Overview of pediatric nephropathology.
I have given a brief overview of the morphologic basis of renal disease in children. Obviously I have been unable to include all the important and well-done studies of various conditions, which together cover the entire spectrum of pediatric renal disease. It is evident from the many studies that the renal biopsy has been, is, and will be quite helpful in elucidating the histologic pattern and severity of injury in the child with clinical evidence of renal disease. As therapy becomes more effective for renal diseases known to cause progressive renal insufficiency, the impact of the renal biopsy will become even greater. Because of the frequent discordance between clinical laboratory findings and renal histologic severity, an initial or baseline biopsy is often the only way to stage the alterations in renal structure. Present tests of renal function are imperfect and are insensitive parameters of insidious and progressive renal disease. The capacity of the kidney to compensate for nephron loss by hypertrophy and modification of the remaining nephrons can mask progressive renal disease and thus impair our ability to detect meaningful differences in therapeutic results. A repeated biopsy or "second look" allows detailed comparison and study of the effects of various therapeutic regimens on the renal disease process. Continued, detailed clinical-morphologic correlations and studies using improved techniques hopefully will provide us with better profiles or predictors of the type, severity, and pathogenesis of the renal disease in the individual patient. Determination of the histologic pattern by renal biopsy at present remains one of the, if not the, most important and reliable prognostic indicators in the individual patient and allows us a unique look at the host response to the varying types of injuries leading to pediatric renal disease.