Clinical Approach to Diagnosing Acute and Chronic Tubulointerstitial Disease.

Tubulointerstitial diseases are a relatively common cause of acute and/or chronic kidney disease. Acute tubulointerstitial nephritis (ATIN) most commonly develops in patients exposed to various medications; however, it can occur from infections, autoimmune and systemic diseases, environmental exposures, and some idiopathic causes. Chronic tubulointerstitial nephritis may develop in patients with previous ATIN or may be the initial manifestation of an autoimmune, systemic, environmental, or metabolic process. It can be challenging for clinicians to differentiate the various causes of acute and chronic kidney disease. In particular, distinguishing ATIN from other causes of acute kidney injury, such as acute tubular necrosis or a rapidly progressive glomerulonephritis, is important as treatment and prognosis are often quite different. To this end, clinicians use clinical assessment, certain laboratory data, and various imaging tests to make a diagnosis. Unfortunately, most of these tests are insufficient for this purpose. As a result, kidney biopsy is often required to accurately diagnose ATIN and guide management. For chronic tubulointerstitial nephritis, kidney biopsy is needed less often as available therapies for this entity, with a few exceptions, are limited and primarily supportive.