Snapshot A 53-year-old woman with a past medical history of thyroid disease presents to her physician’s office for weakness. She reports that she has been feeling weak, has difficulty climbing the stairs, and combing her hair every morning. Today, she also has difficulty arising out of her chair. Physical exam reveals decreased strength, especially in the shoulders. She also has an impressive lilac periorbital rash and a sunburn on her cheeks. She is sent for further laboratory workup and counseled on the likely initiation of high-dose steroids. Introduction Clinical definition login to view 5 more bullets Epidemiology login to view 9 more bullets Pathogenesis login to view 8 more bullets Associated conditions login to view 6 more bullets Prognosis login to view 2 more bullets Presentation Symptoms login to view 4 more bullets Physical exam login to view 11 more bullets Studies Labs login to view 11 more bullets Muscle biopsy login to view 8 more bullets Making the diagnosis login to view 1 more bullet Differential Systemic lupus erythematosus Localized scleroderma Infectious myopathy Myasthenia gravis Treatment Management approach login to view 1 more bullet Conservative login to view 3 more bullets Medical login to view 16 more bullets Complications Cardiomyopathy Macrophage activation syndrome