Management of suspected acute interstitial nephritis

AIN: acute interstitial nephritis; IV: intravenous.
* The clinical presentation of AIN includes acute kidney injury and sterile pyuria, possibly associated with rash and eosinophilia; the duration between initiation of an offending agent and onset of acute kidney injury is variable. Refer to UpToDate topics on diagnosis of AIN for details.
¶ Many drugs can be associated with AIN. In selected situations in which multiple potential offending agents are being used, they may be discontinued sequentially rather than consecutively, depending upon the availability of alternatives. For instance, if one potentially offending agent is considered crucial and has limited alternatives, the other drug may be discontinued first and the more crucial drug discontinued only if there is no improvement. Refer to UpToDate topics on etiology of AIN for details.
Δ Refer to UpToDate topics on contraindications to kidney biopsy for details.
◊ Some, but not all, authors of the related topic (refer to UpToDate topics on the treatment of AIN for details) recommend IV methylprednisolone (eg, 500 to 1000 mg daily) as initial treatment for 3 days followed by oral prednisone if renal replacement therapy is imminent. If renal replacement therapy is not imminent, we initiate oral prednisone (typically 1 mg/kg/day).
§ Glucocorticoids may be started after the biopsy, if the biopsy is able to be performed on the same day. In all other cases, empiric initiation of glucocorticoid therapy is reasonable prior to the kidney biopsy.
¥ Some patients may not fully recover to their preinjury baseline. Recurrence of acute kidney injury while tapering glucocorticoids should trigger an evaluation for alternate etiologies. Refer to UpToDate topics on management of AIN for details.