Mycophenolate Mofetil Use in Severe Myocarditis Complicating Systemic Lupus

Cardiac involvement represents an increasingly frequent complication in systemic lupus, with pericarditis being the most classic cardiac manifestation. However, the most severe and fatal form seems to be myocarditis. We present the case of a patient with systemic lupus complicated by cardiogenic shock secondary to troponin-negative acute myopericarditis and successfully treated with mycophenolate mofetil and corticosteroid therapy. A 33-year-old woman with no past medical history presented with asthenia and inflammatory arthralgia. She was admitted in June 2021 for acute heart failure. Transthoracic cardiac ultrasound showed dilated cardiomyopathy with global hypokinesis (20-25% of ejection fraction) and right ventricular dysfunction without significant mitral and aortic valve disease. She had raised proBNP (pro-brain natriuretic peptide), low troponin, normochromic normocytic anemia at 10.4 g/dL, positive direct Coombs, lymphopenia at 460/mm³, serum creatinine at 23.9 mg/L, and proteinuria/creatininuria 2.48 g/g. Cardiac magnetic resonance imaging (CMR) suggested the diagnosis of myopericarditis. The etiological assessment did not identify an infectious, toxic, or medicinal cause. The clinical picture suggested the possibility of an autoimmune disease. The patient presented with lesions suggestive of cutaneous vasculitis, with oral ulcers with polyarthritis. The autoimmune workup showed anti-nuclear antibodies at 1:1,280, anti-native DNA antibodies at 210 IU/mL (normal < 10 IU/mL), and positive anti-SM Abs. The diagnosis of lupus myopericarditis complicated by cardiogenic shock was made, which was associated with acute renal impairment. The patient was initiated on heart failure medications along with corticosteroids and mycophenolate mofetil. On day 15, the left ventricular ejection fraction improved to 45-50%, with clinical improvement in signs of heart failure and general condition. The existence of myopericarditis without obvious etiology, especially when there are extra-cardiac signs such as skin and joint involvement, should lead us to look for systemic lupus in order to start etiological treatment in addition to cardiac medical treatment. Until now, there is no standard treatment for lupus myocarditis, but the use of mycophenolate mofetil seems to be a promising treatment.