Idiopathic Inflammatory Myopathies

This article describes the various idiopathic inflammatory myopathies, including their clinical presentation, pathogenesis, diagnosis, and treatments. While many disorders fall under this umbrella, this article focuses on dermatomyositis, antisynthetase syndrome, immune-mediated necrotizing myopathy, polymyositis, and overlap syndrome.

The diagnosis of inflammatory myopathy has traditionally relied heavily on muscle biopsy, which continues to be an essential diagnostic tool. However, the identification of myositis-specific antibodies has allowed for the deferment of biopsy in some cases, while also providing guidance on severity, prognosis, risk for underlying cancer, other organ involvement, and therapy. The treatment of inflammatory myopathy hinges on the use of evolving immunotherapies.

Given that highly effective treatments exist for inflammatory myopathy, neurologists must use all available diagnostic tools to quickly identify inflammatory myopathy and initiate appropriate therapy. While the primary goal is to treat muscle weakness, it is important to consider other organs that may be affected by these conditions, including the lungs, heart, joints, and skin, and to exclude underlying malignancy or infection when appropriate.