Association of Anti-Signal Recognition Particle Myopathy with Systemic Lupus Erythematosus

This document reports a rare case of a 17-year-old girl with anti-signal recognition particle (SRP) positive necrotizing autoimmune myopathy (NAM) associated with systemic lupus erythematosus (SLE). The patient, who also had a history of Graves' disease, presented with symptoms including proximal muscle weakness, dysphagia, weight loss, and hair loss. Laboratory tests confirmed elevated creatine kinase levels and positive anti-SRP antibodies, supporting the diagnosis of NAM. Despite the typical poor response of anti-SRP myopathy to corticosteroids, the patient showed significant improvement in muscle strength and creatine kinase levels after treatment with oral prednisolone and methotrexate. This case expands the spectrum of autoimmune diseases associated with anti-SRP myopathy, highlighting the potential for a good response to treatment in such cases.