title: Differential diagnosis of idiopathic inflammatory myopathies.
abstract: Symmetric proximal muscle weakness has many potential etiologies. An onset over weeks to months and elevated serum levels of muscle enzymes point to the diagnosis of an idiopathic inflammatory myopathy, including dermatomyositis, polymyositis, and inclusion body myositis. However, there is a broad differential diagnosis, including certain muscular dystrophies, metabolic myopathies, drug- or toxin-induced myotoxicity, neuropathies, and infectious myositides. The differentiation is critical for defining appropriate treatment. In addition, an alternative diagnosis may explain the lack of response to immunosuppressive treatment for some patients with polymyositis. Careful clinical evaluation and choice of available diagnostic tests are required to establish the correct diagnosis.
authors.affiliation: Department of Medicine, Division of Allergy, Immunology, and Rheumatology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Erie County Medical Center, 462 Grider Street, Buffalo, NY 14215, USA. alanbaer@buffalo.edu
authors.forename: Alan N
authors.initials: AN
authors.lastname: Baer
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D001706:Biopsy; D003937:Diagnosis, Differential; D005821:Genetic Techniques; D006801:Humans; D018482:Muscle, Skeletal / Q000201:enzymology / Q000473:pathology*; D009220:Myositis / Q000175:diagnosis* / Q000378:metabolism
chemical_list: D015415:Biomarkers