#5781 DRUG-INDUCED ACUTE INTERSTITIAL NEPHRITIS (D-AIN): HOW TO IDENTIFY THE RESPONSIBLE DRUG?

Abstract

Abstract Background and Aims The mainstay of D-AIN treatment is the removal of the responsible drug. However, it is not always easy to identify the culprit drug as this entity mainly affects elderly patients on multiple medications, they rarely associate systemic symptoms (rash, fever), and the timeline regarding the diagnosis and the associated drug is not always clear. Therefore, the diagnosis and treatment are delayed, making full renal function recovery less likely. The lymphocyte transformation test (LTT) has demonstrated to be useful in the identification of the involved drug in other hypersensitivity-mediated lymphocyte T diseases such as Stevens-Johnson Syndrome or Dress Syndrome. For this reason, we wonder if this test could be relevant in identifying the responsible drug in D-AIN. The aim of this study is to test LTT in patients with clinical and histological diagnosis of D-AIN. Method We have conducted a retrospective observational study in which we have collected data from 2019 to 2022 from our electronic databases. Results: We have registered 9 cases of D-AIN diagnosed with histological confirmation in whom the LTT had been performed. 22.2% of these patients were men. The mean age was 48.1 years (standard deviation of 15.8). None of them had previous chronic kidney disease (CKD). Mean peak creatinine at diagnosis was 4.66 mg/dl (standard deviation of 1.95). Regarding the typical symptoms of the D-AIN, three patients (33%) presented with fever and none of them suffered from rash. 6 patients had sterile pyuria (66%). All of them received steroid treatment. Concerning the LTT results, 7 cases were positive for one of the drugs the patient was taking, and 2 were negative. Among the positive cases, the identified drugs were 1 case of beta lactams (piperacillin), 1 case of PPIs (omeprazole), 1 case of metamizole, 1 case of paracetamol, 1 case of eslicarbazepine and 2 cases of NSAIDs (dexketoprofen), while the negative cases have not been suspected of taking any culprit drug. Conclusion LTT may be a useful test to identify the responsible drug for D-AIN, especially in patients taking multiple medications in which may be included some of great importance like immunotherapy (typical cause of D-AIN) in oncological treatments. In negative cases, it could be expected that the patient had taken medications difficult to be identified in the clinical history or, in some situations, the drug hapten responsible for kidney damage might be a drug metabolite and not the drug itself, which cannot be detected by the test.