Dysimmune tubulo-interstitial nephritis

Abstract

Tubulointerstitial nephritis (TIN) represents the second most common cause of intrinsic renal disease by incidence. Despite its prevalence, diagnosis is challenging because both clinical manifestations and urinalysis may be inconspicuous, often resembling the presentation of tubular necrosis. Therefore, a thorough diagnostic approach is required, most often it will necessitate a kidney biopsy when feasible, as it is the only definitive diagnostic tool. The implications are significant and multifaceted. Without prompt diagnosis and appropriate therapeutic management, there is a high risk of progression to chronic kidney disease. Another crucial aspect concerns the etiological diagnostic approach. TIN is most frequently drug-induced. However, the therapeutic measure of permanently discontinuing the implicated drug necessitates a well-substantiated diagnosis. In addition to drug-induced causes, various dysimmune disorders can manifest as TIN, notably sarcoidosis, Sjögren's syndrome, and TINU syndrome. Considering their extra-renal manifestations and associated complications, these differential diagnoses should not be overlooked. Lastly, although less common, lymphoproliferative disorders, non-drug-related toxic causes, or environmental factors can also be identified.