Most commonly, acute interstitial nephritis (AIN) is caused by drugs. Antibiotics, proton pump inhibitors (PPIs) and nonsteroidal anti-inflammatory drugs (NSAIDs) are well known as causative agents. Most patients do not have any specific symptoms suggestive for this disease and non-invasive tests currently have poor sensitivity and specificity for AIN. Therefore, a kidney biopsy must be performed to confirm the diagnosis. The aim of this study is to compare the clinical characteristics and the biochemical laboratory results of patients with a biopsy-confirmed diagnosis of AIN to those patients where the diagnosis was suspected clinically. For this single-center retrospective analysis, 70 cases consisting of patients with biopsy-proven drug-induced AIN (BP-AIN) and patients who were clinically suspected of having drug-induced AIN (CS-AIN) between 01.01.2007 and 31.12.2024 were included. The BP-AIN group included 18 patients while in the CS-AIN group 52 patients were included. All data is from the Clinical Division of Nephrology at the Medical University of Graz. The data was collected in REDCap (Research Electronic Data Capture). For the statistical analysis the IBM SPSS Statistics 29.0 and Microsoft Excel were used. Patient baseline characteristics were compared, the intake of potential AIN causing drugs at time of diagnosis or prior, the interval between the intake of a drug suspected of causing AIN and the clinically or biopsy-proven AIN diagnosis, clinical symptoms at time of diagnosis and various laboratory parameters obtained from urine and blood samples were collected and compared between those two groups. Furthermore, temporary trends were evaluated by analysing changes in these parameters weeks and months after diagnosis. In this study statistically significant differences of median age between the two groups, presence of hypertension at the time of diagnosis and presence of CKD at time of diagnosis were found. However, no other significant differences in the analysed laboratory parameters and clinical symptoms at time of diagnosis could be found.
Retrospective characterization of patients with biopsy-proven and clinically suspected Interstitial Nephritis
Tomek, B. (Author). 2026
Student thesis: Diploma thesis