Not so natural: hidden NSAID in traditional medicine causing granulomatous interstitial nephritis.

Acute interstitial nephritis (AIN) is a common finding on kidney biopsies indicated for acute kidney injury (AKI). Histologically, it translates into an interstitial inflammatory infiltrate. In less than 1% of biopsy-confirmed nephropathies, this interstitial nephritis presents as granulomas form [1]. AIN can result from multiple causes, including autoimmune diseases, infections, and drug side effects. Here, we report an original case illustrating the importance of a tenacious etiological investigation. A 39-year-old patient using traditional Sri Lankan medicine required intensive care for severe AKI with the need for dialysis, associated with other visceral and skin manifestations. Kidney biopsy revealed AIN with many eosinophilic neutrophils and perivascular granulomas, which were suspected to be allergic in origin. His recovery with corticosteroid therapy enabled us to stop dialysis and achieve full renal recovery. We decided to analyze these traditional medicines that the patient provided and of unknown composition. To this end, we used high-resolution mass spectrometry, which enabled us to identify many chemicals known in Western societies to be nephrotoxic and which could lead to severe allergies.