Macrophage activation syndrome in a Case of dermatomyositis overlapping syndrome with systemic lupus erythematosus: A case report

Introduction Macrophage activation syndrome (MAS) is a rare but aggressive life-threatening auto-immune disease. It is characterized by fever, rash, splenomegaly, blood cytopenia, hypertriglyceridemia, high ferritin levels, liver insufficiency, coagulopathy and neurologic involvement. Persistent activation of inflammatory cells like macrophages, natural killer cells and cytotoxic lymphocytes can lead to a cytokine storm and multi organ damage. MAS is usually triggered by rheumatologic diseases and rarely in the presentation of a new connective disease like systemic lupus erythematosus (SLE). In addition to MAS, the auto-immune conditions of SLE can be associated with different overlapping syndromes notably dermatomyositis. Case description We present a 31-year-old male from a Latin-American background without pre-existent conditions who presented complains of sore throat, joint pain, fever and fatigue. He quickly developed a pancytopenia with increased liver and pancreatic enzymes. In the process of the investigation, he was treated with antibiotics and admitted intubated to the intensive care unit for a severe pneumonia. Result and conclusion We proceeded with a bone marrow biopsy which detected an active MAS. Regarding his muscle weakness, we also revealed an inflammatory myositis on a quadricep muscle biopsy. Further discovery of positive auto-antibodies (ANA and anti-DNA) showed the presence of a LED. We successfully treated his different auto-immune complications with high doses of prednisone, and intravenously immunoglobulins. After 2 months of his admission and 12 days passed in the intensive care unit, the patient returned home with minimal sequelae with a long term immunosuppressive treatment of prednisone, mycophenolate mofetil and hydroxychloroquine. Take-home message The early identification of the cause of MAS is crucial for the accurate management of this disease and preventing further multi organ complications. SLE has remains a complex condition that can present its first manifestations in a broad spectrum of auto-immune diseases.