Severe cardiac involvement in a young woman with mixed connective tissue disease complicated by macrophage activation syndrome.

Reports of severe mixed connective tissue disease or macrophage activation syndrome-associated cardiac involvement are limited. A 37-year-old woman with mixed connective tissue disease was transferred to a local hospital with fever and headache. She was diagnosed with meningitis and treated with glucocorticoid pulse therapy (methylprednisolone 1000 mg/day for 3 days), followed by glucocorticoid tapering. Despite a normal left ventricular ejection fraction on admission, her left ventricular ejection fraction abruptly declined to 7%, and she subsequently developed cardiogenic shock. She then experienced a sudden cardiac arrest, which required initiation of veno-arterial extracorporeal membrane oxygenation and the insertion of an Impella CP. Intravenous cyclophosphamide (1000 mg) was administered for suspected myocarditis, although an endomyocardial biopsy showed no specific positive staining. Cardiac function did not improve after immunosuppressive therapy. Therefore, plasma exchange was performed five times considering for macrophage activation syndrome, which resulted in the recovery of the left ventricular ejection fraction to 71%. Veno-arterial extracorporeal membrane oxygenation was successfully ceased, followed by veno-venous extracorporeal membrane oxygenation and mechanical ventilation to facilitate respiratory recovery for 39 days. The aetiology of the myocardial dysfunction remains unclear; however, both cytokine-mediated myocardial dysfunction associated with macrophage activation syndrome and immune-mediated microvascular injury could not be excluded. We successfully managed with a combined immunosuppressive therapy, including glucocorticoid, intravenous cyclophosphamide, and plasma exchange, under mechanical circulatory support.