Nonneoplastic Renal Diseases

Abstract

A number of primary and secondary processes affect the kidney, and these may be related to inborn errors of metabolism, immune complex deposition, or manifestations of systemic diseases. Upon examination of renal biopsies, diseases can broadly be defined by the histologic compartment that is primarily affected, glomeruli, tubules and interstitium, or blood vessels. Often, the diagnosis of nonneoplastic renal diseases requires the use of light microscopy, immunofluorescent histology, and electron microscopy. Glomerular diseases often become clinically apparent with proteinuria/nephrotic syndrome, nephritic syndrome, or a combination of the two. At the morphologic level, primary glomerular diseases can be classified by the pattern of histologic changes which often correlates with the clinical presentation. Tubulointerstitial processes often present with azotemia and may be related to ascending infection, obstruction, or precipitation of crystalline material or abnormal proteins. Finally, renal dysfunction is a feature of many systemic abnormalities of blood vessels, and it displays pathologic changes that may be seen in biopsies. This chapter highlights pertinent clinical, macroscopic, microscopic, and ultrastructural features of common nonneoplastic renal diseases.