Prognosis and Outcomes of Acute and Chronic Tubulointerstitial Nephritis.

Tubulointerstitial nephritis (TIN) is a rare heterogenous kidney disease and outcomes depend upon many factors including patient characteristics, clinical presentation and histopathological features on kidney biopsy. When considering short-term kidney outcomes, about 20% of adult patients with acute TIN will require dialysis, although many will fully or partially recover without need for maintenance kidney replacement therapy. However, current evidence suggests that long-term kidney outcomes of patients with TIN are far less favorable than originally thought. Risk factors for adverse kidney outcomes include patient characteristics (e.g., older age, hypertension), a higher degree of proteinuria, recurrent acute TIN episodes and signs of disease chronicity or granulomatous interstitial nephritis on kidney biopsy. Pediatric patients have a better long-term prognosis, although a significant proportion of patients will develop CKD as well. In general, drug-induced acute TIN has a better prognosis when compared with autoimmune etiologies, particularly if the inciting drug is discontinued early in the disease course and re-exposure is avoided. Autoimmune etiologies frequently cause CKD, partially because they are associated with recurrent acute TIN episodes. In this review, we summarize the available data regarding prognosis and outcomes of acute and chronic TIN for various etiologies of TIN.