Tubular and interstitial disease

Tubulointerstitial diseases refer to a group of disorders in which inflammatory cell infiltrates within the kidney interstitium and/or tubular epithelium are seen on kidney biopsy. These disorders constitute an important group of kidney diseases with varying prevalences and presentations due to a number of causes. It is difficult to estimate the worldwide incidence of tubular and interstitial disease as it is a histological diagnosis and biopsy rates vary substantially around the world. Increasing incidence of tubulointerstitial nephritis has been related to polypharmacy, particularly in the older population. Tubulointerstitial nephritis may present acutely as an immunologically mediated hypersensitivity reaction to an inciting agent—typically a drug or infection—or chronically as a part of a disease process leading to chronic interstitial fibrosis and tubular atrophy. Allergic interstitial nephritis, analgesic nephropathy, nephrotoxic metals, hyperuricemia, Balkan nephropathy, Mesoamerican nephropathy, aristolochic acid nephropathy, and other rare causes of tubulointerstitial nephritis are covered in this section. Isolated defects of tubular function, tubular disorder-related nephropathies, and electrolyte derangements also constitute important aspects of tubulointerstitial diseases.