[Differential diagnosis and prognosis of inflammatory myopathies].

Inflammatory myopathies are characterized by muscle weakness, occasionally pain, and an inflammatory infiltrate of the skeletal muscle. Despite the description of novel autoantibodies and advances in imaging, the lack of universal consensus on classification criteria and routine clinical use of validated outcome measures has direct implications on treatment trials and observational registries. In this article we discuss the differential diagnosis and prognosis of the idiopathic inflammatory myopathies.