Management of Ulcerative Colitis after Mesalamine-Induced Myocarditis: Successful Treatment with Upadacitinib - A Case Report.

Abstract

Introduction: Mesalamine intolerance occurs in 5-10% of patients with ulcerative colitis (UC), while myocarditis is an extremely rare but potentially fatal complication. Optimal UC management after mesalamine-induced myocarditis remains unclear.

Case presentation: A man in his 30s with left-sided UC developed mesalamine-induced myocarditis 3 weeks after treatment initiation, confirmed by elevated troponin T, reduced ejection fraction (23%), and a positive drug-induced lymphocyte stimulation test. Cardiac function improved with corticosteroids; however, UC relapsed during steroid tapering. After multidisciplinary discussion and shared decision-making, upadacitinib was selected considering potential cardiac risk with anti-TNF therapy and the need to minimize corticosteroid exposure. Rapid clinical improvement was observed, and complete mucosal healing (Mayo endoscopic subscore 0) was confirmed at 6-month follow-up colonoscopy.

Conclusion: This is the first reported case of UC complicated by mesalamine-induced myocarditis successfully treated with upadacitinib. Janus kinase inhibitors may represent a therapeutic option when conventional biologics are unsuitable in patients with severe mesalamine intolerance.