Supplementary Material for: Beyond Ingestion: Nasal Inhalation–Induced Aristolochic Acid Nephropathy from a Traditional Herbal Remedy: A Case Report

Introduction: Aristolochic acid nephropathy (AAN), a progressive form of interstitial nephritis, is predominantly associated with the oral ingestion of herbal remedies containing aristolochic acid (AA). Case Presentation: This report details a rare case of AAN linked to nasal inhalation of a traditional herbal preparation. An 80-year-old monk with chronic kidney disease (CKD) and rapidly declining kidney function underwent kidney biopsy, revealing severe interstitial fibrosis, tubular atrophy, and the presence of AA-DNA adducts, confirming the diagnosis. Further investigation uncovered prolonged use of a nasal inhalation remedy for alertness and nasal decongestion. Analysis of the preparation using LC-DAD-qTOF identified aristolochic acid I, directly linking the remedy to the renal pathology. Conclusion: This case highlights a previously underrecognized route of AA exposure and underscores the critical importance of comprehensive history-taking, increased regulation of alternative medicines, and public awareness to prevent similar cases of nephrotoxicity.