genitourinary disorders
Tubulointerstitial Nephritis
Key Points
Causes of chronic tubulointerstitial nephritis (CTIN) are myriad and much more diverse than those for acute tubulointerstitial nephritis (ATIN), which is usually caused by an allergic reaction to a medication or by an infection. Symptoms are often absent or nonspecific, particularly in CTIN. Suspect the diagnosis based on risk factors and urinary sediment, exclude other causes using imaging, and sometimes confirm the diagnosis by biopsy. Stop causative medications, treat any other causes, and provide supportive treatment. Treat biopsy-proven immune-mediated and sometimes drug-induced ATIN with corticosteroids (within 2 weeks of stopping any causative medications). 