropathy.

While heavy proteinuria and focal segmental glomerulosclerosis (FSGS) are well-recognized features of progressive reflux nephropathy in adults, little is known of their early evolution. We have studied the glomerular changes in renal biopsy specimens obtained from 24 patients aged 5.2-18.8 years, in whom urinary protein excretion was measured as early morning urine protein creatinine ratios, using the Coomassie blue dye-binding method. Segmental sclerotic lesions were found in eight biopsies and traced through serial sections to a hilar origin in every instance. There was a strong positive correlation between the extent of glomerular involvement and the amount of proteinuria (P less than 0.0001). Parahilar hyaline deposits were observed in 16 biopsies, including five of the eight showing FSGS. All unsclerosed glomeruli were enlarged, and the hilar arterioles showed both enlargement and thickening, their walls frequently containing subendothelial hyaline deposits. Since in most patients renal function was comparatively well preserved, despite extensive loss of renal substances, we believe that these glomerular and vascular changes represent the stages in the evolution of hyperfiltration. Microproteinuria is the earliest clinical manifestation of FSGS, and should be sought routinely in all patients with reflux nephropathy.