Mesalazine-induced myocarditis in a patient with ulcerative colitis: a case report.

Background: Mesalazine is an established first-line therapy for inflammatory bowel disease (IBD) and remains the mainstay of treatment for mild to moderate ulcerative colitis (UC). Both mesalazine and UC are rare but recognized causes of myopericarditis. Cardiac magnetic resonance (CMR) is a non-invasive method of assessing for myopericarditis. This case reports highlights the importance of early CMR in diagnosis, and management of myocarditis in a patient with IBD. Case summary: A 28-year-old male was admitted with a 2-day history of chest pain. Three weeks prior to this presentation, the patient was initiated on mesalazine for UC. Serum troponin T and C-reactive protein were elevated. An echocardiogram showed borderline low left ventricular systolic function (LVEF = 50-55%). A CMR showed extensive patchy late gadolinium enhancement (LGE) in the mid to epicardial basal and mid lateral wall. The findings were consistent with acute myocarditis, and a working diagnosis of mesalazine-induced myocarditis was made. Mesalazine was stopped and guideline-directed anti-inflammatories initiated. Oral prednisolone was also introduced for IBD control. Follow-up CMR at four months showed near complete resolution of LGE. Discussion: Myocarditis in the context of IBD may be infective, immune-mediated or due to mesalazine hypersensitivity. Histological conformation was not available in this case. This case report highlights the importance of access to early CMR in order establish the diagnosis and withdrawal of the culprit medication. In the majority of cases, CMR will replace the need for endomyocardial biopsy; however, this may still be required in the most severe cases.