New-onset systemic lupus erythematosus presenting with macrophage activation syndrome: A case report of rare and life-threatening complication

A variant of hemophagocytic lymphohistiocytosis (HLH), macrophage activation syndrome (MAS) is seen in autoimmune diseases such as systemic lupus erythematosus (SLE), Systemic onset juvenile idiopathic arthritis. It is known to present as a complication in the course of these autoimmune conditions. However, the occurrence of MAS as the first presentation of SLE, can pose a challenge in its timely diagnosis and management in account of the similarity in their clinical presentation. Herein we report a case of a young postpartum lady with new- onset SLE that surfaced with MAS. The patient presented with cytopenia, hepatic dysfunction, dyselectrolytemia and neurological derangement, which was complicated with polyserositis, myocarditis, and evolving nephritis. Further investigations prompted towards a hyperinflammatory, autoimmune state. These findings, alongside her systemic symptoms, satisfied the classification criteria for MAS and SLE, solidifying the diagnosis of MAS in conjunction with SLE. She was effectively managed with high dose intravenous Methylprednisolone, oral Prednisolone and Intra-venous immunoglobulins (IVIG), following which patient showed significant improvement, with resolution of hematologic abnormalities and neurological recovery and was discharged with an elaborate follow-up plan.