Macrophage activation syndrome: A nearly fatal presentation, and review of diagnosis and treatment guidelines

Introduction: Macrophage activation syndrome (MAS) is a rare but life-threatening systemic inflammatory complication, usually arising from superimposed viral infections or flares of underlying rheumatological conditions. It is characterized by an uncontrolled immune response, involving the expansion of T-Cells, Macrophages, and the hypersecretion of proinflammatory cytokines. The pathophysiology of this disease is not fully understood, and the diagnostic criteria have been debated. In 2016, an international panel of experts released new guidelines for the classification criteria of MAS, with greater sensitivity, specificity, and laboratory guidelines. Our case provides support for these new guidelines, and is possibly the first published after their release. Furthermore, treatment using glucocorticoids and alternative immunosuppressants is also reviewed. Case Report: A 33-year-old Hispanic male without significant history presented with an unremitting fever for five days, associated with myalgias, fatigue, night sweats, and a rash. Upon admission, he was tachycardic, hypotensive and febrile at 103°F (39.4°C). Physical examination revealed Luis W. Dominguez1, Valentin D. Marian2 Affiliations: 1Department of Internal Medicine, Jersey City Medical Center; 2Department of Rheumatology and Assistant Program Director, Jersey City Medical Center Jersey City Medical Center, Jersey City NJ, USA. Corresponding Author: Luis W. Dominguez MD, MPH. Department of Internal, Medicine, Jersey City Medical Center, 355 Grand St. Jersey City, NJ. 07302. USA; Email: [email protected] Received: 01 June 2017 Accepted: 22 June 2017 Published: 19 July 2017 a diffuse, non-blanching, maculopapular rash sparing the face, palms and soles. Labs revealed pancytopenia, transaminitis, elevated ferritin, and low fibrinogen. He was started on empiric antibiotics. Blood cultures were drawn and returned negative, yet he continued to spike fevers. On 4th day, he suffered acute respiratory distress syndrome (ARDS), requiring mechanical ventilation. He was transferred to the intensive care unit (ICU) where he continued to deteriorate. Given the persistent fever, pancytopenia, transaminitis, low fibrinogen and elevated ferritin, MAS was considered, based on recent classification criteria. He was started on high-dose methylprednisolone. He rapidly recovered, and was extubated within 24 hours and discharged later that week. Conclusion: Macrophage activation syndrome is a rare condition with a debated definition, and a mortality rate of up to 30%. As a result, it remains a diagnostic challenge. This case supports the new 2016 guidelines and confirms methylprednisolone as a first-line treatment. Furthermore, MAS seems to have occurred in the absence of underlying rheumatological disease.