Immune-Mediated Necrotizing Myopathy, Associated With Antibodies to Signal Recognition Particle, Together With Lupus Nephritis: Case Presentation and Management

A male patient with limb weakness, myalgia and edema was subsequently found to have an immune-mediated necrotizing myopathy (IMNM) on biopsy. Targeted myopathic antibody analysis revealed antibodies to signal recognition particle (SRP). Anti-SRP-associated necrotizing myopathy was diagnosed. This case was complicated by the concurrent development of class III lupus nephritis. We discuss an interesting case progression and development as well as the management of these difficult to treat conditions.