Immunoallergic granulomatous interstitial nephritis following treatment with omeprazole

A 69-year-old male who had a long history of ocular myasthenia was treated with omeprazole for 3 months. Progressive renal insufficiency was discovered fortuitously. There were no clinical or laboratory manifestations of immunoallergy. Renal biopsy revealed severe granulomatous interstitial nephritis, tubular injury and fibrosis. Histology of a liver nodule disclosed hepatic granulomatous involvement. Withdrawal of omeprazole and a short course of corticosteroids were followed by improvement but not normalization of renal function. This is the eighth report of omeprazole-induced interstitial nephritis. In the present case as in 2 others in the literature, the patients had been followed up for an autoimmune disease previously, which suggests that in patients with such a background, patients should be examined regularly for renal functional impairment during treatment with omeprazole.