P2.M242: Not Just Sjögren's: A Unique Presentation of Macrophage Activation Syndrome

Introduction: Hemophagocytic Lymphohistiocytosis (HLH) represents a medical emergency, marked by an excessive and potentially fatal immune reaction, which can originate spontaneously (primary) or be triggered by an external condition (secondary) such as infection, cancer, or rheumatological disorder (1). Macrophage activating syndrome (MAS) is a subset of secondary HLH triggered by autoimmune conditions (2). We describe a rare case of MAS as a first-time presentation of Sjogren's syndrome in a pediatric patient without sicca symptoms.

Case Description: An 8-year-old female with no medical history presented with fever, sore throat, and generalized myalgias and arthralgias after failing outpatient treatment for Streptococcal Pharyngitis four days prior. After admission, she continued to have persistent fevers on Augmentin and was escalated to intravenous Unasyn. Laboratory studies revealed elevated inflammatory markers, transaminitis, coagulopathy, elevated troponin, elevated ferritin, and hypoalbuminemia. The initial presentation was suggestive of MIS-C versus Kawasaki’s disease, and she was treated with intravenous immunoglobulins (IVIG). Despite IVIG, the patient did not show clinical improvement, and continued to have up-trending inflammatory markers and transaminitis. The patient subsequently developed epistaxis, gingival bleeding, and hemoptysis prompting bone marrow biopsy which showed hemophagocytosis. The clinical presentation and investigations were consistent with MAS, and she was started on pulse doses of methylprednisolone and Anakinra with significant improvement in symptoms and laboratory studies. Further work-up for rheumatic diseases as a trigger for MAS revealed findings consistent with Sjogren’s syndrome, including positive ANA, anti-SSA antibodies, and multiple cystic lesions within the bilateral parotid glands visualized on ultrasound and MRI. Salivary gland biopsy was not performed during acute illness but is currently planned for completion of work-up.

Discussion: MAS manifests as a severe inflammatory response known as a cytokine storm, which can lead to multiple organ system failure and is often fatal. The diagnosis is based on a combination of clinical signs and laboratory findings including persistent fevers, hyperferritinemia, cytopenia, disseminated intravascular coagulation, neurological sequelae, and transaminitis (2). The development of MAS secondary to autoimmune diseases such as systemic juvenile idiopathic arthritis, Kawasaki disease, and systemic lupus erythematosus have been previously reported. However, juvenile Sjögren's syndrome is a rare condition that has not been documented widely and has no validated classification criteria in the pediatric age group. Moreover, the development of MAS secondary to Sjögren’s syndrome is exceptionally rare in all patient populations. Unfortunately, MAS often remains underrecognized and poorly defined until later stages (3), with diagnosis made more difficult in pediatric patients with no known rheumatologic history as it requires a high index of clinical suspicion.

Conclusion: Prompt recognition and treatment of life-threatening conditions such as MAS is crucial as lack of treatment is associated with rapid mortality. Sjogren’s syndrome is a lesser known and potentially underrecognized cause of MAS in the pediatric population.