[Chronic interstitial nephritis and mesalazine: 3 new cases?]

We report three new cases of chronic interstitial nephritis occurring in two patients with Crohn's disease and one patient with ulcerative colitis treated with mesalazine. In the three cases asymptomatic renal disease was revealed by an increase in serum creatinine which was normal before treatment. Renal biopsy showed features of severe chronic interstitial nephritis. Mesalazine withdrawal and administration of steroids in two cases led to partial improvement of renal function. Mechanism of renal toxicity of mesalazine is unknown. These observations stress the need for monitoring renal function in patients with inflammatory bowel disease treated with mesalazine.