A Case of Acute Tubulointerstitial Nephritis Manifesting Steroid Dependence Successfully Treated with Cyclosporine

Acute tubulointerstitial nephritis (ATIN) is a prominent cause of acute kidney injury that is often triggered by drug reactions and autoimmune diseases. Although the treatment of ATIN should ideally target the underlying cause, in cases of progression, a consideration of immunosuppressive therapy is warranted. Glucocorticoids are typically the first-line therapeutic agents, with discontinuation following a response. In the case described herein, glucocorticoid therapy was initiated after diagnosing ATIN with an undetermined etiology. Although, the patient showed an initial response to the glucocorticoids, recurrent episodes of ATIN occurred upon the tapering of these drugs. Given the necessity for an alternative immunosuppressive agent, cyclosporine was administered, leading to the recovery of renal function. Notably, even after the cessation of steroid treatment, the patient continued to experience favorable outcomes when administered cyclosporine alone. This case highlights the importance of transitioning to alternative immunosuppressive agents when glucocorticoid therapy either fails or presents challenges regarding tapering during the initial management of ATIN. Moreover, it indicates that cyclosporine can be a viable option for the treatment of this condition.