Abstract
Idiopathic inflammatory myopathies, also known as immune-mediated myopathies or myositis for short, are a group of relatively treatable diseases characterized by inflammation of striated muscle, in which the underlying mechanism involves disorders of the immune system. In addition to muscle tissue, this disorder can also cause damage to other organ systems such as the skin, lung parenchyma, cardiac muscle, and the digestive system. The heterogeneous nature of this disease makes diagnosis, prognosis, and treatment approach somewhat challenging. Initial diagnosis requires a combination of clinical examination, muscle enzyme testing, electrophysiological diagnosis, serologic antibody testing, muscle MRI, and muscle biopsy. From the first diagnostic criteria proposed by Bohan and Peter in 1975 to newer understandings of serology and pathology, the diagnostic criteria and subgroup classification have changed considerably. As a result, treatment and prognosis depend heavily on these changes. This presentation will summarize the current diagnostic criteria, classification, and treatment approach, through the application of clinical scenarios, autoantibodies, and muscle biopsy.
