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  • Updated 01.04.2020
  • Released 03.11.1994
  • Expires For CME 01.04.2023

Polymyositis, necrotizing autoimmune myositis, myofasciitis, and overlap-myositis


This article includes discussion of polymyositis, necrotizing autoimmune myositis, myofasciitis, and overlap-myositis, polymyositis, necrotizing autoimmune myositis and fasciitis, and polymyositis and fasciitis. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.

Historical note and terminology

Although first recorded by Wagner in 1863 (138), polymyositis became a recognized clinical entity 75 years later when Walton and Adams published a remarkable monograph titled Polymyositis (139). These authors defined the term “polymyositis” as an all-inclusive designation of a group of myopathies characterized by a single basic disease process related to "other collagen" diseases or arising as the result of "hypersensitivity response to allergic inflammation." Today, described by neurologists as a neuromuscular disorder, polymyositis is cared for not only by neurologists but also by rheumatologists, who approach the illness as in a setting of other rheumatic diseases. Polymyositis is a rare disorder that, by all accounts, is the most overdiagnosed acquired myopathy. It is discussed in conjunction with 3 similar but more distinct and more frequent entities as evolved in the last decade, namely necrotizing myositis, myofasciitis, and overlap myositis.

The study of polymyositis requires a scholarly review of the neurologic examination, muscle histopathology, immunopathology, and biochemistry to ensure that toxic, metabolic, or mitochondrial muscle diseases are not missed and that 2 more common entities, the inclusion body myositis and the necrotizing autoimmune myositis, are not overlooked (12; 67; 29; 30; 36; 37; 39; 46; 47; 49; 121; 40; 105; 46; 46).

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