Primary chronic interstitial nephritis in Crohn's disease.

Objective: In Crohn's disease, cases of interstitial nephritis with renal failure have been reported in connection with the use of mesalamine.

Methods: We observed 4 patients with severe interstitial nephritis proven by examination of kidney biopsy specimens. Renal failure was discovered before or simultaneously with the diagnosis of Crohn's disease, and patients were not treated with mesalamine. Impairment of renal function progressed to end-stage renal failure in 3 of the 4 patients.

Results: Our results show that the kidney can be an extraintestinal target of Crohn's disease.

Conclusions: Several unanswered questions remain concerning the frequency of interstitial nephritis in patients with Crohn's disease, as well as the exact role of mesalamine in the development of chronic interstitial nephritis.