Fatal case of macrophage activation syndrome (MAS) in a patient with dermatomyositis and cytomegalovirus (CMV) viraemia.

We describe a case of an adult with dermatomyositis (DM) who presents with a rash, high fevers, tachycardia and hypotension, initially concerning for an infectious aetiology or a DM flare. She was found to have cytomegalovirus viraemia which improved after starting valganciclovir. After extensive workup and lack of improvement with broad-spectrum antimicrobial therapy, intravenous immunoglobulin and steroids, the patient was diagnosed with macrophage activation syndrome after bone marrow biopsy and levels of soluble CD25 (soluble interleukin (IL)-2 receptor) and IL2 were obtained. Unfortunately, despite therapy with dexamethasone, anakinra and etoposide, the patient decompensated and the patient's family opted for comfort care. The patient subsequently expired in the intensive care unit.