Snapshot A 49-year-old woman with polymyositis presents to her physician’s office for weakness. She reports that she feels unusually tired and weak. She works as a makeup artist and in the past few weeks has experienced difficulty applying makeup on her clients. She finds it difficult to work while she has her arms raised. She denies any fevers, weight gain or loss, or any other motor deficits. Physical exam reveals decreased strength in her shoulders. No rash is appreciated. Laboratory evaluation reveals increased creatinine phosphokinase, positive antinuclear antibody, and positive anti-signal recognition particle. She is started on high-dose corticosteroids. (Polymyositis) Introduction Clinical definition login to view 5 more bullets Epidemiology Demographics login to view 3 more bullets Risk factors login to view 2 more bullets ETIOLOGY Pathogenesis login to view 8 more bullets Associated conditions login to view 6 more bullets Presentation Symptoms login to view 4 more bullets Physical exam login to view 13 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 Inclusion body myositis login to view 2 more bullets 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 Prognosis Dermatomyositis login to view 1 more bullet