Background: Mesalamine or 5-aminosalicylic acid (5-ASA) has proven efficacy in treating patients with ulcerative colitis (UC). Although mesalamine is considered safe, it has been associated with acute interstitial nephritis and renal failure.

Methods: Herein we present a case of a child with UC who developed acute renal failure on mesalamine therapy.

Results: A 15-year-old African-American girl with well-controlled UC presented to the Johns Hopkins Hospital with a four-day history of high fever, malaise, generalized body aches, and productive non-bloody cough. Over the next three days, she developed acute renal failure with fluid retention, and elevated serum creatinine and blood urea nitrogen. A kidney biopsy showed drug induced acute interstitial nephritis and focal segmental glomerulosclerosis with viral inclusion bodies likely secondary to cytomegalovirus.

Conclusions: When treating UC patients with a history of underlying renal disease, it is advised to carefully monitor renal function while on mesalamine therapy.